Renewables

Agios Efstratios becomes Greece’s first energy-autonomous island

Agios Efstratios Greece first energy autonomous island

Photo: Terna Energy

Published

August 22, 2025

Country

Comments

comments icon

0

Share

Published:

August 22, 2025

Country:

Comments:

comments icon

0

Share

A hybrid energy project transforming Agios Efstratios into the first energy-autonomous island in Greece is in trial operation. The system consists of a wind turbine, solar power plant, batteries, electric boilers and a district heating network.

It is a benchmark for the non-interconnected islands that won’t be connected to the mainland grid with undersea power cables.

Agios Efstratios is no longer renowned only for its history and natural beauty. It is an example of energy autonomy and sustainability. The island, also known as Ai Stratis, became the first non-interconnected Greek island with a 100% electricity supply from renewables. And more.

A pioneering energy complex is in trial operation. Agios Efstratios, which has only some 250 permanent residents, is in a group of small islands undergoing transformation through projects launched at the national level and benefiting from European Union funding.

Terna Energy completed hybrid energy system in Agios Efstratios

The Centre for Renewable Energy Sources and Saving (CRES or KAPE), an independent public entity, is responsible for the endeavor, on behalf of the Municipality of Agios Efstratios. Terna Energy, owned by Masdar, is the contractor for the works in the small North Aegean island.

The new hybrid energy system includes a 900 kW Enercon E44 wind turbine and a solar power unit of 225 kW. Their combined annual output is estimated at above 3 GWh.

Excess electricity is stored. One unit is a Tesla Megapack battery energy storage system (BESS) of 1.25 MW in operating power and a two-hour duration. It means the capacity is 2.5 MWh. There is also an electric boiler facility of 1 MW with hot water storage tanks that can hold 500 cubic meters of water at 120 degrees Celsius. It corresponds to 25 MWh.

The district heating network in Agios Efstratios is four kilometers long. It will be tested in the winter.

An oil-fired generator operated by state-controlled Public Power Corp. (PPC) remains as backup. It can work alongside the hybrid power plant.

Greece is connecting many islands to mainland power grid

The solutions from Agios Efstratios can be applied in other islands or in microgrids, CRES noted and said residents are getting cheaper energy.

The government launched its Islands Decarbonization Fund last year, with financing from the European Investment Bank (EIB). Together they aim to provide at least EUR 1.6 billion, and mobilize total investments of EUR 3 billion to EUR 5 billion.

In the hot summer months, there are many non-interconnected islands that can’t meet their power demand, especially because of the tourist season. Some are also struggling with water supply, prompting the need for desalination, which requires electricity. They rely on fuel oil generators.

The country’s Independent Power Transmission Operator (IPTO or, in Greek, Admie) is investing in major interconnection projects. A link to the mainland grid has improved the living conditions in the Cyclades islands of Syros, Paros and Mykonos. Together with a project for the western part of the archipelago, the transmission system operator is planning subsea cables to the Dodecanese and the Northeast Aegean.

Comments (0)

Be the first one to comment on this article.

Enter Your Comment
Please wait... Please fill in the required fields. There seems to be an error, please refresh the page and try again. Your comment has been sent.

Related Articles

eu western balkans cbam electricity market amendments

EU’s amendments to CBAM: possibility of relief, but January 1 brought market uncertainty

06 January 2026 - Long-awaited implementing acts and amendments to the CBAM Regulation brought only a minor relief for...

After adding PV unit Slovenian gas power plant TEB battery project

After adding PV unit, Slovenian gas power plant TEB launches battery project

06 January 2026 - The management of the Brestanica gas power plant has decided to diversify its activities further with a battery energy storage system

D Trading offtake 200 MW solar PPA with Econergy Romania

D.Trading to offtake 200 MW of solar in PPA with Econergy in Romania

06 January 2026 - DTEK Group's D.Trading signed an offtake deal with Econergy for 200 MW of solar power in Romania, including the country's largest PV plant

montenegro TSO cges investments ranko redzic

Montenegro’s TSO CGES to invest EUR 200 million

05 January 2026 - Montenegrin TSO CGES plans to invest EUR 200 million, according to Ranko Redžić, manager of the company's national dispatching center