the structure of a case study

How to write a case study — examples, templates, and tools

It’s a marketer’s job to communicate the effectiveness of a product or service to potential and current customers to convince them to buy and keep business moving. One of the best methods for doing this is to share success stories that are relatable to prospects and customers based on their pain points, experiences, and overall needs.

That’s where case studies come in. Case studies are an essential part of a content marketing plan. These in-depth stories of customer experiences are some of the most effective at demonstrating the value of a product or service. Yet many marketers don’t use them, whether because of their regimented formats or the process of customer involvement and approval.

A case study is a powerful tool for showcasing your hard work and the success your customer achieved. But writing a great case study can be difficult if you’ve never done it before or if it’s been a while. This guide will show you how to write an effective case study and provide real-world examples and templates that will keep readers engaged and support your business.

In this article, you’ll learn:

What is a case study?

How to write a case study, case study templates, case study examples, case study tools.

A case study is the detailed story of a customer’s experience with a product or service that demonstrates their success and often includes measurable outcomes. Case studies are used in a range of fields and for various reasons, from business to academic research. They’re especially impactful in marketing as brands work to convince and convert consumers with relatable, real-world stories of actual customer experiences.

The best case studies tell the story of a customer’s success, including the steps they took, the results they achieved, and the support they received from a brand along the way. To write a great case study, you need to:

• Celebrate the customer and make them — not a product or service — the star of the story.
• Craft the story with specific audiences or target segments in mind so that the story of one customer will be viewed as relatable and actionable for another customer.
• Write copy that is easy to read and engaging so that readers will gain the insights and messages intended.
• Follow a standardized format that includes all of the essentials a potential customer would find interesting and useful.
• Support all of the claims for success made in the story with data in the forms of hard numbers and customer statements.

Case studies are a type of review but more in depth, aiming to show — rather than just tell — the positive experiences that customers have with a brand. Notably, 89% of consumers read reviews before deciding to buy, and 79% view case study content as part of their purchasing process. When it comes to B2B sales, 52% of buyers rank case studies as an important part of their evaluation process.

Telling a brand story through the experience of a tried-and-true customer matters. The story is relatable to potential new customers as they imagine themselves in the shoes of the company or individual featured in the case study. Showcasing previous customers can help new ones see themselves engaging with your brand in the ways that are most meaningful to them.

Besides sharing the perspective of another customer, case studies stand out from other content marketing forms because they are based on evidence. Whether pulling from client testimonials or data-driven results, case studies tend to have more impact on new business because the story contains information that is both objective (data) and subjective (customer experience) — and the brand doesn’t sound too self-promotional.

Case studies are unique in that there’s a fairly standardized format for telling a customer’s story. But that doesn’t mean there isn’t room for creativity. It’s all about making sure that teams are clear on the goals for the case study — along with strategies for supporting content and channels — and understanding how the story fits within the framework of the company’s overall marketing goals.

Here are the basic steps to writing a good case study.

1. Identify your goal

Start by defining exactly who your case study will be designed to help. Case studies are about specific instances where a company works with a customer to achieve a goal. Identify which customers are likely to have these goals, as well as other needs the story should cover to appeal to them.

The answer is often found in one of the buyer personas that have been constructed as part of your larger marketing strategy. This can include anything from new leads generated by the marketing team to long-term customers that are being pressed for cross-sell opportunities. In all of these cases, demonstrating value through a relatable customer success story can be part of the solution to conversion.

2. Choose your client or subject

Who you highlight matters. Case studies tie brands together that might otherwise not cross paths. A writer will want to ensure that the highlighted customer aligns with their own company’s brand identity and offerings. Look for a customer with positive name recognition who has had great success with a product or service and is willing to be an advocate.

The client should also match up with the identified target audience. Whichever company or individual is selected should be a reflection of other potential customers who can see themselves in similar circumstances, having the same problems and possible solutions.

Some of the most compelling case studies feature customers who:

• Switch from one product or service to another while naming competitors that missed the mark.
• Experience measurable results that are relatable to others in a specific industry.
• Represent well-known brands and recognizable names that are likely to compel action.
• Advocate for a product or service as a champion and are well-versed in its advantages.

Whoever or whatever customer is selected, marketers must ensure they have the permission of the company involved before getting started. Some brands have strict review and approval procedures for any official marketing or promotional materials that include their name. Acquiring those approvals in advance will prevent any miscommunication or wasted effort if there is an issue with their legal or compliance teams.

3. Conduct research and compile data

Substantiating the claims made in a case study — either by the marketing team or customers themselves — adds validity to the story. To do this, include data and feedback from the client that defines what success looks like. This can be anything from demonstrating return on investment (ROI) to a specific metric the customer was striving to improve. Case studies should prove how an outcome was achieved and show tangible results that indicate to the customer that your solution is the right one.

This step could also include customer interviews. Make sure that the people being interviewed are key stakeholders in the purchase decision or deployment and use of the product or service that is being highlighted. Content writers should work off a set list of questions prepared in advance. It can be helpful to share these with the interviewees beforehand so they have time to consider and craft their responses. One of the best interview tactics to keep in mind is to ask questions where yes and no are not natural answers. This way, your subject will provide more open-ended responses that produce more meaningful content.

4. Choose the right format

There are a number of different ways to format a case study. Depending on what you hope to achieve, one style will be better than another. However, there are some common elements to include, such as:

• An engaging headline
• A subject and customer introduction
• The unique challenge or challenges the customer faced
• The solution the customer used to solve the problem
• The results achieved
• Data and statistics to back up claims of success
• A strong call to action (CTA) to engage with the vendor

It’s also important to note that while case studies are traditionally written as stories, they don’t have to be in a written format. Some companies choose to get more creative with their case studies and produce multimedia content, depending on their audience and objectives. Case study formats can include traditional print stories, interactive web or social content, data-heavy infographics, professionally shot videos, podcasts, and more.

5. Write your case study

We’ll go into more detail later about how exactly to write a case study, including templates and examples. Generally speaking, though, there are a few things to keep in mind when writing your case study.

• Be clear and concise. Readers want to get to the point of the story quickly and easily, and they’ll be looking to see themselves reflected in the story right from the start.
• Provide a big picture. Always make sure to explain who the client is, their goals, and how they achieved success in a short introduction to engage the reader.
• Construct a clear narrative. Stick to the story from the perspective of the customer and what they needed to solve instead of just listing product features or benefits.
• Leverage graphics. Incorporating infographics, charts, and sidebars can be a more engaging and eye-catching way to share key statistics and data in readable ways.
• Offer the right amount of detail. Most case studies are one or two pages with clear sections that a reader can skim to find the information most important to them.
• Include data to support claims. Show real results — both facts and figures and customer quotes — to demonstrate credibility and prove the solution works.

6. Promote your story

Marketers have a number of options for distribution of a freshly minted case study. Many brands choose to publish case studies on their website and post them on social media. This can help support SEO and organic content strategies while also boosting company credibility and trust as visitors see that other businesses have used the product or service.

Marketers are always looking for quality content they can use for lead generation. Consider offering a case study as gated content behind a form on a landing page or as an offer in an email message. One great way to do this is to summarize the content and tease the full story available for download after the user takes an action.

Sales teams can also leverage case studies, so be sure they are aware that the assets exist once they’re published. Especially when it comes to larger B2B sales, companies often ask for examples of similar customer challenges that have been solved.

Now that you’ve learned a bit about case studies and what they should include, you may be wondering how to start creating great customer story content. Here are a couple of templates you can use to structure your case study.

Template 1 — Challenge-solution-result format

• Start with an engaging title. This should be fewer than 70 characters long for SEO best practices. One of the best ways to approach the title is to include the customer’s name and a hint at the challenge they overcame in the end.
• Create an introduction. Lead with an explanation as to who the customer is, the need they had, and the opportunity they found with a specific product or solution. Writers can also suggest the success the customer experienced with the solution they chose.
• Present the challenge. This should be several paragraphs long and explain the problem the customer faced and the issues they were trying to solve. Details should tie into the company’s products and services naturally. This section needs to be the most relatable to the reader so they can picture themselves in a similar situation.
• Share the solution. Explain which product or service offered was the ideal fit for the customer and why. Feel free to delve into their experience setting up, purchasing, and onboarding the solution.
• Explain the results. Demonstrate the impact of the solution they chose by backing up their positive experience with data. Fill in with customer quotes and tangible, measurable results that show the effect of their choice.
• Ask for action. Include a CTA at the end of the case study that invites readers to reach out for more information, try a demo, or learn more — to nurture them further in the marketing pipeline. What you ask of the reader should tie directly into the goals that were established for the case study in the first place.

Template 2 — Data-driven format

• Start with an engaging title. Be sure to include a statistic or data point in the first 70 characters. Again, it’s best to include the customer’s name as part of the title.
• Create an overview. Share the customer’s background and a short version of the challenge they faced. Present the reason a particular product or service was chosen, and feel free to include quotes from the customer about their selection process.
• Present data point 1. Isolate the first metric that the customer used to define success and explain how the product or solution helped to achieve this goal. Provide data points and quotes to substantiate the claim that success was achieved.
• Present data point 2. Isolate the second metric that the customer used to define success and explain what the product or solution did to achieve this goal. Provide data points and quotes to substantiate the claim that success was achieved.
• Present data point 3. Isolate the final metric that the customer used to define success and explain what the product or solution did to achieve this goal. Provide data points and quotes to substantiate the claim that success was achieved.
• Summarize the results. Reiterate the fact that the customer was able to achieve success thanks to a specific product or service. Include quotes and statements that reflect customer satisfaction and suggest they plan to continue using the solution.
• Ask for action. Include a CTA at the end of the case study that asks readers to reach out for more information, try a demo, or learn more — to further nurture them in the marketing pipeline. Again, remember that this is where marketers can look to convert their content into action with the customer.

While templates are helpful, seeing a case study in action can also be a great way to learn. Here are some examples of how Adobe customers have experienced success.

Juniper Networks

One example is the Adobe and Juniper Networks case study , which puts the reader in the customer’s shoes. The beginning of the story quickly orients the reader so that they know exactly who the article is about and what they were trying to achieve. Solutions are outlined in a way that shows Adobe Experience Manager is the best choice and a natural fit for the customer. Along the way, quotes from the client are incorporated to help add validity to the statements. The results in the case study are conveyed with clear evidence of scale and volume using tangible data.

The story of Lenovo’s journey with Adobe is one that spans years of planning, implementation, and rollout. The Lenovo case study does a great job of consolidating all of this into a relatable journey that other enterprise organizations can see themselves taking, despite the project size. This case study also features descriptive headers and compelling visual elements that engage the reader and strengthen the content.

Tata Consulting

When it comes to using data to show customer results, this case study does an excellent job of conveying details and numbers in an easy-to-digest manner. Bullet points at the start break up the content while also helping the reader understand exactly what the case study will be about. Tata Consulting used Adobe to deliver elevated, engaging content experiences for a large telecommunications client of its own — an objective that’s relatable for a lot of companies.

Case studies are a vital tool for any marketing team as they enable you to demonstrate the value of your company’s products and services to others. They help marketers do their job and add credibility to a brand trying to promote its solutions by using the experiences and stories of real customers.

When you’re ready to get started with a case study:

• Think about a few goals you’d like to accomplish with your content.
• Make a list of successful clients that would be strong candidates for a case study.
• Reach out to the client to get their approval and conduct an interview.
• Gather the data to present an engaging and effective customer story.

Adobe can help

There are several Adobe products that can help you craft compelling case studies. Adobe Experience Platform helps you collect data and deliver great customer experiences across every channel. Once you’ve created your case studies, Experience Platform will help you deliver the right information to the right customer at the right time for maximum impact.

To learn more, watch the Adobe Experience Platform story .

Keep in mind that the best case studies are backed by data. That’s where Adobe Real-Time Customer Data Platform and Adobe Analytics come into play. With Real-Time CDP, you can gather the data you need to build a great case study and target specific customers to deliver the content to the right audience at the perfect moment.

Watch the Real-Time CDP overview video to learn more.

Finally, Adobe Analytics turns real-time data into real-time insights. It helps your business collect and synthesize data from multiple platforms to make more informed decisions and create the best case study possible.

Request a demo to learn more about Adobe Analytics.

https://business.adobe.com/blog/perspectives/b2b-ecommerce-10-case-studies-inspire-you

https://business.adobe.com/blog/basics/business-case

https://business.adobe.com/blog/basics/what-is-real-time-analytics

All You Wanted to Know About How to Write a Case Study

What do you study in your college? If you are a psychology, sociology, or anthropology student, we bet you might be familiar with what a case study is. This research method is used to study a certain person, group, or situation. In this guide from our dissertation writing service , you will learn how to write a case study professionally, from researching to citing sources properly. Also, we will explore different types of case studies and show you examples — so that you won’t have any other questions left.

What Is a Case Study?

A case study is a subcategory of research design which investigates problems and offers solutions. Case studies can range from academic research studies to corporate promotional tools trying to sell an idea—their scope is quite vast.

What Is the Difference Between a Research Paper and a Case Study?

While research papers turn the reader’s attention to a certain problem, case studies go even further. Case study guidelines require students to pay attention to details, examining issues closely and in-depth using different research methods. For example, case studies may be used to examine court cases if you study Law, or a patient's health history if you study Medicine. Case studies are also used in Marketing, which are thorough, empirically supported analysis of a good or service's performance. Well-designed case studies can be valuable for prospective customers as they can identify and solve the potential customers pain point.

Case studies involve a lot of storytelling – they usually examine particular cases for a person or a group of people. This method of research is very helpful, as it is very practical and can give a lot of hands-on information. Most commonly, the length of the case study is about 500-900 words, which is much less than the length of an average research paper.

The structure of a case study is very similar to storytelling. It has a protagonist or main character, which in your case is actually a problem you are trying to solve. You can use the system of 3 Acts to make it a compelling story. It should have an introduction, rising action, a climax where transformation occurs, falling action, and a solution.

Here is a rough formula for you to use in your case study:

Problem (Act I): > Solution (Act II) > Result (Act III) > Conclusion.

Types of Case Studies

The purpose of a case study is to provide detailed reports on an event, an institution, a place, future customers, or pretty much anything. There are a few common types of case study, but the type depends on the topic. The following are the most common domains where case studies are needed:

• Historical case studies are great to learn from. Historical events have a multitude of source info offering different perspectives. There are always modern parallels where these perspectives can be applied, compared, and thoroughly analyzed.
• Problem-oriented case studies are usually used for solving problems. These are often assigned as theoretical situations where you need to immerse yourself in the situation to examine it. Imagine you’re working for a startup and you’ve just noticed a significant flaw in your product’s design. Before taking it to the senior manager, you want to do a comprehensive study on the issue and provide solutions. On a greater scale, problem-oriented case studies are a vital part of relevant socio-economic discussions.
• Cumulative case studies collect information and offer comparisons. In business, case studies are often used to tell people about the value of a product.
• Critical case studies explore the causes and effects of a certain case.
• Illustrative case studies describe certain events, investigating outcomes and lessons learned.

Need a compelling case study? EssayPro has got you covered. Our experts are ready to provide you with detailed, insightful case studies that capture the essence of real-world scenarios. Elevate your academic work with our professional assistance.

Case Study Format

The case study format is typically made up of eight parts:

• Executive Summary. Explain what you will examine in the case study. Write an overview of the field you’re researching. Make a thesis statement and sum up the results of your observation in a maximum of 2 sentences.
• Background. Provide background information and the most relevant facts. Isolate the issues.
• Case Evaluation. Isolate the sections of the study you want to focus on. In it, explain why something is working or is not working.
• Proposed Solutions. Offer realistic ways to solve what isn’t working or how to improve its current condition. Explain why these solutions work by offering testable evidence.
• Conclusion. Summarize the main points from the case evaluations and proposed solutions. 6. Recommendations. Talk about the strategy that you should choose. Explain why this choice is the most appropriate.
• Implementation. Explain how to put the specific strategies into action.
• References. Provide all the citations.

How to Write a Case Study

Let's discover how to write a case study.

Setting Up the Research

When writing a case study, remember that research should always come first. Reading many different sources and analyzing other points of view will help you come up with more creative solutions. You can also conduct an actual interview to thoroughly investigate the customer story that you'll need for your case study. Including all of the necessary research, writing a case study may take some time. The research process involves doing the following:

• Define your objective. Explain the reason why you’re presenting your subject. Figure out where you will feature your case study; whether it is written, on video, shown as an infographic, streamed as a podcast, etc.
• Determine who will be the right candidate for your case study. Get permission, quotes, and other features that will make your case study effective. Get in touch with your candidate to see if they approve of being part of your work. Study that candidate’s situation and note down what caused it.
• Identify which various consequences could result from the situation. Follow these guidelines on how to start a case study: surf the net to find some general information you might find useful.
• Make a list of credible sources and examine them. Seek out important facts and highlight problems. Always write down your ideas and make sure to brainstorm.
• Focus on several key issues – why they exist, and how they impact your research subject. Think of several unique solutions. Draw from class discussions, readings, and personal experience. When writing a case study, focus on the best solution and explore it in depth. After having all your research in place, writing a case study will be easy. You may first want to check the rubric and criteria of your assignment for the correct case study structure.

Read Also: 'CREDIBLE SOURCES: WHAT ARE THEY?'

Although your instructor might be looking at slightly different criteria, every case study rubric essentially has the same standards. Your professor will want you to exhibit 8 different outcomes:

• Correctly identify the concepts, theories, and practices in the discipline.
• Identify the relevant theories and principles associated with the particular study.
• Evaluate legal and ethical principles and apply them to your decision-making.
• Recognize the global importance and contribution of your case.
• Construct a coherent summary and explanation of the study.
• Demonstrate analytical and critical-thinking skills.
• Explain the interrelationships between the environment and nature.
• Integrate theory and practice of the discipline within the analysis.

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Case Study Outline

Let's look at the structure of an outline based on the issue of the alcoholic addiction of 30 people.

Introduction

• Statement of the issue: Alcoholism is a disease rather than a weakness of character.
• Presentation of the problem: Alcoholism is affecting more than 14 million people in the USA, which makes it the third most common mental illness there.
• Explanation of the terms: In the past, alcoholism was commonly referred to as alcohol dependence or alcohol addiction. Alcoholism is now the more severe stage of this addiction in the disorder spectrum.
• Hypotheses: Drinking in excess can lead to the use of other drugs.
• Importance of your story: How the information you present can help people with their addictions.
• Background of the story: Include an explanation of why you chose this topic.
• Presentation of analysis and data: Describe the criteria for choosing 30 candidates, the structure of the interview, and the outcomes.
• Strong argument 1: ex. X% of candidates dealing with anxiety and depression...
• Strong argument 2: ex. X amount of people started drinking by their mid-teens.
• Strong argument 3: ex. X% of respondents’ parents had issues with alcohol.
• Concluding statement: I have researched if alcoholism is a disease and found out that…
• Recommendations: Ways and actions for preventing alcohol use.

Writing a Case Study Draft

After you’ve done your case study research and written the outline, it’s time to focus on the draft. In a draft, you have to develop and write your case study by using: the data which you collected throughout the research, interviews, and the analysis processes that were undertaken. Follow these rules for the draft:

• Your draft should contain at least 4 sections: an introduction; a body where you should include background information, an explanation of why you decided to do this case study, and a presentation of your main findings; a conclusion where you present data; and references.
• In the introduction, you should set the pace very clearly. You can even raise a question or quote someone you interviewed in the research phase. It must provide adequate background information on the topic. The background may include analyses of previous studies on your topic. Include the aim of your case here as well. Think of it as a thesis statement. The aim must describe the purpose of your work—presenting the issues that you want to tackle. Include background information, such as photos or videos you used when doing the research.
• Describe your unique research process, whether it was through interviews, observations, academic journals, etc. The next point includes providing the results of your research. Tell the audience what you found out. Why is this important, and what could be learned from it? Discuss the real implications of the problem and its significance in the world.
• Include quotes and data (such as findings, percentages, and awards). This will add a personal touch and better credibility to the case you present. Explain what results you find during your interviews in regards to the problem and how it developed. Also, write about solutions which have already been proposed by other people who have already written about this case.
• At the end of your case study, you should offer possible solutions, but don’t worry about solving them yourself.

Use Data to Illustrate Key Points in Your Case Study

Even though your case study is a story, it should be based on evidence. Use as much data as possible to illustrate your point. Without the right data, your case study may appear weak and the readers may not be able to relate to your issue as much as they should. Let's see the examples from essay writing service :

‍ With data: Alcoholism is affecting more than 14 million people in the USA, which makes it the third most common mental illness there. Without data: A lot of people suffer from alcoholism in the United States.

Try to include as many credible sources as possible. You may have terms or sources that could be hard for other cultures to understand. If this is the case, you should include them in the appendix or Notes for the Instructor or Professor.

Finalizing the Draft: Checklist

After you finish drafting your case study, polish it up by answering these ‘ask yourself’ questions and think about how to end your case study:

• Check that you follow the correct case study format, also in regards to text formatting.
• Check that your work is consistent with its referencing and citation style.
• Micro-editing — check for grammar and spelling issues.
• Macro-editing — does ‘the big picture’ come across to the reader? Is there enough raw data, such as real-life examples or personal experiences? Have you made your data collection process completely transparent? Does your analysis provide a clear conclusion, allowing for further research and practice?

Problems to avoid:

• Overgeneralization – Do not go into further research that deviates from the main problem.
• Failure to Document Limitations – Just as you have to clearly state the limitations of a general research study, you must describe the specific limitations inherent in the subject of analysis.
• Failure to Extrapolate All Possible Implications – Just as you don't want to over-generalize from your case study findings, you also have to be thorough in the consideration of all possible outcomes or recommendations derived from your findings.

How to Create a Title Page and Cite a Case Study

Let's see how to create an awesome title page.

Your title page depends on the prescribed citation format. The title page should include:

• A title that attracts some attention and describes your study
• The title should have the words “case study” in it
• The title should range between 5-9 words in length
• Your name and contact information
• Your finished paper should be only 500 to 1,500 words in length.With this type of assignment, write effectively and avoid fluff

Here is a template for the APA and MLA format title page:

There are some cases when you need to cite someone else's study in your own one – therefore, you need to master how to cite a case study. A case study is like a research paper when it comes to citations. You can cite it like you cite a book, depending on what style you need.

Citation Example in MLA ‍ Hill, Linda, Tarun Khanna, and Emily A. Stecker. HCL Technologies. Boston: Harvard Business Publishing, 2008. Print.

Citation Example in APA ‍ Hill, L., Khanna, T., & Stecker, E. A. (2008). HCL Technologies. Boston: Harvard Business Publishing.

Citation Example in Chicago Hill, Linda, Tarun Khanna, and Emily A. Stecker. HCL Technologies.

Case Study Examples

To give you an idea of a professional case study example, we gathered and linked some below.

Eastman Kodak Case Study

Case Study Example: Audi Trains Mexican Autoworkers in Germany

To conclude, a case study is one of the best methods of getting an overview of what happened to a person, a group, or a situation in practice. It allows you to have an in-depth glance at the real-life problems that businesses, healthcare industry, criminal justice, etc. may face. This insight helps us look at such situations in a different light. This is because we see scenarios that we otherwise would not, without necessarily being there. If you need custom essays , try our research paper writing services .

Get Help Form Qualified Writers

Crafting a case study is not easy. You might want to write one of high quality, but you don’t have the time or expertise. If you’re having trouble with your case study, help with essay request - we'll help. EssayPro writers have read and written countless case studies and are experts in endless disciplines. Request essay writing, editing, or proofreading assistance from our custom case study writing service , and all of your worries will be gone.

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What Is a Case Study?

Weighing the pros and cons of this method of research

Kendra Cherry, MS, is a psychosocial rehabilitation specialist, psychology educator, and author of the "Everything Psychology Book."

