EXECUTIVE SUMMARY

Centrica Energy, the trading and optimization division of Centrica plc, has executed a physical tolling agreement with renewable energy developer Zelestra for the 99 MW / 297 MWh Hilgermissen battery energy storage system (BESS) in Lower Saxony, Germany. The deal expands Centrica Energy’s flexible asset portfolio while advancing Zelestra’s utility-scale storage pipeline in Europe.

Under the terms of the agreement, Zelestra will manage development, engineering, procurement, and ownership of the facility. Procurement activities are scheduled for completion in 2026, with construction beginning in 2027 and commercial operation expected by 2028.

Once online, Centrica Energy will operate and optimize the asset across Germany’s Day-Ahead, Intraday, and Ancillary Services markets via its multi-market trading platform. Under the tolling structure, Zelestra retains asset ownership while Centrica handles market dispatch and trading strategies to capture commercial value.

Located in Lower Saxony, the project targets a region characterized by heavy wind generation, biomass production, and substantial industrial electricity demand from manufacturing and agriculture. The 3-hour duration BESS will store excess renewable generation during peak production windows and discharge back to the grid during peak demand, reducing renewable curtailment and enhancing grid stability.

"This agreement marks a key milestone for our German operations and aligns with our strategy to scale our flexibility portfolio in one of Europe’s most active energy storage markets," said Cassim Mangerah, Managing Director of Centrica Energy.