Denmark unveiled plans for one or more ‘energy islands’ each supporting at least 10GW of offshore wind at a cost of up to DKr300bn ($44.5bn), in what could be the world’s most ambitious renewable energy scheme to date.

Denmark’s energy ministry said early work to identify possible sites for the massive hubs is now underway, in a move that would allow huge amounts of offshore wind to be harnessed for hard-to-decarbonise sectors such as transport and heating.

A statement from the ministry said the ‘energy island’ concept could cover physical islands or artificial platforms, each acting as a hub for interconnected offshore wind, and supporting facilities such as energy storage or green hydrogen production.

If it advances, the Danish plan could dwarf other offshore wind and renewable energy mega-projects around the world. Each ‘island’ could power 10 million homes, the ministry reckons. The "vast majority" of the DKr200-300bn needed would come from private investors, it added, but the government has put in an initial DKr65m for exploratory work.

Climate and energy minister Dan Jørgensen said: "It is a huge project. We need to build more than five times as much capacity as we have today. We need a sensible and ambitious plan for expansion. Therefore, we are now engaged in preliminary studies."

Denmark will look at potential sites in the North Sea, Baltic and Kattegat and hold talks with surrounding nations over the plan. It said the first step will be to see “if it is practically possible to establish one or more energy islands in relation to nature, environment and planning”.

Plans for energy islands and interconnected, meshed networks of offshore wind are gathering pace across Europe. Denmark’s own offshore wind pacesetter Orsted recently unveiled plans for a 5GW hub on the island of Bornholm connecting Denmark, Poland, Sweden and Germany, and supporting large-scale production of green hydrogen.

Denmark – historically a pioneer in the wind sector – last week passed legislation legally binding it to 70% emissions reductions by 2030.

Its next big offshore wind project will be the up-to 1GW Thor, the first of three major developments planned before 2030.

Jørgensen added: "Offshore wind is central to the green transition. If we seriously need to realise the enormous potential of offshore wind holds, so we must develop tomorrow's technologies to transform the green power fuel for aircraft, ships and industry."

Industry body WindEurope said in a study released last month that offshore wind power could carry Europe to carbon-neutrality by mid-century, reaching an installed base of 450GW and meeting 30% of the continent’s power demand.

Note: Version corrects timescale for Denmark's 70% target to 2030.