Cara Lustik is a fact-checker and copywriter.

Verywell / Colleen Tighe

• Pros and Cons

What Types of Case Studies Are Out There?

Where do you find data for a case study, how do i write a psychology case study.

A case study is an in-depth study of one person, group, or event. In a case study, nearly every aspect of the subject's life and history is analyzed to seek patterns and causes of behavior. Case studies can be used in many different fields, including psychology, medicine, education, anthropology, political science, and social work.

The point of a case study is to learn as much as possible about an individual or group so that the information can be generalized to many others. Unfortunately, case studies tend to be highly subjective, and it is sometimes difficult to generalize results to a larger population.

While case studies focus on a single individual or group, they follow a format similar to other types of psychology writing. If you are writing a case study, we got you—here are some rules of APA format to reference.  

At a Glance

A case study, or an in-depth study of a person, group, or event, can be a useful research tool when used wisely. In many cases, case studies are best used in situations where it would be difficult or impossible for you to conduct an experiment. They are helpful for looking at unique situations and allow researchers to gather a lot of˜ information about a specific individual or group of people. However, it's important to be cautious of any bias we draw from them as they are highly subjective.

What Are the Benefits and Limitations of Case Studies?

A case study can have its strengths and weaknesses. Researchers must consider these pros and cons before deciding if this type of study is appropriate for their needs.

One of the greatest advantages of a case study is that it allows researchers to investigate things that are often difficult or impossible to replicate in a lab. Some other benefits of a case study:

• Allows researchers to capture information on the 'how,' 'what,' and 'why,' of something that's implemented
• Gives researchers the chance to collect information on why one strategy might be chosen over another
• Permits researchers to develop hypotheses that can be explored in experimental research

On the other hand, a case study can have some drawbacks:

• It cannot necessarily be generalized to the larger population
• Cannot demonstrate cause and effect
• It may not be scientifically rigorous
• It can lead to bias

Researchers may choose to perform a case study if they want to explore a unique or recently discovered phenomenon. Through their insights, researchers develop additional ideas and study questions that might be explored in future studies.

It's important to remember that the insights from case studies cannot be used to determine cause-and-effect relationships between variables. However, case studies may be used to develop hypotheses that can then be addressed in experimental research.

Case Study Examples

There have been a number of notable case studies in the history of psychology. Much of  Freud's work and theories were developed through individual case studies. Some great examples of case studies in psychology include:

• Anna O : Anna O. was a pseudonym of a woman named Bertha Pappenheim, a patient of a physician named Josef Breuer. While she was never a patient of Freud's, Freud and Breuer discussed her case extensively. The woman was experiencing symptoms of a condition that was then known as hysteria and found that talking about her problems helped relieve her symptoms. Her case played an important part in the development of talk therapy as an approach to mental health treatment.
• Phineas Gage : Phineas Gage was a railroad employee who experienced a terrible accident in which an explosion sent a metal rod through his skull, damaging important portions of his brain. Gage recovered from his accident but was left with serious changes in both personality and behavior.
• Genie : Genie was a young girl subjected to horrific abuse and isolation. The case study of Genie allowed researchers to study whether language learning was possible, even after missing critical periods for language development. Her case also served as an example of how scientific research may interfere with treatment and lead to further abuse of vulnerable individuals.

Such cases demonstrate how case research can be used to study things that researchers could not replicate in experimental settings. In Genie's case, her horrific abuse denied her the opportunity to learn a language at critical points in her development.

This is clearly not something researchers could ethically replicate, but conducting a case study on Genie allowed researchers to study phenomena that are otherwise impossible to reproduce.

There are a few different types of case studies that psychologists and other researchers might use:

• Collective case studies : These involve studying a group of individuals. Researchers might study a group of people in a certain setting or look at an entire community. For example, psychologists might explore how access to resources in a community has affected the collective mental well-being of those who live there.
• Descriptive case studies : These involve starting with a descriptive theory. The subjects are then observed, and the information gathered is compared to the pre-existing theory.
• Explanatory case studies : These   are often used to do causal investigations. In other words, researchers are interested in looking at factors that may have caused certain things to occur.
• Exploratory case studies : These are sometimes used as a prelude to further, more in-depth research. This allows researchers to gather more information before developing their research questions and hypotheses .
• Instrumental case studies : These occur when the individual or group allows researchers to understand more than what is initially obvious to observers.
• Intrinsic case studies : This type of case study is when the researcher has a personal interest in the case. Jean Piaget's observations of his own children are good examples of how an intrinsic case study can contribute to the development of a psychological theory.

The three main case study types often used are intrinsic, instrumental, and collective. Intrinsic case studies are useful for learning about unique cases. Instrumental case studies help look at an individual to learn more about a broader issue. A collective case study can be useful for looking at several cases simultaneously.

The type of case study that psychology researchers use depends on the unique characteristics of the situation and the case itself.

There are a number of different sources and methods that researchers can use to gather information about an individual or group. Six major sources that have been identified by researchers are:

• Archival records : Census records, survey records, and name lists are examples of archival records.
• Direct observation : This strategy involves observing the subject, often in a natural setting . While an individual observer is sometimes used, it is more common to utilize a group of observers.
• Documents : Letters, newspaper articles, administrative records, etc., are the types of documents often used as sources.
• Interviews : Interviews are one of the most important methods for gathering information in case studies. An interview can involve structured survey questions or more open-ended questions.
• Participant observation : When the researcher serves as a participant in events and observes the actions and outcomes, it is called participant observation.
• Physical artifacts : Tools, objects, instruments, and other artifacts are often observed during a direct observation of the subject.

If you have been directed to write a case study for a psychology course, be sure to check with your instructor for any specific guidelines you need to follow. If you are writing your case study for a professional publication, check with the publisher for their specific guidelines for submitting a case study.

Here is a general outline of what should be included in a case study.

Section 1: A Case History

This section will have the following structure and content:

Background information : The first section of your paper will present your client's background. Include factors such as age, gender, work, health status, family mental health history, family and social relationships, drug and alcohol history, life difficulties, goals, and coping skills and weaknesses.

Description of the presenting problem : In the next section of your case study, you will describe the problem or symptoms that the client presented with.

Describe any physical, emotional, or sensory symptoms reported by the client. Thoughts, feelings, and perceptions related to the symptoms should also be noted. Any screening or diagnostic assessments that are used should also be described in detail and all scores reported.

Your diagnosis : Provide your diagnosis and give the appropriate Diagnostic and Statistical Manual code. Explain how you reached your diagnosis, how the client's symptoms fit the diagnostic criteria for the disorder(s), or any possible difficulties in reaching a diagnosis.

Section 2: Treatment Plan

This portion of the paper will address the chosen treatment for the condition. This might also include the theoretical basis for the chosen treatment or any other evidence that might exist to support why this approach was chosen.

• Cognitive behavioral approach : Explain how a cognitive behavioral therapist would approach treatment. Offer background information on cognitive behavioral therapy and describe the treatment sessions, client response, and outcome of this type of treatment. Make note of any difficulties or successes encountered by your client during treatment.
• Humanistic approach : Describe a humanistic approach that could be used to treat your client, such as client-centered therapy . Provide information on the type of treatment you chose, the client's reaction to the treatment, and the end result of this approach. Explain why the treatment was successful or unsuccessful.
• Psychoanalytic approach : Describe how a psychoanalytic therapist would view the client's problem. Provide some background on the psychoanalytic approach and cite relevant references. Explain how psychoanalytic therapy would be used to treat the client, how the client would respond to therapy, and the effectiveness of this treatment approach.
• Pharmacological approach : If treatment primarily involves the use of medications, explain which medications were used and why. Provide background on the effectiveness of these medications and how monotherapy may compare with an approach that combines medications with therapy or other treatments.

This section of a case study should also include information about the treatment goals, process, and outcomes.

When you are writing a case study, you should also include a section where you discuss the case study itself, including the strengths and limitiations of the study. You should note how the findings of your case study might support previous research. 

In your discussion section, you should also describe some of the implications of your case study. What ideas or findings might require further exploration? How might researchers go about exploring some of these questions in additional studies?

Need More Tips?

Here are a few additional pointers to keep in mind when formatting your case study:

• Never refer to the subject of your case study as "the client." Instead, use their name or a pseudonym.
• Read examples of case studies to gain an idea about the style and format.
• Remember to use APA format when citing references .

Crowe S, Cresswell K, Robertson A, Huby G, Avery A, Sheikh A. The case study approach .  BMC Med Res Methodol . 2011;11:100.

Crowe S, Cresswell K, Robertson A, Huby G, Avery A, Sheikh A. The case study approach . BMC Med Res Methodol . 2011 Jun 27;11:100. doi:10.1186/1471-2288-11-100

Gagnon, Yves-Chantal.  The Case Study as Research Method: A Practical Handbook . Canada, Chicago Review Press Incorporated DBA Independent Pub Group, 2010.

Yin, Robert K. Case Study Research and Applications: Design and Methods . United States, SAGE Publications, 2017.

By Kendra Cherry, MSEd Kendra Cherry, MS, is a psychosocial rehabilitation specialist, psychology educator, and author of the "Everything Psychology Book."

Home Blog Business How to Present a Case Study: Examples and Best Practices

How to Present a Case Study: Examples and Best Practices

Marketers, consultants, salespeople, and all other types of business managers often use case study analysis to highlight a success story, showing how an exciting problem can be or was addressed. But how do you create a compelling case study and then turn it into a memorable presentation? Get a lowdown from this post! 

Table of Content s

• Why Case Studies are a Popular Marketing Technique 

Popular Case Study Format Types

How to write a case study: a 4-step framework, how to do a case study presentation: 3 proven tips, how long should a case study be, final tip: use compelling presentation visuals, business case study examples, what is a case study .

Let’s start with this great case study definition by the University of South Caroline:

In the social sciences, the term case study refers to both a method of analysis and a specific research design for examining a problem, both of which can generalize findings across populations.

In simpler terms — a case study is investigative research into a problem aimed at presenting or highlighting solution(s) to the analyzed issues.

A standard business case study provides insights into:

• General business/market conditions 
• The main problem faced 
• Methods applied 
• The outcomes gained using a specific tool or approach

Case studies (also called case reports) are also used in clinical settings to analyze patient outcomes outside of the business realm. 

But this is a topic for another time. In this post, we’ll focus on teaching you how to write and present a business case, plus share several case study PowerPoint templates and design tips! 

Why Case Studies are a Popular Marketing Technique 

Besides presenting a solution to an internal issue, case studies are often used as a content marketing technique . According to a 2020 Content Marketing Institute report, 69% of B2B marketers use case studies as part of their marketing mix.

A case study informs the reader about a possible solution and soft-sells the results, which can be achieved with your help (e.g., by using your software or by partnering with your specialist). 

For the above purpose, case studies work like a charm. Per the same report: 

• For 9% of marketers, case studies are also the best method for nurturing leads. 
• 23% admit that case studies are beneficial for improving conversions. 

Moreover, case studies also help improve your brand’s credibility, especially in the current fake news landscape and dubious claims made without proper credit. 

Ultimately, case studies naturally help build up more compelling, relatable stories and showcase your product benefits through the prism of extra social proof, courtesy of the case study subject. 

Most case studies come either as a slide deck or as a downloadable PDF document. 

Typically, you have several options to distribute your case study for maximum reach:

• Case study presentations — in-person, virtual, or pre-recorded, there are many times when a case study presentation comes in handy. For example, during client workshops, sales pitches, networking events, conferences, trade shows, etc. 
• Dedicated website page — highlighting case study examples on your website is a great way to convert middle-on-the-funnel prospects. Google’s Think With Google case study section is a great example of a web case study design done right.

• Blog case studies — data-driven storytelling is a staunch way to stand apart from your competition by providing unique insights, no other brand can tell. 
• Video case studies — video is a great medium for showcasing more complex business cases and celebrating customer success stories.

Once you decide on your case study format, the next step is collecting data and then translating it into a storyline. There are different case study methods and research approaches you can use to procure data. 

But let’s say you already have all your facts straight and need to organize them in a clean copy for your presentation deck. Here’s how you should do it. 

1. Identify the Problem 

Every compelling case study research starts with a problem statement definition. While in business settings, there’s no need to explain your methodology in-depth; you should still open your presentation with a quick problem recap slide.

Be sure to mention: 

• What’s the purpose of the case study? What will the audience learn? 
• Set the scene. Explain the before, aka the problems someone was facing. 
• Advertise the main issues and findings without highlighting specific details.

The above information should nicely fit in several paragraphs or 2-3 case study template slides

2. Explain the Solution 

The bulk of your case study copy and presentation slides should focus on the provided solution(s). This is the time to speak at length about how the subject went from before to the glorious after. 

Here are some writing prompts to help you articulate this better:

• State the subject’s main objective and goals. What outcomes were they after?
• Explain the main solution(s) provided. What was done? Why this, but not that? 
• Mention if they tried any alternatives. Why did those work? Why were you better?

This part may take the longest to write. Don’t rush it and reiterate several times. Sprinkle in some powerful words and catchphrases to make your copy more compelling.

3. Collect Testimonials 

Persuasive case studies feature the voice of customer (VoC) data — first-party testimonials and assessments of how well the solution works. These provide extra social proof and credibility to all the claims you are making. 

So plan and schedule interviews with your subjects to collect their input and testimonials. Also, design your case study interview questions in a way that lets you obtain quantifiable results.

4. Package The Information in a Slide Deck

Once you have a rough first draft, try different business case templates and designs to see how these help structure all the available information. 

As a rule of thumb, try to keep one big idea per slide. If you are talking about a solution, first present the general bullet points. Then give each solution a separate slide where you’ll provide more context and perhaps share some quantifiable results.

For example, if you look at case study presentation examples from AWS like this one about Stripe , you’ll notice that the slide deck has few texts and really focuses on the big picture, while the speaker provides extra context.

Need some extra case study presentation design help? Download our Business Case Study PowerPoint template with 100% editable slides. 

Your spoken presentation (and public speaking skills ) are equally if not more important than the case study copy and slide deck. To make a strong business case, follow these quick techniques. 

Focus on Telling a Great Story

A case study is a story of overcoming a challenge, and achieving something grand. Your delivery should reflect that. Step away from the standard “features => benefits” sales formula. Instead, make your customer the hero of the study. Describe the road they went through and how you’ve helped them succeed. 

The premises of your story can be as simple as:

• Help with overcoming a hurdle
• Gaining major impact
• Reaching a new milestone
• Solving a persisting issue no one else code 

Based on the above, create a clear story arc. Show where your hero started. Then explain what type of journey they went through. Inject some emotions into the mix to make your narrative more relatable and memorable. 

Experiment with Copywriting Formulas 

Copywriting is the art and science of organizing words into compelling and persuasive combinations that help readers retain the right ideas. 

To ensure that the audience retains the right takeaways from your case study presentation, you can try using some of the classic copywriting formulas to structure your delivery. These include:

• AIDCA — short for A ttention, I nterest, D esire, C onviction, and A ction. First, grab the audience’s attention by addressing the major problem. Next, pique their interest with some teaser facts. Spark their desire by showing that you know the right way out. Then, show a conviction that you know how to solve the issue—finally, prompt follow-up action such as contacting you to learn more. 
• PADS — is short for Problem, Agitation, Discredit, or Solution. This is more of a sales approach to case study narration. Again, you start with a problem, agitate about its importance, discredit why other solutions won’t cut it, and then present your option. 
• 4Ps — short for P roblem, P romise, P roof, P roposal. This is a middle-ground option that prioritizes storytelling over hard pitches. Set the scene first with a problem. Then make a promise of how you can solve it. Show proof in the form of numbers, testimonials, and different scenarios. Round it up with a proposal for getting the same outcomes. 

Take an Emotion-Inducing Perspective

The key to building a strong rapport with an audience is showing that you are one of them and fully understand what they are going through. 

One of the ways to build this connection is by speaking from an emotion-inducing perspective. This is best illustrated with an example: 

• A business owner went to the bank
• A business owner came into a bank branch 

In the second case, the wording prompts listeners to paint a mental picture from the perspective of the bank employees — a role you’d like them to relate to. By placing your audience in the right visual perspective, you can make them more receptive to your pitches. 

One common question that arises when creating a case study is determining its length. The length of a case study can vary depending on the complexity of the problem and the level of detail you want to provide. Here are some general guidelines to help you decide how long your case study should be:

• Concise and Informative: A good case study should be concise and to the point. Avoid unnecessary fluff and filler content. Focus on providing valuable information and insights.
• Tailor to Your Audience: Consider your target audience when deciding the length. If you’re presenting to a technical audience, you might include more in-depth technical details. For a non-technical audience, keep it more high-level and accessible.
• Cover Key Points: Ensure that your case study covers the key points effectively. These include the problem statement, the solution, and the outcomes. Provide enough information for the reader to understand the context and the significance of your case.
• Visuals: Visual elements such as charts, graphs, images, and diagrams can help convey information more effectively. Use visuals to supplement your written content and make complex information easier to understand.
• Engagement: Keep your audience engaged. A case study that is too long may lose the reader’s interest. Make sure the content is engaging and holds the reader’s attention throughout.
• Consider the Format: Depending on the format you choose (e.g., written document, presentation, video), the ideal length may vary. For written case studies, aim for a length that can be easily read in one sitting.

In general, a written case study for business purposes often falls in the range of 1,000 to 2,000 words. However, this is not a strict rule, and the length can be shorter or longer based on the factors mentioned above.

Our brain is wired to process images much faster than text. So when you are presenting a case study, always look for an opportunity to tie in some illustrations such as: 

• A product demo/preview
• Processes chart 
• Call-out quotes or numbers
• Custom illustrations or graphics 
• Customer or team headshots 

Use icons to minimize the volume of text. Also, opt for readable fonts that can look good in a smaller size too.

To better understand how to create an effective business case study, let’s explore some examples of successful case studies:

Apple Inc.: Apple’s case study on the launch of the iPhone is a classic example. It covers the problem of a changing mobile phone market, the innovative solution (the iPhone), and the outstanding outcomes, such as market dominance and increased revenue.

Tesla, Inc.: Tesla’s case study on electric vehicles and sustainable transportation is another compelling example. It addresses the problem of environmental concerns and the need for sustainable transportation solutions. The case study highlights Tesla’s electric cars as the solution and showcases the positive impact on reducing carbon emissions.

Amazon.com: Amazon’s case study on customer-centricity is a great illustration of how the company transformed the e-commerce industry. It discusses the problem of customer dissatisfaction with traditional retail, Amazon’s customer-focused approach as the solution, and the remarkable outcomes in terms of customer loyalty and market growth.

Coca-Cola: Coca-Cola’s case study on brand evolution is a valuable example. It outlines the challenge of adapting to changing consumer preferences and demographics. The case study demonstrates how Coca-Cola continually reinvented its brand to stay relevant and succeed in the global market.

Airbnb: Airbnb’s case study on the sharing economy is an intriguing example. It addresses the problem of travelers seeking unique and affordable accommodations. The case study presents Airbnb’s platform as the solution and highlights its impact on the hospitality industry and the sharing economy.

These examples showcase the diversity of case studies in the business world and how they effectively communicate problems, solutions, and outcomes. When creating your own business case study, use these examples as inspiration and tailor your approach to your specific industry and target audience.

Finally, practice your case study presentation several times — solo and together with your team — to collect feedback and make last-minute refinements! 

1. Business Case Study PowerPoint Template

To efficiently create a Business Case Study it’s important to ask all the right questions and document everything necessary, therefore this PowerPoint Template will provide all the sections you need.

Use This Template

2. Medical Case Study PowerPoint Template

3. Medical Infographics PowerPoint Templates

4. Success Story PowerPoint Template

5. Detective Research PowerPoint Template

6. Animated Clinical Study PowerPoint Templates

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Case Study Basics

What is a case study *.

A case study is a snapshot of an organization or an industry wrestling with a dilemma, written to serve a set of pedagogical objectives. Whether raw or cooked , what distinguishes a pedagogical case study from other writing is that it centers on one or more dilemmas. Rather than take in information passively, a case study invites readers to engage the material in the case to solve the problems presented. Whatever the case structure, the best classroom cases all have these attributes: (1)The case discusses issues that allow for a number of different courses of action – the issues discussed are not “no-brainers,” (2) the case makes the management issues as compelling as possible by providing rich background and detail, and (3) the case invites the creative use of analytical management tools.

Case studies are immensely useful as teaching tools and sources of research ideas. They build a reservoir of subject knowledge and help students develop analytical skills. For the faculty, cases provide unparalleled insights into the continually evolving world of management and may inspire further theoretical inquiry.

There are many case formats. A traditional case study presents a management issue or issues calling for resolution and action. It generally breaks off at a decision point with the manager weighing a number of different options. It puts the student in the decision-maker’s shoes and allows the student to understand the stakes involved. In other instances, a case study is more of a forensic exercise. The operations and history of a company or an industry will be presented without reference to a specific dilemma. The instructor will then ask students to comment on how the organization operates, to look for the key success factors, critical relationships, and underlying sources of value. A written case will pre-package appropriate material for students, while an online case may provide a wider variety of topics in a less linear manner.

Choosing Participants for a Case Study

Many organizations cooperate in case studies out of a desire to contribute to management education. They understand the need for management school professors and students to keep current with practice.

Organizations also cooperate in order to gain exposure in management school classrooms. The increased visibility and knowledge about an organization’s operations and culture can lead to subsidiary benefits such as improved recruiting.

Finally, organizations participate because reading a case about their operations and decision making written by a neutral observer can generate useful insights. A case study preserves a moment in time and chronicles an otherwise hidden history. Managers who visit the classroom to view the case discussion generally find the experience invigorating.

The Final Product

Cases are usually written as narratives that take the reader through the events leading to the decision point, including relevant information on the historical, competitive, legal, technical, and political environment facing the organization. A written case study generally runs from 5,000 to 10,000 words of text supplemented with numerous pages of data exhibits. An online raw case may have less original text, but will require students to extract information from multiple original documents, videos of company leaders discussing the challenges, photographs, and links to articles and websites.

The first time a case is taught represents something of a test run. As students react to the material, plan to revise the case to include additional information or to delete data that does not appear useful. If the organization’s managers attend the class, their responses to student comments and questions may suggest some case revisions as well.

The sponsoring professor will generally write a “teaching note” to give other instructors advice on how to structure classroom discussion and useful bits of analysis that can be included to explicate the issues highlighted in the case study.

Finally, one case may inspire another. Either during the case writing process or after a case is done, a second “B” case might be useful to write that outlines what the organization did or that outlines new challenges faced by the organization after the timeframe of the initial case study.

* Portions of this note are adapted from E. Raymond Corey, “Writing Cases and Teaching Notes,” Harvard Business School case 399-077, with updates to reflect Yale School of Management practices for traditional and raw cases.

• Introduction
• About Case Study Reports
• Section A: Overview

Section B: Planning and Researching

• Section C: Parts of a Case Study

Section D: Reviewing and Presenting

• Section E: Revising Your Work

Section F: Resources

• Your Workspace
• Guided Writing Tools

• About Lab Reports
• Section C: Critical Features
• Section D: Parts of a Lab Report

• About Literature Review
• Section C: Parts of a Literature Review
• Section D: Critical Writing Skills

• About Reflective Writing
• Section B: How Can I Reflect?
• Section C: How Do I Get Started?
• Section D: Writing a Reflection

Case Study Report Prepared by University of Guelph

On this page, you will find a comprehensive list of resources provided within this guide. These resources include examples, printable handouts, and additional links.

Summary of Resources

Within this section, we have provided you with

• our sample case study report,
• typical structure of a case study report,
• all of the handouts found within this guide,
• external links and resources, and
• activities and exercises.

Prepared by

Case Study Report Template

Case study report outline template.

This outline sample of a Case Study Report should serve as a useful guide to help you get started.

Download PDF

Download the Case Study Report Outline Template .

