Alternative Energy - a simple rule for windfarms
Site them in windy areas...
From the London
Daily Mail:
Blowing in the wind: Millions wasted on wind farms without a breeze
For anyone building a wind farm, it might seem an unnecessary piece of advice - put it somewhere windy.
Astonishingly, however, many turbines are going up on sites which are simply not breezy enough, energy consultants have claimed.
They say farms are being built in the "wrong places" because of the pressure to hit Government targets in the race to produce green energy.
But the "badly sited and underperforming" turbines are not reliable enough to keep the nation's television sets, toasters and lights switched on.
Michael Jefferson, an independent engineering consultant and former economist for Shell, said the industry often exaggerated the amount of energy each farm would supply.
New sites are assessed on the basis of average wind speeds over a year - a measure called the "load factor".
The industry recommends an average load factor of 30 per cent for a turbine to operate efficiently.
Yet although the load factor can be as high as 45 per cent in parts of Scotland and Wales, some farms achieve less than 20 per cent, he said.
Only five wind farms in the east of England achieve load factors of 30 per cent or more: "That's just five out of 25," he said.
"We should be putting our money where the wind is and that is quite often not where the development pressure is.
"Even in a high average-wind-speed area you really have to be absolutely precise as to where you site them.
"In Cumbria, for instance, you've got two - one which achieves a load factor of about 36 per cent and the other a mere 2.3km away which achieves just 20 to 21 per cent."
The Government wants 15 per cent of Britain's electricity to be generated by wind farms and other renewable energy sources by 2014.
Jim Oswald, an engineering consultant, said wind speeds were too unreliable and variable to meet that target. "It's the power swings that worry us," he said. "Over a 20-hour period you can go from almost 100 per cent wind output to 20 per cent.
"When you have a very large number of wind farms on the grid and that happens, you are talking about massive power swings on the system."
To cope with the variation in wind energy over a normal day, gas and coal generators would need to be turned on and off continually.
"They are not designed for that, and the net effect is to put them under mechanical strain and also increase their carbon dioxide," said Mr Oswald.
The simple act of erecting a tower with measurement equipment (anemometer) and taking readings for one year would be a cheap way to determine the site's load factor. Siting these things based on development pressure is ludicrous...
Posted by DaveH at August 31, 2007 9:42 PM
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