Palmer Energy Technology acquires Brill Power and announces new investment to accelerate UK leadership in battery energy storage
28 August 2025
Palmer Energy Technology Limited (PETL), a UK maker of Battery Energy Storage Systems founded by former Aston Martin CEO and Nissan COO, Dr Andy Palmer CMG and Wei Shao, today announced the acquisition of Brill Power.
Brill Power is an Oxford University spin‑out known for cell‑level control and active balancing technology in battery management systems. PETL will embed Brill Power electronics across its systems with immediate effect.
The deal brings together PETL’s automotive‑grade battery storage systems and Brill Power’s sophisticated control platform that improves battery safety and extends service life by drawing the optimum current from each cell based on its state of health.
Brill Power’s control software is engineered and validated in the UK. With all operational data stored on UK-based servers to support security and compliance.
FirstGroup plc, a leading UK public transport operator, and also a customer of PETL, joins Barclays Climate Ventures and the University of Oxford as a strategic investor in PETL. Barclays Climate Ventures were an investor in Brill Power and join this new series of investment. FirstGroup Energy Limited, the dedicated energy investment arm of FirstGroup plc, has acted as the co-lead investor in the Series A round of ~£5m. Faizan Muhammad, Investment Director at FirstGroup plc, will be representing FirstGroup Energy Limited on the PETL board.
The Brill Power brand will continue for module sales to third parties. Long-term, PETL plans to expand UK assembly and manufacturing to improve quality control and to shorten supply lines.
Andy Palmer, CEO and co‑founder of PETL, said:
“PETL’s acquisition of Brill Power enables us to embed the Brill software in all of our systems, instantly giving PETL a leading position in the space to serve customers such as FirstGroup.
“With buses at the forefront of the transition to electric vehicles and net zero transportation, I’m delighted to welcome investment from FirstGroup, as well as Barclays and Oxford University, to advance development of next generation control systems. This will allow us to accelerate our business and give the UK a leading position in BESS technology.”
Faizan Muhammad, Investment Director at FirstGroup plc,
“This investment continues our strategy of backing new and innovative companies aimed at supporting our long-term public commitment of achieving a zero emission fleet by 2035. PETL, along with its acquisition of Brill Power, will unlock innovative energy procurement solutions whilst providing second life use cases when batteries are taken off electric buses.”
Adam Workman, Head of Investments and New Ventures at Oxford University Innovation said:
“It is great to see the coming together of PETL and Brill Power to accelerate their novel energy storage technologies. Alongside FirstGroup, we hope that the combined business will accelerate the commercialisation of its energy platforms.”
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About Palmer Energy Technology
Palmer Energy Technology Limited, PETL, was founded by Dr Andy Palmer CMG and entrepreneur Wei Shao. The company designs and manufactures Battery Energy Storage Systems that apply automotive‑grade principles to stationary applications. PETL specifies premium cells, uses liquid cooling as standard and focuses on intelligent control to drive down operating costs for customers in transport, industry and the grid.
About Brill Power
Brill Power is an Oxford University spin‑out founded in 2016. The company develops battery management systems that actively balance cells to increase safety and extend life. Brill Power has been supported by Barclays, Oxford University and L&G, with its technology is now being integrated across PETL systems.
About FirstGroup
FirstGroup plc (LSE: FGP.L) is a leading private sector provider of public transport services. With around 29,000 employees, we reported revenue of £5.1 billion and transported almost 2m passengers a day in FY 2025. We create solutions that reduce complexity, making travel smoother and life easier. Our businesses are at the heart of our communities and the essential services we provide are critical to delivering wider economic, social and environmental goals. Each of our divisions is a leader in its field: First Bus is one of the largest bus operators in the UK, serving more than 25% of the population in the UK with a fleet of c.5,800 buses, and carrying more than a million passengers a day. First Rail is one of the UK’s most experienced rail operators, with many years of experience running long-distance, commuter, regional and sleeper rail services. We operate a fleet of c.1,800 locomotives and rail carriages through two DfT contracted train operating companies: WCP (incorporating Avanti West Coast and West Coast Partnership Development) and GWR, and two open access routes (Hull Trains and Lumo). We are formally committed to operating a zero emission First Bus commercial fleet by 2035, and First Rail will help support the UK Government’s goal to remove all diesel-only trains from service by 2040. During FY 2025 FirstGroup received MSCI’s highest possible ESG rating of AAA, was named one of the world’s cleanest 200 public companies for the sixth consecutive year and holds an Industry Top-Rated status with Sustainalytics and Sustainability Yearbook membership with S&P Global. We provide easy and convenient mobility, improving quality of life by connecting people and communities. Visit our website at www.firstgroupplc.com and follow us @firstgroupplc on X.
About Oxford University Innovation Ltd
Oxford University Innovation (OUI) is the University of Oxford’s Innovation Office, recognised worldwide for its ability to engage academic prowess through licensing, catalyse innovative solutions through consulting services, and support the creation of outstanding companies. OUI is dedicated to showcasing these transformative technologies on the global stage, bridging the realms of academia and the commercial world, thereby weaving a future where knowledge, innovation and partnership drive forward solutions to global challenges.