Preview: PDF Worksheet

Structure of A Case Study Report

Structure of a case study report.

The components of a case study report will vary depending on your institution and your instructor’s preferences. Be sure to refer to your assignment instructions to find out what will be required.

Most case study reports will include the following major sections and components:

• Cover page including basic student and class information
• Table of contents showing where key parts of the report can be found
• Executive summary of the key recommendations and points of the report
• Introduction to the report and identification of the focal problem being faced
• Analysis of the problem and application of course/program content
• Decision criteria and possible alternatives for solving the problem
• Recommendation for solving the problem
• Implementation plan for executing the recommendation and ensuring its success
• Exhibits that help to elaborate upon the content included in the report
• Reference list of any sources that were used at any point in the case study project

Worksheet: Project Schedule Worksheet

Use this helpful worksheet for your Case Study Report .

Download the Project Schedule Worksheet worksheet, or take a look at an Example of a filled out worksheet .

Worksheet: Group Work Contract

Download the Group Work Contract worksheet.

Worksheet: Checklist For Case Study Reports

Download the Checklist For Case Study Reports worksheet.

Worksheet: Planning for the Presentation

Download the Planning for the Presentation worksheet, or take a look at an example of a filled out worksheet .

Annotated Case Study Report

Section c: reviewing and presenting, example: annotated case study report.

Learn more about writing strategies for Annotated Case Study Report .

Interactive Activity

Launch the Case Study Report annotated example that you can review in your browser.

Preview: Interactive Version

Download the Case Study Report annotated example that you can review and print.

Preview: PDF Version

Alley, M. (1998). The craft of scientific writing. (3rd ed.). New York, NY: Springer.

Cook, C. K. (1986). Line by line: How to edit your own writing. New York, NY: Houghton Mifflin Harcourt.

Graff, G., Berkenstein, C. & Durst, R. (2008). They say, I say: The moves that matter in academic writing. New York, NY: W.W. Norton.

Hacker, D. & Summers, N. (2001). A Canadian writer’s reference. New York, NY: Bedford/St. Martins.

Hofmann, A. H. (2010). Scientific writing and communication: Papers, proposals, and presentations. Don Mills, ON: Oxford University Press.

Lunsford, A. A. (2005). The everyday writer. (3rd ed.). Boston, MA: Bedford/St. Martins.

Rubens, P. (Ed.). (2001). Science and technical writing: A manual of style. (2nd ed.). New York, NY: Routledge.

University of Guelph. (2015). Case Study Report Outline Template . (Interactive Activity).

University of Guelph. (2015). Worksheet: Project Schedule Worksheet . (PDF).

University of Guelph. (2015). Worksheet: Group Work Contract . (PDF).

University of Guelph. (2015). Worksheet: Checklist for Case Study Reports . (PDF).

University of Guelph. (2015). Worksheet: Planning for the Presentation .

University of Guelph. (2015). Example: Annotated Case Study Report . (Interactive Activity).

University of Guelph. (2015). Example: Annotated Case Study Report . (PDF).

Williams, J. & Nadel, I. B. (2004). Style: Ten lessons in clarity and grace. Toronto, ON: Pearson Canada.

Wyrick, J. (2008). Steps to writing well. (10th ed.). Boston, MA: Thomson Wadsworth.

Zinsser, W. (2006). On writing well. New York, NY: Harper Perennial.

Online Resources

Gopen, G. & Swan, J. (1990, Nov./Dec.). The science of scientific writing. American Scientist. Retrieved June 6, 2015 from http://www.americanscientist.org/issues/id.877,y.0,no., content.true,page.1,css.print/issue.aspx

Purdue University. (2015). Online writing lab. Retrieved from https://owl.english.purdue.edu/owl/resource/560/08/

Next: Review and Practice

Now that you have reviewed this guide, you can try our interactive Guided Writing Tools to work on sections of your own Case Study Report.

Organizing Your Social Sciences Research Assignments

• Annotated Bibliography
• Analyzing a Scholarly Journal Article
• Group Presentations
• Dealing with Nervousness
• Using Visual Aids
• Grading Someone Else's Paper
• Types of Structured Group Activities
• Group Project Survival Skills
• Leading a Class Discussion
• Multiple Book Review Essay
• Reviewing Collected Works
• Writing a Case Analysis Paper
• Writing a Case Study
• About Informed Consent
• Writing Field Notes
• Writing a Policy Memo
• Writing a Reflective Paper
• Writing a Research Proposal
• Generative AI and Writing
• Acknowledgments

Definition and Introduction

Case analysis is a problem-based teaching and learning method that involves critically analyzing complex scenarios within an organizational setting for the purpose of placing the student in a “real world” situation and applying reflection and critical thinking skills to contemplate appropriate solutions, decisions, or recommended courses of action. It is considered a more effective teaching technique than in-class role playing or simulation activities. The analytical process is often guided by questions provided by the instructor that ask students to contemplate relationships between the facts and critical incidents described in the case.

Cases generally include both descriptive and statistical elements and rely on students applying abductive reasoning to develop and argue for preferred or best outcomes [i.e., case scenarios rarely have a single correct or perfect answer based on the evidence provided]. Rather than emphasizing theories or concepts, case analysis assignments emphasize building a bridge of relevancy between abstract thinking and practical application and, by so doing, teaches the value of both within a specific area of professional practice.

Given this, the purpose of a case analysis paper is to present a structured and logically organized format for analyzing the case situation. It can be assigned to students individually or as a small group assignment and it may include an in-class presentation component. Case analysis is predominately taught in economics and business-related courses, but it is also a method of teaching and learning found in other applied social sciences disciplines, such as, social work, public relations, education, journalism, and public administration.

Ellet, William. The Case Study Handbook: A Student's Guide . Revised Edition. Boston, MA: Harvard Business School Publishing, 2018; Christoph Rasche and Achim Seisreiner. Guidelines for Business Case Analysis . University of Potsdam; Writing a Case Analysis . Writing Center, Baruch College; Volpe, Guglielmo. "Case Teaching in Economics: History, Practice and Evidence." Cogent Economics and Finance 3 (December 2015). doi:https://doi.org/10.1080/23322039.2015.1120977.

How to Approach Writing a Case Analysis Paper

The organization and structure of a case analysis paper can vary depending on the organizational setting, the situation, and how your professor wants you to approach the assignment. Nevertheless, preparing to write a case analysis paper involves several important steps. As Hawes notes, a case analysis assignment “...is useful in developing the ability to get to the heart of a problem, analyze it thoroughly, and to indicate the appropriate solution as well as how it should be implemented” [p.48]. This statement encapsulates how you should approach preparing to write a case analysis paper.

Before you begin to write your paper, consider the following analytical procedures:

• Review the case to get an overview of the situation . A case can be only a few pages in length, however, it is most often very lengthy and contains a significant amount of detailed background information and statistics, with multilayered descriptions of the scenario, the roles and behaviors of various stakeholder groups, and situational events. Therefore, a quick reading of the case will help you gain an overall sense of the situation and illuminate the types of issues and problems that you will need to address in your paper. If your professor has provided questions intended to help frame your analysis, use them to guide your initial reading of the case.
• Read the case thoroughly . After gaining a general overview of the case, carefully read the content again with the purpose of understanding key circumstances, events, and behaviors among stakeholder groups. Look for information or data that appears contradictory, extraneous, or misleading. At this point, you should be taking notes as you read because this will help you develop a general outline of your paper. The aim is to obtain a complete understanding of the situation so that you can begin contemplating tentative answers to any questions your professor has provided or, if they have not provided, developing answers to your own questions about the case scenario and its connection to the course readings,lectures, and class discussions.
• Determine key stakeholder groups, issues, and events and the relationships they all have to each other . As you analyze the content, pay particular attention to identifying individuals, groups, or organizations described in the case and identify evidence of any problems or issues of concern that impact the situation in a negative way. Other things to look for include identifying any assumptions being made by or about each stakeholder, potential biased explanations or actions, explicit demands or ultimatums , and the underlying concerns that motivate these behaviors among stakeholders. The goal at this stage is to develop a comprehensive understanding of the situational and behavioral dynamics of the case and the explicit and implicit consequences of each of these actions.
• Identify the core problems . The next step in most case analysis assignments is to discern what the core [i.e., most damaging, detrimental, injurious] problems are within the organizational setting and to determine their implications. The purpose at this stage of preparing to write your analysis paper is to distinguish between the symptoms of core problems and the core problems themselves and to decide which of these must be addressed immediately and which problems do not appear critical but may escalate over time. Identify evidence from the case to support your decisions by determining what information or data is essential to addressing the core problems and what information is not relevant or is misleading.
• Explore alternative solutions . As noted, case analysis scenarios rarely have only one correct answer. Therefore, it is important to keep in mind that the process of analyzing the case and diagnosing core problems, while based on evidence, is a subjective process open to various avenues of interpretation. This means that you must consider alternative solutions or courses of action by critically examining strengths and weaknesses, risk factors, and the differences between short and long-term solutions. For each possible solution or course of action, consider the consequences they may have related to their implementation and how these recommendations might lead to new problems. Also, consider thinking about your recommended solutions or courses of action in relation to issues of fairness, equity, and inclusion.
• Decide on a final set of recommendations . The last stage in preparing to write a case analysis paper is to assert an opinion or viewpoint about the recommendations needed to help resolve the core problems as you see them and to make a persuasive argument for supporting this point of view. Prepare a clear rationale for your recommendations based on examining each element of your analysis. Anticipate possible obstacles that could derail their implementation. Consider any counter-arguments that could be made concerning the validity of your recommended actions. Finally, describe a set of criteria and measurable indicators that could be applied to evaluating the effectiveness of your implementation plan.

Use these steps as the framework for writing your paper. Remember that the more detailed you are in taking notes as you critically examine each element of the case, the more information you will have to draw from when you begin to write. This will save you time.

NOTE : If the process of preparing to write a case analysis paper is assigned as a student group project, consider having each member of the group analyze a specific element of the case, including drafting answers to the corresponding questions used by your professor to frame the analysis. This will help make the analytical process more efficient and ensure that the distribution of work is equitable. This can also facilitate who is responsible for drafting each part of the final case analysis paper and, if applicable, the in-class presentation.

Framework for Case Analysis . College of Management. University of Massachusetts; Hawes, Jon M. "Teaching is Not Telling: The Case Method as a Form of Interactive Learning." Journal for Advancement of Marketing Education 5 (Winter 2004): 47-54; Rasche, Christoph and Achim Seisreiner. Guidelines for Business Case Analysis . University of Potsdam; Writing a Case Study Analysis . University of Arizona Global Campus Writing Center; Van Ness, Raymond K. A Guide to Case Analysis . School of Business. State University of New York, Albany; Writing a Case Analysis . Business School, University of New South Wales.

Structure and Writing Style

A case analysis paper should be detailed, concise, persuasive, clearly written, and professional in tone and in the use of language . As with other forms of college-level academic writing, declarative statements that convey information, provide a fact, or offer an explanation or any recommended courses of action should be based on evidence. If allowed by your professor, any external sources used to support your analysis, such as course readings, should be properly cited under a list of references. The organization and structure of case analysis papers can vary depending on your professor’s preferred format, but its structure generally follows the steps used for analyzing the case.

Introduction

The introduction should provide a succinct but thorough descriptive overview of the main facts, issues, and core problems of the case . The introduction should also include a brief summary of the most relevant details about the situation and organizational setting. This includes defining the theoretical framework or conceptual model on which any questions were used to frame your analysis.

Following the rules of most college-level research papers, the introduction should then inform the reader how the paper will be organized. This includes describing the major sections of the paper and the order in which they will be presented. Unless you are told to do so by your professor, you do not need to preview your final recommendations in the introduction. U nlike most college-level research papers , the introduction does not include a statement about the significance of your findings because a case analysis assignment does not involve contributing new knowledge about a research problem.

Background Analysis

Background analysis can vary depending on any guiding questions provided by your professor and the underlying concept or theory that the case is based upon. In general, however, this section of your paper should focus on:

• Providing an overarching analysis of problems identified from the case scenario, including identifying events that stakeholders find challenging or troublesome,
• Identifying assumptions made by each stakeholder and any apparent biases they may exhibit,
• Describing any demands or claims made by or forced upon key stakeholders, and
• Highlighting any issues of concern or complaints expressed by stakeholders in response to those demands or claims.

These aspects of the case are often in the form of behavioral responses expressed by individuals or groups within the organizational setting. However, note that problems in a case situation can also be reflected in data [or the lack thereof] and in the decision-making, operational, cultural, or institutional structure of the organization. Additionally, demands or claims can be either internal and external to the organization [e.g., a case analysis involving a president considering arms sales to Saudi Arabia could include managing internal demands from White House advisors as well as demands from members of Congress].

Throughout this section, present all relevant evidence from the case that supports your analysis. Do not simply claim there is a problem, an assumption, a demand, or a concern; tell the reader what part of the case informed how you identified these background elements.

Identification of Problems

In most case analysis assignments, there are problems, and then there are problems . Each problem can reflect a multitude of underlying symptoms that are detrimental to the interests of the organization. The purpose of identifying problems is to teach students how to differentiate between problems that vary in severity, impact, and relative importance. Given this, problems can be described in three general forms: those that must be addressed immediately, those that should be addressed but the impact is not severe, and those that do not require immediate attention and can be set aside for the time being.

All of the problems you identify from the case should be identified in this section of your paper, with a description based on evidence explaining the problem variances. If the assignment asks you to conduct research to further support your assessment of the problems, include this in your explanation. Remember to cite those sources in a list of references. Use specific evidence from the case and apply appropriate concepts, theories, and models discussed in class or in relevant course readings to highlight and explain the key problems [or problem] that you believe must be solved immediately and describe the underlying symptoms and why they are so critical.

Alternative Solutions

This section is where you provide specific, realistic, and evidence-based solutions to the problems you have identified and make recommendations about how to alleviate the underlying symptomatic conditions impacting the organizational setting. For each solution, you must explain why it was chosen and provide clear evidence to support your reasoning. This can include, for example, course readings and class discussions as well as research resources, such as, books, journal articles, research reports, or government documents. In some cases, your professor may encourage you to include personal, anecdotal experiences as evidence to support why you chose a particular solution or set of solutions. Using anecdotal evidence helps promote reflective thinking about the process of determining what qualifies as a core problem and relevant solution .

Throughout this part of the paper, keep in mind the entire array of problems that must be addressed and describe in detail the solutions that might be implemented to resolve these problems.

Recommended Courses of Action

In some case analysis assignments, your professor may ask you to combine the alternative solutions section with your recommended courses of action. However, it is important to know the difference between the two. A solution refers to the answer to a problem. A course of action refers to a procedure or deliberate sequence of activities adopted to proactively confront a situation, often in the context of accomplishing a goal. In this context, proposed courses of action are based on your analysis of alternative solutions. Your description and justification for pursuing each course of action should represent the overall plan for implementing your recommendations.

For each course of action, you need to explain the rationale for your recommendation in a way that confronts challenges, explains risks, and anticipates any counter-arguments from stakeholders. Do this by considering the strengths and weaknesses of each course of action framed in relation to how the action is expected to resolve the core problems presented, the possible ways the action may affect remaining problems, and how the recommended action will be perceived by each stakeholder.

In addition, you should describe the criteria needed to measure how well the implementation of these actions is working and explain which individuals or groups are responsible for ensuring your recommendations are successful. In addition, always consider the law of unintended consequences. Outline difficulties that may arise in implementing each course of action and describe how implementing the proposed courses of action [either individually or collectively] may lead to new problems [both large and small].

Throughout this section, you must consider the costs and benefits of recommending your courses of action in relation to uncertainties or missing information and the negative consequences of success.

The conclusion should be brief and introspective. Unlike a research paper, the conclusion in a case analysis paper does not include a summary of key findings and their significance, a statement about how the study contributed to existing knowledge, or indicate opportunities for future research.

Begin by synthesizing the core problems presented in the case and the relevance of your recommended solutions. This can include an explanation of what you have learned about the case in the context of your answers to the questions provided by your professor. The conclusion is also where you link what you learned from analyzing the case with the course readings or class discussions. This can further demonstrate your understanding of the relationships between the practical case situation and the theoretical and abstract content of assigned readings and other course content.

Problems to Avoid

The literature on case analysis assignments often includes examples of difficulties students have with applying methods of critical analysis and effectively reporting the results of their assessment of the situation. A common reason cited by scholars is that the application of this type of teaching and learning method is limited to applied fields of social and behavioral sciences and, as a result, writing a case analysis paper can be unfamiliar to most students entering college.

After you have drafted your paper, proofread the narrative flow and revise any of these common errors:

• Unnecessary detail in the background section . The background section should highlight the essential elements of the case based on your analysis. Focus on summarizing the facts and highlighting the key factors that become relevant in the other sections of the paper by eliminating any unnecessary information.
• Analysis relies too much on opinion . Your analysis is interpretive, but the narrative must be connected clearly to evidence from the case and any models and theories discussed in class or in course readings. Any positions or arguments you make should be supported by evidence.
• Analysis does not focus on the most important elements of the case . Your paper should provide a thorough overview of the case. However, the analysis should focus on providing evidence about what you identify are the key events, stakeholders, issues, and problems. Emphasize what you identify as the most critical aspects of the case to be developed throughout your analysis. Be thorough but succinct.
• Writing is too descriptive . A paper with too much descriptive information detracts from your analysis of the complexities of the case situation. Questions about what happened, where, when, and by whom should only be included as essential information leading to your examination of questions related to why, how, and for what purpose.
• Inadequate definition of a core problem and associated symptoms . A common error found in case analysis papers is recommending a solution or course of action without adequately defining or demonstrating that you understand the problem. Make sure you have clearly described the problem and its impact and scope within the organizational setting. Ensure that you have adequately described the root causes w hen describing the symptoms of the problem.
• Recommendations lack specificity . Identify any use of vague statements and indeterminate terminology, such as, “A particular experience” or “a large increase to the budget.” These statements cannot be measured and, as a result, there is no way to evaluate their successful implementation. Provide specific data and use direct language in describing recommended actions.
• Unrealistic, exaggerated, or unattainable recommendations . Review your recommendations to ensure that they are based on the situational facts of the case. Your recommended solutions and courses of action must be based on realistic assumptions and fit within the constraints of the situation. Also note that the case scenario has already happened, therefore, any speculation or arguments about what could have occurred if the circumstances were different should be revised or eliminated.

Bee, Lian Song et al. "Business Students' Perspectives on Case Method Coaching for Problem-Based Learning: Impacts on Student Engagement and Learning Performance in Higher Education." Education & Training 64 (2022): 416-432; The Case Analysis . Fred Meijer Center for Writing and Michigan Authors. Grand Valley State University; Georgallis, Panikos and Kayleigh Bruijn. "Sustainability Teaching using Case-Based Debates." Journal of International Education in Business 15 (2022): 147-163; Hawes, Jon M. "Teaching is Not Telling: The Case Method as a Form of Interactive Learning." Journal for Advancement of Marketing Education 5 (Winter 2004): 47-54; Georgallis, Panikos, and Kayleigh Bruijn. "Sustainability Teaching Using Case-based Debates." Journal of International Education in Business 15 (2022): 147-163; .Dean,  Kathy Lund and Charles J. Fornaciari. "How to Create and Use Experiential Case-Based Exercises in a Management Classroom." Journal of Management Education 26 (October 2002): 586-603; Klebba, Joanne M. and Janet G. Hamilton. "Structured Case Analysis: Developing Critical Thinking Skills in a Marketing Case Course." Journal of Marketing Education 29 (August 2007): 132-137, 139; Klein, Norman. "The Case Discussion Method Revisited: Some Questions about Student Skills." Exchange: The Organizational Behavior Teaching Journal 6 (November 1981): 30-32; Mukherjee, Arup. "Effective Use of In-Class Mini Case Analysis for Discovery Learning in an Undergraduate MIS Course." The Journal of Computer Information Systems 40 (Spring 2000): 15-23; Pessoa, Silviaet al. "Scaffolding the Case Analysis in an Organizational Behavior Course: Making Analytical Language Explicit." Journal of Management Education 46 (2022): 226-251: Ramsey, V. J. and L. D. Dodge. "Case Analysis: A Structured Approach." Exchange: The Organizational Behavior Teaching Journal 6 (November 1981): 27-29; Schweitzer, Karen. "How to Write and Format a Business Case Study." ThoughtCo. https://www.thoughtco.com/how-to-write-and-format-a-business-case-study-466324 (accessed December 5, 2022); Reddy, C. D. "Teaching Research Methodology: Everything's a Case." Electronic Journal of Business Research Methods 18 (December 2020): 178-188; Volpe, Guglielmo. "Case Teaching in Economics: History, Practice and Evidence." Cogent Economics and Finance 3 (December 2015). doi:https://doi.org/10.1080/23322039.2015.1120977.

Writing Tip

Ca se Study and Case Analysis Are Not the Same!

Confusion often exists between what it means to write a paper that uses a case study research design and writing a paper that analyzes a case; they are two different types of approaches to learning in the social and behavioral sciences. Professors as well as educational researchers contribute to this confusion because they often use the term "case study" when describing the subject of analysis for a case analysis paper. But you are not studying a case for the purpose of generating a comprehensive, multi-faceted understanding of a research problem. R ather, you are critically analyzing a specific scenario to argue logically for recommended solutions and courses of action that lead to optimal outcomes applicable to professional practice.

To avoid any confusion, here are twelve characteristics that delineate the differences between writing a paper using the case study research method and writing a case analysis paper:

• Case study is a method of in-depth research and rigorous inquiry ; case analysis is a reliable method of teaching and learning . A case study is a modality of research that investigates a phenomenon for the purpose of creating new knowledge, solving a problem, or testing a hypothesis using empirical evidence derived from the case being studied. Often, the results are used to generalize about a larger population or within a wider context. The writing adheres to the traditional standards of a scholarly research study. A case analysis is a pedagogical tool used to teach students how to reflect and think critically about a practical, real-life problem in an organizational setting.
• The researcher is responsible for identifying the case to study; a case analysis is assigned by your professor . As the researcher, you choose the case study to investigate in support of obtaining new knowledge and understanding about the research problem. The case in a case analysis assignment is almost always provided, and sometimes written, by your professor and either given to every student in class to analyze individually or to a small group of students, or students select a case to analyze from a predetermined list.
• A case study is indeterminate and boundless; a case analysis is predetermined and confined . A case study can be almost anything [see item 9 below] as long as it relates directly to examining the research problem. This relationship is the only limit to what a researcher can choose as the subject of their case study. The content of a case analysis is determined by your professor and its parameters are well-defined and limited to elucidating insights of practical value applied to practice.
• Case study is fact-based and describes actual events or situations; case analysis can be entirely fictional or adapted from an actual situation . The entire content of a case study must be grounded in reality to be a valid subject of investigation in an empirical research study. A case analysis only needs to set the stage for critically examining a situation in practice and, therefore, can be entirely fictional or adapted, all or in-part, from an actual situation.
• Research using a case study method must adhere to principles of intellectual honesty and academic integrity; a case analysis scenario can include misleading or false information . A case study paper must report research objectively and factually to ensure that any findings are understood to be logically correct and trustworthy. A case analysis scenario may include misleading or false information intended to deliberately distract from the central issues of the case. The purpose is to teach students how to sort through conflicting or useless information in order to come up with the preferred solution. Any use of misleading or false information in academic research is considered unethical.
• Case study is linked to a research problem; case analysis is linked to a practical situation or scenario . In the social sciences, the subject of an investigation is most often framed as a problem that must be researched in order to generate new knowledge leading to a solution. Case analysis narratives are grounded in real life scenarios for the purpose of examining the realities of decision-making behavior and processes within organizational settings. A case analysis assignments include a problem or set of problems to be analyzed. However, the goal is centered around the act of identifying and evaluating courses of action leading to best possible outcomes.
• The purpose of a case study is to create new knowledge through research; the purpose of a case analysis is to teach new understanding . Case studies are a choice of methodological design intended to create new knowledge about resolving a research problem. A case analysis is a mode of teaching and learning intended to create new understanding and an awareness of uncertainty applied to practice through acts of critical thinking and reflection.
• A case study seeks to identify the best possible solution to a research problem; case analysis can have an indeterminate set of solutions or outcomes . Your role in studying a case is to discover the most logical, evidence-based ways to address a research problem. A case analysis assignment rarely has a single correct answer because one of the goals is to force students to confront the real life dynamics of uncertainly, ambiguity, and missing or conflicting information within professional practice. Under these conditions, a perfect outcome or solution almost never exists.
• Case study is unbounded and relies on gathering external information; case analysis is a self-contained subject of analysis . The scope of a case study chosen as a method of research is bounded. However, the researcher is free to gather whatever information and data is necessary to investigate its relevance to understanding the research problem. For a case analysis assignment, your professor will often ask you to examine solutions or recommended courses of action based solely on facts and information from the case.
• Case study can be a person, place, object, issue, event, condition, or phenomenon; a case analysis is a carefully constructed synopsis of events, situations, and behaviors . The research problem dictates the type of case being studied and, therefore, the design can encompass almost anything tangible as long as it fulfills the objective of generating new knowledge and understanding. A case analysis is in the form of a narrative containing descriptions of facts, situations, processes, rules, and behaviors within a particular setting and under a specific set of circumstances.
• Case study can represent an open-ended subject of inquiry; a case analysis is a narrative about something that has happened in the past . A case study is not restricted by time and can encompass an event or issue with no temporal limit or end. For example, the current war in Ukraine can be used as a case study of how medical personnel help civilians during a large military conflict, even though circumstances around this event are still evolving. A case analysis can be used to elicit critical thinking about current or future situations in practice, but the case itself is a narrative about something finite and that has taken place in the past.
• Multiple case studies can be used in a research study; case analysis involves examining a single scenario . Case study research can use two or more cases to examine a problem, often for the purpose of conducting a comparative investigation intended to discover hidden relationships, document emerging trends, or determine variations among different examples. A case analysis assignment typically describes a stand-alone, self-contained situation and any comparisons among cases are conducted during in-class discussions and/or student presentations.

