Big isn't any better with wind power YOUR article on windfarms managed to avoid the fundamental truth about generating electricity from wind ("Giant steps towards a low-carbon future", last week). It is erratic, unreliable and unpredictable. It always was and it always will be.  Imagine the furore if power stations were only supplied with fuel on average two days a week and some weeks not at all. Unless, of course, comments from Steve Holliday, the head of National Grid, are meant to imply that this is precisely what we can expect in the future.  Wind turbines depend on massive subsidies from you and me, otherwise they are totally uneconomic. Shell has already pulled out of the London array scheme, so one suspects that even with the subsidies and renewables obligation certificates, the economics are borderline.  The article suggests that making wind turbines even more gigantic will somehow solve the problem; frankly, making them as tall as the Empire State Building won't make an iota of difference. as I write, the contribution that wind is making to electricity demand is the same as before Christmas 2010 - 0.1%.  David Simmons Cambridge