Poland’s capacity market supports BESS investment, OX2 joins with 120 MWh project

Swedish developer OX2 has reached investment decision on a 50 MW/120 MWh energy storage facility in Osiek Jasielski, Poland, after securing a 17-year capacity market agreement.

The new BESS will be backed by a 2027 capacity market contract and is expected to contribute to flexibility in a Polish market that is increasingly grappling with curtailment and negative pricing hours in the electricity market.

The Osiek Jasielski project is OX2’s first battery project in Poland. The developer has also taken investment decision on a 165 MWp solar farm in the Lubuskie Voivodeship, which secured support in a December 2024 capacity auction for the sale of electricity from renewable sources. OX2 has secured a long-term project financing package with NORD/LB and CaixaBank for the projects.

Matthias Taft, CEO of OX2, said the two projects strengthen the company’s position in the Polish market. “Osiek enhances system flexibility and supports the integration of more renewable power, while Lion brings stable production and long-term value creation,” said Taft. “Combines, these projects reflect our commitment to building a balanced and resilient portfolio that supports the country’s energy transition.”

Meanwhile Green Capital S.A. and Prime Capital AG announced a joint venture on May 19 to build two BESS projects with power totaling 300 MW/1,200 MWh, with construction of the first project to commence in the first half of 2026. Like OX2’s Osiek BESS, both projects have secured 17-year capacity market contracts.

Under the terms of the transaction, Prime Capital has acquired a 50% stake in the project due to begin construction in imminently, while the partners have also entered an agreement for the second large-scale BESS project which is expected to reach ready-to-build status by the end of 2026.

The new BESS investment decisions capped off a busy May for Poland’s BESS market, which also saw R.Power and Axpo agree on a BESS optimization contract for a new 300 MW/1,200 MWh project to be built in Dzięgielewo, east-central Poland. The deal means R.Power now has a 1.7 GW/6.3 GWh Polish energy storage pipeline.