From The Telegraph
Britain’s wind farms are wearing out far more rapidly than previously thought, making them more expensive as a result, according to an authoritative new study.
By Robert Mendick, Chief Reporter
8:40AM GMT 30 Dec 2012
The analysis of almost 3,000 onshore wind turbines — the biggest study of its kind —warns that they will continue to generate electricity effectively for just 12 to 15 years.
The wind energy industry and the Government base all their calculations on turbines enjoying a lifespan of 20 to 25 years.
The study estimates that routine wear and tear will more than double the cost of electricity being produced by wind farms in the next decade.
Older turbines will need to be replaced more quickly than the industry estimates while many more will need to be built onshore if the Government is to meet renewable energy targets by 2020.
The extra cost is likely to be passed on to households, which already pay about £1 billion a year in a consumer subsidy that is added to electricity bills.
The report concludes that a wind turbine will typically generate more than twice as much electricity in its first year than when it is 15 years old.
The report’s author, Prof Gordon Hughes, an economist at Edinburgh University and a former energy adviser to the World Bank, discovered that the “load factor” — the efficiency rating of a turbine based on the percentage of electricity it actually produces compared with its theoretical maximum — is reduced from 24 per cent in the first 12 months of operation to just 11 per cent after 15 years.
The decline in the output of offshore wind farms, based on a study of Danish wind farms, appears even more dramatic. The load factor for turbines built on platforms in the sea is reduced from 39 per cent to 15 per cent after 10 years.
Prof Hughes said in his conclusion: “Adjusted for age and wind availability, the overall performance of wind farms in the UK has deteriorated markedly since the beginning of the century.
“In addition, larger wind farms have systematically worse performance than smaller wind farms.”
The study also looked at onshore turbines in Denmark and discovered that their decline was much less dramatic even though its wind farms tended to be older.
Prof Hughes said that may be due to Danish turbines being smaller than British ones and possibly better maintained.
He said: “I strongly believe the bigger turbines are proving more difficult to manage and more likely to interfere with one another.
“British turbines have got bigger and wind farms have got bigger and they are creating turbulence which puts more stress on them.
“It is this stress that causes the breakdowns and maintenance requirements that is underlying the problem in performance that I have been seeing.”
Prof Hughes examined the output of 282 wind farms —about 3,000 turbines in total — in the UK and a further 823 onshore wind farms and 30 offshore wind farms in Denmark.
The report, published last week by the Renewable Energy Foundation (REF), a think tank that has campaigned against wind farms, will give ammunition to sceptics, especially within the Conservative Party, who believe the cost of subsidies to the wind industry is far too high and that the growing number of turbines are blighting the countryside.
Dr John Constable, the director of REF, said: “This study confirms suspicions that decades of generous subsidies to the wind industry have failed to encourage the innovation needed to make the sector competitive.
“Bluntly, wind turbines onshore and offshore still cost too much and wear out far too quickly to offer the developing world a realistic alternative to coal.”