RWE confirms £200mn battery storage project at Pembroke site

RWE has confirmed the final investment decision for a battery storage project worth nearly £200mn ($253mn) at its Pembroke site in South Wales. The development marks the group’s largest energy storage facility in the United Kingdom, with a peak capacity of 350 megawatts (MW) for two hours, or 700 megawatt-hours (MWh) of storage.

Construction of the system, comprising 212 lithium-ion battery containers, is scheduled to begin in the first half of 2026. Commissioning is expected in the second half of 2028, subject to securing an updated grid connection. The 5.1-hectare site is located south of the RWE-owned Pembroke Power Station, the largest electricity producer in both the UK and Wales.

Integration into the UK Capacity Market

The project received planning consent in January and secured a route to market through the latest UK Capacity Market auction. The battery system will support grid stability by storing surplus electricity and discharging it during peak demand periods.

According to technical specifications, the 350 MW continuous discharge capacity would be enough to power nearly 300,000 typical UK homes for two hours. RWE views this infrastructure as a critical component for enhancing national energy system flexibility.

Local anchoring around the Pembroke Net Zero Centre

The storage facility is a core element of the Pembroke Net Zero Centre, an industrial decarbonisation platform under development by RWE. The initiative forms part of a broader energy strategy, with RWE currently operating more than 3 GW of installed capacity in Wales, around 1 GW of which is renewable.

RWE employs approximately 300 people in the region via offices in Baglan, Dolgarrog, and at its power plants. The company has also invested over £21mn ($26.6mn) in neighbouring Welsh communities through its wind farm community benefit funds.

Outlook and impact on Welsh energy system

The First Minister of Wales announced the project during the Wales Investment Summit, positioning the initiative as an example of attracting large-scale energy infrastructure investment. The facility is expected to strengthen electricity supply security amid rising variability from renewable sources.

In parallel, RWE plans to implement biodiversity measures around the site, including meadow creation, native woodland planting, and a new wildlife pond. These efforts are included in the development plan without affecting the industrial function of the project.