BYD, Greenvolt Sign Poland's Largest 600 MW / 2.4 GWh BESS Deal for Siedlce
Greenvolt Power and BYD Energy Storage signed a supply agreement for the 600 MW / 2.4 GWh Siedlce BESS project — set to be Poland's largest battery-storage facility and one of Europe's biggest, with commercial operation planned for end-2027.
Key Takeaways
Greenvolt Power and BYD Energy Storage signed a supply agreement for the 600 MW / 2.4 GWh Siedlce BESS, set to be Poland's largest battery storage facility and one of Europe's biggest, with commercial operation planned for end-2027.
BYD will supply its Haohan container-scale system built around the 2,710 Ah Blade Battery; construction starts in Q3 2026, delivering frequency response, capacity and flexibility services to Poland's grid.
The Siedlce project already has contracted revenues secured through Poland's capacity market, giving developers cash-flow certainty before construction begins.
It is the third BYD-Greenvolt project in Poland, following the 200 MW / 800 MWh Turośń Kościelna and Nowa Wieś Ełcka sites signed in March 2025, bringing their combined Polish storage pipeline to 2.8 GW.
Poland is central to Greenvolt's asset-rotation strategy, which delivered 1 GW of sales in 2025.
Kaan Tınmaz
Portuguese renewables developer Greenvolt Power has signed a supply agreement with BYD Energy Storage for the 600 MW / 2.4 GWh Siedlce battery energy storage system in Poland — set to become the country's largest BESS and one of the biggest ever built in Europe when it enters commercial operation at the end of 2027.
BYD Haohan powers Europe's next mega-BESS
Under the deal announced June 30 and expanded on July 1, BYD Energy Storage will supply its Haohan container-scale system — built around the 2,710 Ah Blade Battery — for the Siedlce project in eastern Poland. Construction is scheduled to start in Q3 2026, with the facility providing frequency response, capacity and system flexibility services to Poland's grid.
Revenues already locked in through Poland's capacity market
Siedlce has already secured contracted revenues through Poland's capacity market mechanism, giving the developers cash-flow certainty before construction begins. Greenvolt CEO João Manso Neto called energy storage 'a critical enabler of more resilient and flexible energy systems,' while Weronika Nowak, CEO of Greenvolt Power, said the project 'reflects both the scale of our ambitions in Poland and the capabilities we have built in energy storage.'
Second act after Turośń Kościelna and Nowa Wieś Ełcka
Siedlce is the third joint project between BYD and Greenvolt in Poland, following two 200 MW / 800 MWh sites — Turośń Kościelna and Nowa Wieś Ełcka — the pair signed in March 2025 for a combined 1.6 GWh. Together with Siedlce, the two developers now have 2.8 GW of Polish storage in the works. Poland is also a keystone of Greenvolt's asset-rotation strategy, which delivered 1 GW of sales in 2025, and follows this week's Reliance 120 GWh LFP BESS gigafactory commissioning and Peak Energy's Sacramento sodium-ion gigafactory as evidence that grid-scale storage supply is now scaling in step with renewables buildouts.
Reporting based on coverage from Greenvolt, ESS News, Argus and BYD.
Siedlce is a 600 MW / 2.4 GWh battery energy storage system in eastern Poland being developed by Greenvolt Power with BYD Energy Storage as equipment supplier. It will be Poland's largest BESS and one of Europe's biggest, with commercial operation planned for the end of 2027.
What technology will BYD supply for the project?
BYD Energy Storage will supply its Haohan container-scale storage system, built around the 2,710 Ah Blade Battery. The facility will provide frequency response, capacity and system flexibility services to Poland's grid.
When will construction of the Siedlce facility begin?
Construction is scheduled to start in Q3 2026, with commercial operation targeted for the end of 2027.
Have BYD and Greenvolt worked together before in Poland?
Yes. Siedlce is their third joint Polish project, following two 200 MW / 800 MWh sites — Turośń Kościelna and Nowa Wieś Ełcka — signed in March 2025 for a combined 1.6 GWh. Together the developers now have 2.8 GW of Polish storage in the works.
