The next step will see the 9 Governments involved – Germany, France, Belgium, the Netherlands, Luxembourg, Denmark, Sweden and Ireland and the UK – start to put together firm plans to begin building a high-voltage direct current network, to commence within the next decade.

It is seen by some as vital if the European Union is to make good on its pledge that, by 2020, 20% of its energy will come from renewable sources.

"We recognise that the North Sea has huge resources, we are exploiting those in the UK quite intensively at the moment," said the UK's energy and climate change minister, Lord Hunt, quoted in the UK's Guardian newspaper. "But there are projects where it might make sense to join up with other countries, so this comes at a very good time for us."

More than 100GW of offshore wind projects are under development in Europe, around 10% of the EU's electricity demand, and equivalent to about 100 large coal-fired plants. In the UK alone, The Crown Estate will shortly announce the consortia chosen to develop up to 20GW of wind power from offshore wind zones in the North Sea.

This surge in wind power - together with a growing need to use stored-up energy from hydro dams, and allow grids to cope with variable sources of clean energy - means the continent's grid needs to be adapted.

Commenting on the declaration Justin Wilkes, European Wind Energy Association (EWEA) policy director, said, “these nine countries have taken a step in the right direction. The building of a supergrid in the North Sea is vital for fully exploiting Europe’s biggest energy source - offshore wind. More than 100 GW of offshore wind projects are at various stages of planning, which could provide more than 10% of the EU’s electricity. A new multi-billion Euro European industry is emerging; one that will create thousands of jobs, provide affordable electricity, boost Europe’s energy security and help fight climate change.”