The Case Analysis . Fred Meijer Center for Writing and Michigan Authors. Grand Valley State University; Mills, Albert J. , Gabrielle Durepos, and Eiden Wiebe, editors. Encyclopedia of Case Study Research . Thousand Oaks, CA: SAGE Publications, 2010; Ramsey, V. J. and L. D. Dodge. "Case Analysis: A Structured Approach." Exchange: The Organizational Behavior Teaching Journal 6 (November 1981): 27-29; Yin, Robert K. Case Study Research and Applications: Design and Methods . 6th edition. Thousand Oaks, CA: Sage, 2017; Crowe, Sarah et al. “The Case Study Approach.” BMC Medical Research Methodology 11 (2011):  doi: 10.1186/1471-2288-11-100; Yin, Robert K. Case Study Research: Design and Methods . 4th edition. Thousand Oaks, CA: Sage Publishing; 1994.

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Case Studies: How to write a case study

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• How to write a case study
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Structure of a case study

A case study is a type of paper that focuses on a specific problem affecting a population, place, or organization. Examples of subjects in a case study include a person, a group, city, company, department, or event.

The typical structure of a case study includes:

1) Introduction: provides background information about what is being studied. Introduce the topic and describe the problem. Consider the following questions when writing your introduction:

• Who or what is being studied?
• What specific problem you will be focusing on?
• Why is the investigation important in the field?

2) Literature review: provides context for the problem being studied.

• How is the problem or the subject you are investigating described in the literature?
• What is the relationship to other cases?
• What interpretations, gaps, conflicts are identified in the literature?
• How do the ideas of other authors relate to the problem you are investigating?

3) Method: provides details about how the problem is being investigated.

• Provide details about the subject (person, population, organization, etc.) that will be the focus of your study.
• Explain why and how the subject and problem were selected.
• Explain how you collected data to investigate the problem. Examples of possible data collection methods: structure or semi-structured interviews, focus groups, observation, surveys, etc.

4) Discussion: describe your findings.

• Reiterate the research problem and describe the main findings of your research.
• Interpret your findings and how they relate to other studies.
• Provide explanations for the findings, identify gaps and limitations, and suggest future areas of research

5) Conclusion: summarize your findings

• Synthesize the findings and how they are connected to the research problem.
• Emphasize the importance of the study and how they contribute to clarify the research problem.
• Provide recommendations based on your findings; if not done so already, clarify gaps, limitations, alternative explanations, and suggest areas for future research.

This section was based on recommendations provided by :

USC Libraries. (2020, November 1). Organizing your social sciences research paper. https://libguides.usc.edu/writingguide/casestudy

Further reading:

Yin, R. K. (2003). Case study research: Design and methods (3rd ed.). Sage Publications. Call number: H62 .Y56 2003

Cengage Learning. (n.d.). Business resources for students: Case studies. https://college.cengage.com/business/resources/casestudies/students/index.html

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CC0006 Basics of Report Writing

Structure of a report (case study, literature review or survey).

• Structure of report (Site visit)
• Citing Sources
• Tips and Resources

The information in the report has to be organised in the best possible way for the reader to understand the issue being investigated, analysis of the findings and recommendations or implications that relate directly to the findings. Given below are the main sections of a standard report. Click on each section heading to learn more about it.

• Tells the reader what the report is about
• Informative, short, catchy

Example - Sea level rise in Singapore : Causes, Impact and Solution

The title page must also include group name, group members and their matriculation numbers.

Content s Page

• Has headings and subheadings that show the reader where the various sections of the report are located
• Written on a separate page
• Includes the page numbers of each section
• Briefly summarises the report, the process of research and final conclusions
• Provides a quick overview of the report and describes the main highlights
• Short, usually not more than 150 words in length
• Mention briefly why you choose this project, what are the implications and what kind of problems it will solve

Usually, the abstract is written last, ie. after writing the other sections and you know the key points to draw out from these sections. Abstracts allow readers who may be interested in the report to decide whether it is relevant to their purposes.

Introduction

• Discusses the background and sets the context
• Introduces the topic, significance of the problem, and the purpose of research
• Gives the scope ie shows what it includes and excludes

In the introduction, write about what motivates your project, what makes it interesting, what questions do you aim to answer by doing your project. The introduction lays the foundation for understanding the research problem and should be written in a way that leads the reader from the general subject area of the topic to the particular topic of research.

Literature Review

• Helps to gain an understanding of the existing research in that topic
• To develop on your own ideas and build your ideas based on the existing knowledge
• Prevents duplication of the research done by others

Search the existing literature for information. Identify the data pertinent to your topic. Review, extract the relevant information for eg how the study was conducted and the findings. Summarise the information. Write what is already known about the topic and what do the sources that you have reviewed say. Identify conflicts in previous studies, open questions, or gaps that may exist. If you are doing

• Case study - look for background information and if any similar case studies have been done before.
• Literature review - find out from literature, what is the background to the questions that you are looking into
• Site visit - use the literature review to read up and prepare good questions before hand.
• Survey - find out if similar surveys have been done before and what did they find?

Keep a record of the source details of any information you want to use in your report so that you can reference them accurately.

Methodology

Methodology is the approach that you take to gather data and arrive at the recommendation(s). Choose a method that is appropriate for the research topic and explain it in detail.

In this section, address the following: a) How the data was collected b) How it was analysed and c) Explain or justify why a particular method was chosen.

Usually, the methodology is written in the past tense and can be in the passive voice. Some examples of the different methods that you can use to gather data are given below. The data collected provides evidence to build your arguments. Collect data, integrate the findings and perspectives from different studies and add your own analysis of its feasibility.

• Explore the literature/news/internet sources to know the topic in depth
• Give a description of how you selected the literature for your project
• Compare the studies, and highlight the findings, gaps or limitations.
• An in-depth, detailed examination of specific cases within a real-world context.
• Enables you to examine the data within a specific context.
• Examine a well defined case to identify the essential factors, process and relationship.
• Write the case description, the context and the process involved.
• Make sense of the evidence in the case(s) to answer the research question
• Gather data from a predefined group of respondents by asking relevant questions
• Can be conducted in person or online
• Why you chose this method (questionnaires, focus group, experimental procedure, etc)
• How you carried out the survey. Include techniques and any equipment you used
• If there were participants in your research, who were they? How did you select them and how may were there?
• How the survey questions address the different aspects of the research question
• Analyse the technology / policy approaches by visiting the required sites
• Make a detailed report on its features and your understanding of it

Results and Analysis

• Present the results of the study. You may consider visualising the results in tables and graphs, graphics etc.
• Analyse the results to obtain answer to the research question.
• Provide an analysis of the technical and financial feasibility, social acceptability etc

Discussion, Limitation(s) and Implication(s)

• Discuss your interpretations of the analysis and the significance of your findings
• Explain any new understanding or insights that emerged as a result of your research
• Consider the different perspectives (social, economic and environmental)in the discussion
• Explain the limitation(s)
• Explain how could what you found be used to make a difference for sustainability

Conclusion and Recommendations

• Summarise the significance and outcome of the study highlighting the key points.
• Come up with alternatives and propose specific actions based on the alternatives
• Describe the result or improvement it would achieve
• Explain how it will be implemented

Recommendations should have an innovative approach and should be feasible. It should make a significant difference in solving the issue under discussion.

• List the sources you have referred to in your writing
• Use the recommended citation style consistently in your report

Appendix (if necessary/any)

Include any material relating to the report and research that does not fit in the body of the report, in the appendix. For example, you may include survey questionnaire and results in the appendix.

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Writing A Case Study

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Having trouble making your case studies stand out? Finding it hard to organise your story? You're not alone! 

Many students struggle with case study writing !

Imagine spending a lot of time on your case studies, but they don't grab your reader's interest.  But don't worry! 

In this guide, we will go step by step through case study formatting, along with practical tips to make your research stand out from the rest! By following our step-by-step approach, you can understand how to write a case study assignment well. 

So, let’s get started!

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• 1. How to Format a Case Study 
• 2. Case Study Format Template
• 3. Case Study Format Examples

How to Format a Case Study 

When it comes to crafting a compelling case study, understanding how to write case study format is key to presenting your research effectively. 

If you are wondering how to make case study format, here are the elements to include in your case study paper format.

Create an interesting title for your work. Keep it simple and short.

Here you need to briefly elaborate on the accomplishment. What you have done and how you got there.

Write about the entire story in one paragraph followed by 2-3 bullet points to display the case study contents.

An introduction about what the case study is all about.

Describe the challenges of the customer prior to using your product or service. Explain the long-term goals or objectives that the customer set out to achieve.

In this 2-3 paragraph section describe how your product or service specifically benefited and helped achieve the goals. You can also use percentages to show your contributions.

In the relevant section of your case study, add 1-2 quotes and visuals to support the story you are telling. You can also use icons to summarise information and highlight areas of your research.

Figure out what a study means and look at where else we can learn more are really important for making academic work have a bigger impact.

Call to action is optional but adding one can encourage your readers to take some action after learning your work.

Case Study Formatting Guidelines 

Effective case study formatting is essential to convey your insights clearly and engage your audience. Follow these guidelines to ensure your case study is well-organised and impactful:

• Opt for easily readable fonts like Arial, Calibri, or Times New Roman.
• Maintain a consistent font size, typically 12 points for the body text.
• Set line spacing to double-spaced for the entire document.
• Use bullet points for concise and scannable information presentation.
• Employ numbered lists for sequences of steps or chronological order of events.
• Bold or italicize key phrases to draw attention to critical points; use underline sparingly.
• Choose left, center, or justified alignment based on your overall design.
• Make your headings clear and organized so readers know what's important.

If you need further assistance, check our case study format for students pdf here:

How To Write A Case Study Pdf

Case Study Format Template

Case studies can be used for different purposes. In social sciences, it can help you understand the problems of other people.

In businesses, it can help you earn the trust of potential customers. But do you even know what are the different  types of case study  and how to write one?

Refer to this case study format pdf before you start writing your own document. This student case study format sample contains all the information you might need when gathering information for your case study.

Case Study Format Examples

Case study examples are the best way to learn the basic techniques for writing a great case study on your own. 

Explore these short case study sample pdfs to gain insights into presenting your research cohesively:

For your help, we have also compiled real-life  case study examples  along with a format that you can refer to while writing your own.

APA Case Study Format

If you are asked to write a case study in APA format, keep in mind there are some specific requirements that you need to adhere to.

Here is a case study APA format example for you to learn how to format a case study.

Business Case Study Format

Business case studies can help businesses sell products or services to prospects. Here is a perfect example for you to learn how to write an impressive business case study.

Case Study Format For MBA Students

Case Study Format Nursing

Writing a great nursing case study can be tough. That’s why we have provided a case study format for nursing students to use as a guide in creating their work. 

Refer to this family case study format example if you are writing a nursing case study for the first time.

Nursing Case Study Format

Harvard Business School Case Study Format

Looking for HBS style business case study? Here is one for you to read and take hints and ideas to prepare this type of case study like a professional.

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Medical Case Study Format

Writing medical case studies is helpful in medical practices as it gives a lot of information about different diseases. Look at this example and learn how to write a detailed medical case study.

Case Study Format Psychology 

To study how the human mind works, you need a clear and organised method. Follow this easy psychology case study format to explore the details of psychological research:

Case Study Format Psychology

To sum it up, getting good at writing case studies means combining a clear structure, good storytelling, and smart presentation. If you follow the tips I've shared in this blog, you're on your way to making interesting stories that grab people's attention.

If your case study is causing problems, consider getting professional help. 

Our custom paper writing service aims to help you secure top grades by meeting the criteria set by professors. 

Our skilled writers are here to assist with any type of assignment you may have. Explore our case study writing service to relieve your stress and excel academically.

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Dr. Barbara is a highly experienced writer and author who holds a Ph.D. degree in public health from an Ivy League school. She has worked in the medical field for many years, conducting extensive research on various health topics. Her writing has been featured in several top-tier publications.

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Guidelines To Writing A Clinical Case Report

What is a clinical case report.

A case report is a detailed report of the symptoms, signs, diagnosis, treatment, and follow-up of an individual patient. Case reports usually describe an unusual or novel occurrence and as such, remain one of the cornerstones of medical progress and provide many new ideas in medicine. Some reports contain an extensive review of the relevant literature on the topic. The case report is a rapid short communication between busy clinicians who may not have time or resources to conduct large scale research.

WHAT ARE THE REASONS FOR PUBLISHING A CASE REPORT?

The most common reasons for publishing a case are the following: 1) an unexpected association between diseases or symptoms; 2) an unexpected event in the course observing or treating a patient; 3) findings that shed new light on the possible pathogenesis of a disease or an adverse effect; 4) unique or rare features of a disease; 5) unique therapeutic approaches; variation of anatomical structures.

Most journals publish case reports that deal with one or more of the following:

• Unusual observations
• Adverse response to therapies
• Unusual combination of conditions leading to confusion
• Illustration of a new theory
• Question regarding a current theory
• Personal impact.

STRUCTURE OF A CASE REPORT[ 1 , 2 ]

Different journals have slightly different formats for case reports. It is always a good idea to read some of the target jiurnals case reports to get a general idea of the sequence and format.

In general, all case reports include the following components: an abstract, an introduction, a case, and a discussion. Some journals might require literature review.

The abstract should summarize the case, the problem it addresses, and the message it conveys. Abstracts of case studies are usually very short, preferably not more than 150 words.

Introduction

The introduction gives a brief overview of the problem that the case addresses, citing relevant literature where necessary. The introduction generally ends with a single sentence describing the patient and the basic condition that he or she is suffering from.

This section provides the details of the case in the following order:

• Patient description
• Case history
• Physical examination results
• Results of pathological tests and other investigations
• Treatment plan
• Expected outcome of the treatment plan
• Actual outcome.

The author should ensure that all the relevant details are included and unnecessary ones excluded.

This is the most important part of the case report; the part that will convince the journal that the case is publication worthy. This section should start by expanding on what has been said in the introduction, focusing on why the case is noteworthy and the problem that it addresses.

This is followed by a summary of the existing literature on the topic. (If the journal specifies a separate section on literature review, it should be added before the Discussion). This part describes the existing theories and research findings on the key issue in the patient's condition. The review should narrow down to the source of confusion or the main challenge in the case.

Finally, the case report should be connected to the existing literature, mentioning the message that the case conveys. The author should explain whether this corroborates with or detracts from current beliefs about the problem and how this evidence can add value to future clinical practice.

A case report ends with a conclusion or with summary points, depending on the journal's specified format. This section should briefly give readers the key points covered in the case report. Here, the author can give suggestions and recommendations to clinicians, teachers, or researchers. Some journals do not want a separate section for the conclusion: it can then be the concluding paragraph of the Discussion section.

Notes on patient consent

Informed consent in an ethical requirement for most studies involving humans, so before you start writing your case report, take a written consent from the patient as all journals require that you provide it at the time of manuscript submission. In case the patient is a minor, parental consent is required. For adults who are unable to consent to investigation or treatment, consent of closest family members is required.

Patient anonymity is also an important requirement. Remember not to disclose any information that might reveal the identity of the patient. You need to be particularly careful with pictures, and ensure that pictures of the affected area do not reveal the identity of the patient.

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https://www.nist.gov/feature-stories/finding-forever-chemicals-wherever-theyre-hiding

They’re in the air we breathe, the water we drink, the food we eat and the soil where that food was grown.

They’re in our carpets, our cookware, our drinking straws, our cosmetics and our clothes.

They’re in medical products, mining chemicals, clean-energy technology and the equipment that manufactures our computer chips.

Finding Forever Chemicals Wherever They’re Hiding

Nist scientists are helping reveal tiny amounts of ‘forever chemicals’ in our food, water, clothing and environment..

They’re called per- and polyfluoroalkyl substances, or PFAS, a group of thousands of compounds that contain a chemical bond between fluorine and carbon. That bond has proved to be one of the most stable and unbreakable known to chemistry — a fact baked into the common nickname “forever chemicals,” because once PFAS are created, they last a very long time.

First manufactured in the 1940s, PFAS have seeped into our daily lives, and our bodies. In recent years, they have emerged as a serious public health concern. Scientists have reported evidence that certain PFAS, at high enough concentrations, may harm health by suppressing the immune system or causing cancers , obesity , thyroid problems and birth defects . 

Forever chemicals have also been found in remote forests, in the Arctic and at the bottom of the ocean. Reminiscent of pesticides like DDT in the 1960s and PCBs in the 1970s, they’ve emerged as some of the most pervasive and troublesome environmental contaminants of our time.

At the same time, health researchers are still determining how harmful PFAS are at the levels most of us are exposed to. And some of the studies that have raised the most alarms have used measurement methods that can overestimate the chemicals’ concentrations.

Researchers and regulators now face a daunting task: They must accurately measure PFAS in the countless places they’ve ended up and assess when and where these compounds have reached dangerous levels. To do so, scientists must often measure the chemicals at extremely low concentrations. PFAS can be found in food, drinking water and other materials in concentrations of parts per billion or even parts per trillion — equivalent to a few drops in an Olympic-size swimming pool.

This is where the National Institute of Standards and Technology (NIST) comes in. NIST scientists have pioneered methods that have made laboratory tests for PFAS in food, water, soil, firefighter gear and other materials more accurate. NIST research will support laboratory tests needed to implement the nation’s first-ever PFAS drinking water regulations , which the Environmental Protection Agency (EPA) is currently developing.  

NIST researchers have also produced one of the world’s largest public databases of empirically measured PFAS masses, to help other researchers and labs more efficiently sniff out these troublesome compounds.

PFAS represent the kind of measurement challenge that NIST was made to tackle.

“In the federal government space, NIST was ahead of the game on PFAS,” says NIST research chemist Jessica Reiner.

A Useful but Troublesome Chemistry

The PFAS industry started in the late 1930s and early 1940s, after an engineer at the company DuPont invented a fluoropolymer that became known as PTFE. Marketed as Teflon, PTFE became a blockbuster, launching a multibillion-dollar industry of nonstick coatings applied to cookware and an almost unlimited range of other products. 

Over the ensuing decades, thousands of PFAS were manufactured and incorporated into industrial lubricants, water-repellent clothing and carpeting, food packaging and more. If you’ve ever marveled how the wrapper around a greasy fast-food burger keeps your hands clean, or how effortlessly your lightweight rain jacket sheds water, you can probably thank a PFAS.

“Chemically they’re amazing — they do amazing things,” says John Kucklick, leader of the Biochemical and Exposure Science Group at NIST. “Anything that repels grease is probably fluorinated.”

The chain of carbon atoms (yellow balls) and fluorine atoms (blue balls) characteristic of PFAS molecules is uniquely good at repelling water and grease.

Chemical companies had evidence of PFAS-related health impacts as early as the 1950s. But only in the late 1990s and early 2000s did government agencies such as the EPA take a hard look at the chemicals, after a lawsuit exposed DuPont-led studies of their harmful effects on factory workers. Around that time, researchers at Michigan State University found PFOS , a major PFAS of concern, in the tissues of fish, birds and mammals throughout Europe and North America, including the Arctic. “That really lit the fuse for all this PFAS research,” says Kucklick. “It became a very hot topic.”

PFAS had proliferated far faster than scientists were able to study each one in detail, creating an urgent need to accurately measure the compounds in all kinds of contexts. Among the first things NIST scientists did was test for PFAS in the tissues of animals kept in the institute’s biorepository , based in Charleston, South Carolina. The repository contains frozen tissue from marine mammals and sea turtles that were collected starting in the 1980s. NIST researchers led by biologist Jennifer Lynch found PFOS and other PFAS in sea turtle blood and marine mammal livers — a concerning result that was consistent with other published studies. 

There were also more encouraging findings. Lynch’s liver measurements revealed that manufacturers’ voluntary phase-outs of certain PFAS starting in the early 2000s had, over time, reduced the levels accumulating in animals.

Reiner kick-started another PFAS-related research program when she joined NIST in 2008. She had studied with the author of the influential animal contamination study and done a postdoc at  the EPA. But after a 2004 paper by an international group of researchers detailed how PFAS measurements could go awry — and suggested that NIST could provide standards — Reiner “realized we had a lot of measurement problems” to solve. At the time, different labs' estimates of PFAS concentrations in the same material deviated by as much as several hundred percent. This made the measurements hard to trust. “It was the wild west,” says Reiner.

In the federal government space, NIST was ahead of the game on PFAS.” —Jessica Reiner, NIST research chemist 

One problem involved compounds that can mimic PFAS in a lab test, leading to errors. Eggs, for example, contain a bile acid that can easily be mistaken for certain PFAS. In a particularly high-profile case, when a scientist with the Food and Drug Administration presented a preliminary finding of high PFAS levels in chocolate cake, the report ignited a media firestorm. “That chocolate cake won’t last forever, but the chemicals in it might,” one headline stated. Follow-up testing by the FDA soon revealed the finding to be a false positive ; the cake contained no detectable PFAS. 

Building on Lynch’s research, Reiner first worked on measuring PFAS accurately in existing NIST reference materials, including human plasma, fish and house dust. These are well-characterized materials that any lab can purchase and measure with its own equipment. If the lab's measurement differs from the NIST-provided value on the label, its equipment needs to be adjusted or calibrated. NIST reference materials have helped make a wide range of important health and environment-related tests more accurate and reliable.

By 2012, Reiner’s team had produced new standard reference materials, or SRMs, for several of the PFAS most commonly found in biological samples. Over several years, the amount that different labs’ PFAS measurements deviated from the average plummeted from several hundred percent to around 40%, indicating that lab testing had become reasonably reliable. Eventually, Reiner thought, “OK, we’re good [with PFAS]; let’s move on.” She started working on flame retardants and plasticizers.

