This is the title of a recent scientific paper published jointly by the Scientific Alliance and the Adam Smith Institute and authored by Dr. Capell Aris, which offers some calculated insight into the contribution of wind power to the UK's energy requirements. The study analyses wind data collected at half-hourly intervals from 22 sites in the UK over a period of nine years, with further measurements from 21 sites in Northern Europe and Ireland. This allows the hour-by-hour output of a fleet of wind turbines of nominal 10GW capacity to be modelled.
The full paper is a demanding read but if you want to check it out in full click here.
The results are revealing, although not surprising to anyone who has taken time to look at actual outputs over different days. Power output is below 20% of nominal capacity for over 20 weeks of the year, and below 10% for nine weeks. The UK system produces 80% or more of its rated output for just 163 hours a year, or less than a week. Rapid swings in output mean that conventional plant must be left idling and ramped up at a moment’s notice.
For anyone who thinks that new wind turbine arrays will replace old coal and gas stations as they close down, the details of this study will be a rude awakening. New gas plants are being built to provide continuity of supply and, in simple terms, there must be conventional stations available to meet the entire capacity of the wind fleet to cope with calm days, particularly at times of high demand in winter.
Another argument often put forward in favour of wind energy is that the wind is always blowing somewhere, so having many turbines spread out over a wide area will to some extent smooth the output. This turns out not to be true; the ‘guaranteed’ output is only about 2% of the nominal rating, or 200MW instead of 10GW. Installing a wider grid, such as the proposed Europe-wide ‘super grid’ would make little difference.
The only way wind and solar power would be able to make more than a modest contribution to energy supplies and emissions reduction is when affordable energy storage is available on a massive scale, but this is still some way over the horizon.
The Scientific Alliance
The UK wind debate assumes that wind farms operate at roughly their average output most of the time. According to Dr. Capell Aris’ new paper produced in concert with the Scientific Alliance this is not true. Power comes only extremely intermittently and variably and there are long periods of negligible efficiency in the long winter months when power is most needed. A 10GW wind fleet would need approximately 9.5GW of fossil capacity to guarantee its output.
Adam Smith Institute
Of course we could always settle for an energy supply network where there's no electricty for hours, days or even weeks on end.
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