Crete–Peloponnese Interconnection

Engineers usually switch to direct current when a sea cable gets long, because an AC cable loses more and more of its capacity to charging current with distance. The Crete–Peloponnese link pushed that limit. At 174 km, running at 150 kV AC, it was on completion the longest submarine and underground AC cable interconnection in the world, according to IPTO, which built it.

IPTO announced completion on 20 May 2021. The route lands at Chania, on the western end of Crete, and at Neapoli in Laconia, at the tip of the south-eastern Peloponnese. At its deepest the cable lies 1,000 metres down. There are two circuits, each rated at 200 MVA, given above as 400 MW. Nexans and Hellenic Cables supplied the cables, and the whole project cost €380 million, co-financed by Greece, the EU and European Investment Bank loans.

The job it was given was a first step. IPTO said the link would cover about a third of Crete’s demand, which on its own would not let the island close its local plants. The savings came from the public service charge that all Greek consumers pay towards the cost of generating power on unconnected islands: IPTO estimated reductions of up to €400 million a year once the old plants could be shut down.

“The future of Greece’s energy transition passes through the sea,” Manousakis said at the time. Energy minister Kostas Skrekas called it a project “of the utmost importance for the whole country, especially for Crete”.

The full connection arrived four years later, in May 2025, with the 1,000 MW Crete–Attica link, a DC cable from Heraklion to Attica. IPTO’s 2021 announcement had aimed for 2023. The Peloponnese cable remains the western, AC half of Crete’s two-cable supply, and for anyone studying subsea power cables it is a useful case of how far an AC design can be stretched.