NIST’s PFAS-Related Standard Reference Materials

NIST Researchers Develop Standards to Help Eliminate ‘Forever Chemicals’ in Firefighting Foams

NIST Releases Great Lakes Sediment Material for Measuring Organic Pollutants

But events soon brought her back to PFAS. In 2016, New York State detected PFOA , another common PFAS, in the Village of Hoosick Falls’ public drinking water supply and Town of Hoosick private drinking water wells above the EPA health advisory level of 70 parts per trillion (ppt). PFOA, though no longer produced in the U.S., had been widely used to make products such as Teflon and foams for fighting fires. It has been linked to elevated cholesterol, thyroid disease, reduced immune response and some forms of cancer. Other studies soon found PFOA and other PFAS in drinking water systems around the country. 

It turned out that Reiner’s — and NIST’s — work on PFAS was just beginning.

Because PFAS don’t break down, they have been able to move widely through the environment, contaminating everything from food to drinking water to marine wildlife.

It’s in the Water

While PFAS is everywhere, it’s made the largest public splash, so to speak, in water. Since the 2016 finding of PFOA in New York, PFAS that leaked or discharged from factories, military bases and other facilities have been found in 45% of the nation’s tap water, according to the U.S. Geological Survey. More than 20 states have since moved toward regulating the chemicals. In March 2023, the Environmental Protection Agency proposed the first national limits for six PFAS in drinking water . The EPA proposed regulating concentrations of PFOA and PFOS, for example, at 4 parts per trillion.

To give regulated entities and broader society confidence, government and private labs will need to accurately quantify PFAS even at very low concentrations. That will require recognizing and controlling for issues that can mess up test results, says NIST research chemist Alix Rodowa. “PFAS are in so many things!” she says. “They’re in the instrumentation we use. Do we have Teflon tape on things? Is it in the materials we’re using to collect the samples? We have to think about all those things, especially at those ultra-trace levels.”

Alix Rodowa in the lab figuring out how to accurately measure PFAS in drinking water.

Rodowa and her colleagues have upgraded their measurement equipment with PFAS-free tubing and developed a suite of “tricks” to reduce contamination. She has been working on an SRM that labs can use to ensure their drinking water tests are accurate. Initially she was considering sending labs bottled water with a known amount of PFAS. But she realized the chemicals were sticking to the sides of the bottle, potentially compromising the analysis results. 

So she switched to a two-pronged approach: ship out a standardized volume of tap water purified using reverse osmosis — among the most effective PFAS filtration methods available — along with an ampule of PFAS diluted in methanol to a known concentration. Methanol reduces intermolecular forces that cause the PFAS to stick to the bottle, allowing for a more uniform mixture of PFAS and water. Lab workers who purchase the SRM can pour the solution into the purified water and test it on their equipment. 

The next step is to send the samples to labs to get feedback, which will help Rodowa further refine the material. Only when labs can consistently use the product to improve test results will NIST add it to its catalog of reference materials. The final product is still at least a year away — "SRMs are really hard to make,” Rodowa says — but when it comes out, “it will absolutely help. It will make the results much more comparable over time and build confidence for consumers of the commercial lab reports.”

The work could especially aid new labs coming online to meet the enormous and growing need for water testing, adds Reiner. “If they have a material like this to help them develop their method and get it set up correctly, they’re going to end up saving a lot of money and a lot of time.”

Fluorinated Food Fears

Few things are more frightening than the thought that the food you eat or feed to your family could contain harmful chemicals. And even if the FDA’s initial chocolate cake report proved a false alarm, PFAS has been showing up in food with distressing regularity. 

NIST’s food-related PFAS work began with Reiner’s studies of fish from the Great Lakes that the institute had already used to make reference materials for other chemical contaminants. But the urgent need for additional PFAS-specific materials became clear a few years ago, when a dairy farmer in Maine discovered the chemicals in high concentrations in his cows, likely because they drank contaminated groundwater or ate contaminated feed. The farmer ended up making the heartbreaking decision to cull his herd. But there was a silver lining — through connections at the FDA and Maine’s public health department, NIST chemists Benjamin Place and Melissa Phillips bought around 135 kilograms (300 pounds) of meat from the farmer. 

The meat arrived in the form of frozen patties. But figuring out how to accurately measure concentrations of PFAS in such a complicated material was far from trivial. The patties were first sent to the Hollings Marine Lab in Charleston, South Carolina, where they were chilled to extremely low temperatures and milled into a powder. Then, Place and his colleagues had to solve various challenges, like preventing the pinkish-red, slurried meat from sticking to lab equipment and test tubes. The process has proved to be one of the more, shall we say, visceral ones NIST researchers have encountered. 

NIST’s Melissa Phillips holds a bag of frozen spinach, while Ben Place holds a vial of frozen ground meat. Both are destined for future SRMs that will help labs accurately measure PFAS in food.

Place and Rodowa are now working to create SRMs for cow and pig meat. Rodowa and Place have also started preparing an SRM based on PFAS-contaminated spinach. And they have plans in the works for animal feed based on fermented corn stalks, which are currently stored in a NIST freezer.

With more and more states discovering PFAS-contaminated food and developing regulations around the chemicals, demand for these products is likely to be high. Already, NIST’s 15 PFAS-related SRMs have become some of the agency’s most popular products. Sales of the Great Lakes fish SRMs doubled between 2019 and 2021; the materials sometimes sell out. “They’ve been flying off the shelves,” says NIST research chemist Kate Rimmer.

Firefighters in the Spotlight

Chemicals in water and food affect everyone. But certain groups are far more likely than the rest of us to be exposed to high levels of PFAS. 

One of those groups includes the people who protect us and our homes from fire. Firefighters have raised alarms as studies have found elevated PFAS levels in their blood compared with the general population, along with higher rates of certain cancers .  

While firefighters could be exposed to PFAS from multiple sources, turnout gear — the familiar yellow and tan outfits firefighters don before plunging into a burning building — has become a prime suspect, thanks in part to university studies that have garnered media attention. This gear must meet stringent requirements for flame retardance and water repellence. And one of the most reliable ways for manufacturers to meet the performance standards is to use PFAS.

A firefighter’s protective "turnout gear" is composed of three distinct layers made of different textiles. In response to concerns about the gear possibly exposing firefighters to PFAS — several of which have been linked to cancer — NIST researchers investigated the presence of the chemicals in textiles used to make the layers.

In 2020, a bill sponsored by Sen. Jeanne Shaheen of New Hampshire directed NIST to identify and quantify the PFAS in turnout gear. 

The congressional funding enabled the research team to buy dozens of PFAS standards — commercially available solutions with precisely calibrated concentrations of the PFAS of interest — to calibrate its equipment. Each standard can run thousands of dollars. The researchers ultimately analyzed 53 compounds and 20 pieces of brand-new turnout gear — the most comprehensive examination published to date. 

Due to the high cost of buying all the gear and chemical standards and the amount of work involved, “I do not think this study could have been done by anybody else other than the federal government,” says Rick Davis, the NIST materials research engineer who led the research.

The team’s first report , released in May 2023, bore both good and troubling news. On the concerning side, all the fabrics contained some PFAS. The moisture barriers — the middle layer firefighters wear — and the outer shells the researchers tested contained the highest concentrations of the chemicals, up to around one part per million. Davis says the chemicals are likely added to make turnout gear waterproof, and that gear manufacturers may be able to achieve similar performance levels without using PFAS.

I do not think this study could have been done by anybody else other than the federal government.” —Rick Davis, NIST materials research engineer

More positively, the thermal liners firefighters wear against their skin contained much less PFAS. Moreover, the chemicals found in high concentrations in the other layers were not PFOA and PFOS — the so-called long-chain PFAS that have been most intensively studied but also largely phased out — but rather chemicals with shorter carbon chains. Such short-chain PFAS are more quickly flushed from the body, though it’s not clear whether that makes them safer. 

A second study released in January 2024 examined gear that had been heated, abraded or weathered — the kinds of wear expected when battling a fire. The team found that abrasion caused the greatest increase of PFAS in all fabric types, whereas heating increased PFAS concentrations substantially in the outer shells and slightly in the thermal liners, while decreasing them in the moisture barriers. Weathered outer shells also showed a large increase in PFAS.  

On the other hand, when gear was laundered, PFAS concentrations declined slightly — though the released chemicals probably ended up in the wastewater stream, raising potential concerns about environmental contamination.

NIST Reports on Firefighter Gear

Researchers Pin Down PFAS Prevalence in Firefighter Gear

Wear and Tear May Cause Firefighter Gear to Release More ‘Forever Chemicals’

Davis stresses that his team’s results do not address whether firefighters’ gear is harming them. “These studies better define the PFAS a firefighter could be exposed to from their gear,” he says, “which gives a narrower PFAS focus for those who will conduct firefighter health exposure studies.” Researchers at universities and other agencies are just starting to examine the health impacts of short-chain PFAS; one major unknown is how readily they move from clothing into the wearer’s body. The NIST studies aim to provide a rigorous and unbiased foundation for future decisions around firefighting gear. 

And the work is far from done. Davis’s next project will look at PFAS in firefighter gloves, hoods and other gear. Another future study will examine PFAS at fire stations and other workplace exposures. 

Another way firefighters could be exposed to PFAS is through aqueous firefighting foams. Starting in the 1960s, these products were used to quench flaming liquids like gasoline at sites such as military bases, oil refineries, airports and chemical factories. PFAS-based surfactants in these foams, which have proved uniquely good at smothering intense, high-temperature fires, can constitute up to 6% of the product’s total weight — an extremely high concentration found virtually nowhere else. During military training exercises, the chemicals often ended up in concrete pits and, from there, leaked into nearby groundwater. In some cases, water contaminated a half-century ago still appears foamy.

Congress has ordered the Department of Defense — the top user of these foams — to phase out most PFAS-containing firefighting foams by 2024. But legacy foams that remain on bases and other facilities could continue to contaminate the environment. To help ensure the fire suppressants people are using are PFAS-free, Reiner and other NIST researchers worked to develop SRMs for foams. The project was challenging, Reiner says, because the foam created when these products are used turned out to have a higher PFAS concentration than the overall product, so if a lab measures just the foam, it will get too high a value. 

In September, the team announced four new SRMs with formulations of PFAS found in several major types of firefighting foams. Labs around the country can use these materials to calibrate the equipment they use to analyze foams for PFAS, Reiner says. 

A series of reference materials contain precise measurements of per- and polyfluoroalkyl substances (PFAS), known as forever chemicals, in firefighting foams. These foams, called aqueous film-forming foams (AFFFs), are used to suppress fuel fires. Analytical labs can use the reference materials for measuring PFAS in the foams so they can be removed.

A Measurement and Mitigation Challenge

Like them or not, PFAS are part of our world — and not all are necessarily acutely dangerous. Fluorinated polymers used to lubricate surfaces and prevent abrasion, for example, are relatively stable and seem to present less urgent health or environmental risks than more mobile compounds like PFOA and PFOS. Such polymers appear in manufacturing equipment used for semiconductors and many clean-energy technologies, highlighting their importance to the modern economy. A push to purge them all would be costly. 

And in some cases, it may be that only PFAS can do the job. If gasoline ignites on a ship or in an airport, you probably want whatever will quench the flames most quickly, even if it contains PFAS.

On the other hand, some products that currently contain PFAS, such as carpets and food wrappers, may not need them. (Indeed, the FDA recently announced that food packaging containing PFAS would no longer be sold in the U.S. ) And reducing levels of the chemicals in food, water and the environment is a clear priority.

NIST’s forthcoming drinking water SRM “will make the results much more comparable over time and build confidence for consumers of the commercial lab reports.” —Alix Rodowa, NIST research chemist 

The challenge facing measurement scientists is to pinpoint the concentrations and situations in which PFAS is truly harmful — and to communicate that science effectively, so that the public is empowered and not just alarmed. The proliferation of PFAS — nearly 15,000 have been identified, according to the EPA — has made this an especially daunting challenge. 

One way NIST is helping is by creating a database of PFAS chemical structures and masses . Researchers with a sample they suspect might contain PFAS can run a process called mass spectrometry and check their results against the NIST database to look for a match. The database contains 132 structures, including many of the most commonly found PFAS compounds and fragments, making it one of the largest public databases of PFAS masses. And there are plans to add more, including by allowing outside researchers to add their own data. 

“We’re hoping that if we can do the hard part and identify those chemicals, others won’t have to,” says Jared Ragland, a NIST research biologist who is leading the database effort.

A second, newly created NIST-based list includes compounds such as the bile acid that can confound PFAS measurements. Within days of a paper about the dataset coming out, Rodowa says she had already received information about four additional PFAS-mimicking substances, highlighting the need for such a resource. She and Reiner, who developed the list along with colleagues at the EPA, FDA and several other institutions, hope it will help prevent reports of exaggerated PFAS concentrations or false positives — which Reiner says can sometimes cause more harm than the chemicals themselves.

By helping the world accurately identify and measure PFAS, NIST scientists aim to guide us toward a safer, cleaner and, hopefully, more empowered and less fearful future. “We need to give people the right information,” Reiner says, “so they can make more informed decisions.”

Learn More About NIST’s Work Tackling PFAS Measurement Challenges

Spotlight: Alix Rodowa and PFAS in Groundwater

Creating a PFAS-Contaminated Meat SRM: A Q&A With NIST Chemists Melissa Phillips and Ben Place

Addressing Measurement Challenges for Detecting Chemicals That Could Cause Cancer

New NIST Database of ‘Forever Chemicals’ Will Help Scientists Monitor Environmental Pollution

Learn More About How These Forever Chemicals Are Measured

How Do You Measure Forever Chemicals?  

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• Published: 28 March 2024

LEAP model-based analysis to low-carbon transformation path in the power sector: a case study of Guangdong–Hong Kong–Macao Greater Bay Area

• Mengke Xu 1 , 2 , 3 ,
• Cuiping Liao 1 , 2 , 3 , 4 ,
• Ying Huang 2 , 3 , 5 ,
• Xiaoquan Gao 2 , 3 ,
• Genglin Dong 1 , 2 , 3 &
• Zhen Liu 2 , 3  

Scientific Reports volume  14 , Article number:  7405 ( 2024 ) Cite this article

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• Energy management
• Energy policy
• Energy supply and demand
• Sustainability

As a major carbon emitter, the power sector plays a crucial role in realizing the goal of carbon peaking and carbon neutrality. This study constructed a low-carbon power system based on the LEAP model (LEAP-GBA) with 2020 as a statistic base aiming of exploring the low-carbon transformation pathway of the power sector in the Guangdong–Hong Kong, and Macao Greater Bay Area (GBA). Five scenarios are set up to simulate the demand, power generation structure, carbon emissions, and power generation costs in the power sector under different scenarios. The results indicate that total electricity demand will peak after 2050, with 80% of it coming from industry, buildings and residential use. To achieve net-zero emissions from the power sector in the GBA, a future power generation mix dominated by nuclear and renewable energy generation and supplemented by fossil energy generation equipped with CCUS technologies. BECCS technology and nuclear power are the key to realize zero carbon emissions from the power sector in the GBA, so it should be the first to promote BECCS technology testing and commercial application, improve the deployment of nuclear power sites, and push forward the construction of nuclear power and technology improvement in the next 40 years.

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Introduction

With President Xi’s goal of “carbon neutrality”, achieving the dual-carbon target has become a major opportunity and challenge for China 1 . As one of the most open and dynamic regions in China, the GBA is an important spatial carrier for China to build world-class city clusters and participate in global competition 2 . Its green and low-carbon transformation and development has attracted much attention. Electricity, as an indispensable material basis for the production and life of modern society, is transformed from fossil energy, nuclear energy, renewable energy and other energy resources, and is the main way of non-fossil energy utilization. With socio-economic development and increasing electrification level, electricity consumption has been increasing year by year. Electricity consumption in the GBA in 2020 will reach 550.8 billion kWh, an increase of 56% compared with 2010, and the installed capacity of power generation will still be dominated by thermal power, which accounts for more than 75% of the total. The development of renewable energy within the GBA has been hindered, with the development of photovoltaics severely hampered by imperfect distributed photovoltaic mechanisms and unequal approval processes. Onshore wind power development is restricted by mountain protection policies 3 , and offshore wind power resources are limited. Hydropower is difficult to continue in-depth development due to resource endowment. The urbanization rate of the GBA in 2020 will have reached more than 85%, with fewer agricultural and forestry resources and limited land available, making it unsuitable for the development of biomass power plants based on agricultural and forestry wastes, and only waste incineration can be developed. 2020 average power generation standard coal consumption of thermal power units in the Greater Bay Area will be around 295 g of standard coal/kWh, which is a large gap compared with the national average of 287 g of standard coal/kWh 4 . Carbon emissions from the power sector in the GBA will account for 49.8% of the total carbon emissions from energy consumption in 2020, and carbon emission reduction in the power sector needs to be addressed urgently.

There have been many studies on low-carbon power transformation. The key to low-carbon power transition lies in the construction of a new type of power system with new energy as the main body, constituting a comprehensive energy service system centered on electricity. It is required to build new power systems that technological innovations, including efficient and low-cost solar and wind power generation technologies 5 , ultra-high voltage transmission and distribution technologies 6 , small reactor nuclear power plant technologies 7 , carbon capture technologies, energy storage technologies 8 and smart grids 9 . However, the relationship between the scale of expansion of the new energy industry and technology should be balanced, taking into account the two dimensions of scale and technology in the process of energy transition 10 .

Considering the long construction period of power generation facilities, they need to be planned in advance. In recent years, research on power system planning simulation has been deepening. The studies mostly use integrated assessment models to analysis the decarbonization pathway of the power sector. They mainly include top–down macro prediction models and bottom-up micro prediction models. Typical macro forecasting model is CGE model. Xu Hongwei 11 , Wang Peng et al. 12 simulated electricity demand and investment return under different paths in the process of low-carbon transition of electricity in GBA by CGE model. The approach is based on general equilibrium theory and is weak on analyses related to abatement technologies. Micro-prediction models include AIM Enduse, LEAP model, etc. Luo Yuejun et al. 13 analyzed the impact of carbon emissions trading mechanism on electricity transition path based on AIM Enduse model. The model focuses on the analysis of the impact of a single technology or policy on overall carbon emissions. Compared with other models, the LEAP model can comprehensively evaluate the impacts of various technologies and policy measures on energy conservation and emission reduction in terms of the supply of energy structure, the level of energy technology, and the demand for energy, which is more suitable for analyzing the medium- and long-term scenarios of the power sector in this study. Nayyar 14 , Cai Liya 15 , and Nojedehi et al. 16 forecasted the medium- and long-term demand for electricity using the LEAP model. Overall, most of the current domestic studies on low-carbon transition paths in the power sector are based on national, provincial and municipal studies, and there are fewer studies on the low-carbon transition of power in urban agglomerations. China’s regions have large differences in energy resource potential, and there is obvious regional heterogeneity in the structure of power generation and energy consumption, and the path of low-carbon transformation of electric power should be adapted to local conditions.

The innovation of this study is to consider the technology learning rate in the model calculation, the carbon capture rate of CCUS technology and the negative carbon emission factor of BECCS technology in the simulation process, and the power self-sufficiency rate and the energy self-sufficiency rate of power generation in the result analysis process. The significance of this paper is that the importance of nuclear power is demonstrated by the substitutability of nuclear power and renewable energy, the contribution of CCUS technology to the low-carbon transition is quantified by the carbon capture rate, and the security of local power generation is considered by the power self-sufficiency rate and the energy self-sufficiency rate of power generation. The results of the study can provide a reference for the government to formulate a carbon–neutral action plan.

This research study chooses the GBA as the research object, and uses the LEAP model as the research tool to simulate the power generation structure and energy consumption structure of the power sector in GBA, and predicts the carbon emissions of the power sector. This study combines energy planning and local electricity supply and demand with conversion in each municipality, considers the constraints of the local economy, population, and urbanization rate, sets the business-as-usual (BAU) scenario (scenario for maintaining the current development trajectory) as the baseline, four low-carbon transition scenarios, analyzes the electricity demand, generation structure, CO 2 emissions, and generation costs under different scenarios, and explores the path to carbon neutrality in the power sector. This paper is structured as follows: “ Introduction ” introduces the research background and research methodology of the power sector low carbon transition study. “ Scenario design ” presents the research methodology and key assumptions used in this study. “ Results and analysis ” presents the methodology for setting up the various scenarios. “ Discussion ” provides a detailed analysis and discussion of the simulation results.

Scenario design

According to Guangdong Province’s 14th Five-Year Plan for Energy Development 17 and Outline Development Plan for the Guangdong–Hong Kong–Macao Greater Bay Area 18 , the future development of the GBA should optimize the energy structure, promote green and low-carbon energy transformation, and build a new type of power system, while improving the level of terminal electrification. This study sets up four low-carbon transition scenarios, clean energy generation (CEG) scenario, carbon capture, utilization and storage (CCUS) scenario, natural gas generation (NGE) scenario, and natural gas generation + carbon capture, utilization, and storage (NGE+CCUS) scenario, using the business-as-usual (BAU) scenario as a reference to analyze the carbon emissions, power generation costs, and power supply reliability of the power sector, and explore the best carbon neutral path in power sector for the GBA.

Electricity demand in the GBA is forecast to be 735 billion kWh in 2025, with an average annual growth rate of about 6% during the 14th Five-Year Plan period, which is basically in line with the 14th Five-Year Plan energy plans of various municipalities. With reference to the planning of key projects in Guangdong, Hong Kong and Macao Greater Bay Area municipalities in 2021, 2022 and 2023, and taking into account the longer construction cycle of generating units and the smaller scale of actual commissioning, the installed local power generation capacity in 2025 is lower than that of the 14th Five-Year Plan in this paper at the time of the scenario parameter setting.

Business-as-usual scenario (BAU)

In the BAU scenario, the power sector’s installed capacity structure and generation structure are based primarily on the energy planning policies of the GBA administrative regions 19 , 20 and no further carbon reduction measures are considered. In principle, there will be no new coal power generation and the old coal power generation units will be retired according to their service life, while gas power generation, renewable energy generation and nuclear power generation will be steadily developed. The key power projects under the 14th Five-Year Plan of each city will be completed, and some of the gas power generation units will be retired gradually after 2045 according to their service life. According to the relevant national standards, thermal power units within the GBA should complete energy-saving retrofits within the retrofit cycle 21 , 22 , 23 . Biomass power generation will be developed according to the existing planning and speed, with a waste incineration treatment capacity of about 159 kilo-tons per day, accounting for about 50% of the amount of waste to be treated. Photovoltaic power generation will be developed according to the current planning and growth rate, with an installed capacity of about 12 million kW to be completed by 2060, and wind and hydropower will be developed according to the existing planning and not further developed due to limited resources. Electricity demand is a continuation of existing policies and trends. The local installed generation capacity and generation structure under the BAU scenario are shown in Fig.  1 a. By 2060, coal-fired, gas-fired, nuclear and renewable energy sources will account for 11.4%, 46.7%, 23.3% and 17.5% of the GBA’s local electricity generation capacity respectively.

Installed capacity and generation structure in GBA under each scenario.

Low carbon transition scenario

This study establishes a low-carbon transition scenario based on the BAU scenario. In this scenario, other carbon reduction measures in addition to existing plans are considered. This study sets up four low-carbon transition scenarios according to different carbon reduction measures. It also compares the power generation costs and reliability of four low-carbon transition paths to identify the optimal low-carbon transition path.

