'Breathes there the man with soul so dead/Who never to himself hath said/'This is my own, my native land - and what a gruesome tip they've made of it...?'" Nobody ravages a landscape more devastatingly than an environmentalist. The crazed drive to promote wind farms has destroyed Scotland's natural beauty by peppering our rural wildernesses with Martian wind turbines - to no practical benefit.

Last week Alex Salmond performed the formal opening ceremony at Whitelee wind farm, outside Glasgow, run by the Spanish company Iberdrola Renovables through its Scottish subsidiary ScottishPower Renewables. This is now the largest onshore wind farm in Europe, comprising 140 wind turbines. The owners' publicity material trumpeted its generating capacity of 322 MWA, to be increased to 600 MWA within a few years.

Promoters of wind power are very keen on proclaiming their turbines' "generating capacity". What they are less keen on broadcasting is the fact that Government figures show an average capacity utilisation factor (CF) of just 28 per cent for onshore wind farms. So all those impressive megawatt and gigawatt figures have to be adjusted accordingly.

A study conducted by the Renewable Energy Foundation discovered that only a few Scottish wind farms attain the 28 per cent of theoretical capacity, while in some parts of England the figure is below 10 per cent. This reflects the fact that turbines will not work if the wind is not strong enough, while if it is too strong the generators have to be locked down to avoid damage. In a speech in the House of Lords on 7 May, Lord Reay claimed an idleness rate for turbines of between 55 and 110 days a year.

Amid its triumphalist announcements last week, Scottish Power made no reference to the remarks made to Reuters news agency on 22 April by Rupert Steele, regulation director at ScottishPower Renewables, in which he warned that Britain, aiming to install some 30 gigawatts (GW) of wind turbines by 2020, will need to build almost an equivalent capacity of backup power generation to cover periods when the turbines are idle. "Thirty gigawatts of wind maybe requires 25 GW of backup," he said. "The problem is that if you've got a high-pressured area, you may have quite a large area where there's no wind at all..."

So, what we are actually doing, at a time of financial stringency, is creating two parallel energy systems, at more than double the necessary cost, to meet demented EU targets, while simultaneously destroying our landscape - in the name of environmentalism. As Lord Reay pointed out, "per delivered megawatt, the capital cost of wind is three to five times the cost of nuclear, ten times the cost of gas and 15 times the cost of coal".

Scotland is the worst loser in the United Kingdom from the wind power hysteria. Our landscape - our greatest national asset - is desperately vulnerable. To look at the online map created by Scottish Natural Heritage, charting the growth of wind farms, is a deeply dismaying experience. The infestation is already far-flung and mostly afflicts sites of natural beauty. The most high-profile current controversy involves the proposed Viking wind farm on Shetland, comprising 150 turbines over 12,800 hectares. Yet Viking Energy itself has produced a worst-case scenario in which it would take 14.9 years to pay back the carbon dioxide emissions potentially produced from drying out peat bog over 25 years' operation.

There are issues of democracy too. So committed is the Scottish Government to renewable energy that wind farm applications in Scotland are seldom rejected, though there is only a 40 per cent approval rate in England. The SNP managed to ban nuclear power by winning a Holyrood vote in January 2008. No person of any sensitivity welcomes nuclear power, with its long-term waste disposal problems; but harsh reality may force it upon us. Of Scotland's two existing nuclear power stations, Hunterston B is due to close in 2016 and Torness in 2023. The notion that this generating capacity can be replaced by a jungle of temperamental whirligigs is infantile.

It is also outdated. True environmentalists subscribe to the Charter of Palermo, recently drawn up by a conference of European artists, academics and environmentalists chaired by former French president Valéry Giscard d'Estaing, condemning wind farms' destruction of Europe's patrimony of natural beauty. In Britain there are already 2,434 turbines in operation, two-thirds as many under construction and more than twice as many planned. They are hideous, costly and inefficient. This madness must end.