Europe needs to build energy islands

“Oblivion”, a film starring Tom Cruise and released in 2013, was quickly relegated to the fate of its title. Still, it was memorable for one thing: gigantic contraptions of alien origin called “hydro-rigs”. They hovered over the Earth’s oceans and sucked up water. Europe’s ambitious plans to build an archipelago of artificial “energy islands” in the North and Baltic seas evoke a similar sci-fi vibe. Some will be huge, the size of dozens of football fields, designed to collect the power generated by hundreds of surrounding wind turbines. In March 2024 Elia, a Belgian power-grid operator, will start building the first one 45km off the country’s coast. But does Europe require such pharaonic projects?

You need not be an engineer to see the benefit of such islands. Today each offshore wind farm has its own cable connecting it to the grid on land. But as Europe gears up to produce 300 gigawatts (GW) from its northern seas by 2050—enough to power all of the continent’s homes—this method will become increasingly inefficient. It is much cheaper first to gather the electricity from several wind farms offshore and then send it onshore through one large cable. Energy islands could also feed power to multiple countries based on demand.

Elia’s “Princess Elisabeth Island” will be the world’s first such electric-network node. It will gather up to 3.5GW from a nearby offshore-wind zone. The power will be processed by two substations on the island and sent to Belgium through a cable, as well as to Britain and Denmark. Costing an estimated €2bn ($2.1bn), the five-hectare island will take a couple of years to build. Based on sand-filled concrete caissons resting on the seabed, it will also have a small harbour and a helicopter pad for maintenance visits.

Others have even bigger goals. Denmark plans to build an island 80km off its coast that will be more than twice the size, to have space for all sorts of add-ons: accommodation for crews (and even tourists), spare parts for wind turbines and, crucially, devices called electrolysers, which turn water into hydrogen and oxygen using electricity. Producing hydrogen would be a key source of revenue. Industries like steelmaking could use it to reduce carbon emissions.

But the project has hit some snags. In June 2023 Denmark again postponed a tender to build the island owing to its anticipated cost. The Danish state, which is meant to own slightly more than 50% of the island, would have had to cough up nearly €7bn on its own. The government has now gone back to the drawing board.

This does not mean the islands are doomed, but their final design is uncertain. Even Elia’s smaller plans may turn out to be overkill. They could end up resembling boring old oil platforms. ■

Ludwig Siegele, European business correspondent, The Economist, Berlin

This article appeared in the Business section of the print edition of The World Ahead 2024 under the headline “Power archipelago”