Photo: Prysmian Group

Italian cable maker Prysmian Group has announced the successful completion of the sea trial tests for ultra-deep installation of a 500 kV HVDC MI1 cable at 2,150 m water depth, a new world record.

This depth will be required for the Tyrrhenian Link, a €3.7bn interconnection project key to the growth of Italian renewables and grid reliability. The plan is to connect Sicily and Sardinia with the Italian mainland via subsea cables.

Prysmian credits an innovative armouring solution combined with their most advanced cable-laying vessel, Leonardo da Vinci, for allowing ever-greater depths.

Prysmian Group Statement:

The use of an innovative armouring solution that in water can be 50% lighter than steel, combined with the state-of-the-art Leonardo da Vinci cable-laying vessel, will enable the installation and maintenance of Terna’s Tyrrhenian Link at a water depth of more than 2,000 metres, the deepest ever reached with a power cable. 

In 2021, Italian transmission operator Terna awarded Prysmian a framework contract worth around €1.71 billion for the “design, supply, submarine, and land installation, and commissioning of a total of over 1,500 km of submarine cables to support the power exchange among Sardinia, Sicily, and Campania.”

This is not the first time Terna has contracted Prysmian for subsea connections. Prysmian also delivered the SAPEI HVDC transmission system between Sardinia and the Italian mainland, currently the world’s deepest underwater interconnection at 1,600 meters deep.

Prysmian’s recent trial tests are another step in the right direction for Tyrrhenian Link, which is expected to come online in 2028.

The Tyrrhenian Link project will connect Sicily and Sardinia with the Italian mainland via a double subsea cable, which will run 970km long and with a capacity of 1,000MW.

The East section of the link will run around 480km from Campania to Sicily. The West section will run 470km from Sicily to Sardinia.

The project is an initiative of the Terna Group, the Italian transmission operator responsible for managing Italy’s national high-voltage transmission grid.

Photo: Prysmian Group

In February 2024, Terna and the European Investment Bank (EIB) signed the contract for the final tranche of €1.9 billion in EIB financing for the Tyrrhenian Link.

The EIB is financing around 50% of the project’s planned €3.7 billion investment. According to the EIB, “the loans have a longer maturity and more competitive costs than those generally available on the market.”

The Tyrrhenian Link is expected to be fully operational in 2028 and more than 250 companies will be involved in its implementation.

Terna S.p.A.:

In Sicily, Sardinia and especially Campania, there is a strong production from non-programmable renewable sources, solar and wind, which is constantly increasing. The Tyrrhenian Link will increase electricity exchange capacity and thus support the development and better use of renewable energy flows.