Electricity generator RWE is powering ahead with its largest UK storage project -Pembroke Battery Storage in Wales - taking a final investment decision.

The circa £200m development, once constructed, plays an important role in the operation of the Pembroke Net Zero Centre decarbonisation hub in South Wales.

The project construction was announced by the first minister for Wales, Eluned Morgan, at the Wales Investment Summit, underlining the Welsh Government’s commitment to attracting major infrastructure investment that will support the nation’s clean energy transition.

The RWE Pembroke Battery project received planning consent in January 2025 and was also successful in the UK’s latest Capacity Market auction, securing a critical route to market. Construction will start in the first half of 2026, with commissioning and operations expected in the second half 2028, subject to receiving an updated and timely grid connection.

The storage system would be located on a 5.1-hectare area to the south of RWE’s Pembroke Power Station and comprises of 212 lithium-ion battery containers.

Once constructed and fully operational, the battery could continually discharge up to 350 megawatts (MW) of electricity directly into the grid for two hours. That’s equal to 700 megawatt-hours (MWh) of stored energy, or equal to keeping the lights on for two hours for almost 300,000 typical UK homes.

Nikolaus Valerius, CEO RWE Generation SE, said: “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. Our Pembroke Battery is our UK flagship storage project and will make an important contribution to stabilising the UK energy market by efficiently storing surplus energy and feeding it into the national grid in a targeted manner when required.”

First minister for Wales, Eluned Morgan, added: “This significant investment by RWE demonstrates Wales’ central role in the UK’s transition to clean and renewable electricity. The Pembroke Battery Storage facility will support our ambitions for a cleaner, more secure energy future while at the same time creating opportunities for good jobs and local communities across South Wales.”