BYD Energy Storage will supply battery systems for Greenvolt Power’s 600 MW/2.4 GWh Siedlce BESS in Poland. The project is scheduled to begin construction in Q3 2026 and start commercial operation by the end of 2027, supporting grid flexibility and renewable energy integration.
PROJECT SNAPSHOT
Project Name: Siedlce Battery Energy Storage System (BESS)
Owner: Greenvolt Power (Greenvolt Group)
Project Type: Utility-scale Battery Energy Storage System (BESS)
Location: Siedlce, Poland
Technology Used: BYD Haohan battery energy storage system
Installed Capacity: 600 MW / 2.4 GWh
Construction Start: Q3 2026
Commercial Operation: End of 2027
Purpose: Improve grid stability, flexibility and renewable energy integration
Expected Output: One of Europe's largest operational battery energy storage facilities
Revenue Support: Secured through the Polish Capacity Market
Technology Supplier: BYD Energy Storage
Greenvolt Power, the utility-scale renewable energy developer, has signed a new supply agreement with BYD Energy Storage for the Siedlce Battery Energy Storage System (BESS) project in Poland. Under the agreement, BYD Energy Storage will provide its BYD Haohan battery storage system for the project, reinforcing the long-term collaboration between the two companies in the Polish energy storage market.
The Siedlce BESS will have a planned capacity of 600 MW/2.4 GWh, making it the largest battery energy storage facility in Poland and one of the largest in Europe. The project represents another milestone in Greenvolt Power's growing battery storage portfolio as the company continues developing large-scale energy storage infrastructure across Europe.
The construction of the project is scheduled to begin in the third quarter of 2026. Commercial operations are expected by the end of 2027 after the project secured revenue support through Poland's capacity market mechanism. The long-term revenue arrangement provides financial certainty while supporting the deployment of large-scale battery storage infrastructure.
Once operational, the facility will help to enhance Poland's electricity network by providing grid stability and operational flexibility. The battery system will also support balancing electricity supply and demand by enabling greater integration of renewable energy sources such as solar and wind while enhancing the reliability of the country's power system.
The agreement further expands the partnership between Greenvolt Power and BYD Energy Storage. In March 2025, the companies signed agreements covering battery storage technology for the Turośń Kościelna and Nowa Wieś Ełcka BESS projects. Each project has a planned capacity of 200 MW/800 MWh, bringing their combined storage capacity to 1.6 GWh. The Siedlce agreement significantly increases the scale of collaboration between the two companies in Poland.
Poland remains one of Greenvolt Group's strategic markets. The company currently has a diversified development pipeline in the country comprising 238 MW of wind projects, 657 MW of solar projects and 2,595 MW of battery energy storage capacity. The projects are part of Greenvolt Group's portfolio of 12.8 GW of renewable energy projects around the world.
Greenvolt states that the Siedlce project is one of the company's initiatives to develop utility-scale battery storage facilities across Europe through its expansion as the adoption of renewable energy grows. The project also supports Greenvolt Group's broader asset rotation strategy, which reached 1 GW of completed asset sales during 2025.