Jonathan Leake, Environment Editor TimesOnline
THE first detailed study of Britain’s onshore wind farms suggests some treasured landscapes may have been blighted for only small gains in green energy.
The analysis reveals that more than 20 wind farms produce less than a fifth of their potential maximum power output.
One site, at Blyth Harbour in Northumberland, is thought to be the worst in Britain, operating at just 7.9% of its maximum capacity. Another at Chelker reservoir in North Yorkshire operates at only 8.7% of capacity.
Both are relatively small and old, but larger and newer sites fared badly, too, according to analyses of data released by Ofgem, the energy regulator, for 2008.
Siddick wind farm in Cumbria, now operated by Eon, achieved only 15.8% of capacity, the figures suggest. The two turbines at High Volts 2, Co Durham, the largest and most powerful wind farm in Britain when it was commissioned in 2004, achieved 18.7%.
Turbine efficiency is calculated by comparing theoretical maximum output with what the farms actually generate. The best achieve about 50% efficiency and the norm is 25%-30%.
Experts say the figures for individual wind farms have to be treated with caution as output can vary sharply because of factors such as breakdowns.
The revelation that so many wind farms are performing well below par, however, will reinforce the view of objectors who believe many turbines generate too little power to justify their visual impact.
Britain has 245 onshore wind farms. Although wind power is expensive, the industry has boomed because of the “renewable obligation” subsidy system, under which consumers pay roughly double the normal price for energy from wind.
Michael Jefferson, professor of international business and sustainability at London Metropolitan Business School, who is also a former lead author for the Intergovernmental Panel on Climate Change, has cited the efficiency figures in peer-reviewed papers. He says the subsidy encourages the construction of wind farms.
“Too many developments are underperforming,” he said. “It’s because developers grossly exaggerate the potential. The subsidies make it viable for developers to put turbines on sites they would not touch if the money was not available.”
Nick Medic of Renewable UK, which represents the wind industry, said Britain’s ambitious targets for clean power meant the country needed “every bit of green energy it could generate”.