Wind farms in the South West are only generating around a fifth of the electricity they are capable of, according to official figures from the energy regulator.
Statistics from every major wind farm in Britain show that more than half are operating at less than 25 per cent capacity. In England, the figure rises to 70 per cent of onshore developments.
Industry experts believe generous subsidies mean that turbines are being erected on sites which are simply not productive enough.
The worst performing wind farm in the country is in Blyth Harbour in Northumberland, where the nine turbines lining the East Pier reached just 4.9 per cent of its 2.7MW capacity.
There are eight operational wind farms in Cornwall and one in Devon. The Bears Down site, near Padstow, operated at 23.9 per cent over 12 months with Delabole, in North Cornwall, at 22.8 per cent.
St Breock, near Wadebridge, recorded a figure of 21.76 per cent while Cold Northcott, near Launceston, generated 20 per cent of its 6.8MW capacity. Four Burrows wind farm, near Truro, was the worst performing at 19.5 per cent. No figures were provided for the other sites.
The figures were analysed by Michael Jefferson, a professor of international business and sustainability, who said incentives designed to help Britain meet green energy targets had encouraged firms to site their developments badly. He said: "There is a political motivation to drive non-fossil fuel energy, which I very much respect, but we need more focus."
Professor Jefferson, of the London Metropolitan Business School, believes the full subsidy be restricted to turbines hitting capacity of 30 per cent or more – managed by just eight of England's 104 on-shore wind farms last year.
Those that fall below 25 per cent should not be eligible for any subsidy. "That would focus the mind to put them in a sensible place," he added.
A spokesman for renewable energy agency Regen South West said assessments had established where the best "wind resources" were in the region.
"Regen SW has therefore carried out 'wind resource assessments' to pinpoint where these places are.
"From these assessments it is clear that we are very fortunate in the Westcountry, as we have the best wind resource not only in the UK, but also in Europe.
"Having such a resource on our doorstep is an excellent opportunity. It means that we have the chance to deliver clean, green renewable energy that will help us keep the lights on years into the future.
"It's also the reason why Regen SW is encouraging local groups to come forward, embrace the technology, and develop the wind farms and other types of renewables that will benefit their own communities in our Communities for Renewables initiative.
"It's also important to remember that – regardless of the capacity factor – for every unit of electricity that is produced by a wind turbine, it displaces one unit of generated from fossil fuels."