Terna breaks ground on Sardinia-Corsica-Tuscany interconnection

Terna, the Italian national transmission grid operator, has begun land-based construction of Sa.Co.I.3, the 200kV DC electrical interconnection that will link Sardinia, Corsica and Tuscany.

According to Terna in a release, the project will contribute to strengthening the European electricity market and promoting the integration of renewable energy sources.

Moreover, the infrastructure will be essential in guaranteeing the connection between the Corsican and Italian electricity systems, thanks to the construction of the Lucciana terminal by EDF, the French national electricity grid operator in Corsica.

The opening of the sites confirms the commitment of the company led by Giuseppina Di Foggia to the execution and implementation of the electrical infrastructure, which is essential for achieving the targets set by Italy’s Integrated National Energy and Climate Plan.

A total investment of around €1.35 billion ($1.42 billion) is planned for the works controlled by Terna, with a cost-sharing scheme between Italy and France in accordance with the coordinated decision of the respective regulators. The project, scheduled to enter operation in 2029, was authorised by the Italian Ministry of the Environment and Energy Security in 2023.

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Sa.Co.I.3 has received approval from the European Council for a €200 million ($209.3 million) funding under the REPowerEU programme and includes the modernisation and enhancement of the current Sa.Co.I.2 interconnection, which has been in operation since the 1990s. The original infrastructure between Sardinia and Tuscany, commissioned in 1967, was the world’s first 200kV direct current connection.

The first land-based construction sites have been opened in Santa Teresa Gallura (SS) to build the landing point for the submarine cables between Sardinia and Corsica. From March 2025, works will also begin in Salivoli (LI).

The construction sites in the two coastal municipalities will be paused at the end of May for the summer break and will resume in October to minimise the impact on local activities.

The infrastructure consists of 120km of submarine power lines between Tuscany, Corsica and Sardinia, as well as two new electrical substations: one adjacent to the existing plant in Codrongianos (SS), and one in Suvereto (LI), within the Terna electrical substation of the same name.

In Sardinia, 6km of underground cable will be installed in the municipality of Santa Teresa Gallura, enabling the demolition of 5km of overhead power lines, while 1.2km of underground cables will be laid in the municipality of Piombino, in Tuscany.

Every aspect of the project has been designed to integrate with the surrounding environment, minimising its impact at all stages, from construction to operation.

For the cable landing points, sustainable solutions such as guided drilling will be used to significantly reduce environmental effects on the marine ecosystem and coastline during the installation of the power cables.

Specifically, the converter stations, thanks to an architectural competition promoted by Terna in collaboration with the involved municipal administrations, will be designed to ensure the best integration into the natural landscape of the two regions affected by the project.