Greenvolt starts building 2.4 GWh Siedlce BESS in Poland

Greenvolt Power has started construction of the 600 MW / 2.4 GWh Siedlce battery energy storage project in Poland. Announced on 24 September 2026, the project will become Poland’s largest and one of Europe’s largest battery storage facilities, according to the company. Commercial operation is planned for the end of 2027.

210 battery containers from BYD

According to Greenvolt, BYD Energy Storage is supplying the batteries. The facility will comprise 210 battery containers and 105 transformer containers with power conversion systems. P&Q is responsible for engineering and construction and ONDE for the electrical infrastructure.

1 GW / 4 GWh in Poland

Greenvolt’s 200 MW / 800 MWh Turośń Kościelna facility has been operating since July 2026, while the Ełk project of the same size is expected online in the fourth quarter of 2026. Together with Siedlce, the three projects will total 1 GW / 4 GWh. The company’s probability-weighted BESS pipeline stands at around 4.6 GW, of which about 2.4 GW is in Poland.

João Manso Neto, CEO of Greenvolt Group, said that with Siedlce the company is once again moving from plans to delivery, adding that Poland is a key market and battery storage is becoming an increasingly important part of its growth.