Landmark energy infrastructure project to strengthen security of supply and support Greece’s productive capacity
KEY HIGHLIGHTS
Athens, Greece / London, United Kingdom – 15 October 2026 – METLEN and Karatzis Group of Companies inaugurated Greece’s largest standalone battery energy storage system (BESS) in Larissa, Thessaly on 14 October. With a power capacity of 330 MW and an energy storage capacity of 790 MWh, it is also one of the largest facilities of its kind in Europe. The project was delivered through the strategic partnership between METLEN and Karatzis Group of Companies, via a joint investment vehicle in which they hold stakes of 49% and 51%, respectively.
The inauguration was attended by Prime Minister Kyriakos Mitsotakis, Minister of Environment and Energy Stavros Papastavrou, representatives of the Greek Parliament, of regulatory and productive bodies, as well as of local authorities.
The new BESS facility is an energy infrastructure project of strategic importance, as storage, grid works and interconnections are essential preconditions to attract investment and strengthen the production base of both Greece and Europe. The Thessaly storage facility also illustrates the importance of mature projects, modern infrastructure and companies with the scale and expertise to turn investment plans into operational assets. It is a flagship project for the new energy era and an important step towards building the productive capacity that will underpin the next chapter of Greece’s economic growth. METLEN undertook the construction, operation and maintenance of the facility, drawing on its international experience in complex energy storage projects.
In his speech during the inauguration ceremony, Prime Minister Kyriakos Mitsotakis referred to the new facility as an important step towards building the Greece of the future. He highlighted the contribution of the investment to the energy security and competitiveness of the country, congratulating METLEN and Karatzis Group for the completion of the project. You can access the Prime Minister’s full speech here (in Greek).
Evangelos Mytilineos, Executive Chairman of METLEN, said: “I am particularly proud that today, here in Thessaly, we are inaugurating Greece’s largest standalone energy storage facility in Eastern Europe and one of the largest across the European Union. This project reflects the new reality of the energy system, as storage, alongside grids and interconnections, is essential if we are to use the clean energy we generate with efficiency and provide businesses and consumers with a more reliable and predictable energy supply. I would like to thank our partners at Karatzis Group, Antonis Karatzis personally, and everyone at METLEN who contributed to the delivery of this landmark project.”
Antonis Karatzis, Chairman and CEO of Karatzis Group of Companies, said: “Today marks an important milestone for Karatzis Group and for the country’s energy future. Our participation in a storage project of this scale reflects our strategic choice to invest in infrastructure with a long-term horizon and a meaningful value for the Greek economy. Together with METLEN, we are showing how two leading Greek companies can combine strengths, expertise and willingness to invest, delivering projects to international standards, increase the use of renewable energy, strengthen grid stability and enhance Greece’s energy security. For us, this project marks the beginning of a new era in which we intend to play an active and meaningful role.”
The successful delivery and commissioning of a project of such scale such as the Thessaly standalone energy storage, demonstrate the partners’ technical expertise and ability to turn complex investment plans into operational infrastructure that will support the country’s growth prospect for decades to come.
The investment is implemented with loan support from the EU’s Recovery and Resilience Facility – NextGenerationEU.
