METLEN and the Karatzis Group of Companies inaugurated Greece’s largest standalone battery energy storage system (BESS) on Wednesday, October 14, in Larissa — a 330 MW, 790 MWh facility that also ranks among the largest installations of its kind in Europe. The project was developed through a strategic partnership between METLEN and the Karatzis Group, via a joint investment vehicle in which they hold 49% and 51% stakes respectively.
The inauguration ceremony was attended by Prime Minister Kyriakos Mitsotakis, Minister of Environment and Energy Stavros Papastauros, as well as representatives from parliament, regulatory and industry bodies, and local government.
The new BESS facility in Thessaly represents a strategically important energy infrastructure project, as storage, grid infrastructure, and interconnections are essential prerequisites for attracting investment and strengthening the productive base of both Greece and Europe. It demonstrates in practice the value of mature projects, modern infrastructure, and companies with the scale and expertise not only to invest, but — crucially — to deliver. The facility stands as a landmark project for the new energy era and a significant step toward building the productive reserves that will underpin the next chapter of the Greek economy. METLEN took responsibility for the construction, operation, and maintenance of the facility, drawing on its international experience in complex energy storage projects.
In his address at the inauguration, Prime Minister Kyriakos Mitsotakis described the facility as a major step toward the Greece of the future, highlighting the investment’s contribution to energy security and national competitiveness, while congratulating METLEN and the Karatzis Group on the achievement.
Evangelos Mytilineos, Executive Chairman of METLEN, stated: “I am particularly proud to be inaugurating today, here in Thessaly, the largest standalone energy storage facility in Eastern Europe and one of the largest across all European Union member states. This is a project that reflects the new reality of the energy system — storage, alongside grids and interconnections, is essential if we are to make effective use of the clean energy we produce and ensure more reliable, predictable power for businesses and society alike. I would like to warmly thank our partners at the Karatzis Group, and personally Antonis Karatzis, as well as all the people at METLEN who contributed to the realization of this landmark project.”
Antonis Karatzis, Chairman and CEO of the Karatzis Group of Companies, noted: “Today marks a significant milestone for the Karatzis Group and for the country’s energy future. Our participation in an energy storage project of this scale confirms our strategic choice to invest in long-horizon infrastructure that delivers real, lasting value to the Greek economy. Together with METLEN, we are proving that two leading Greek companies can join forces, expertise, and investment ambition to deliver projects of international standards — projects that strengthen the uptake of renewable energy, the stability of the electricity system, and Greece’s energy security. For us, this project marks the starting point of a new era, one in which we intend to play an active and meaningful role.”
The successful completion and delivery of a project of this scale — a standalone battery energy storage facility in Thessaly — highlights the technical competence and execution capability of both partners in transforming complex investment plans into operational infrastructure that will support Greece’s development trajectory for decades to come.
The investment is being financed with loan support from the European Union’s Recovery and Resilience Facility — NextGenerationEU.
