Metlen and Karatzis Group open Greece's largest standalone battery storage plant in Larissa

The plant

Metlen and the Karatzis Group inaugurated a standalone battery storage facility in Nea Karyes, Larissa, on Wednesday, 14 October. The plant has a capacity of 330 MW and a storage capacity of 790 MWh, and the companies describe it as the largest standalone battery unit in Greece and one of the largest in Europe. The investment totals €170 million and operates without any operating or investment subsidy. The plant stores surplus output from renewable sources and feeds it back into the grid when demand rises or the system needs it. Metlen holds 49% of the joint investment scheme and the Karatzis Group 51%, and Metlen handled construction, operation and maintenance.

Official remarks

Prime Minister Kyriakos Mitsotakis attended the ceremony with Environment and Energy Minister Stavros Papastavrou, Metlen executive chairman Evangelos Mytilinaios and Antonis Karatzis, chairman and chief executive of the Karatzis Group. Mitsotakis said that flexibility was essential in managing renewable output and that storage investments play a key role in achieving it. He pointed to a shift in the country's power mix, with more than half of domestic electricity now coming from renewable sources and Greece having become a net exporter. He recalled that in 2019 Greece had the highest wholesale electricity prices in Europe, and said prices are now often below the European average.

We always needed to import electricity. That deficit has now turned into a surplus.

Mitsotakis linked the country's lower prices to this change, arguing that the less natural gas the country uses, the better prices will be. He added that storage has been supported through Recovery and Resilience Facility funding and that a further €200 million is being allocated to similar projects.

Energy security and prices

Mytilinaios described the plant as a concrete example of a strategy in which storage, networks and interconnections support industry and new productive activity. He argued that the energy transition now carries a geopolitical and economic dimension, not only a climate one, because international crises and fuel price swings make dependence on imported resources costly.

A new reality is taking shape today, in which energy security and resilience carry greater weight.

He said a country that covers more of its energy needs from domestic, diversified resources is less exposed to international price swings and geopolitical turbulence. Mytilinaios also thanked the Karatzis Group partners, Antonis Karatzis personally, and Metlen staff, and said the company will continue to invest in this direction in Greece and internationally.

Grid role

Mytilinaios explained that renewable generation does not always coincide in time with demand, so the larger the share of renewables in the mix, the greater the need for storage. The plant reduces losses from renewable output that the grid cannot absorb immediately. It also gives operators more room to manage both supply and demand as renewable penetration rises. Mitsotakis said that storage must complement further renewable investment so that electricity can be used whenever and wherever it is needed.