The Greenvolt Group, through Greenvolt Power, its utility-scale renewables business, has begun constructing the Siedlce battery energy storage system (BESS) in Poland, with a capacity of 600 MW / 2.4 GWh. The project will be the largest BESS installation in the country and one of the largest in Europe, with commercial operation expected to commence by the end of 2027, according to a press release.
According to the same source, Siedlce forms part of Greenvolt’s portfolio of battery energy storage projects, which currently totals 4.6 GW, including around 2.4 GW in Poland. Battery energy storage is taking on increasing importance in Greenvolt’s growth strategy, covering both large-scale projects and behind-the-meter solutions for commercial and industrial customers across several European markets, via Greenvolt Next.
“With Siedlce, we are once again moving from plans to execution. The most important thing is to build assets, create real value and reinforce the infrastructures needed to integrate more renewable energy into the system. Poland is a strategic market for us, and battery energy storage is taking on an increasingly important role in our growth,” said João Manso Neto, CEO of the Greenvolt Group.
With a 600 MW capacity and 2.4 GWh of storage, Siedlce will provide greater flexibility to the Polish electricity system, storing electricity during periods of high renewable energy production and making it available when demand rises. This system will contribute to the integration of wind and solar generation and will help balance electricity supply and demand.
Siedlce continues Greenvolt Power’s expanding track record in developing battery storage projects in Poland. Turośń Kościelna, with 200 MW / 800 MWh, came into operation in July 2026, while Ełk, also with 200 MW / 800 MWh, is due to enter commercial operation in the fourth quarter of this year. When the three projects are operational, they will together provide 1 GW of capacity and 4 GWh of storage.
“We are now moving ahead with Siedlce to the construction phase, with battery supply and grid connection agreements already in place. The experience we have gained with Turośń Kościelna and Ełk provides us with a solid foundation to deliver a project of this scale, and our priority is to maintain this pace and bring Siedlce into operation by the end of 2027,” said Weronika Nowak, CEO of Greenvolt Power.
BYD Energy Storage will supply the battery technology. The project comprises 210 battery container units and 105 transformer container units equipped with energy conversion systems, enabling the flow of electricity between the batteries and the grid.
Greenvolt Power is working with engineering and construction company P&Q and renewable energy contractor ONDE on the development of the project’s electrical infrastructure.