CEG scenario

The scenario is set up to consider more clean energy generation and reduce carbon emissions from the power generation sector. Considering that CO 2 emissions from the power sector are mainly from fossil fuel generation, the CEG scenario further promotes renewable energy generation and nuclear power and retires coal-, gas- and oil-fired power plants year by year according to their lifetimes. In this scenario, to achieve 100% clean energy generation and further promote nuclear power construction, the Daya Bay Nuclear Power Station in Shenzhen adopts new nuclear units to replace older units. The total installed capacity of nuclear power in the GBA will reach 34.5 million kW in 2060. Considering the economic development, the future direction of solar power generation in GBA is mainly in rooftop PV. According to each city planning and research, the installed PV power generation in the current plan is only 50% of the buildable installed capacity in GBA, so solar power generation is further promoted based on existing policies. The scenario sets up an annual growth of 56 MW in installed PV capacity, reaching 26.24 GW by 2060. Due to the resource endowment, both wind power and hydropower in GBA are developed according to the existing plan, and the installed wind power and hydropower in 2060 are 2.85 GW and 1.78 GW, respectively. According to the forecast of urban domestic waste generation per capita and population, the domestic waste volume in GBA in 2060 can reach 364 kilo-tons per day, setting the incineration treatment ratio at 80% 24 , and the installed power generation capacity can reach 7.75 GW. This scenario retains only a small amount of coal and gas power as backup units by 2060. By 2060, coal-fired power, gas-fired power, nuclear power, and renewable energy power will account for 0.2%, 1.5%, 73.5%, and 24.8% respectively in local power generation in GBA. The structure of installed capacity and generation under the CEG scenario are shown in Fig.  1 b.

CCUS scenario

The commercial deployment of CCUS technology is critical to achieving carbon neutrality in the power sector. This scenario is based on the BAU scenario deploying CCUS technology on a unit-size basis after 2035, with all retained coal-fired and gas-fired power plants covered by 2060. BECCS technology has a carbon-negative role, and is deployed in this scenario after 2035, assuming that 150,000 kW of new BECCS installed capacity is added each year, covering all biomass generating units by 2060. The carbon emission factor for BECCS technology is set at − 3.214 25 . The carbon capture rate for CCUS-coal and CCUS-gas generation is 85% 26 . By 2060, CCUS-coal-fired, CCUS-gas-fired, nuclear and renewables will account for 10.8%, 33.5%, 44.9% and 10.3% of GBA’s local electricity generation, respectively. The installed local generation mix and the local generation mix in the CCUS scenario are shown in Fig.  1 c.

NGE scenario

Natural gas is generally regarded as a clean fossil energy source that emits less carbon than other fossil fuels and reduces the production of other air pollutants significantly. In this scenario based on the BAU scenario, natural gas-fired power generation is the main form of power generation in GBA, the merit order is adjusted from 2 to 1, the coal and oil power units are gradually retired, and the incentive for gas-fired power generation is stimulated through policies such as improving the natural gas price mechanism. By 2060, local power generation in this scenario mainly consists of natural gas-fired power generation, renewable power generation, and nuclear power generation, with the proportion of 43.7%, 45.2%, and 11.1% respectively. The structure of installed local generation and local generation capacity in the NGE scenario are shown in Fig.  1 d.

NGE + CCUS scenario

The natural gas power generation process still generates some carbon emissions. Therefore, the NGE+CCUS scenario is set based on the NGE scenario. The CCUS technology is deployed gradually after 2035 according to the size of natural gas power plants, with an average of 2.5 million kW of new CCUS-natural gas-fired generation capacity per year, covering all natural gas-fired power plants by 2060. The structure of installed local generation and local generation capacity under the NGE+CCUS scenario is shown in Fig.  1 e.

Results and analysis

This study predicts the future electricity demand and carbon emissions in GBA through the LEAP model and designs four low-carbon transition scenarios. The four power supply scenarios are compared in terms of carbon emission, power supply reliability, and cost to find out the optimal low-carbon transition path for the power sector in GBA.

Electricity demand forecast

The forecast results of total electricity demand and that by sector in GBA from 2020 to 2060 are shown in Figs.  2 and 3 . It is in a period of rapid development for GBA from 2020 to 2060. With the rapid growth in population, GDP, and electrification levels and the level of energy efficiency of equipment across all sectors, electricity demand in the GBA peaks at 1055.8 billion kWh in 2050 under the BAU scenario, and it peaks at 1029.8 billion kWh in 2040 under the Low-carbon transition scenario. Comparing the electricity demand in different scenarios, the BAU scenario peaks in 2055. The low-carbon transition scenario has its peak shifted forward to 2050, and its electricity demand maximum is lower than that in the BAU scenario. This is largely attributed to increased energy efficiency levels in consumer-side devices. As can be seen from Fig.  3 , the electricity demand mainly comes from the industrial sector and the construction sector. Electricity demand in the transportation sector increases year by year in both the BAU scenario and the low carbon transition scenario. Unlike the BAU scenario, its growth rate slows down after 2035 in the low-carbon transition scenario. This is due to the reduction in unit electricity consumption resulting from further improvements in electric vehicle technology and energy efficiency in the low-carbon transition scenario. In the BAU scenario, industrial sector electricity demand peaks at 433.2 billion kWh in 2045, and it peaks at 432.6 billion kWh 5 years ahead of schedule due to the accelerated pace of implementation of energy efficiency policies and the accelerated upgrading of energy efficiency levels in the low-carbon transition scenario. Electricity demand in the building sector increases annually in both scenarios, but it slows down significantly after 2035 in the low-carbon transition scenario. In the BAU scenario, agricultural electricity demand has been on an upward trend. The low-carbon transition scenario, on the other hand, accelerates energy efficiency and promotes high-tech and green agriculture, whose electricity demand peaks in 2035 and then begins to decline annually.

Total electricity demand forecasts.

Electricity demand forecasts by scenario sub-sector.

Sensitivity analysis

Sensitivity analysis of electricity supply and demand.

Electricity demand fluctuations will challenge the security of GBA’s electricity supply, due to the impact of uncertainty factors, there are fluctuations in electricity demand, and sensitivity analysis should be carried out on the balance of electricity supply and demand. In 2020, the GBA purchased power outside the province of 320 billion kWh, 140 billion kWh of which came from hydropower, assuming that the total amount of electricity purchased outside the province will remain unchanged in the future. Purchase of electricity from outside the province mainly from the neigh-boring cities in the east, north and west of Guangdong, Yangjiang six sets of 1.25 million kW of nuclear power in the end of 2019, all completed and put into operation, Shanwei Lufeng nuclear power plant six sets of 1.25 million kW of nuclear power units, Haifeng nuclear power plant eight sets of 1 million kW of nuclear power units, Shaoguan nuclear power plant four sets of 1.25 million kW of nuclear power units are in the planning of the construction. It is expected that by 2060, 26.98 million kW of nuclear power units will be put into operation to ensure the supply of electricity, generating 200 billion kWh of electricity annually. According to the Offshore Wind Power Development Plan of Guangdong Province ( 2017–2030 ), in the eastern and western regions of Guangdong, the installed capacity in the offshore shallow water area is 8.35 million kW, and the installed capacity in the offshore deep water area is 57 million kW, with a total installed capacity of up to 65 million kW, and a total power generation of up to 200 billion kWh. In the coastal areas of eastern and western Guangdong, a series of large-scale coal-fired units with a total installed capacity of about 18 million kW have been built because of their geographical advantages. There are also some large coal-fired units under construction in key planning projects in Guangdong Province. It is expected that by 2025, the installed capacity of large coal-fired units in eastern and western Guangdong will reach 20 million kW, providing 80 billion kWh of electricity. Assuming that end-use electricity consumption is raised by 5%, 10%, and 15% respectively under the low-carbon scenario, an analysis of the balance of electricity supply and demand in the GBA is shown in Fig.  4 .

Balance analysis of electricity supply and demand in GBA.

Within the 5% confidence interval, only the CEG and CCUS scenarios basically meet electricity demand, and within the 10% and 15% confidence intervals, an additional 50 billion kWh and 90 billion kWh of out-of-province power purchases are required in 2025 to meet electricity demand under the low-carbon scenario.

Sensitivity analysis of installed nuclear power capacity to electricity generation

Nuclear power, as clean electricity, is able to maintain a stable high output and is an important way to replace fossil energy sources. This paper analyses the installed amount of renewable energy that can be replaced by nuclear power installation according to the principle of power equivalence as shown in Fig.  5 . It is expected that 34.5 million kW of nuclear power will be commissioned in the GBA by 2060, which can replace 190.2 million kW of photovoltaic power generation or 111.0 million kW of wind power, discounted on the basis of the 2020 average annual power generation hours of wind power and solar power. Considering the complementary nature of wind–photovoltaic power generation, 140.2 million kW can be replaced by a 1:1 wind-photovoltaic mix. The amount of electricity reflects the effective generation time, the capacity reflects the generation capacity, and the reliability of renewable energy generation is low. The upper and lower confidence limits of wind power capacity are 26.37% and 7.68% respectively 27 , and the confidence limits of photovoltaic capacity are 13.7% and 23.2% considering the daytime and all-day period respectively 28 , and the upper and lower confidence limits of wind and photovoltaic integrated capacity are 25% and 5% respectively 29 . The new energy installed capacity that can be replaced by nuclear power with capacity equivalence is shown in Fig.  6 . According to the principle of capacity substitution, in 2060, the installed nuclear power capacity in the GBA can replace the upper limit of 2.8 billion kW and the lower limit of 560 million kW of wind-photovoltaic mix power generation, which is a considerable benefit.

Electricity equivalent nuclear and renewable energy installed substitution.

Capacity-equivalent nuclear and renewable energy installations.

Carbon emission prediction

In this study, the energy consumption of power generation is calculated based on the power generation structure of the power sector, and the carbon emissions of the power sector in GBA are calculated based on that. The carbon emission factor of purchased electricity adopts the average carbon emission factor of the power grid in Guangdong Province. The carbon emission projections under each scenario are shown in Fig.  7 . Carbon emissions in the BAU scenario decline slowly each year after peaking at 295.13 million tons in 2030, to 227.32 million tons in 2060. The CO 2 emissions per unit of electricity generation will decline annually to 218.75 g/kWh by 2060. Therefore, it is difficult to achieve net-zero emissions in the power sector under the current policy trend. Carbon emissions in the CEG scenario peak at 299.76 million tons in 2025 and then decline each year to 4.05 million tons in 2060. And the CO 2 emissions per unit of electricity generation declining annually to 4.26 g/kWh by 2060. Therefore, enhanced implementation of clean energy policies could lead to an earlier peak in carbon emissions and a 98% reduction in power sector carbon emissions by 2060. Carbon emissions in the CCUS scenario peak at 315.99 million tons in 2030 and then decline each year to 11.80 million tons in 2060. And the CO 2 emissions per unit of electricity generation declining annually to 12.42 g/kWh by 2060. So consideration of CCUS deployment could reduce carbon emissions in 2060 but also increase peak carbon emissions. Carbon emissions in the NGE scenario peak at 311.68 million tons in 2030 and then decline each year to 56.25 million tons in 2060. The CO 2 emissions per unit of electricity generation declining annually to 59.22 g/kWh by 2060. Carbon emissions in the NGE+CCUS scenario peak at 311.68 million tons in 2030 and then decline each year to 7.11 million tons in 2060. And the CO 2 emissions per unit of electricity generation declining annually to 7.49 g/kWh by 2060. So considering the coal-to-gas policy reduces carbon emissions less, while considering that CCUS deployment can reduce carbon emissions by 96.9% in 2060, which is lower than the carbon reductions in the CEG scenario. The percentage of CO 2 emission reduction under each scenario is shown in Table 1 . The simulation results show that accelerating the decommissioning of coal-fired power plants while accelerating the application of CCUS technology and promoting renewable power generation and nuclear power generation can help achieve carbon neutrality goals for the power sector in GBA.

CO 2 emission prediction for each scenario.

Reliability analysis

This study also considers the reliability of electricity supply under different scenarios. The power sector supply reliability δ can be calculated from the electricity self-sufficiency rate λ and the energy self-sufficiency rate μ of power generation. It can be expressed as follows:

which are shown in Table 2 .

In the BAU scenario, the λ in GBA decreases to 41.59% in 2060 while the μ increases to 67.96%. The δ increases from 27.76% in 2020 to 28.26% in 2060. In the CEG scenario, the λ in GBA decreases to 36.15% in 2060, which is due to the limited availability of renewable energy resources and the difficulty of nuclear power siting, while the μ increases to 100%. So the δ increases from 27.76% in 2020 to 36.15% in 2060. In the CCUS scenario, the λ in GBA decreases to 45.50% in 2060, which is due to the impact of energy prices, and the μ increases to 56.63%. So the δ decreases from 27.76% in 2020 to 25.77% in 2060. In the NGE scenario, the λ in GBA decreases to 44.21% in 2060, which is due to the natural gas price and geographical resource constraints, and the μ increases to 56.68%. So the δ decreases from 27.76% in 2020 to 25.06% in 2060. In the NGE+CCUS scenario, the λ in GBA decreases to 44.21% in 2060 and the μ decreases to 47.23%. The δ decreases from 27.76% in 2020 to 20.88% in 2060. This indicates that both the deployment of CCUS technology and the conversion of coal power to gas power will reduce the reliability of the electricity supply and that policies to promote clean energy generation should be accelerated.

Cost of electricity generation analysis

In this study, the total power generation cost and the unit power generation cost under different scenarios are shown in Fig.  8 and Table 3 . In the BAU scenario, the total cost of generating electricity peaks at 254.40 billion yuan in 2050 and then declines each year to 243.02 billion yuan in 2060. And the cost per unit of electricity generation increased yearly to 0.56 yuan/kWh. In the CEG scenario, the total cost of generating electricity peaks at 271.70 billion yuan in 2035 and then declines each year to 165.87 billion yuan in 2060. The cost per unit of electricity generation peaks at 0.49 yuan/kWh in 2050 and then declines yearly to 0.48 yuan/kWh, which is 14.10% lower than that in the BAU scenario for 2060. In the CCUS scenario, the total cost of generating electricity peaks at 296.51 billion yuan in 2050 and then declines yearly to 290.10 billion yuan in 2060. The cost per unit of electricity generation increased yearly to 0.67 yuan/kWh, which is 19.37% higher than that in the BAU scenario for 2060. In the NGE scenario, the total cost of generating electricity peaks at 275.44 billion yuan in 2045 and then declines yearly to 245.31 billion yuan in 2060. The cost per unit of electricity generation increased yearly to 0.58 yuan/kWh, which is 3.89% higher than that in the BAU scenario for 2060. In the NGE+CCUS scenario, the total cost of generating electricity peaks at 301.04 billion yuan in 2050 and then declines yearly to 291.56 billion yuan in 2060. The cost per unit of electricity generation increased yearly to 0.69 yuan/kWh, which is 23.48% higher than that in the BAU scenario for 2060. The simulation results show that an increase in clean energy generation can be achieved by controlling fuel costs in a way that reduces generation costs, while the deployment of CCUS increases both fuel costs and the O&M costs of power equipment.

Power generation cost under different scenarios.

Electricity demand mainly comes from industry, buildings, and residential life, accounting for more than 80% of the total electricity demand. So increased electrification of the industry sector and the building sector is the key to reducing electricity demand in the GBA. Due to the instability of natural gas prices, gas-fired power is less economical and should not be the dominant power generation technology. Considering the local natural resource endowment of the GBA, wind- and hydroelectric power generation are also highly restricted. Therefore, accelerating the decommissioning of coal power plants and promoting the development of solar power, biomass power, and nuclear power are key to achieving carbon neutrality in the power sector of the GBA.

Large-scale renewable energy generation into the grid will bring greater volatility to the grid, the later O&M costs greatly increase, so the abandoned wind, abandoned light phenomenon is serious currently. Smart grid technology and energy storage technology can increase the flexible scheduling of electricity, maintain grid stability, and reduce the operation and maintenance costs of the grid. At present, both the State Grid and the Southern Power Grid have built a strong smart grid. Energy storage technology still has certain technical barriers and has a greater impact on the cost of power generation after large-scale application. Electricity-hydrogen integration is still in the technology demonstration stage. Research on the impact of smart grid technology and energy storage technology on power generation costs will be carried out in the follow-up research.

CCUS technology plays an important role in carbon emission reduction in the power sector. However, due to high cost and energy consumption, CCUS technology is still in the demonstration and promotion stage due to a lack of experience in large-scale demonstration projects. Moreover, the complete industrial chain of carbon dioxide capture, storage, and utilization has not yet been formed, which prevents the combination of carbon-emitting enterprises and carbon-demanding enterprises from forming an integrated CCUS model. The carbon cycle of the power sector of GBA should be realized in combination with the good storage conditions of the submarine saltwater layer in Guangdong Province and the good foundation of gas hydrate extraction technology of carbon dioxide replacement.

As a policy tool to push enterprises to make energy-saving and emission-reduction transitions, carbon market trading is playing an increasingly important role. The carbon market is efficient and flexible but requires a complex set of institutional designs to support it. The core of the carbon trading market is carbon pricing, and the impact of carbon pricing on carbon emission reduction and power generation costs in the power sector will also be continued in the follow-up research.

Conclusions and recommendations

This study examines the ways to achieve carbon neutrality in the power sector in the GBA, a city cluster in the Pearl River Delta of China. This study adopts the LEAP model to construct a low-carbon power system in the GBA. The electricity demand in the GBA from 2020 to 2060 is analyzed from the demand side, and the power supply, power generation cost and CO 2 emission of the power sector under different scenarios from 2020 to 2060 are analyzed from the supply side. The results of the scenario analyses are available for policy makers.

The total electricity demand in the GBA will increase annually over the next 20–30 years and then decrease annually as energy efficiency levels improve. Electricity demand in the industrial sector will peak in 2040–2045 and then gradually begin to decline, and building and residential electricity use will grow slowly through 2060 with no inflection point. As electricity demand grows, an additional 40 billionkWh of out-of-province electricity should be purchased in 2025 to meet electricity demand under the 10% confidence interval and to ensure security of supply.

Carbon emissions from the power sector vary under different scenarios. Under the BAU Scenario, CEG Scenario, CCUS Scenario, NGE Scenario, and NGE+CCUS Scenario, the CO 2 emissions per unit of electricity generation are 219 g/kWh, 4 g/kWh, 12 g/kWh, 59 g/kWh, and 7 g/kWh by 2060, respectively. Accelerated decommissioning of coal plants, coal-to-gas conversion, and CCUS technology can all significantly reduce carbon emissions from the power generation sector. However, due to the limitation of carbon capture rate, CCUS technology cannot achieve zero carbon emission. Only through the development of nuclear power and renewable energy power generation can we truly realize zero carbon emissions from the power sector. Considering the volatility of power demand, a small amount of fossil power generation should be retained as a standby unit to ensure the reliability of power supply in the power sector. To ensure net-zero emissions from the power sector, all fossil energy generation and biomass generation should adopt CCUS and BECCS technologies by 2060.

Generation costs vary across scenarios. Deployment of CCUS technologies increases energy consumption costs and O&M costs in the power sector, and an increased share of natural gas generation raises fuel costs. Unit generation costs are highest in the NGE+CCUS scenario, reaching 0.69 yuan/kWh by 2060. The modeling results suggest that accelerating the retirement of thermal power plants and promoting clean energy generation can help reduce the cost of power generation. Meanwhile, the study considers the reliability of the power sector. Due to the limited use of renewable energy and the development of nuclear power in the GBA, a small amount of fossil power generation should be retained to improve the reliability of power supply, and CCUS technology should be adopted to reduce carbon emissions.

Recommendations

Strengthening demand-side management of electricity.

Between 2010 and 2020, terminal electricity consumption, per capita electricity demand and electricity consumption per unit of GDP in the GBA have increased year by year and electricity consumption per unit of GDP is higher than the level of international power-saving countries, so in the future, we should promote the decoupling of economic growth and electricity consumption by improving the ladder tariffs, valley-peak tariffs and smart grids etc., which can vigorously promote the demand-side management of electricity.

Strict control of coal power installation

The Central Government’s working opinion on the implementation of carbon neutrality suggests that fossil energy consumption should be strictly controlled, the pace of coal reduction should be accelerated, and the growth of coal consumption should be strictly controlled during the Fourteenth Five-Year Plan period and gradually reduced during the Fifteenth Five-Year Plan period. As the main source of carbon emissions in the power sector, coal power should be integrated into the future development process to maintain supply and peak adjustment, strictly control the addition of coal power units, and gradually retire old coal power units, accelerate the energy-saving upgrading and flexibility transformation of existing coal power units, and gradually transform coal power from the main force of power generation to a standby unit, and progressively reduce or even prohibit the bulk burning of coal.

Properly addressing the relationship between carbon neutrality in the long term and the development of natural gas in the near term

In recent years, the GBA has been actively encouraging the application of natural gas, actively developing natural gas-fired power generation, identifying natural gas sources and gradually constructing and improving the natural gas pipeline network, and upgrading the reception, transmission and distribution capacity of the trunk pipeline network. Natural gas-fired power generation, with its flexible operation, short start-up and stopping time and fast climbing rate, is a necessary support for the large-scale development of renewable energy. Therefore, the relationship between the long-term carbon neutral target and the near-term transition of natural gas power generation should be properly handled, the natural gas price mechanism should be improved, and appropriate laws, regulations and policy documents should be introduced when necessary to stimulate the power generation enthusiasm of natural gas units.

Promoting cleaner purchased electricity

In the next 40 years, it should continue to broaden the green channel for clean power from outside the region to enter the Bay, sign long-term strategic agreements, build a cross-provincial and cross-regional power transmission system for foreign clean power, and enhance the ability of clean energy bases to transmit power. Accelerate the promotion of inter-regional investment in renewable energy power plants by municipalities in the GBA, and tap the clean energy resources of the province's eastern, northern and western Guangdong.

Promoting energy efficiency of thermal power generating units in the GBA

The thermal power units in the GBA started early and are old, and the standard coal consumption per unit of power generation is higher than the domestic average. It is possible to optimize the energy system and improve the energy efficiency level of the units by designating measures for a special action program for energy efficiency improvement, increasing green financial expenditures 30 , upgrading the management level of energy efficiency indicators, and improving the unit's online performance calculation, indicator and consumption analysis system.

Methodology

The Low Emissions Analysis Platform (LEAP) model, developed by the Stockholm Environment Institute, is widely used for energy policy analysis and climate change mitigation assessment. It is based on scenario analysis with built-in energy, emissions, and cost–benefit accounting, allowing a comparison of energy demand, social costs and benefits, and environmental impacts under different scenarios.

LEAP framework and basic data

This study analyzes the pathway to carbon neutrality in the power sector of the GBA by 2060. The study consists of five modules: key assumptions, power demand, power supply, CO 2 emission, and power generation cost. The key assumptions module mainly includes GDP, population, urbanization rate, and industrial structure. The power demand module is used to simulate the electricity consumption structure on the demand side of GBA, which includes four sectors: industry, transportation, construction, and agriculture. The power supply module simulates the power installation structure and power generation structure on the supply side while considering the transmission and distribution losses. LEAP software is used to construct the Low Carbon Power Model of the GBA model, and the model framework is shown in Fig.  9 .

Power planning model structure of GBA.

Total electricity demand calculation method

Electricity demand is mainly influenced by factors such as activity level, energy intensity, and electrification level. Activity levels can be measured by economic indicators (such as industrial value added) or physical indicators (such as miles traveled, passenger turnover, floor space, etc.), and energy intensity can be measured by energy consumption per unit of activity. Total local electricity generation mainly depends on the structure of installed local generation and the generating hours. Purchased electricity is determined by electricity demand and local generation. CO 2 emissions from the power sector are determined by the power supply structure and the carbon emission factors of each power technology 31 .

