Sun, wind and wave-powered: Europe unites to build renewable energy 'supergrid'

It would connect turbines off the wind-lashed north coast of Scotland with Germany's vast arrays of solar panels, and join the power of waves crashing on to the Belgian and Danish coasts with the hydro-electric dams nestled in Norway's fjords: Europe's first electricity grid dedicated to renewable power will become a political reality this month, as nine countries formally draw up plans to link their clean energy projects around the North Sea.

The network, made up of thousands of kilometres of highly efficient undersea cables that could cost up to €30bn (£26.5bn), would solve one of the biggest criticisms faced by renewable power – that unpredictable weather means it is unreliable.

With a renewables supergrid, electricity can be supplied across the continent from wherever the wind is blowing, the sun is shining or the waves are crashing.

Connected to Norway's many hydro-electric power stations, it could act as a giant 30GW battery for Europe's clean energy, storing electricity when demand is low and be a major step towards a continent-wide supergrid that could link into the vast potential of solar power farms in North Africa.

By autumn, the nine governments involved – Germany, France, Belgium, the Netherlands, Luxembourg, Denmark, Sweden and Ireland and the UK – hope to have a plan to begin building a high-voltage direct current network within the next decade. It will be an important step in achieving the European Union's 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. "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. The surge in wind power means the continent's grid needs to be adapted, according to Justin Wilkes of the European Wind Energy Association (EWEA). An EWEA study last year outlined where these cables might be built and this is likely to be a starting point for the discussions by the nine countries.

Renewable energy is much more decentralised and is often built in inhospitable places, far from cities. A supergrid in the North Sea would enable a secure and reliable energy supply from renewables by balancing power across the continent.