The Capenhurst Battery Energy Storage System is a 100 MW / 100 MWh grid-scale battery facility located near Capenhurst, Cheshire, England, developed and operated by Zenobē. Commissioned in early 2023, it is the first battery in the world to hold a commercial contract to **absorb reactive power directly from a transmission network** and was, at commissioning, the largest transmission-connected battery in Europe. The site contributes to grid stability and supports the integration of renewable generation in the Mersey region.

The project was delivered as part of National Grid ESO’s Pathfinder programme to address the growing need for reactive power services, which help manage voltage levels as renewable capacity increases. Capenhurst’s direct connection to the 275 kV transmission network enables it to provide stacked services, including reactive power absorption and active power capacity, delivering these at lower cost to consumers compared with traditional solutions. Over its first 15 years of operation, the facility is forecast to prevent over **1.3 million tonnes of CO₂ emissions** compared to conventional sources.

By reducing reliance on fossil-fuel-based reactive power sources and lowering the amount of curtailment for renewable energy, the Capenhurst BESS enhances energy security and network flexibility. Its deployment under revised planning regulations also made it the first large-scale battery in England to use the updated regime for 100 MW projects, setting a precedent for future grid-connected storage developments.