Industrial sector electricity demand can be calculated based on the activity level, energy intensity, and electrification level of each branch. It can be expressed as follows:

where E p, i is the industrial sector electricity demand, AL i, j is the product output (million ton) of branch i product j in the industrial sector, EI i,j is energy intensity of branch i product j in the industrial sector, expressed in energy consumption per unit of product (million tons of standard coal per ton), EL i is the electrification level of branch i , and i is the traditional industries in the industry sector. AL k,j is the industrial value added (billion yuan) branch k product j in the industrial sector, EI k,j is the energy intensity of branch k product j in the industrial sector, expressed in energy consumption per unit of industrial value added (million tons of standard coal per billion yuan), EL k is the electrification level of branch k , and k is the emerging industries in the industry sector.

The building sector is divided into commercial buildings and residential buildings. The commercial building electricity demand can be calculated based on the building area, energy intensity, and electrification level. It can be expressed as follows:

where E P,b1 is commercial building electricity demand, A i is the building area of branch i (million square meters), EI i is unit area energy consumption of branch i (tons of standard coal per m 2 ·a ), EL i is electrification level of branch i .

The residential building electricity demand is calculated based on per capita living area, population, urbanization rate, energy intensity, and electrification level. It can be expressed as follows:

where EP,b 2 is residential building electricity demand, A j is the per capita living area in administrative area j (square meter), P j is the population in administrative area j , UR j is the urbanization rate in administrative area j , EI UR,j is energy intensity of urban residential life in administrative area j , EL UR,j is electrification level of urban residential life in administrative area j , EI R,j is energy intensity of rural residential life in administrative area j , EL R,j is electrification level of rural residential life in administrative area j .

Electricity demand in the transportation sector can be calculated based on the activity level, energy intensity, and electricity consumption per unit activity level of each transportation type 32 . It can be expressed as follows:

where E' P,t is transportation sector electricity demand, E i is 100 km energy consumption of transport i (tons of standard coal per 100 km), L i is annual mileage of transport i (per vehicle-km), N i is ownership of transport i (vehicles), EL i is the percentage of new energy vehicles in transport i, and i is the type of urban passenger transport other than the metro, E j is energy consumption per unit passenger turnover or freight turnover of transport j (tons of standard coal per passenger-km) or (tons of standard coal per tonne-km), L j is activity level of transport j (passenger-km) or (tonne-km), EL j is electrification level of transport j . And j is the type of transport except i .

Electricity demand in the agricultural sector can be calculated by activity level, energy intensity, and electrification level. Considering the data availability, the value added of the primary industry is used as the activity level of the agricultural sector. It can be expressed as follows:

where E P,a is agricultural sector electricity demand, AL is the activity level of the agricultural sector (billion yuan), EI is energy consumption per activity level (million tons of standard coal per billion yuan), and EL is the electrification level of the agricultural sector.

The total electricity demand is the sum of Eqs. ( 1 ), ( 2 ), ( 3 ), ( 4 ), ( 5 ). It can be expressed as follows:

In the power supply module, the electrical transformation and distribution include transmission line losses, transformer losses, and other equipment losses. Considering the availability of data, only transmission line losses are considered here. The average line loss rate of 3.63% 3 in Guangdong Province in 2020 is used as the average transmission line loss share of electric utilities in the GBA in that year. Activity levels, energy intensity, and electrification levels for each sector are derived from statistical yearbooks and research and analysis by the project team 33 , 34 , 35 , 36 , 37 .

The specification of generation technologies

The power generation module includes coal-fired power, oil-fired power, gas-fired power, hydro-power, nuclear power, wind power, biomass power, and photovoltaic power. For each generation technology, the dispatch rule, process efficiency, historical production, exogenous capacity, maximum availability, merit order, dispatch-able, lifetime, etc. are shown in Table 4 .

Methodology for calculating carbon emissions in the power sector

Carbon emissions from the power sector include carbon emissions from local power generation and purchased power. Carbon emissions from local power generation can be calculated based on the energy consumption structure of local power generation and carbon emission factors. The carbon emission of purchased electricity can be calculated based on the purchased electricity and the average CO 2 emission factor of Guangdong electricity. It can be expressed as follows:

where ECO 2 is carbon emissions from the power sector, EG i,j is electricity generation from category i fuel j power plant, bf i,j is standard coal consumption rate for power generation for category i fuel j power plant, EF i is CO 2 emission factor for category i fuel, PE is purchased electricity, EMF is the average CO 2 emission factor of Guangdong province 38 . The average carbon emission factor of the future power grid in Guangdong Province is determined by the future power generation structure in Guangdong Province.

Transformation costs methodology

Transformation costs include fuel demand costs, transformation capital costs, and fixed and variable O&M costs 14 . It can be expressed as follows:

where C t is the total cost, c i is the capital cost of power technology i , IC i is installed capacity of power technology i , f i is the fixed O&M costs for power technology i , v i is the variable O&M costs for power technology i , EG i is electricity generation by power technology i , c j is usage cost of fuel j , D j is the demand for fuel j . The various cost parameters are shown in Table 5 39 , 40 , 41 .

Previous studies have typically used learning curve models to predict trends in generation costs. The learning curve model based on the “learning by doing” effect can be formulated as follows:

where c i ( n ) is the generation cost of power generation technology i in year n , c i ( 0 ) is the initial cost per unit of power generation technology i , IC i ( n ) is the cumulative power generation capacity of power generation technology i in year n , α i is the elastic coefficient of power generation technology i , L i is technology learning rate of power generation technology i , LR i is the technological progress rate of power generation technology i . Learning rates for wind power, photovoltaic, coal power, CCUS, biomass power, etc. refer to relevant references 42 , 43 , 44 , 45 , 46 .

Socioeconomic parameters assumptions

The GDP growth rate, population, urbanization rate, and industrial structure of the GBA in 2020 are statistically calculated concerning the Statistical Yearbook of the nine prefecture-level cities of Guangdong Province within the GBA, the Statistical Yearbook of Hong Kong and the Statistical Yearbook of Macao in 2019–2020. The GDP growth rate of GBA from 2020 to 2035 is set concerning the existing growth rate trend and the Outline of the Fourteenth Five-Year Plan for the National Economic and Social Development of Guangdong Province and the Visionary Goals for 2035 47 , and the industrial structure from 2020 to 2035 is set by the trend of changes in the existing industrial structure and the Outline of the Fourteenth Five-Year Plan for the National Economic and Social Development of Guangdong Province and the Visionary Goals for 2035 47 , meanwhile, the impact of changes in GDP growth rate and industrial structure under the 2020–2021 epidemic is considered comprehensively. The GDP growth rate and industrial structure in 2035–2060 are set according to the trend of GDP growth rate and industrial structure change in 2020–2035. The population growth rate of GBA in 2020–2030 is set concerning the Population Development Plan of Guangdong Province ( 2017–2030 ) 48 , and the population growth rate in 2031–2060 is set concerning the trend of population growth rate in 2020–2030. The urbanization rate of GBA in 2020–2035 is set concerning the New Urbanization Plan of Guangdong Province ( 2021–2035 ) 49 , and the population growth rate in 2035–2060 is set concerning the trend of change in urbanization rate in 2020–2035. The socioeconomic parameters setting is shown in Table 6 . Discount rate analysis and projections based on historical discount rate trends.

Data availability

In this study, the data on electricity demand, population, and GDP used for prediction are from the website: http://stats.gd.gov.cn/ (accessed on 19 September 2023), and the data on installed power, electricity generation, and energy consumption are derived from a study of individual power plants.

Abbreviations

Low emissions analysis platform

Guangdong, Hong Kong, and Mocal Greater Bay Area

Carbon capture, utilization and storage

Bioenergy with carbon capture and storage

Stochastic impacts by regression on population, affluence, and technology

Operation and maintenance

Clean energy generation

Natural gas generation

Business-as-usual

Photovoltaic

M 2 multiplied by age

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Acknowledgements

We are so grateful to every power plant for their cooperation in data collection. Thanks to Songyan Ren for his precious opinions on the original draft writing.

This study is supported by the Collaborative Research Fund project entitled “Turning 2060 Carbon Neutrality into Reality: a cross-disciplinary Study of Air Pollution and Health Co-benefits of Climate Change Mitigation of the Guangdong-Hong Kong-Macau Greater Bay Area (GBA)” (Project No.: C7041-21GF) of the Hong Kong Research Grant Council; Science and technology projects of Zhejiang Province [Project No.: 2022C03168].

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Conceptualization, M.X. and C.L.; methodology, M.X. and C.L.; investigation, M.X., Y.H, Z.L. and G.D.; writing—original draft preparation, M.X.; writing—review and editing, M.X., X.G., G.D., and Z.L.; supervision, C.L.; project administration, C.L.; funding acquisition, C.L. All authors have read and agreed to the published version of the manuscript.

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Xu, M., Liao, C., Huang, Y. et al. LEAP model-based analysis to low-carbon transformation path in the power sector: a case study of Guangdong–Hong Kong–Macao Greater Bay Area. Sci Rep 14 , 7405 (2024). https://doi.org/10.1038/s41598-024-57703-w

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Gangue grouting filling in subsequent space of coal green mining: methodology and case study

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• Kunpeng Yu 1 ,
• Liqiang Ma 1 , 2 ,
• Ichhuy Ngo 1 ,
• Jiangtao Zhai 1 ,
• Yujun Xu 3 ,
• Zhiyang Zhao 1 ,
• Hui Wang 1 &
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Underground backfilling stands out as a crucial technological strategy for the eco-friendly and effective management of solid waste in mining operations. However, existing backfilling techniques have led to increased production processes at the working face, resulting in a reduction in coal extraction efficiency. Addressing the temporal and spatial interference between mine solid waste backfilling and coal mining is essential. To overcome this challenge, this study introduces a novel post-mining spatial gangue slurry backfilling method. Radar detection was employed to ascertain the typical characteristics of the subsequent space collapse roof shape. Stress monitoring and compaction experiments were conducted to establish the relationship between stress and the bulking coefficient of the overlying rock mass, identifying subsequent spatial void structure characteristics. The development of a CO 2 mineralized coal-based solid waste filling material, utilizing conventional low-calcium fly ash under normal temperature and pressure conditions, was presented. This paper provides a comprehensive understanding of the post-mining spatial gangue slurry backfilling method, outlines the spatial layout approach for the corresponding system, and analyzes research challenges associated with gangue slurry backfilling materials and the technology of slurry injection borehole layout. The research aims to innovate an efficient underground disposal model for gangue, contributing to the refinement of the technical system for the comprehensive disposal and utilization of gangue.

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Introduction

Coal is one of the primary sources of energy worldwide and plays a significant role in economic development (Zhang et al. 2019a , b , c ; Gao et al. 2018 ). The healthy development of the coal industry is crucial for energy security and sustainable economic growth (Chen et al. 2020a , b ; Xu et al. 2020 ). While coal has made tremendous contributions to industrial development, it has also brought a series of environmental damage issues, significantly impacting surface ecology and groundwater environments, particularly in ecologically vulnerable areas (Singh and Guha 2018 ; Li et al. 2019 ). The contradiction between large-scale coal extraction and environmental protection is particularly pronounced in areas characterized by coalfields with thick coal seams, shallow burial, limited water resources, and fragile ecosystems (Wang et al. 2018a , b , c ; Chen et al. 2020a , b , 2021 ; Zhong et al. 2019 ). In response to the ecological damage caused by large-scale mechanized mining methods, the current scientific development strategy for coal resources needs to shift from “passive restoration” to “active protection” and from “intensive mining” to “harmonious coordination” (Zeng et al. 2019 ; Liu et al. 2020 ).

Due to the limited conditions for coal occurrence, around 90% of coal in China is primarily extracted through underground mining (Wang et al. 2019 ; Huang et al. 2022 ; Qi et al. 2019 ). In accordance with the overall requirements of ecological civilization construction and prioritizing environmental protection, as well as emphasizing natural restoration, efforts should be made to minimize and control the ecological damage caused by mining operations underground. Currently, the main methods used to prevent ground ecosystem disruption resulting from coal mine strata collapse are pillar extraction and backfill mining (Zhu et al. 2018 ; Zhang et al. 2017a , b ; Wang et al. 2018a , b , c ). However, the pillar extraction method leads to resource wastage and reduces the service life of mines. It also affects production layout and efficient coal recovery (Bai et al. 2022b ; Li et al. 2016 ). On the other hand, traditional backfill mining incurs high costs and poor economic viability, making it unsuitable for large-scale promotion and implementation by coal mining enterprises (Wang et al. 2018a , b , c ; Yu et al. 2020a , b ; Shao et al. 2020 ). Therefore, it is crucial to explore a comprehensive, scientifically sound, and efficient coal mining technique that minimizes subsidence and ensures water preservation, which is a vital and practical requirement for green and efficient mining at the current stage (Meng et al. 2021 ; Hou et al. 2021 ; Yuan et al. 2021 ).

In underground mining, longwall mining method, compared to other mining methods, enables continuous coal extraction and possesses advantages such as high productivity, efficiency, recovery rate, and strong applicability (Zhang et al. 2017a , b ; Liu et al. 2023 ). Consequently, it has been widely applied and developed. However, the damage caused by longwall mining to the surface and groundwater in mining areas should not be underestimated (Doulati et al. 2022 ; Bai et al. 2022a ). Since most longwall mining methods primarily adopt the full caving method to manage the roof, the roof collapse area is extensive, resulting in significant displacement and deformation of overlying rock layers from the coal seam to the surface (He et al. 2015 ; Bai and Tu 2019 ). In cases where the coal seam is close to aquifers or surface water bodies, mining-induced fractures may penetrate the aquifer sealing layers, leading to water resource loss and sudden inrush of water in working areas, thereby triggering a series of ecological, environmental, and production safety issues (Gao et al. 2019 ; Yu et al. 2020a , b ; Hu et al. 2018 ). The various environmental and safety problems caused by underground coal mining essentially revolve around the loss of water resources induced by mining operations (Li et al. 2020 ; Xu et al. 2019 ).

Backfill mining is an effective method that limits the impact on water, soil resources, and infrastructure within the tolerable range of ecological tolerance for mining activities (Liu et al. 2018 ; Hu et al. 2017a , b ; Chen et al. 2019 ; Zhang et al. 2020a , b ). Promoting advanced technologies such as efficient backfill mining in an adaptable manner and conducting feasibility studies on coal mine backfill mining are among the key tasks for comprehensive management of mining subsidence areas (Zhao et al. 2019 ; Ma et al. 2018 ; Zhang et al. 2019a , b , c ; Wang et al. 2020 ). Backfilling the goaf is currently one of the most effective approaches to water conservation in coal mining (Liu et al. 2019 ; Zhang et al. 2020a , b ; Xie et al. 2016 ; Xu et al. 2017 ). However, traditional goaf backfilling encounters challenges such as insufficient time and space for timely backfilling before the roof collapses after coal extraction (Chen et al. 2018 ; Yang et al. 2017 ; Wu et al. 2016 ; Zhao et al. 2020 ). Additionally, mining and backfilling operations occur within the same limited space, making it difficult to coordinate parallel operations and causing backfilling to affect mining progress (Zhang et al. 2019a , b , c ; Shi et al. 2019 ; Hu et al. 2017a , b ; Wang et al. 2021a , b ). In coal mining environments characterized by complex geological conditions, a specialized approach to backfill mining has been implemented. This practice entails utilizing materials like gangue, sand, and crushed stone to fill the goaf, with the primary objective of minimizing subsidence associated with the mining process (Yang et al. 2019 ; Jiang et al. 2018 ; Liu et al. 2021 ). However, whether using coal gangue backfilling, cementitious backfilling, partial substitution of fly ash for cement in backfilling, or concrete backfilling, the unit cost is generally high. The relatively high investment cost significantly impacts the economic benefits of enterprises and objectively limits the widespread application of this method.

Regarding this particular situation, the authors propose a delayed backfilling approach for goaf filling. The backfilling operation is delayed compared to the mining operation, allowing for the natural collapse of the goaf roof. This results in a completely or nearly completely filled goaf area formed by the natural collapse of the goaf roof after coal mining. The authors utilize the fragmentation and expansion properties of the collapsed rocks. On the side close to the working face, a designated delayed filling zone is determined. Through directional drilling or upper-level roadways near the working face, the voids in the collapsed zone are grouted before compaction, consolidating the collapsed zone to form a load-bearing structure with certain strength, as depicted in Fig.  1 . Radar detection was utilized to characterize the typical shape of the roof collapse in the subsequent space. Stress monitoring and compaction experiments were carried out to establish the correlation between stress and the bulking coefficient of the overlying rock mass, revealing the characteristics of the subsequent spatial void structure. The paper introduced the development of a CO 2 mineralized coal-based solid waste filling material, employing conventional low-calcium fly ash under normal temperature and pressure conditions. It systematically elaborated on the concept of the subsequent space gangue grouting filling method and provided the spatial layout approach for the subsequent space gangue grouting filling system. The challenges in the development of gangue grouting filling materials and the technology for grouting borehole layout were thoroughly examined. The backfilling volume and range only cover a portion of the mined-out space. After reinforcing the collapsed rock mass with backfill material, it supports the overlying strata and achieves the objectives of controlling strata movement and water conservation while mining proceeds parallelly. The advantage of this method is that it separates the mining and backfilling processes, avoiding interference between them. Based on field investigations, the authors provide a detailed analysis of the characteristics of the collapsed goaf roof and the height of the collapsed zone, establishing the boundaries for grout filling. By monitoring the stress of the goaf in real-time, a stress distribution model for the delayed filling zone of the collapsed rock mass is established. This provides theoretical support for determining the timing of delayed grout filling in the collapsed goaf and understanding the development patterns of overlying strata fractures in the delayed filling zone.

Idea of subsequent space gangue grouting filling technology

Study area and hydrogeological conditions

The Yushen mining area is located in the arid inland region of central and western China, characterized by scarce water resources, making it a typical ecologically fragile mining area (Fig.  2 ). Groundwater in this region mainly relies on atmospheric precipitation, with an annual average precipitation ranging from 248.7 to 724.9 mm and a long-term average precipitation of 471.5 mm. Due to the terrain and landform, most of the precipitation forms surface runoff and is lost, with less than 15% infiltrating into the rock and soil layers. Moreover, the area experiences a high average annual evaporation of 1611 mm, leading to severe water shortage (Ma et al. 2022 ). In the early twenty-first century, the Yushen mining area began adopting modern coal mining technologies such as large working faces and one-time full-height mining. Due to the shallow burial of coal seams, thin overlying bedrock, and thick wind-blown sand cover on the surface, this high-intensity, integrated mining leads to deformation and fracture zones known as “double zones.” The structural damage to the aquifers results in the infiltration of water from the bedrock aquifer and the loose water-bearing layers of the Quaternary system into the goaf. This has caused a series of mining environmental geological effects, including leakage of underground water resources, sudden inrush of water and sand underground, groundwater level decline, and degradation of the ecological environment. The original fragile ecological environment of the mining area has become even more difficult to restore. For example, on July 13, 2003, when the 1310 working face in the Dalitata mine advanced to a position 16.7 m away from the cutting eye, the roof collapsed completely, leading to a geological disaster of water inrush and sand outburst, with a maximum water inflow of 510 m 3 /h (Ma et al. 2022 ). According to the statistics of water inflow in the Yushen mining area in recent years, the average water inflow of the Dalitata, Bulianta, and Shigetai mines exceeds 13,000 m 3 /d. The maximum water inflow is 16,853 m 3 /d (Shigetai). The average flow rate of the Mother River Spring Domain in the Dalitata mining field was 5961 m 3 /d before coal mining, with a maximum average flow rate of 106,273 m 3 /d (Fan et al. 2018 ). However, in recent years, due to the damage and drainage of the Quaternary water-bearing layer caused by coal mining, the flow rate of the Mother River Spring Domain has decreased to only 1680 m 3 /d, a reduction of 72% (Song et al. 2021 ). Protecting and utilizing groundwater resources in coal mining has become an urgent issue in the scientific development of coal resources in ecologically fragile areas of central and western China.

Location of Yu-Shen mining area

The project proposes the technique of delayed backfilling for low-carbon water-conserving mining in goaf areas. It determines the space for delayed backfilling in goaf areas, the layout of grouting holes for backfilling, and parameters for delayed grouting and backfilling. The main contents include the fragmentation characteristics of collapsed rock blocks in goaf areas, the initial distance for delayed backfilling, the ultimate distance for delayed backfilling, the stratigraphic position for delayed backfilling, the arrangement of surface grouting holes and underground grouting holes, hole spacing, hole structure, and grouting volume.

The typical comprehensive stratigraphic column of the Yu-Shen coal area and the lithological characteristics are shown in Fig.  3 . The surface is primarily covered by Quaternary strata, and bedrock outcrops are sporadically distributed in valleys. The mining area is defined within the coal field, and it comprises six mineable coal seams at various depths. The total estimated coal resources amount to 1.24 billion tons, with a remaining reserve of 1.19 billion tons. The designed production capacity of the mine is 8 million tons per year, and the expected mine service life is 67.9 years. As of October 2021, the mining operation has completed the extraction in the 301 panel area, including ten working faces (30,101–30,110), and the extraction is ongoing in the 302 panel area, specifically in the 30,201 working face. In the next three years, the mine plans to extract from the 30,201 and 30,202 working faces. The 301 panel area adopts a multi-slice longwall (MSL) method with a mining height of 5 m, while the 302 panel area plans to use a single pass longwall (SPL) method with a mining height of 7.2 m.

Comprehensive geological histogram of the Yu-Shen coal area

Based on the groundwater occurrence conditions and hydraulic characteristics, they are divided into two types: the Quaternary loose rock porous confined aquifer and the Jurassic Middle System Zhijialu Formation and Yan'an Formation sandstone fractured confined aquifer. From top to bottom, it can be divided into five aquifer layers (formations): the Quaternary Holocene alluvial layer porous confined aquifer, the Upper Pleistocene lacustrine layer porous confined aquifer, the Quaternary Middle Pleistocene loess layer porous fractured confined aquifer, the Jurassic clastic rock weathered crust fractured aquifer, and the clastic rock fractured confined aquifer. The aquitards mainly consist of Quaternary Middle Pleistocene relative aquitard and the mudstone and sandy mudstone aquitard between the Jurassic sandstone layers (Table  1 ).

Upon analyzing the distribution characteristics of aquifers in the mining area, two main types of aquifers were identified: the loose rock mass aquifer with pore and fissure water in the Quaternary system, and the fractured rock aquifer in the Jurassic clastic rocks. As for the distribution characteristics of aquitards in the mining area, two major aquitards were identified: the relative aquitard composed of middle-lower Quaternary loess in the Quaternary system and the interbedded aquitard in the Jurassic bedrock. Current research indicates that the focus of water hazard prevention and control lies in ensuring safe mining operations by minimizing the inflow of water from the roof during the mining process. Properly controlling the position of the interface between the water-conductive fractured zone and the aquifers based on the hydrogeological conditions of the mined coal seam and preventing damage to the aquitards caused by mining activities are essential approaches to achieve water-conserving mining practices.

Field detection of collapsed roof form

The detection area is the goaf of the No. 3 coal seam in the 301 panel area. The ZTR12 series geological radar (GR) utilizes shielded antennas to emit high-frequency electromagnetic waves ranging from 1 MHz to 2.5 GHz, while the receiving antennas collect the corresponding signals, which are then stored and displayed by a computer. The ZTR12 series GR has a central antenna frequency of 100 MHz, a length of less than 1 m for each individual antenna, a step size smaller than 2 × 10 –12  s, an output signal of 10 × 10 –9  s, and a voltage of 90 V. Additionally, when generating a 100 MHz transmission pulse, the amplitude ratio between the pulse and ripple increases significantly to over 30 dB, allowing the effective mapping depth of the GR to reach within a range of 30 m below the No. 3 coal seam, making it fully applicable in underground mining environments. The ZTR12 series GR was employed to detect the roof strata of the goaf in the No. 3 coal seam. The GR has a detection depth of 30 m and a detection distance of 70 m. The detection area is illustrated in Fig.  4 , and the GR system conducted tests at 1024 sampling points.

