A combination of a wind farm and a pumped storage hydroelectric plant can meet the entire demand for electricity in the small Aegean island of Sifnos in Greece. The local energy cooperative is working on the hybrid solution, which may include a photovoltaic system.

The Energy and Development Cooperative of Sifnos intends to make the island with less than 3,000 inhabitants the first in the Cyclades archipelago that would produce 100% of its electricity from renewable sources. It has applied with the Regulatory Authority for Energy (RAE) of Greece for a hybrid power plant and produced a study in cooperation with the Hellenic Mediterranean University of Crete.

The document shows the project would also fully cover the need for energy in transportation.

Sifnos would have enough electricity for 16 days if wind stops

Four wind turbines with a capacity of 3 MW each would play the main role and excess electricity is planned to be stored by a pumped storage hydropower plant. It would be designed to cover a maximum of 860 MWh or 16 days of average consumption in the Aegean island. The system could be further boosted with a solar power plant, according to Kostas Soulis, the president of the association, which is also known as Sifnos Island Cooperative.

The proposed 8.74 MW pumped storage hydroelectric system would use seawater

At times of low demand, the hydroelectric facility would pump seawater to an upper reservoir of more than 1.1 million cubic meters, placed at an altitude of 332 meters. The idea is to install four Pelton type turbines with a combined capacity of 8.74 MW and twelve centrifugal pumps of 10.28 MW in total. The seawater would be used to produce power when electricity demand exceeds the wind park’s output, for instance when wind is weak.

Wind farm would be oversized to enable desalination, green hydrogen production

The proposed location is on the northeastern coastline, two and a half kilometers from the nearest homes. The facility would basically not be visible from human settlements or tourist spots. The site is outside of the boundaries of a local Natura 2000 area and away from archeological digs.

The share of the expected surplus from the wind farm’s annual output is estimated at more than 40%, and the excess energy can be used for desalination and the production of green hydrogen to fuel vessels, the study revealed. Authors called on the Greek government to back the project, saying it could be paid off within eight years.

The cooperative said locals can become members with a minimum share of EUR 100 per person while no individual is allowed to hold more than 20% of the overall capital.

Greece intends to transform the way of life on a series of small islands with renewable energy and energy efficiency projects, digitalization and the introduction of electricity in transportation. They are now mostly dependent on diesel-fueled generators and electricity bills on islands are subsidized.