Tilting at windmills as the wind drops

This is almost accurate but doesn't tell the whole story. Denmark does produce an amount of electricity from wind power equivalent to 20% of its electricity use.

However, due to the excessive variability, some of that power is exported to Norway at a low cost, where it is stored by hydro, and Denmark then buys the equivalent back at a more expensive tariff.

Wind actually only directly supplies 10 per cent to 14 per cent of Denmark's electricity and Danish consumers have some of the most expensive electricity in Europe so, economically, this isn't great, although, technically, hydro and wind can be an excellent fit.

Scotland, however, does not have the amount of pumped-storage hydro needed to replicate this system (it would require many pumped-storage facilities to balance the amount of wind envisaged and they are very expensive to build) and the Scottish enthusiasm for a "supergrid" is partly to allow Scotland to use Norway's hydro in the same way. It is easy to see what Norway gains from the proposed arrangement - less so for the economy of the UK.

Helen McDade, Head of Policy, John Muir Trust

YOUR front page reports that last month wind turbines generated but half the power expected of them, sadly handing another card to the anti-renewables lobby.

All renewables have weak points (ie, tide and wave power generators may be more costly to maintain) but it beats me why we rush to pour so much subsidy into wind power - the least predictable and controllable renewable source. I suspect the land-owning lobby spotted another public money teat to start sucking on, and mobilised before anyone else had a chance. They will under-deliver, of course, and when the teat runs dry go elsewhere for another subsidy.

Public subsidy for renewables should start by solar panels becoming compulsory elements of every new-build house, office and factory: our First Minister could enact that with a simple stroke of the pen. Why hasn't he? It should go on to major its development and application subsidies on wave and tide - more predictable, reliable sources - and the windmill lobby should be our last resort, not first.

If, like bankers' bonuses, subsidies to the windmill people were repayable when they failed to deliver, we would begin with realistic estimates of their ability to deliver, and fewer would raid the public money pot.David Fiddimore, Edinburgh

YOUR environment correspondent reports that unusually calm weather this year has reduced wind powered electricity by half and that, as other sources decline, we can expect inadequate power supplies in the future, though perhaps wind somewhere in the UK will usually suffice.

In fact, wind turbine output and electricity from other sources, posted continuously on the NETA website have shown, typically, that the 2,800 UK wind turbines contribute proportionately only one percent of our needs or less.

The windpower situation is far worse, therefore, than the developers want us to know and most of our politicians seem to be turning a blind eye, having been duped by sales talk of Scotland's "Saudi" potential.

In Denmark, where the greatest effort has been put into wind power, under half of their renewable sources' electricity is available in practice, with no evidence of saving of money or carbon dioxide output or even of net job creation. The Germans are expected to stop subsidising renewables, and have found solar power very disappointingly uneconomical.

As the costs and landscape damage attributable to developing renewables are vast and the returns so paltry, surely it is time we had a national Task Force of experts in power generation, ungoverned by short-term political or commercial pressures, to give best, unbiased advice to those in political charge, so as to anticipate Britain's looming power shortfall.

This would allow rational choices for investment of the public's money. We are owed that, but it is not yet happening.

Charles Wardrop, Perth