EMPIRICAL evidence based on what real wind turbines produce suggests that wind turbines in an array can generate, both on and off-shore, random pulses of electricity amounting, annually, to around 2000 MWh of the wrong kind of electricity per installed MW.

The right kind of electricity is, of course, the "firm" thermal electricity that keeps our lights on 24-7 and comes from fossil fuel and nuclear power stations in the UK and in France from time to time.

Alyn Smith continues to wax lyrical on the "resurgent Scottish renewables industry's march of progress" (Letters, September 6). This march to fuel poverty is supported by an SNP government that appears to believe that intermittent supplies, backed up to the hilt with dwindling supplies of fossil fuels, is going to create tens of thousands of clean green jobs making Scotland the centre of the new world economy. There are only four companies that have been persuaded to enter the Saltire Prize competition; each company will need to put a minimum of £500m of hardware in the water and there can only be one winner of the rather paltry £10 million prize. It is certain that all these companies will drop out in the next year or so, leaving the £10 million unclaimed.

My suggestion would be to use this spare cash to build a care home for all the bewildered and delusional politicians who think that Scotland will become the Saudi Arabia of renewables and that a plethora of ill-advisedd renewable energy "planet friendly" schemes will save the Earth from overheating.

Andrew H Mackay,

Causewayside, Glenaldie, Tain.

PETER Mumford is mistaken if he accepts the Moray wind farm developer's claim that it would provide electricity for a million homes (Letters, September 5). His maths may show this but he is overlooking the nature of wind generation which cannot provide "firm" or controlled generation. At times the Moray wind farm won't provide any electricity. Power station backup is required 24/7 and this hidden cost and the increasing "constraint" payments paid to wind farms to shut down in windy conditions when the grid has excess electricity must be added to the public and consumer subsidies being paid. It is estimated that by 2020 electricity bills will have risen by 58% because of the increase in wind turbines alone.

This isn't how wind farms are usually presented and other costs like permanent topological degradation, landscape destruction and loss of wildlife habitat must be taken into account. Your Public Notices (September 4) carried information on two wind farm applications, one south-east of Fort Augustus and another north-west of Invermoriston. Tourism is clearly at risk. Claims of CO2 emission reduction because of wind farms remain unsubstantiated.

A R Nelson,

5 Scarletmuir, Lanark.