Wind farm turbines wear sooner than expected, says study

December 31, 2012 by  
Filed under Green Energy News

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

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

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

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

Prof Hughes said his analysis had uncovered a “hidden” truth that was not even
known to the industry. His report was sent to an independent statistician at
University College London who confirmed its findings.

The report has been disputed by the wind farm industry. It points out that the
consumer subsidy is paid only when turbines produce electricity, meaning
there is a strong incentive for wind farms to be properly maintained to
protect them from wear and tear.

Dr Gordon Edge, dthe irector of policy at RenewableUK, the body that
represents Britain’s wind farm industry, said: “Wind farm developers only
earn money for the clean electricity they actually generate, so it’s very
much in their interests to make sure that their turbines are maintained… to
an optimum level, which includes upgrading as the technology improves.

“Better turbines are being developed all the time, so it’s absurd to focus
purely on the past as this report does, and pretend that that’s the way
things are going to be in the future.”

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