Green Capital S.A. (renewable energy developer) and Prime Capital AG (Independent asset management firm)have announced a strategic partnership to develop a 300 MW portfolio of Battery Energy Storage Systems in Poland, marking what both companies describe as the first combination of institutional capital and storage projects at this scale in the Polish market.

The agreement, announced, involves the formation of a joint venture and commits both parties to delivering two large-scale battery energy storage projects across a phased development timeline.

Deal Structure and Project Timeline

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 begin in the second quarter of 2026.

A second agreement covers the joint realization of a separate large-scale project that is on track to reach Ready-to-Build status by the end of 2026. Together, the two projects will deliver a combined capacity of 300 MW and 1,200 MWh of battery storage.

The first project's construction commencement in Q2 2026 places it among the earliest utility-scale battery storage projects of this size to break ground in Poland.

The second project's pathway to RTB status by late 2026 provides what both companies characterize as a clear and structured route for the full portfolio to reach operation.

Capacity Market Contracts Underpin Commercial Case

A central feature of the partnership's commercial foundation is that both projects have secured 17-year capacity market contracts. These contracts provide fixed availability payments tied to the BESS capacity of each installation.

The long duration of the contracts is intended to underpin the financial viability of the portfolio and provide revenue certainty across the assets' operational lifetimes.

Dr. Mathias Bimberg, head of Energy Infrastructure at Prime Capital, cited these contracts as central to the investment thesis. "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," he said. "We look forward to working together to bring this 300 MW portfolio to operation, backed by long-term capacity market contracts."

Strategic Significance for Green Capital

For Green Capital, the agreement represents a significant step in a broader corporate transition. The Warsaw-based developer, founded in 2015 by Michał Polanowski, is moving from a pure development model toward operating as an Independent Power Producer and flexibility service provider.

The company has previously sold more than 250 MW of projects to institutional partners, and this joint venture structure represents a shift toward retaining operational involvement in developed assets.

Green Capital's domestic pipeline exceeds 13 GW, and the company currently has 26 MW of photovoltaic assets in operation, 80 MW of battery energy storage projects under construction, and more than 240 MW with construction commencement dates planned for 2026.

The company has secured grid connection conditions for over 2 GW of renewable energy and BESS projects in Poland over the past decade and has advanced more than 400 MW to ready-to-build status.

Polanowski described the partnership as a defining moment for the company. "By establishing a joint venture for the realization of a 300 MW / 1,200 MWh BESS portfolio, we are marking a transformative moment for Green Capital," he said.

"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."

Prime Capital Expands European Storage Footprint

For Prime Capital, the Polish transaction extends an existing focus on battery energy storage as part of its energy infrastructure investment strategy. The Frankfurt and Luxembourg-based asset manager, founded in 2006, specializes in alternative investments, including energy infrastructure and private debt.

As of December 2025, the firm managed approximately USD 4.75 billion in assets under management and EUR 9.0 billion in assets under administration, and employs approximately 120 people.

The company describes the Poland transaction as significantly expanding its battery energy storage footprint and deepening its presence in the European storage market more broadly. Prime Capital is regulated by BaFin and the CSSF and is owned by management alongside current and former senior employees.

Grid Stability and Poland's Energy Transition

Both companies framed the portfolio's role within the context of Poland's broader energy transition. Battery storage at grid scale is increasingly being deployed to manage the intermittency of renewable generation, and the two projects are described as critical to stabilizing the Polish grid and facilitating the integration of additional renewable capacity.

Poland's capacity market, which provides the contractual basis for the fixed payments underpinning both projects, is designed to ensure adequate generation and storage capacity is available to meet electricity demand.

The 17-year duration of the contracts secured by these projects reflects the long-term planning horizon of that mechanism and the extended operational life expected from utility-scale battery installations.

Green Capital noted that beyond Poland, the company is also expanding across Central and Eastern Europe, Africa, and South America, with activity at the intersection of renewable energy and digital infrastructure.

The company manages the full project lifecycle from land acquisition and permitting through construction to long-term asset operations across battery storage, solar, and onshore wind technologies.

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