Greenvolt Power has commenced construction of a 600 MW/2.4 GWh battery energy storage system (BESS) in Siedlce, Poland, with expectations to begin commercial operations by the end of 2027. BYD Energy Storage will provide the battery technology for the project, which will utilize 210 battery containers and 105 transformer containers equipped with power conversion systems to facilitate electricity transfer between the batteries and the grid.
P&Q will be responsible for connecting the BESS to the transmission network managed by Polskie Sieci Elektroenergetyczne (PSE) at a voltage of 400 kV. This connection will involve the construction of a new 400/110 kV substation along with 400 kV and 110 kV cable links.
The facility is designed to charge during periods of high renewable generation and discharge when electricity demand increases. Greenvolt anticipates that the project will enhance system flexibility, support the integration of wind and solar power, and assist in balancing supply and demand.
Greenvolt has been expanding its battery storage portfolio across Europe, including behind-the-meter systems for commercial and industrial customers through its Greenvolt Next subsidiary. The company currently operates a 200 MW/800 MWh battery storage project at Turośń Kościelna in Poland, which became operational in July 2026. Additionally, a second 200 MW/800 MWh project at Ełk is expected to begin commercial operations in the fourth quarter of 2026.
Upon completion of the Siedlce, Turośń Kościelna, and Ełk projects, Greenvolt will have a total of 1 GW of battery power capacity and 4 GWh of storage capacity in Poland, positioning the company to play a significant role in providing flexibility as Poland increases its variable renewable generation.