Estimates of Britain’s energy capacity margins may be overoptimistic, as the National Grid has based its figures for wind power output on an assumption that wind farms will generate at least 23 percent of their capacity, it has emerged. The report by National Grid also assumes that lost capacity at a number of facilities which were unexpectedly closed will be reintroduced. If that assumption is incorrect the margin may dip into negative figures.
The assumptions were spotted by climate and energy blogger Bishop Hill, who wrote on his blog “it’s perfectly normal for the whole of the UK to simultaneously experience very low windspeeds (or no wind at all), and this has been known to happen even in the depths of winter, for example the very cold winters of 2009/10 and 2010/11.
“I had therefore assumed that the Grid would have to plan on the basis that they might get nothing from windfarms at all, but in fact they do nothing of the sort. According to Table 16, the grid assumes that they will get 23 percent of nameplate capacity, or some 1.7GW.”
Last month, Breitbart London reported on a study by the Scientific Alliance and the Adam Smith Institute, which found that, on average, wind farms only operate at eight percent of total capacity, whilst the base line for wind is just two percent. Essentially, although it is true to say that the wind is always blowing somewhere, it is also true to say that often it’s not blowing very much.
The National Grid has forecast a generating margin of 2.3GW this winter, but 1.7GW of that is predicted to be from wind. If Britain experiences a calm period taking wind out of the equation, the margin drops to just 0.6GW, or a mere 1 percent.
The report notes the closure of Hartlepool and Heysham, which they predict would reduce capacity by less than half a percent, but states that “EdF have confirmed that one unit at Heysham and one unit at Hartlepool will return at the beginning of November, with Hartlepool 1 returning at the end of November,” although Heysham is not expected back online until the end of the year. They expect an overall reduction in capacity of 20 percent. In addition, one of the two units damaged at the Ferrybridge coal plant was also expected to be brought back into service in November.
Nonetheless, Ferrybridge and the Hartlepool only contribute less than one percent of capacity to the system. The estimate of a margin of 2.3GW is likely to be wildly optimistic, causing Bishop Hill to comment “I do hope they are unmothballing a lot of power plants.”