A LEADING power company has claimed wind energy is so unreliable that even if 13,000 turbines are built to meet EU renewable energy targets, they could be relied on to provide only 7 per cent of the country's peak winter electricity demand.
E.On has argued that, during the coldest days of winter, so little wind blows that 92 per cent of installed wind capacity would have to be backed up by traditional power stations.
It argues this would require new coal-fired power stations to be built so they could be used in an emergency when little wind blows.
This, E.On suggests, will mean that, to meet renewable targets of 20 per cent of energy being provided from renewables by 2020, the UK's installed power base will need to rise from 76 gigawatts today to more than 100GW.
The company estimates this could cost 100 billion.
The John Muir Trust, which campaigns against wind farms in Scotland's beauty spots, said E.On's claims back its view that the country is depending too heavily on wind power.
Helen McDade, the trust's policy officer, thinks instead far more should be done to improve energy efficiency.
"Energy conservation is by far the best use of money," she said. "The question is why we are not doing more of this."
She criticised the "assumption that as long as it's got a renewable tag on it we can carrying on using energy at the level we have been".
However, Friends of the Earth Scotland accused E.On, which is trying to build a new coal-fired plant at Kingsnorth in Kent, of "scaremongering".
"I'm not at all surprised to find a company trying to build new coal-fired power stations using unfounded assumptions about the renewables industry," he said.
"Essentially, what they are doing is taking a very simplistic analysis and arguing that we need to massively back up for the worst possible scenarios."
Dr Richard Dixon, director of conservation charity WWF Scotland, agreed. "It's not surprising, given their agenda is all about building massive coal-fired power stations," he said.
He said by 2020 wind turbines will be more efficient, there will be more storage within the grid, and the UK could be connected to the European grid – all measures which will undermine the need for back-up from coal-fired power stations.
E.On argues in its response to a House of Lords inquiry into the economics of renewable energy that if 40,000 megawatts of wind capacity – about 13,000 turbines – is needed to meet renewable targets, just 3,600MW will be able to be relied on to meet the peak demand in winter.
It says this is because on the very coldest days there is very little wind, because of anti- cyclones.
A spokesman said the question had to be asked how power companies would make money from plants that only run when the wind is not blowing.
"Under the current trading system for power, you just wouldn't build it so clearly there has to be some sort of encouragement," he said.
1,382 megawatts of installed hydro power in Scotland.
1,367 megawatts of installed wind power in Scotland.
100 megawatts of installed energy from waste in Scotland.
79 megawatts of installed biomass electricity in Scotland.
29 megawatts of installed biomass heat in Scotland.
2 megawatts of installed wave power in Scotland.
31 per cent of Scotland's electricity to be generated from renewable sources by 2011 under Scottish Government targets