Brendan Turvey of Scottish Natural Heritage says "some areas ...

are near the capacity of the landscape to absorb further wind farm development" ("Scotland 'running out of land' for wind farms", The Herald, December 26). Travelling south from Biggar will provide evidence of that. But at times it is beyond the capacity of the grid to absorb the output of wind farms as evidenced more than once this year when National Grid asked for several wind farms to be shut down at great financial cost during windy weather.

This is the opposite of what we are led to believe, that wind generation replaces power station generation. Wind electricity is so unreliable and uncontrollable it can't replace reliable generation without continuous backup to ensure a stable electricity supply.

That's why there are only claims of emission reduction and never any evidence. Would Friends of the Earth and the Greens please take note?

Perhaps surprisingly, the Scottish Government in the 2009 Climate Change Adaptation publication said: "If electricity supply becomes increasingly reliant on wind power generation, electricity generation will necessarily vary according to the weather". With the extensive, permanent landscape effect and the effect on nature and the cost in subsidy, wind farms are a lose/lose project.

A R Nelson,

5, Scarletmuir,

Lanark.

I AGREE with Bob McDougall when he says that it is time to call a halt to the rush to build wind turbines and points to their susceptibility to recent "turbulent weather" (Letters, December 27). This reminds me of a recent comment by a representative of Scottish Renewables when addressing the reported poor performance of renewables in 2010, namely, "if we look at 2010, we see that it was a very unusual year that saw weather patterns we had not seen for years". If this were not such a serious issue, this would be laughable.

Any country which sets out to develop an electricity generation system based on the weather, such as Scotland is presently embarked upon, is doomed to economic oblivion. Before it's too late, can we implement a pragmatic, cost-efficient and reliable electricity generation strategy which utilises the knowledge and expertise of our engineers, rather than one based on political dogma and vested interests, supported by the ignorance of environmental lobby groups with no expertise in this critical area of life support?

Dr G M Lindsay,

Whinfield Gardens, Kinross.