A new study of cheap energy wind farms in the UK reveals that many are not as efficient as they should be.
Research conducted by Professor Michael Jefferson on behalf of the Campaign to Limit Onshore Windfarm Development (Clowd) claims that 20 of the UK's wind farms produce less than 20 per cent of their maximum output.
Some warm farms were found to produce less than ten per cent of their maximum output, with Blyth Harbour in Northumberland thought to produce just 7.9 per cent - the worst performing site surveyed.
The findings were contested by Nick Medic, head of communications at RenewableUK, who maintained that the average efficiency factor for onshore wind in the UK is 29.3 per cent - the best in Europe.
"To suggest that developers have overestimated capacity is plain wrong," he said.
"Statistics are expected to show that wind energy provided enough electricity for 2.5 million homes in 2009."
If you want to find out more about your energy options and how you could save up to £378 in minutes, click here.