RWE Builds Mega Battery in Wales: RWE to Construct its Largest Battery Storage Facility in the UK

Essen/Pembroke (UK) - The Essen-based energy company RWE is pushing ahead with the expansion of its storage infrastructure in the United Kingdom and has made the final investment decision for the Pembroke Battery in South Wales.

With an investment volume of around 200 million pounds, the project is, according to RWE, the company’s largest battery storage facility in the UK to date. Construction is scheduled to begin in the first half of 2026, with commissioning planned for the second half of 2028.

The plan is to install a lithium-ion storage system with up to 212 containers on a 5.1-hectare site south of the Pembroke power station. The project is designed as a two-hour storage system, meaning the facility will have a power output of 350 MW and an energy capacity of 700 MWh. RWE already holds a valid building permit for the project.

RWE views the project as a strategic component for enhancing security of supply. “ In a dynamic energy world with more and more renewable energy, there is an increasing need for mature technologies that can instantly support the electricity grid. Battery storage systems are ideal for this because they are fast, efficient and competitive,” said Nikolaus Valerius, CEO of RWE Generation. The Pembroke Battery is a “flagship storage project” and will make an important contribution to stabilizing the UK energy market.

The Welsh Government also highlights the project’s energy and regional policy importance. “This significant investment by RWE demonstrates Wales' central role in the UK’s transition to clean and renewable electricity,” said First Minister Eluned Morgan. The battery storage system will support ambitions for a cleaner and more secure energy future while creating good jobs and opportunities for local communities across South Wales.

Against the backdrop of the UK’s goal of a cleaner energy system, flexible storage solutions are becoming increasingly important to balance peak loads and offset fluctuations from wind and solar power. RWE currently operates around 1.2 gigawatts of battery storage capacity worldwide, with a further 2.7 gigawatts under construction. As an integral part of its growth strategy, RWE plans a significant expansion of its global battery storage capacities.

Source: IWR Online, 02 Dec 2025