Reflections on a Summer Internship at Chronos Sustainability

Claire Sullivan, First-Year Maths and Economics Student at Durham University

I thoroughly enjoyed my ten weeks at Chronos Sustainability. From the outset, the team took time to understand my background and interests, shaping my projects so that I could meaningfully contribute while developing new skills. It was clear early on that this would not be a generic internship: my work was thoughtfully matched to my strengths, and I always felt my input was valued. The supportive and welcoming atmosphere made it easy to feel part of the team from day one.

Corporate benchmarking

My first project involved conducting preliminary assessments of 17 global companies on their workplace mental health disclosures. This involved structured desk research, comparing company policies and practices against the benchmark framework and criteria. I also contributed to the technical side of the project, carrying out data analysis in Excel to explore year-on-year changes, and sectoral trends. I was responsible for ensuring the accuracy of the dataset: checking formulas, uploading and cleaning raw data, and validating outputs used in reporting. While the analysis was a smaller part of the project, it was one I particularly enjoyed, as it stretched my Excel skills and showed me how versatile it can be for organising and interrogating data. Through this work, I gained a clear sense of the types of skills that are increasingly important in sustainability consulting, including quantitative analysis, data management, and technical proficiency.

Careers in sustainability consulting guide

A central focus of my internship was the development of a Careers in Sustainability Consulting guide. I interviewed 21 consultants at different career stages – from recent graduates to professionals with 30+ years’ experience – working across a variety of firms and roles. The interviews explored skills and qualifications, major industry trends, and practical advice, as well as more personal reflections on career highlights, challenges and motivations.

Drawing on these insights, I drafted a report, including an overview of the market, key skills and experiences for success, emerging trends, and practical advice for students and early-career professionals. This project allowed me to build on my strengths in research and writing, while taking ownership of a deliverable from start to finish. Conducting the interviews was particularly rewarding, offering candid insights into the realities of careers in consulting. A common theme was the passion people felt for their work – the intellectual challenges of working in sustainability and the opportunity to make a tangible impact.

Large-scale data cleaning

Another major project was a large-scale data cleaning exercise for an established benchmark on farm animal welfare, which has been running for 14 years. Chronos is analysing these data to assess how companies’ management of farm animal welfare has evolved, and how investor engagement can accelerate progress. My role was to build a clean dataset to support this analysis. This was not a trivial task given changes in the company universe and the benchmark methodologies over that time.  Amongst other tasks, involved validating company names, confirming countries of origin and ownership structures, correcting errors, reconstructing missing data, and recalculating scores where necessary. While I occasionally used coding in RStudio to replicate earlier calculations, the main challenge was systematically checking and rebuilding the dataset to ensure reliability for future use. This experience strengthened my attention to detail and gave me first-hand experience of handling complex datasets used in high-profile benchmarks and reinforced the importance of robust data in informing decision-making.

AI guidance and applications

I also developed an internal guidance document on AI addressing two key issues: practical prompting strategies to improve outputs, and responsible-use guidelines tailored to Chronos’ consulting workflows, including quality assurance measures on AI-generated outputs. These resources are now being used to guide the team’s adoption of AI in relevant areas of their work. In parallel, I supported testing of AI-enabled benchmarking tools, trialing prompt templates, comparing outputs against expert assessments, and recommending refinements.

Other contributions

Beyond my core projects, I also contributed to research on air pollution, reviewing academic and policy sources to build PESTLE risk tables for systemic and enterprise-level risks associated with air quality regulation (e.g. Euro 7 standards, disclosure requirements) and regional market trends such as the decline of diesel in Europe.

Reflections

Looking back, the internship struck a balance between building on my existing skills with giving me opportunities to learn new ones. I developed stronger capabilities in data analysis, coding, and research, alongside greater commercial awareness and understanding of consulting. I also gained insight into the role of technology and AI in sustainability. Above all, I valued working with such a supportive and knowledgeable team, and I’m grateful to have contributed to their work.

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Read reflections from other Chronos interns here