METLEN, Tsakos Start Building 251.9-MW Solar-Storage Plant in Greece

• METLEN and Tsakos Group started building a 251.9-MW solar plant with about 375 MWh of storage in Domokos, Central Greece.
• Tsakos holds 60% of the project company and METLEN 40%; METLEN is also the builder.
• The companies targeted completion in early 2028 when they signed the partnership in January.

METLEN and Tsakos Group have started building a hybrid power plant in Domokos, Central Greece, that pairs a 251.9-MW solar plant with an energy storage system of an expected 375 MWh. The companies held a groundbreaking ceremony at the site, METLEN said in a statement on Nov. 12.

The project belongs to a special purpose vehicle in which Tsakos Group holds 60% and METLEN 40%. METLEN is building the plant and will also handle its energy and commercial management. The investment has loan support from the European Union's Recovery and Resilience Facility, part of NextGenerationEU. METLEN did not disclose the cost, the power rating of the battery storage in MW, or the equipment suppliers.

Greece had 11,538 MWp of grid-connected solar at the end of 2025 after adding 1,840 MWp during the year, according to statistics from HELAPCO, the Greek association of photovoltaic companies. At least 800 MW more was built in 2025, with grid connection scheduled for 2026, the group said.

The project in numbers

• 251.9 MW of photovoltaic capacity in Domokos, in the region of Central Greece.
• 375 MWh of expected storage capacity; the companies have not given the battery's MW rating.
• 1.49 MWh of storage for every MW of solar (list.solar calculation).
• 60% / 40% ownership split between Tsakos Group and METLEN.
• 100.8 MW of solar and 150 MWh of storage attributable to METLEN's 40% stake (list.solar calculation).
• About 2.2% of Greece's end-2025 connected solar fleet, based on HELAPCO data (list.solar calculation).

The two groups signed the partnership on Jan. 22. In July, METLEN took its 40% stake by entering an existing Tsakos special purpose vehicle, which will develop, build and operate the plant. For Tsakos Group, a shipping business, Domokos is a move into power generation. Earlier this year, Masdar agreed to buy a 550-MW Greek solar project from Lightsource bp.

"Today marks the transition from planning to implementation," Evangelos Mytilineos, METLEN's executive chairman, said in the statement.

When the deal was signed in January, METLEN said work would start in 2026 and the plant was targeted for completion in early 2028. The November statement did not give a new date.