Fifty times more wind turbines by 2020

Britain will have to install six times more wind turbines on land and 50 times more wind turbines at sea by the end of the next decade under rules to be announced by Brussels next week.

Experts say that EU's country-by-country share-out of targets for renewables will mean that Britain has to generate nearly 40 per cent of its electricity by renewable means to help tackle global warming. This is because the mandatory target which EU sources say Britain will face is 13-14 per cent of total energy use to come from renewable sources by 2020 - up from 2 per cent today. It applies to total energy use, not just electricity generation as targets have in the past.

This target was signed up to by Tony Blair, who defied advice from business leaders and ministerial colleagues that it would be hard to meet at a summit of EU leaders last March. It was confirmed by Gordon Brown in the autumn. Experts estimate that by 2020 no more than 6-7 per cent of the heating of homes and businesses will be converted to renewable sources - such as biomass boilers, ground source heat pumps and solar - and road transport will be at best only 10 per cent biofuels, so the rest of the slack will have to be taken up by the electricity generating companies.

Gordon Edge, director of economics and markets at the British Wind Energy Assocation, said: "It will be electricity that has to do the heavy lifting." The BWEA estimates that meeting the EU target will take 13,000 megawatts of electricity generation by onshore wind farms - an increase from 2,000 mw working at present, 900 mw under construction and 5,000 mw in the planning system. They also estimate that 20,000 mw of capacity will be needed offshore - an increase from 400 mw at present.

By then wave and tidal power might be expected to be generating one megawatt in total of expected electricity demand. Wind and tidal alone will therefore to amount to nearly 30 per cent of total energy use. There will then be small contributions from biomass - straw and wood- existing hydro as forms of electricity generation.