Green Capital S.A., a prominent renewable energy developer, and Prime Capital AG, a leading independent asset manager, have signed strategic agreements to jointly realise a 300 MW portfolio of battery energy storage systems (BESS) in Poland.

Under the terms of the transaction, Prime Capital has acquired a 50% stake in one advanced-stage project within the portfolio, with construction scheduled to commence in 2Q26. Simultaneously, the partners have entered into an agreement regarding the joint realisation of the second large scale project, which is on the track to achieve ready-to-build status by the end of 2026, securing a clear path for the development of both assets.

Both projects have successfully secured 17-year capacity market contracts providing fixed availability payments for their BESS capacity and underpinning the commercial viability of the portfolio.

For Green Capital, the partnership with Prime Capital constitutes a pivotal step in its transition from a developer to an independent power producer and flexibility service provider. The BESS projects are critical to stabilising the Polish grid and facilitating the integration of further renewable generation.

With these transactions in Poland, Prime Capital significantly expands its battery energy storage footprint and deepens its presence in the rapidly growing European storage market, enhancing power system resilience.

Michal Polanowski, CEO, Green Capital, noted: “We are delighted to welcome Prime Capital as our partner. By establishing a joint venture for the realisation of a 300 MW/1200 MWh BESS portfolio, we are marking a transformative moment for Green Capital. Prime Capital brings proven expertise in hybrid infrastructure investment across Europe, including a strong BESS track record, and together we are the first to bring this combination of scale and institutional capital to the Polish storage market. This portfolio will play a crucial role in balancing the national grid, enabling a faster and safer energy transition.”

Dr Mathias Bimberg, Head of Energy Infrastructure at Prime Capital, added: “This strategic partnership with Green Capital perfectly aligns with our infrastructure investment focus. By acquiring a stake in one project and committing to the joint development of the broader portfolio, we are securing a strong foothold in the rapidly growing Polish storage market. We look forward to working together to bring this 300 MW portfolio to operation, backed by long-term capacity market contracts.”