MIDGES and sea salt could reduce the power generated by Highland wind farms by as much as a quarter, denting the industry’s profitability in Scotland.

Wind farm managers will test to check how much the combined weight of millions of the tiny dead insects on the giant blades slow down the turbines.

“Suicidal” flying insects have proved a big problem for wind farms abroad, in some cases reducing the potential for electricity generation by a quarter or more.

Tests will also be done to establish the threat to offshore wind farms — such as the 60-turbine Robin Rigg scheme in the Solway Firth — from accumulated sea salt on the blades.

AMEC, which is proposing one of the world’s biggest wind farms on the Isle of Lewis, says it is aware of the potential midge threat to its £600m scheme for 300 turbines. The project aims to generate 600 megawatts for the national grid.

The Lewis scheme is in the centre of a large peat bog, where midges love to live and breed.

AMEC is also planning schemes for 31 turbines at Aultmore in Moray and 47 turbines at Clashindarroch.

Other schemes in midge country likely to be affected include the world’s largest wind farm project — 360 turbines to be built by a London-based firm called Wind Energy on the skylines of Ardnamurchan and Morvern peninsulas and in the north of Mull.

AMEC said it was monitoring the situation: “It is common practice to monitor the power output of operational wind turbines and should a reduction in performance be observed due to insect build-up, the blades would be cleaned to restore optimum performance.”

The British Wind Energy Association admitted there was a potential problem similar to those experienced in Spain and California: “Insects do decrease the performance of the blades by commiting hara-kiri on them. Sea salt is also an issue for offshore turbines. Tests have shown that can lead to a reduction of 20%-30% in output.”

A2SEA, a Danish company, has developed the first automatic wind turbine cleaner which washes and waxes the blades. It was unveiled in Germany in September and will be available for hire to the proposed Scottish schemes.

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