Location of GR detection

The GR detection data collected were processed through zero-point calibration, denoising, filtering, and gain adjustment to obtain the GR detection images. These images clearly reflect the collapse status of the roof strata after coal seam extraction in the detection area, as shown in Fig.  5 . From Fig.  5 , it can be observed that within a distance of 30 to 70 m from the detection starting point, there are four distinct alternating strong and weak reflection zones. Specifically, a weak reflection zone appears in the 60 to 70 m position, and its phase is generally consistent with the surrounding medium reflection image. Therefore, the black dashed-line area represents a mildly damaged region where the roof exhibits minor fragmentation and relatively high integrity. On the other hand, a strong reflection zone appears in the 50 to 60 m positions, and its phase differs from the surrounding medium reflection image. Hence, the white dashed-line area represents a severely damaged region where the roof exhibits significant fragmentation and poor integrity. This cyclic pattern of alternating reflection zones follows the advancing direction of the working face and is in basic agreement with the results obtained from on-site borehole observations. Based on the aforementioned detection results, the collapsed morphology of the roof in the goaf of the No. 3 coal seam was reconstructed, as shown in Fig.  6 .

Processed detection results of GR data

Inversion map of breaking structure form with GR of coal seam mining

From Fig.  6 , it can be observed that after the extraction of the No. 3 coal seam, the immediate roof (carbonaceous mudstone) and the overlying roof (siltstone) exhibit well-developed fractures, and the fracture development has extended into the mudstone layer. However, the upper portion of the siltstone layer is minimally affected by the extraction of the No. 3 coal seam, with a collapse zone height of 25 m.

Collapse rock mass expansion characteristics

Based on the theory of overlying stress in collapsed rock blocks within goaf areas, the stress variation and dilatancy coefficient of the collapsed rock blocks within the goaf are divided into different zones. By analyzing the stress variation patterns and dilatancy characteristics of the collapsed rock blocks within the goaf, the initial lag filling distance is determined.

Zoning of stress in collapsed rock blocks

After the collapse of the roof in the goaf area, the overlying load is transferred and redistributed, resulting in the formation of supporting pressure. Based on the principles of limit equilibrium and conservation of overlying load, the calculation methods for the range of coal wall support influence and stress recovery zone are studied. The deformation zoning of the lag filling zone is analyzed, and the corresponding stress paths during mining are determined based on the longitudinal and transverse stress variation patterns of the overlying strata. A stress-distance distribution model for the collapsed rock blocks in the lag-filling zone is established. Combining the theories of cantilever beams and elastic foundation beams, the stress variation patterns of collapsed rock blocks in the goaf area are analyzed. Based on the subsidence of the underlying rock layer in the 302 panel area, the stress zones of the collapsed rock blocks in the goaf area are classified as follows: low stress zone (LSZ), stress-increasing zone (SIZ), and stress-stable zone (SSZ), as shown in Fig.  7 .

Schematic diagram of stress distribution in goaf

The relationship between stress \(\sigma_{I}\) in low-stress zone of collapsed rock mass and the position l of coal wall in the working face satisfies:

In the equation: \(\sigma_{I}\) represents the stress in the low-stress zone of the collapsed rock mass in MPa; l represents the distance from the coal wall in meters; \(\Delta C\) represents the compensation parameter; a and b are coordination parameters determined through stress measurement experiments on the collapsed rock mass.

Distribution of fragmentation and swelling characteristics of collapsed rock blocks

Based on the relationship between rock swelling coefficient and axial pressure, the distribution characteristics of fragmentation and swelling of collapsed rock blocks are analyzed. Since the rock swelling coefficient is not a constant value but a function of stress variation, the rock swelling coefficient and the characteristics of swelling can only be obtained when the regression coefficients are determined. In the field of the 302 panel area, random samples of collapsed rock blocks were collected, crushed, and placed in rigid cylinders for compaction experiments. By using a Multi-functional Mechanical Test Loading System (MMTLS), as shown in Fig.  6 , the rock swelling coefficient under compression was calculated (Table  2 ), and the relationship curve between the swelling coefficient and stress was plotted (Fig.  8 ).

Collapse rock mass compaction experiment

At the initial filling stage, the fragmentation coefficient is relatively large, and at this time, the initial delayed filling position is located in the low-stress zone. According to Eq. ( 1 ), the relationship between the fragmentation coefficient ( k p ) of the collapsed rock block and the distance ( l ) from the working face to the coal wall is given by:

In the equation, \(\alpha\) and \(\beta\) represent the regression coefficients related to the overlying rock stress in the goaf area, while c and d are the coordinating parameters for overlying rock stress determination. ΔE represents the compensatory parameter. It should be noted that the distance between the coal mining face and the backfill body needs to be greater than the initial collapse step distance of the roof. The calculation formula for the roof's ultimate collapse step distance is as follows:

Here, L represents the collapse step distance of the roof. Q denotes the load borne by the strata beam of the overlying roof. R T is the ultimate tensile strength of the strata at that location. H represents the thickness of the overlying roof strata. k is the coefficient that accounts for the influence of the support stress generated by the mining face advancement and the production technical conditions.

Analyzing the stress distribution of the collapsed rock mass in the goaf, the stress in the collapsed rock mass is mainly derived from the overlying strata pressure. The overlying strata above the adjacent coal seam form a cantilever beam structure, which restricts the stress exerted by the overlying strata on the collapsed rock mass. According to the principle of limited stress distribution in the overlying strata near the coal seam (Wang et al. 2021a ; b ), the relationship between the stress in the collapsed rock mass ( σ ) and the position of the mining face relative to the coal seam ( l ) can be expressed as follows:

In the equation, σ represents the stress in the collapsed rock mass, MPa. l represents the distance from the coal seam, m. ΔC represents the compensation parameter. a and b are coordination parameters determined through experimental measurements of the stress in the collapsed rock mass.

After coal extraction, VSP530 vibrating wire rock stress meters were installed on the mining floor, along with the GT204A vibrating wire readout instrument, to measure the overburden stress of the collapsed rock blocks (Fig.  9 ). Based on the measured stress data of the collapsed rock mass in the goaf, an approximate exponential relationship curve was fitted, which showed good agreement with the established mathematical model (Fig.  10 ). It was observed that the closer the distance to the coal wall, the smaller the stress exerted by the overlying strata on the collapsed rock mass, with the corresponding parameters of ΔC  = − 0.02, a  = 7, and b  = 0.03.

Testing of overlying strata stress on the collapsed rock mass

Stress-position relationship of the collapsed rock mass

Determination of the delayed backfilling zone in the goaf area

Considering the natural caving state of the roof after coal mining operations in the 302-panel area, the technique of delayed backfilling with low-carbon water-retaining mining was proposed. A precise slurry system was established on the ground to produce a slurry of coal gangue, water, and additives with a certain mass fraction. Then, the gangue slurry was transported through a pipeline system and high-pressure injection to fill the space behind the working face, thereby achieving the disposal of coal gangue in an environmentally friendly manner without affecting normal production (Fig.  11 ).

Schematic diagram of delayed backfilling in the goaf area

To support the overlying strata and control the development of water-conducting fractures, delayed backfilling plays a crucial role in preventing the connection with aquifers. Therefore, before determining the backfilling area, it is necessary to identify the layers for groundwater protection. Based on the distances between the 3# coal roof and major aquifers within the scope of the 302-panel area, as shown in Table  1 , it is observed that the Zhenwu Cave Sandstone is located at a distance of 0.99 to 18.38 m from the coal seam, which is too close to be protected through goaf backfilling. On the other hand, the Qili Town Sandstone is situated at a distance of 40.97 to 99.05 m from the coal seam, which is sufficiently far to be protected through delayed backfilling. Consequently, the groundwater protection layers are identified as the Qili Town Sandstone aquifer and the overlying Fourth Series Sandstone aquifer.

The distance for delayed backfilling in the goaf

Based on the geological data of the 302-panel area, the initial collapse step distance of the roof is estimated to be 41.6 m. Through the rock fragmentation compaction experiments, the initial filling coefficient of the collapsed rock blocks in the 302-panel area is determined to be 1.5. By applying Eq.  3 , the distance from the mining face to the coal wall is calculated to be 46 m, which exceeds the roof collapse step distance. Combining surface observations in the Yushen mining area and surface subsidence monitoring of the 30,201 working faces in the Hanglaiwan coal mine, it is observed that the initiation phase of the surface movement for the 30,201 working face lasts for 6 days, with a starting distance of 59 m. With an average daily mining progress of 10.38 m, the underground mining distance during the initiation phase is determined to be 62 m. Therefore, the final determined distance for the initially delayed backfilling is 62 m.

The further the distance from the working face, the more compact the collapsed rock blocks in the goaf become, leading to a decrease in the void ratio between the rock blocks. When the residual fragmentation coefficient is less than 1.03, it is not feasible to carry out delayed backfilling work. Based on the fitted relationship between the fragmentation coefficient and the overlying rock stress, according to Eq.  3 , the distance to the mining face is calculated to be 706 m in this case. Combining surface observations in the Yushen mining area and surface subsidence monitoring of the 30,201 working faces in the Hanglaiwan coal mine, it is observed that the surface movement duration is 220 days, with an average active phase of 71 days. With an average daily mining progress of 10.38 m, the underground mining distance at this stage is determined to be 737 m. Therefore, the final determined distance for the maximum delayed backfilling is 737 m.

The stratigraphic position for delayed backfilling in the goaf

The stratigraphic position for delayed backfilling in the goaf is determined by the sum of the collapsed rock layer thickness and the coal seam extraction thickness. By analyzing the hydrogeological data of the 302-panel area and considering the occurrence conditions and physical–mechanical properties of the overlying rock layers in the mining area, along with empirical calculations based on mining height, collapsed zones, and fracture zones, the relative position relationship between the overlying aquifer and the collapsed zones/fracture zones is determined to ensure that the collapse and fracture zones do not extend into the aquifer. In the 302-panel area, the coal seam extraction thickness is 7.2 m, and empirical formulas yield a collapsed zone height of 30 m and a fracture zone height of 154.8 m.

The thickness of the collapsed rock layer and the position for delayed backfilling are determined based on the accumulated height of the collapsed zone on the immediate roof and the gap height between the immediate roof and the old roof. If the collapse thickness of the immediate roof layer is \(\Sigma h\) , then the accumulated height after the collapse is \(k_{p} \Sigma h\) , and the gap left between the immediate roof and the old roof is denoted as \(\Delta\) :

In the equation, M represents the thickness of the extracted coal seam, and \(\Sigma h\) represents the thickness of the collapsed rock layer.

When \(M = \Sigma h(k_{p} - 1)\) , \(\Delta = 0\) , the collapsed rock layer fills the goaf completely. At this point, the bending and sinking of the immediate roof are usually negligible and can be disregarded. Therefore, the thickness of the collapsed rock layer \(\Sigma h{ = }h^{\prime}\frac{M}{{k_{p} - 1}}\) , where h’ represents the safety factor for caving, \(h^{\prime}{ = }5\sim 5.5\) .

The position of the backfill layer in the goaf is determined by the sum of the thickness of the collapsed rock layer and the thickness of the coal seam being mined. Different backfill regions correspond to different coefficients of rock fragmentation for the collapsed rock in the goaf, resulting in different positions for the backfill layer. In the initial stage of backfilling, when the coefficient of rock fragmentation for the collapsed rock in the goaf is 1.5 and a safety factor of 5.5 is chosen, the calculation yields a rock collapse thickness of 97.2 m. With a coal seam thickness of 7.2 m in the 302-panel area, the position of the backfill layer in the goaf is determined to be 86.4 m. In the ultimate stage of backfilling, when the coefficient of rock fragmentation for the collapsed rock in the goaf is 1.35 and a safety factor of 5 is chosen, the calculation yields a rock collapse thickness of 102.9 m. With a coal seam thickness of 7.2 m in the 302-panel area, the position of the backfill layer in the goaf is determined to be 110 m. Therefore, the position of the backfill layer in the goaf ranges from 86.4 m to 110 m.

Preparation of CO 2 mineralized fly ash backfill material

During coal mining operations, a significant amount of solid waste and CO 2 is generated. In the context of the peak carbon and carbon neutrality goals, the comprehensive utilization of solid waste and CO 2 is an important approach for achieving green and low-carbon development in the coal industry. Traditional CO 2 mineralization of fly ash typically requires high-temperature, high-pressure, and high-calcium conditions to enhance the reaction rate, mineralization conversion rate, and strength of the backfill material. However, in engineering practice, it is difficult to meet the requirements of high-temperature and high-pressure mineralization conditions, and there are safety risks involved.

To address this challenge, the development of CO 2 -mineralized fly ash backfill material under conventional low-calcium conditions at ambient temperature and pressure is pursued. The main raw material for the backfill material is the fly ash from a power plant in Zhengzhou, Henan Province, China, with Ordinary Portland Cement (OPC) procured from Zhucheng Yangchun Co., Ltd. as an additive and CO 2 as the mineralization gas supplemented with alkaline activator SA. The experimental process is outlined in Fig.  12 . The chemical properties of fly ash, the characteristics of OPC and details about the mixing procedure of the negative carbon filling material (NCFM) are the same as previous studies (Ngo et al. 2023 ). Mortar samples were prepared in accordance with the Chinese standard GB/T17671-2021. The Unconfined Compressive Strength (UCS) tests for NCFM samples were conducted following the identical procedures, utilizing the same equipment, and maintaining consistent parameter settings as described in previous studies (Ngo et al. 2023 ). The CO 2 -mineralized fly ash backfill material is filled into the goaf, achieving both water retention during coal mining and sequestration of CO 2 and fly ash.

Preparation of NCFM backfill material

The CO 2 mineralization reaction is conducted during the preparation of the backfill material, resulting in the development of mineralized backfill. The alkaline activator SA is added to tap water to prepare an activating agent solution, which is then added to the solid mixture at a water-to-ash ratio of 1:2. CO 2 is introduced into the mixture during the stirring process to initiate a mineralization reaction. The backfill slurry is prepared into cylindrical specimens measuring 50 mm × 100 mm and cured at constant temperature and humidity (humidity: 95 ± 1%, temperature: 20 ± 1 °C) for 3, 7, 14, 28, and 56 days. The composition ratios of the CO 2 mineralized fly ash backfill material are shown in Table  3 . The rheological parameters and fitting results of the slurry are presented in Table  4 . The influence of curing time and fly ash content on the unconfined compressive strength (UCS) of the negative carbon filling material (NCFM) specimens are illustrated in Fig.  13 .

UCS of NCFM backfill material

The yield stresses of FA50-FA80 are 36.01 Pa, 26.75 Pa, 16.76 Pa, and 15.99 Pa, respectively. The yield stress of the NCFM slurry decreases with an increase in the mass of fly ash. During the carbonation process, CO 2 reacts with the hydration products of cement to form C–S–H gel, consuming free water in the slurry and reducing its fluidity. Therefore, slurry with a lower fly ash content requires higher yield stress for pumping. However, when the fly ash content is increased to 90%, the yield stress increases to 17.09 Pa. This is due to the excessive fly ash content, which increases the specific surface area of particles in the slurry and adsorbs a large amount of free water.

To ensure the transportation of filling materials through pipelines, the yield stress of the slurry needs to be within 200 Pa, and thus the yield stress of NCFM meets the industrial application requirements. Regarding hydration and carbonation reactions, the adoption of ambient temperature and pressure CO 2 mineralization method produces silica-based gel and CaCO 3 , providing strength to high fly ash filling materials and overcoming the disadvantage of low strength in conventional low-calcium fly ash in filling applications. The flowability and UCS of NCFM filling materials meet the requirements for underground filling. The UCS at 3 days and 28 days are 2.70 MPa and 5.12 MPa, respectively. The silica-based gel generated from the reaction of CO 2 with alkali activators compensates for the low binding property of high fly ash filling materials, exhibiting early strength characteristics and subsequently promoting the reaction of volcanic ash, thereby increasing the long-term strength of NCFM. Based on market prices, the direct cost of NCFM filling materials is approximately 131 RMB per ton. Compared to conventional fly ash filling materials and traditional filling materials, NCFM filling materials can save direct costs of 28 RMB per ton and 59 RMB per ton, respectively. For detailed cost analysis, refer to Table  5 .

The arrangement of drilling and grouting parameters

The arrangement of drilling involves a combination of surface drilling and underground directional drilling. Due to being unaffected by factors such as the coal seam dip angle, priority is given to surface drilling and grouting filling (Fig.  14 ). If surface conditions do not permit drilling, directional drilling is conducted in the vicinity of the mining area (Figs.  15 and 16 ).

Schematic diagram of surface grouting drilling hole arrangement

Arrangement of directional drilling for grouting (Option 1)

Arrangement of directional drilling for grouting (Option 2)

Drilling spacing

Referring to experimental measurements and empirical data, the diffusion radius of the backfill slurry is determined to be 100–150 m (Shi et al. 2021 ). Applying a safety factor of 1.5, the grouting hole spacing is set at 66–100 m. For the 302 panel area with a working face length of 300 m, the surface grouting drilling arrangement is shown in Fig.  14 . Three holes are arranged along the inclined direction of the working face with a spacing of 75 m. The underground directional drilling arrangement is shown in Figs.  13 and 14 . Based on the determined distance and stratigraphic position of delayed filling, directional drilling is conducted from the filling drifts on both sides towards the fractured zone above the goaf. Two directional drilling holes are arranged on each side of the filling drifts, and four directional drilling holes are arranged along the inclined direction of the working face. Two options are considered: Option 1, where the two directional drilling holes are located in the same vertical cross-section with a spacing of 75 m (Fig.  15 ); Option 2, where the two directional drilling holes are located at the same horizontal stratigraphic position but staggered, with a spacing of 37.5 m (Fig.  16 ).

Drilling parameters

Both the vertical and inclined sections of the borehole require permanent cement grouting to ensure water sealing and meet the requirements for drilling and grouting construction, thereby ensuring construction safety.

The borehole structure is determined based on factors such as the comprehensive treatment approach, geological conditions, and equipment capabilities. The surface borehole has a diameter of Ф311 mm, and a surface casing of Ф244.5 mm × 8.94 mm is inserted down to the bedrock and cemented for wellbore integrity.

The underground directional drilling borehole has a diameter of Ф135 mm, and the horizontal section is left unlined.

Maximum grouting volume

There is a certain relationship between the grouting volume of the collapsed zone with fragmented gangue and the rock mass dilation characteristics. The dilation coefficient ( k p ) of the rock mass in the study area is generally between 1.12 and 1.5, and the grout cannot completely fill the voids in the collapsed zone. Depending on the block size of the fragmented rock mass, the filling capacity under grout pressure can only reach 60–90% of the dilation volume, i.e., the filling degree (the ratio of grouting volume to rock mass volume) γ is between 0.6 and 0.9. The maximum grouting volume ( V g _) of the entire collapsed zone with backfill slurry is given by:

where V g is the grouting volume of the slurry, V m is the volume of coal extraction, V r is the original volume of the roof that collapses during coal extraction, k p is the rock mass dilation coefficient. By definition, when γ  =  V g /( k p V r ), we can obtain:

The maximum grouting volume of the entire backfilling space is influenced by the mining volume, the original volume of the collapsed roof, and the rock mass dilation coefficient. Since the mining volume and the original volume of the collapsed roof are constant, the maximum grouting volume can be obtained by integrating the dilation coefficient equation along the length in the mining direction and substituting it into Eq. ( 7 ).

Following the principle of initial dilution, subsequent concentration, and final dilution, grouting filling is carried out. The maximum grouting pressure is determined to be 6 MPa based on the water inflow from the goaf to the working face, the horizontal thrust of the collapsed rock blocks on the support, and the maximum compressive strength of the grouting pipe during grouting. The filling degree ranges from 68 to 80%, and the filling degree after water leakage is ensured to be above 50%.

Mining volume of the grouting section at the working face is as follows:

where L is the length of the grouting section at the working face, m. D is the width of the working face, taken as 300 m. M is the mining thickness, taken as 7.2 m. η is the recovery rate, taken as 100% (without considering the gangue content).

Volume of post-mining collapse at the working face is as follows:

where q o is the settlement coefficient of full extraction at the working face.

Volume of injected backfill material required for subsidence reduction ( n /%) is as follows:

where A is the backfill coefficient.

Grouting volume is as follows:

where x is the water-to-cement ratio, taken as 0.5. For the 302 panel, the calculated unit grouting volume is 1400 kg/m 3 .

Conclusions

Underground backfilling was essential for environmentally friendly waste disposal in mines. However, addressing temporal and spatial interference between mine waste backfilling and coal mining was crucial to overcome technical challenges. This paper proposed a post-mining gangue grouting filling method for goaf collapse blocks, utilizing post-mining space efficiently. Collapse roof morphology in the post-mining space was determined using radar detection. The intrinsic relationship between roof stress in collapse blocks and the swelling coefficient was established through stress monitoring and compaction experiments, revealing structural characteristics and spatiotemporal evolution of post-mining space voids. NCFM was developed under normal temperature, pressure, and conventional low-calcium fly ash conditions. Key parameters for grouting filling were meticulously designed.

The study identified two main aquifer types: Quaternary loose rock porous and fractured confined aquifers, and Jurassic clastic rock fractured confined aquifers. Two main aquitards were also recognized: the Quaternary middle and lower Pleistocene loess relative aquitard and the Jurassic interbedded aquitard rock group.

The stress variation law of collapse blocks in the goaf, the distribution characteristics of block swelling, and the observation of surface (roof) subsidence in the mining area are analyzed, determining the initial lag filling distance of 62 m and the ultimate lag filling distance of 737 m. The thickness of the collapsed rock layer that fills the goaf is determined based on the accumulated height of the directly collapsed roof and the void between the directly collapsed roof and the old roof, and the final lag filling stratum is determined to be 86.4 m to 110 m.

Under standard temperature and pressure conditions, and employing conventional low-calcium fly ash, NCFM was synthesized. Demonstrating suitable flowability, setting time, and UCS, NCFM met the stringent requirements for underground filling, exhibiting UCS values of 2.70 MPa at 3 days and 5.12 MPa at 28 days. The silica gel produced from the reaction between CO 2 and alkali activators compensated for the low binding capacity inherent in high fly ash filling materials. This phenomenon facilitated the formation of a dense structure in the early stages and enhanced the long-term strength of NCFM through volcanic ash reactions. The financial benefits of employing NCFM, in comparison to conventional fly ash and traditional filling materials, amounted to 28 yuan/ton and 59 yuan/ton, respectively.

The innovative slurry injection method for backfilling coal mine gob post-mining improved the technical system for comprehensive gob disposal. This approach, reducing emissions at the source and promoting on-site disposal, holds significant promise for efficient solid waste disposal and ecological protection in coal mining.

Data availability

Data available on request from the authors.

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The authors would like to make an appreciation to the Fundamental Research Funds for the Central Universities (2022QN1004) for financial support.

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Kunpeng Yu, Liqiang Ma, Ichhuy Ngo, Jiangtao Zhai, Zhiyang Zhao & Hui Wang

Key Laboratory of Xinjiang Coal Resources Green Mining (Xinjiang Institute of Engineering), Ministry of Education, Urumqi, 830023, China

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State Key Laboratory of Mining Response and Disaster Prevention and Control in Deep Coal Mines, Anhui University of Science and Technology, Huainan, 232001, Anhui, China

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K. Y. and L. M. wrote the main manuscript text and Z. Z and H. W. prepared Figs. 1 , 2 , 3 , 4 . All authors reviewed the manuscript.

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Yu, K., Ma, L., Ngo, I. et al. Gangue grouting filling in subsequent space of coal green mining: methodology and case study. Environ Earth Sci 83 , 217 (2024). https://doi.org/10.1007/s12665-024-11514-4

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