Cyprus–Crete power interconnector cable cleared for installation at a depth of 3,000 metres

French company Nexans has completed the qualification of a 525 kV subsea direct-current cable system for the Great Sea Interconnector between Cyprus and Crete. As the company reported on 27 August, it is the only system of its voltage class in the world approved for installation at a depth of up to 3,000 metres.

The tests covered not only the cable itself, but also the factory joints and a flexible repair joint designed to withstand the loads involved in lowering it to great depths. During the mechanical tests, the system was subjected to a tensile force of 842 kN, simulating the conditions of laying it on the seabed of the Eastern Mediterranean. Nexans presented the technical results at the CIGRE 2026 international session in Paris.

The certification is based on a full-scale test carried out in March 2026: a section of cable together with the joint was lowered to a depth of 3,000 metres in waters west of Sicily and then brought back up. Electrical tests and a visual inspection showed that the system returned without damage or deformation, while the high-voltage tests after recovery were conducted at a level 30% above the accepted industry standards.

The Great Sea Interconnector is intended to link the power grids of Greece and Cyprus, and eventually Israel as well. The subsea line will be approximately 1,200 km long, with a rated capacity of 1,000 MW and the possibility of increasing it to 2,000 MW. Nexans is building the Greece–Cyprus section under a €1.43 billion contract: the cable is being manufactured at plants in Halden, Norway, and Futtsu, Japan, and is to be laid by the Nexans Aurora and Nexans Skagerrak vessels.

For the island, this is a question of tariffs and reliability: Cyprus remains the only EU country without an electricity interconnection to the wider grid. At the same time, the interconnector itself, estimated to cost around €1.9 billion, is lagging behind schedule: the line was supposed to become operational as early as 2024, but the deadlines were pushed back because of maritime disputes in the Eastern Mediterranean and financing issues.