Two gigantic submarine cables between Spain and Italy, among the large European electrical interconnection projects

The European Union is immersed in a full energy transformation at two levels: the transition towards renewable sources and a structural change deep, so that success depends less on each country’s individual generation and more on the ability to move that energy efficiently across borders. In this framework, the European Network of Electricity Transmission Network Operators (ENTSO-E) works on a continental grid that eliminates technical bottlenecks. An example: the energy island called the Iberian Peninsula.

The objective is for energy to flow from areas with surplus to others with deficit, preventing it from being trapped without a commercial outlet due to lack of transportation capacity. With that logic, the ENTSO-E just published its complete portfolio of the Ten-Year Network Development Plan 2026 with almost 200 transmission projects, 22 of them completely new. Among these novelties there are two particularly important for the Iberian Peninsula: they connect Spain with Italy.

The cables. Apollo Link and Iberia Link are two high-voltage direct current submarine cable projects that would cross the Mediterranean to connect the Iberian Peninsula with northern Italy. They are independent of each other but share the same mission: to create a direct electric highway between an area with great renewable generation capacity such as Spain and one of the industrial regions with the highest electricity consumption in Europe, northern Italy.

None of the projects has support from the transport network operators of each state, Red Eléctrica and Terna, respectively, but rather They are initiatives of private investors of Italian origin whose identity has not been revealed.

Why is it important. The emerging continental grid is vital for the decarbonization of the continent as it allows the full use of renewable energy surpluses: Spain is one of the leaders in solar and wind energy (Italy stands out in solar, but not so much in wind) and this interconnection makes it possible that when there is excess production in the Iberian Peninsula, that clean energy can supply Italian demand instead of being left without a commercial outlet due to lack of transport capacity. The foreseeable net flow would be predominantly from west to east, although the connection would also allow energy to be imported from Italy in times of shortage on the Peninsula.

But for the Iberian Peninsula it is even more relevant: this future east-west corridor allows its surpluses to be evacuated to the rest of Europe, thus ending its limited interconnection capacity. And also something essential: this connection provides security of supply (as evidenced the blackout) and the possibility of coupling markets to reduce electricity prices for the final consumer.

Context. The Iberian Peninsula is considered an energy island within Europe. Its interconnection capacity with France round 3,000 MW, far below of the 15% target of installed capacity established by European regulations. And this has consequences: in times of high renewable generation, prices become negative within the peninsula and surplus energy cannot be exported. In times of scarcity, it cannot be easily imported either.

This is just one of the projects that seek to end the energy isolation of the peninsula: they are also on the table the Bay of Biscay submarine cable planned for 2028 and included in all PCI lists since 2013. And under construction is a new northern interconnection of Portugal with Galicia which will add an extra 1,000 MW of exchange capacity. On the other hand, the trans-Pyrenean projects in Navarra and Aragon they are still blocked and with no date on the horizon to unclog them.

Retail. Some technical curiosities of both cables:

• Apollo Link is the more ambitious of the two. It consists of an interconnection between Spain and northern Italy with a capacity of 2 GW planned to enter service in 2032. It would implement the most modern standard for long-distance underwater transmission for bidirectional control and minimize losses, bipolar HVDC technology with VSC converters. It would operate with the standard adopted by the European industry of 525 kV, facilitating interoperability. Its capacity allows it to supply several million homes. According to its promoters, it would generate more than 300 million euros annually in net social benefits.
• Iberia Link shares the same technology and operating voltage, but has a lower capacity: 1.2 GW. What distinguishes it is its length: 1,034 kilometers of submarine cable between southern Spain and northern Italy, which would make it one of the longest underwater electrical links in the world. It has no published entry into service date.

Specifications of both cables. TYNDP map

Yes, but. That they are included in the TYNDP 2026 is the prerequisite to qualify for the status of Project of Common Interest that opens the doors to community financing and an accelerated regulatory framework, but for the moment the situation of both is “under consideration”, which means that they are in the study phase and do not yet have European regulatory approval: they will have to pass the cost-benefit analyzes of the ENTSO-E to take the first step to materialize (we will know in the last quarter of 2026).

And furthermore, they do not have the support of state operators, nor permits or approved layout because they are in preliminary phases. Likewise, the history of blocking similar projects invites caution. But even if they became a reality, these projects would only partially mitigate the electrical isolation of the peninsula: they are only 3.2GW of the 10-15GW of total interconnection necessary to truly influence the European market.

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Cover | ENTSOE