As I mentioned, I said I would email the MD of the owner/operator of the "350 ft giant" which the article claimed achived 15% of capacity.
Here is his response (N.B. as we have corresponded/messaged before it's really informal...) "Hi Nick, yep that one is ours. Things worth knowing on this front are - The figures they quote as efficiency measures (was it 20% for this windmill?) are actually Load Factor figures. Load Factor is a measure of the degree to which something operates at it's maximum capability over the year. Efficiency is a very different beast - our windmills are over 90% fuel efficient. The Load Factor of windmills is actually a measure of two things, the energy efficiency of a machine and the wind regime it operates within. The wind industry uses Load Factors as measures of on site wind resource. So for example typical load factors in England are 30% on shore. 40% in Scotland and 40% offshore. Typical load factors for coal, gas and nuclear plants are around 50% - and these are generators that do not depend on the weather for their operation. Typical fuel efficiency of coal might be 30 to 40%, Gas 40 to 50% and nuclear somewhere in between. Typical load factors for other every day items - cars - less than 1% mobile phones 1 or 2% kettles less than 1% These devices are not reckoned to be inefficient or un worthwhile because we do not use them anything like to their maximum rated potential. So this load factor argument is just a statistical device to discredit wind energy, a trap for the unwitting. Hope this helps." ----------------------------------------------------------------------------- Different subject - Jed wrote: "However, unlike wind power, PV produces peak electricity at exactly the moment when demand peaks during the summer, because air conditioning kicks in when the sun is hottest." America is not the whole world! In Britain, we don't really use air-con much. I guess our peak electricity is in the winter when we have electric fires on. Nick Palmer On the side of the Planet - and the people - because they're worth it Blogspot - Sustainability and stuff according to Nick Palmer http://nickpalmer.blogspot.com