Poland’s largest battery energy storage project has reached another major milestone with the arrival of a high-voltage transformer at the Żarnowiec construction site in northern Poland.
The delivery represents a crucial step in preparing the 262 MW / 981 MWh battery energy storage system (BESS) for connection to Poland’s transmission network. Once operational, the facility will become one of the largest grid-scale battery storage installations in Europe and a strategic asset for integrating growing volumes of renewable energy into the Polish power system.
The Żarnowiec project is being developed by PGE Polska Grupa Energetyczna, with LG Energy Solution Wrocław selected as the turnkey contractor responsible for designing and constructing the installation. The contract covers the delivery of a large-scale battery storage facility with a capacity of approximately 981 MWh.
“The construction of the Żarnowiec energy storage facility has entered another important stage. We have already installed more than 150 DC-Link units, and commissioning works will begin shortly,” PGE said, describing the transformer delivery as one of the key moments in the project timeline.
A Korean link in Europe’s emerging battery storage supply chain
The arrival of the transformer highlights the increasingly international nature of Europe’s battery storage build-out.
The unit travelled from South Korea to Poland as part of a complex logistics operation involving maritime transport and specialised heavy-load transport. The transformer weighs approximately 260 tonnes and will serve as the electrical bridge between the battery installation and the national transmission system.
The South Korean connection is particularly significant because LG Energy Solution has become one of the world’s leading battery technology companies and a major supplier of energy storage solutions. Through its Polish operations, LG Energy Solution Wrocław has become an important European manufacturing and engineering hub for battery technologies.
For the Żarnowiec project, LG Energy Solution’s role extends beyond battery supply. The company is delivering the project in a turnkey EPC model, combining battery systems, power electronics, control systems and integration works required for a utility-scale storage facility.
Transformer will connect battery system to 400 kV network
The newly delivered transformer is one of the most technically important elements of the project.
The battery installation operates at medium-voltage levels, while Poland’s transmission network operates at much higher voltages. The transformer will increase the voltage level from the battery system side to the 400 kV transmission network, enabling large-scale electricity exchange between the storage facility and the national grid.
This connection will allow the Żarnowiec BESS to perform its core functions: absorbing electricity during periods of excess renewable generation and returning power to the system when demand rises or renewable output falls.
Unlike conventional power plants, battery storage facilities can respond within fractions of a second, making them valuable tools for frequency regulation, balancing services and maintaining grid stability.
Storage becomes essential as Poland expands renewables
The Żarnowiec project comes at a time when Poland’s electricity system is undergoing a fundamental transformation.
Rapid growth in solar PV capacity, planned offshore wind development in the Baltic Sea and the gradual reduction of coal-based generation are increasing the need for flexible assets capable of balancing a more variable electricity system.
“Renewable energy expansion requires not only new generation capacity but also technologies that provide flexibility and security for the power system,” PGE has stated in relation to the project.
The location of the project adds strategic value. The battery facility is being built next to the existing Żarnowiec Pumped Storage Power Plant, one of Poland’s most important energy storage assets for decades.
By combining pumped hydro storage with modern battery technology, Żarnowiec is becoming a national flexibility hub linking established and emerging forms of energy storage.
A landmark project for Poland’s energy transition
The arrival of the transformer signals that Poland’s first large-scale battery storage ambitions are moving from plans into physical reality.
When completed, the Żarnowiec facility will provide almost 1 GWh of energy storage capacity, helping optimise renewable generation, support grid balancing and reduce pressure on Poland’s electricity infrastructure.
The project also demonstrates the growing role of Asian technology companies in Europe’s energy transition. South Korean companies such as LG Energy Solution are becoming key partners as European markets accelerate investment in batteries, grid flexibility and renewable integration.
For Poland, Żarnowiec represents more than a single battery installation. It marks the beginning of a new phase in which energy storage becomes a central component of a modern, renewable-based electricity system.
