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Misleading numbers from the wind energy lobby

I noticed this BBC news story the other day telling us how great the wind resource is in Britain. The report comes from Oxford University's 'Environmental Change Institute'. Malcolm Wicks has obviously been taken in by it.

"The UK's wind is better for generating electricity than that of its rivals, according to a government-backed study.

Steady stiff breezes had meant a more reliable supply than the more extreme blusters of Denmark and Germany over the last 35 years, researchers found.

UK turbines had produced 27% of their maximum possible energy, compared with 20% in Denmark and 15% in Germany, the Oxford University study said.

Energy Minister Malcolm Wicks said: 'This new research is a nail in the coffin of some of the exaggerated myths peddled by opponents of wind power.We have a vast and dependable wind resource in the UK, the best in Europe.' "

The 27% is actually a reduction on the 30 to 35% figure the wind energy industry and their environmental lobby supporters normally claim. The idea that Britain is Europe's windiest country seems to come from various windspeed maps which turn out to have been published by the British Wind Energy Association. (Do a Google search on " windiest country" to see how often this claim is repeated). So I decided to try and locate a less partisan source, and found this link from Stanford University in the USA:
Using the map on this link I would say Denmark is the windiest country in Europe, followed by the Netherlands and then the UK (basing the windiness of a country on how many black,red and yellow dots it has relative to its land area). The UK is however definitely windier than Germany.

Denmark being the windiest country in Europe would fit in with the fact that Denmark has had a wind power industry since 1891 (that is 1891 and not 1981, wind power is actually the world's oldest commercial electricity generating industry) and wind turbines are currently its biggest export industry. The Netherlands being windy would fit in with the mental association most people have between Holland and windmills.

The next step is to explain how Britain could achieve a better capacity figure than Denmark, 27% against 20%. I think the reason for that is simply that the average wind turbine size has increased rapidly in the last 15 years. According to the International Energy Agency the average wind turbine rotor diameter has gone up from 27 m in 1990 to 65 m in 2003. To ensure that the blades do not touch the ground, a higher tower also accompanies the bigger rotor diameter, so that means the average turbine height has more than doubled over the past 15 years. Since wind velocity increases with height above ground level, the taller turbines should give a better capacity figure (as well as being an even bigger eyesore). Therefore the British turbines may have a better capacity figure simply because they have been more recently constructed than the ones in the more mature Danish wind industry, and are therefore significantly taller.

Also the British optimism over the reliability of the wind resource is not shared by other European countries. A news story appeared last year with Dutch scientists predicting poor future wind turbine performance due to, guess what, climate change:

"Dutch Windmills at Risk from Climate Change

October 21, 2005 — By Anna Mudeva, Reuters

DE BILT, Netherlands — Windmills, one of the Netherlands' trademarks, may go idle because of less wind as a result of climate change, Dutch scientists predict.

New research shows scientists could have been wrong when they forecast years ago that global warming would cause more storms and wind in northwestern Europe, Albert Klein Tank of the Royal Netherlands Meteorological Institute (KNMI) told Reuters.

'We said that 10-15 years ago and what we see in the observations is that the climate is warming but the number of storms is actually decreasing," said Klein Tank, who leads a team making climate scenarios for the Netherlands. We don't have a good explanation for that,' he told Reuters in an interview on Wednesday. "