THE letters of Neil Craig and G I Crawford (January 15) contain a number of inaccuracies which I hope you will allow me to correct.

If, as Mr Craig claims, it is very difficult to get wind generation above 10% of supply, then we will shortly find this out. As reported in the Sunday Herald on January 14, onshore wind currently accounts for just under 10% of Scottish electricity. If Mr Craig is right, then the the lights will start flickering in Scotland this year, as increased wind capacity is commissioned. I have put a note in my diary for January 2008 to check whether Mr Craig is right or not. If he is right I will apologise to him in this newspaper. Will he give a similar undertaking if I am right and the lights don't start flickering?

Over a year, the average UK wind farm does, indeed, produce around 27% of its theoretical output were it to run at 100% of rated output all year. That is as expected and is not a reason to stop building them. No form of generation runs at 100% of rated output all year; the comparable figures for gas power stations are 60%, nuclear 71%, hydro 37%, pumped storage 10% and coal 62%. The overall average figure for the UK electricity network is around 55%, but that does not mean that no electricity is generated for 45% of the year. None of these figures is a measure of reliability, as Mr Craig claims; they are a measure of how plant is utilised.

Nuclear is certainly not the cheapest form of generation. The large station size and inherent inflexibility of nuclear generation mean that large amounts of back-up are necessary to keep the lights on when such plants suddenly fail, which they do in the UK with some regularity. Neither does nuclear generation emit zero carbon dioxide, as both letter-writers claim.

It is time that the politicians started acting in the public interest, instead of mouthing platitudes and doing the wrong thing. That would involve a massively enhanced programme of energy conservation, continuing with onshore wind and boosting other renewables. Nuclear generation can be allowed to wither without causing massive blackouts. The politicians also need to get serious about the majority of energy consumption, and thus greenhouse gas emissions, which is not related to electricity. For example, expanding airports and roads, which the Labour/LibDem government is doing with the support of most of the other political parties, will increase greenhouse gas emissions.

David Hansen, 9a Duke Street, Leith