Our story
Welcome to One Bright Green, and thank you for taking the time to learn more about who we are and what inspires our work.
I am Sofia Kesidou, Founder and Director of One Bright Green Ltd, an independent sustainability consultancy with over 23 years’ experience delivering sustainability advice and building sustainability assessments across the built environment.
My passion for sustainable building design began in the late 1990s while studying Architectural Studies at the University of Nottingham. I was fortunate to be taught by Robert and Brenda Vale, the pioneering authors of The Autonomous House, whose vision of sustainable living left a lasting impression on me. That experience sparked a lifelong commitment to sustainability, which I continued through a Master of Research (Distinction) at the University of Leeds, where my research focused on energy efficiency refurbishment solutions.
In March 2001, I moved to London to begin my career with ECD Energy & Environment, a respected sustainability consultancy that had co-developed the original BREEAM methodology with BRE. At the time, only a handful of organisations were licensed to deliver BREEAM assessments, and I was fortunate to be trained by some of the industry’s pioneers while working on live projects from my very first day. I had found my professional home.
Over the following two decades, my career evolved through organisations including Oscar Faber, FaberMaunsell, AECOM, URS and Ramboll. Along the way, I worked on hundreds of successful projects alongside developers, contractors, architects and multidisciplinary design teams, helping clients navigate increasingly ambitious sustainability goals while balancing commercial, technical and programme demands.
Looking back, it is remarkable how much our industry has evolved. We have moved beyond simply reducing environmental impact towards creating buildings that actively contribute to healthier communities and a more resilient future. We have witnessed the Paris Agreement, growing recognition of the climate emergency, greater emphasis on health, wellbeing and inclusion, and the continuing evolution of ESG, sustainable finance and environmental regulation.
Yet one statistic remains a powerful reminder of why our work matters. When I began my career in 2001, atmospheric carbon dioxide levels were approximately 371 parts per million. Today, they exceed 430 parts per million. While our profession has made significant progress, there is still much more to do.
A FAVOURITE QUOTE ALWAYS REMINDING ME THAT WE NEED TO DO THINGS DIFFERENTLY…
“…there is plenty to do, of a different sort of “doing.” The future can’t be predicted, but it can be envisioned and brought lovingly into being. Systems can’t be controlled, but they can be designed and redesigned. We can’t surge forward with certainty into a world of no surprises, but we can expect surprises and learn from them and even profit from them. We can’t impose our will on a system. We can listen to what the system tells us, and discover how its properties and our values can work together to bring forth something much better than could ever be produced by our will alone.”
Donellal Meadows, Thinking in Systems, A Primer.
One Bright Green was founded from a desire to focus on what matters most: helping projects realise their sustainability potential by bringing clarity to complexity. Today’s projects face competing priorities, increasing regulatory requirements and growing stakeholder expectations. Success depends on aligning people, ambitions and resources from the earliest stages.
We believe the best outcomes come from listening carefully, asking thoughtful questions and creating space for learning, collaboration and informed decision-making. Whether supporting strategic planning or project delivery, our aim is always the same: to help projects move forward with confidence, transparency and purpose.
The way we work
Practising what we advise.
As an independent sustainability consultancy, we believe credibility starts with our own actions — operating responsibly while helping our clients achieve ambitious outcomes.
Low-impact by design
Our digital infrastructure runs on 100% renewable energy. We keep a lean, low-impact practice - prioritising remote collaboration, minimising travel, and reducing waste and resource use.
Local & fair
Wherever possible we work with local suppliers and independent businesses, strengthening local economies. We value diversity of backgrounds and perspectives - inclusive teams make better decisions and better places.
Kindness first
We believe professionalism and compassion belong together. By approaching every project with empathy, honesty and respect, we build lasting relationships built on open communication and a willingness to learn.