Ameresco entered into a $249M contract and Long-Term Service agreement with Atlantic Green for one of the UK’s largest Battery Energy Storage Projects

Ameresco, Inc., a leading cleantech integrator specializing in energy efficiency and renewable energy, today announced that Ameresco and Envision Energy have been chosen by Atlantic Green to build the Cellarhead project, a 300-megawatt (MW) battery energy storage project (BESS) with a maximum energy capacity of 624 megawatt hours (MWh). The Cellarhead BESS project will be connected to National Grid’s Cellarhead sub-station and will provide the UK with additional energy security and reliability.

Construction is anticipated to commence on site this year with connection to the electricity grid anticipated at the end of 2026. With a maximum energy capacity of 624 megawatt hours, the Cellarhead BESS project will support the UK’s ambition to achieve net zero, supporting the increased penetration of clean energy generation, decrease reliance on fossil fueled generation, and ultimately mitigate greenhouse gas (GHG) emissions.

Atlantic Green was established in 2021, as a joint venture between two entrepreneurial shareholders Nofar Energy, and Interland Group, as a UK-based platform to invest, develop, and operate grid-scale standalone battery energy storage systems across the UK. With a mission to develop a c.2 GW capacity of battery energy storage to fuel the UK’s clean energy transition, the Cellarhead BESS represents a key milestone for both Atlantic Green’s development journey and wider sustainability objectives. As part of the BESS project Ameresco entered into an EPC and O&M contract including battery supply, balance of plant, warranty, and availability guarantees. The EPC full wrap price is c. $249 million (196.5 million GBP). Tier 1 OEM Envision Energy will provide the BESS and associated services, as well as the equipment warranties.

Ameresco and Atlantic Green expect to finish the BESS and secure grid connection by the middle of 2026. Following completion, Atlantic Green will own and operate the BESS as an energy storage asset.

“We believe that a continuous development of battery energy storage is a vital step in the UK’s journey to achieving net-zero carbon emissions, and we are excited to team up with Ameresco to bring this vision to life,” said Nick Bradford, Managing Director of Atlantic Green. “Since our founding, Atlantic Green has consistently prioritized finding strategic ways to leverage our battery storage assets with the wider community and we are eager to answer the rising demand for battery storage with this new project with such a level of energy capacity, to really make the impact on the UK electricity system that is much needed.”

“We’re excited to announce our collaboration with Atlantic Green to construct one of the largest battery energy storage projects in the United Kingdom,” said Mark Apsey, MBE, Senior Vice President of UK Operations at Ameresco. “Energy storage is one of the key technologies required to achieve the UK’s net zero targets. Atlantic Green’s strong company leadership and robust track record of developing similar projects makes them an excellent partner in this endeavor. Together, Ameresco and Atlantic Green will help support the UK’s progress towards increased power autonomy and achieving net-zero carbon emissions by 2050.”

“This project exemplifies our commitment to pushing the boundaries of battery storage technology, a cornerstone of sustainable energy systems,” said Kane Xu, Global VP, Envision Energy. “Partnering with Atlantic Green and Ameresco allows us to demonstrate the pivotal role that advanced battery solutions play in enhancing energy security and enabling a seamless transition to renewable energy sources. We are proud to contribute our cutting-edge technology to this landmark UK initiative.”