Spain Plans a 363-km Undersea Cable to Power Mallorca Cleanly
Cleaner, cheaper electricity for islanders — and a blueprint other islands could copy.
Islands have a power problem most of us never think about. Because they aren't plugged into a bigger grid, they have to generate nearly all their own electricity — usually with diesel or gas plants. That's expensive and dirty, and it makes it harder to switch to solar and wind, because a small grid has less room to absorb the ups and downs of weather-driven power. The Spanish grid operator wants to fix that for the Balearic Islands by building a second high-capacity link to the mainland.
The technology is called HVDC, or high-voltage direct current — think of it as a very long, very efficient extension cord that can carry large amounts of power underwater without losing much along the way. The specific flavour here, VSC (a converter that lets operators steer power flow precisely and steady the grid), will be built as a pair of 200-megawatt cables, together 400 megawatts, running about 363 kilometres beneath the sea from a substation near Castellón on the Spanish coast to an existing substation at San Martín on Mallorca. The paper, written by engineers at the Spanish transmission operator, lays out the technical challenges of decarbonising an island system.
So what does it mean for you? If you live in or visit the Balearics, it points to a grid that can lean on cheap mainland renewables, which should mean lower generation costs and less local pollution over time. Sun-drenched Mallorca could also export surplus solar power back to the mainland on good days — a two-way street. For everyone else, it's a test case: as countries try to clean up their grids, subsea cables are becoming the plumbing that ties it all together, from the North Sea to the Mediterranean.
The catch is that this is a described plan, not a finished project. Subsea cables are costly, slow to build, and exposed to fishing gear, anchors, and seabed conditions. And leaning on one link means islanders depend on it staying healthy — which is exactly why this is a *second* interconnection rather than the only one.
- A planned undersea cable would send mainland power to Mallorca, so the islands can use more solar and wind instead of gas and diesel.
- It's big: two 200-megawatt cables, roughly 363 kilometres long, from near Valencia to an existing substation on Mallorca.
- The win is a steadier, cleaner, likely cheaper island grid — but such cables are expensive to build and vulnerable to damage.
Why It Matters
Cleaner, more reliable and potentially cheaper electricity for island residents, with a template other islands may follow.