Tuesday, April 12, 2011

Nosebleeds and windfarms

Matt Ridley graphically suggests that in response to a problem which might be likened to a nosebleed, we have adopted policies akin to applying a tourniquet round the patient's neck.  He highlights a couple of recent papers.  The first is on sea level rise.
"To translate: sea level is rising more slowly than expected, and the rise is slowing down rather than speeding up. Sea level rise is the greatest potential threat to civilisation posed by climate change because so many of us live near the coast. Yet, at a foot a century and slowing, it is a slight nosebleed. So are most of the other symptoms of climate change. . . "
The second peer reviewed paper addresses the impact of the move to biofuels for energy as reported in a paper in the :
“The production of biofuels may have led to at least 192,000 additional deaths and 6.7 million additional lost disability-adjusted life years in 2010. These estimates are conservative [and] exceed the World Health Organisation’s estimates of the toll of death and disease for global warming. Thus, policies to stimulate biofuel production, in part to reduce the alleged impacts of global warming on public health, particularly in developing countries, may actually have increased death and disease globally.”
A report by the John Muir Trust last week indicated that assumptions for energy produced from wind turbines has been over estimated - at least if the last three years are anything to go by.  The report lists five challenges  to Government claims which are reproduced below.

As you read them think of the public money which has been pumped into this effort to kick start the industry. Perhaps a contributory factor is that 2010 may have been one of the least windy years since 1824.

1. 'Wind turbines will generate on average 30% of their rated capacity over a year'In fact, the average output from wind was 27.18% of metered capacity in 2009, 21.14% in 2010, and 24.08% between November 2008 and December 2010 inclusive.
2. 'The wind is always blowing somewhere'On 124 separate occasions from November 2008 to December 2010, the total generation from the windfarms metered by National Grid was less than 20MW (a fraction of the 450MW expected from a capacity in excess of 1600 MW). These periods of low wind lasted an average of 4.5 hours.
3. 'Periods of widespread low wind are infrequent.'Actually, low wind occurred every six days throughout the 26-month study period. The report finds that the average frequency and duration of a low wind event of 20MW or less between November 2008 and December 2010 was once every 6.38 days for a period of 4.93 hours.
4. 'The probability of very low wind output coinciding with peak electricity demand is slight.'At each of the four highest peak demand points of 2010, wind output was extremely low at 4.72%, 5.51%, 2.59% and 2.51% of capacity at peak demand.
5. 'Pumped storage hydro can fill the generation gap during prolonged low wind periods.'The entire pumped storage hydro capacity in the UK can provide up to 2788MW for only 5 hours then it drops to 1060MW, and finally runs out of water after 22 hours.

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