Final phase of Cyclades interconnection project crosses finish line

July 3, 2026, by Nadja Skopljak

The fourth and final phase of the Cyclades interconnection project, which aims to increase the security and reliability of supply in Greece’s island systems, has been completed.

Greek electricity grid operator Independent Power Transmission Operator (IPTO) reported that the construction of the Southern Cyclades electrical interconnection had been completed, connecting Santorini, Folegandros, Milos and Serifos to the mainland power system via Attica.

This marks the fourth and final phase of the project that aims to reshape the energy infrastructure of the Cyclades.

With a total budget of €385.7 million, the project includes 294 kilometers of high-voltage submarine and underground cables and four fully digital gas-insulated substations (GIS).

“Its gradual integration into the National Electricity Transmission System begins with Santorini. The interconnection will enhance the islands’ energy security, reduce their environmental footprint and lower costs for consumers through reduced Public Service Obligation (PSO) charges,” IPTO reported.

The project has received €164.5 million in EU funding through the Greece 2.0 Recovery and Resilience Facility and is also financed through loans from the European Investment Bank and additional resources from the Recovery and Resilience Facility.