One of the 2MW Turbines at Haupland Muir in Ayrshire. Typically these turbines generate electricty 70-85% of the time but actual output depends on wind speed. Over a year it will generate 30% of its theoretical maximum (load factor), Hunterston B a few miles from here has a load factor of 60%. What this means is with wind power you need huge over capacity at different geographic locations, and/or conventional power stations available to plug the gap at short notice..... or you just let your lights go out