New partner joins Greece’s ‘largest and most complex’ subsea interconnector project

Greece’s electricity transmission system operator (TSO), Independent Power Transmission Operator (IPTO or ADMIE), has received the blessing of its board of directors for a partial divestment of a stake in its subsidiary which is developing a subsea interconnector cable between the island of Crete and the Greek mainland.

IPTO extended the second phase of its tender to dispose of a 20% interest in the special purpose company, Ariadni Interconnection AEES, in May 2024, enabling candidates to submit their offers until June 21. This company is a 100% subsidiary of the Greek TSO and is working to bring the electrical interconnection of Attica–Crete to life.

According to IPTO, its board has now greenlighted the 20% allocation of Ariadni Interconnection to State Grid International Development Belgium, which submitted a binding, improved offer in the relevant tender. However, the completion of the transaction is subject to the approval of the competent authorities.

The Greek TSO describes the Attica-Crete electrical interconnection as “the largest and most complex” electricity transmission project in Greece and one of the three deepest marine interconnections worldwide.

While the construction part of the project has been completed by laying all the underwater electrical (500 kV) and optical cables, the wiring and installation of the outdoor equipment are said to be in the final stretch.

As a result, the electrification of the cable is set to begin on a trial basis in early 2025 and become operational by next summer. Nexans was tasked with designing, manufacturing, and installing a 335-kilometer subsea HVDC cable system for Ariadne Interconnection, under a contract won in May 2020.

The activities were performed by the company’s cable-laying vessel Nexans Aurora. Upon completion, the project is expected to ensure energy security for the island of Crete and enable the transition from fossil fuel generation to greener options such as wind and solar energy resources.

The cable link will connect the Attica region on the Greek mainland to the Heraklion area in Crete, thanks to Nexans providing one 500 MW HVDC subsea cable system to form half of the total 1,000 MW bipole interconnection and Prysmian handling the other half of the interconnection and two subsea telecom links. 

Recently, Asso.subsea wrapped up its work for the fourth phase of Greece’s Cyclades interconnection project designed to boost supply security and address stability issues for the Cyclades’ electrical system through the connection to the Greek mainland power transmission system.

Meanwhile, IPTO is gearing up to invite Prysmian, Nexans, and Fulgor to hand in final offers for the tender process regarding submarine alternating current (AC) cables destined for Aegean Islands interconnectors.

This comes after a deal was reached for a multibillion-euro underwater high voltage direct current (HVDC) interconnector project, which will link Europe, the Middle East, and Asia, connecting the green electricity transmission dots for the Cyprus-Greece-Israel triangle.