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GOLDBECK SOLAR Polska has completed a large-scale renewable energy project in Poland with the commissioning of the MIX Marszewo system, integrating the existing Marszewo Wind Farm with the newly constructed Postomino Photovoltaic Power Plant. The project investor is TAURON Zielona Energia. Implemented using cable pooling technology, the system utilises the wind farm’s existing grid connection infrastructure to transmit the combined output of both installations. This represents one of the first solutions of this type in Poland at the 110 kV voltage level.
Project scope and specifications
The investment included the construction of a 90 MW photovoltaic power plant, a double-section 20 kV medium-voltage switchgear with 20 fields, two 50 MVA 110/20 kV power transformers with 110 kV transformer fields, a 110 kV line field and a reactive power compensation system based on two 11 MVAr STATCOM units. Over 7 km of 110 kV underground cable was installed and connected in a cable pooling configuration to the existing overhead export line of the wind farm.
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System integration and operation
The entire system is managed through a modern control and monitoring platform that coordinates the operation of both the photovoltaic and wind installations. Installed at the newly constructed photovoltaic substation (GPO), the system automatically brings the photovoltaic plant online when the wind farm does not fully utilise its grid connection capacity. During periods of low wind, the photovoltaic plant can deliver up to approximately 64 MW.
Construction timeline and project delivery
Construction began in spring 2024, with the photovoltaic plant and the 110 kV line completed by mid-2025. Following coordination with the grid operator and completion of all formal requirements, the plant was energised in August 2025, initiating testing and commissioning. Final synchronisation with the wind farm and implementation of the joint control system enabled the facility to become fully operational, with handover to TAURON Zielona Energia in December 2025.
The project’s successful delivery was achieved through close cooperation between the investor, contractor, subcontractors, design teams and HSE services, ensuring the work was completed safely, on schedule and within budget.
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Benefits of cable pooling
Tobias Schüßler, COO of the GOLDBECK SOLAR Group, noted that cable pooling is not only an advanced technical solution but also a practical response to the challenges facing the power system. It enables more efficient use of existing infrastructure, accelerates the development of renewable energy sources and provides a more stable generation profile, which is crucial for Poland’s energy security.
The MIX Marszewo project demonstrates that Poland possesses the competencies, experience and technical capacity required to deliver complex high-voltage infrastructure and renewable energy projects, paving the way for further cable pooling initiatives. (mg)
