John Muir Trust Study On Whether Wind Power Can Contribute Significantly To UK Energy Supply
A study on the ability of wind power as a source of renewable energy to contribute significantly to the UK’s energy supply has been released by the John Muir Trust.
The John Muir Trust study questions whether wind power in the UK is able to provide electricity when it’s most needed. The Analysis of UK Wind Generation Report looked at windfarm output from Scottish windfarms over a period of 26 months – Nov 2008 to Dec 2010.
The report concluded that for a number of long periods, Scottish wind turbines linked to the National Grid were generating less than 20MW of electricity. To put this into context, this is enough power for people in around 6667 homes to boil a kettle.
The John Muir Trust is a charity which tries to protect wild land for both nature and people. It was founded in 1983 to safeguard the future of wild lands against development and takes its name from the Scotsman John Muir who was the first to call for the protection of wild land.
The Scottish Government and those involved in the wind industry promote the advantages of wind power but the John Muir Trust report challenges five assertions frequently made by these organisations.
The first assertion is that wind turbines will generate an average 30% of their rated capacity over the course of a year. The analysis however, showed that in fact in 2009 the average output was 27.18% of metered capacity, in 2010 it was 21.14% and between Nov 2008 and Dec 2010 it was 24.08%.
The second argument used by proponents of wind power is that the wind is always blowing somewhere. However, the report found that between Nov 2008 and Dec 2010 there were 124 different occasions when the total amount of electricity generated by wind farms was less than 20MW. On average it says these episodes of low wind lasted for between 4 and 5 hours.
The third argument relates to these periods of low wind with those in favour of wind power saying that low wind doesn’t happen often. The report however says that during the period studied, low wind occurred every 6 days.
The fourth assertion is that there’s very little chance that these periods of low wind will coincide with peak demand. However, analysis shows that during 2010 at each of the four highest points of peak demand wind output was low at 4.72%, 5.51%, 2.59% and 2.51% of capacity.
The final argument used by those in favour of wind is that pumped storage hydro capacity can make up the shortfall during periods of low wind. However, the report found that pumped storage hydro capacity can only provide 2788MW of electricity for 5 hours and then it drops to 1060MW and after 22 hours it runs out.
The author of the report, Stuart Young, said “Over the two-year period studied in this report, the metered windfarms in the U.K. consistently generated far less energy than wind proponents claim is typical. The intermittent nature of wind also gives rise to low wind coinciding with high energy demand. Sadly, wind power is not what it’s cracked up to be and cannot contribute greatly to energy security in the UK”.
He added “It was a surprise to find out just how disappointingly wind turbines perform in a supposedly wind-ridden country like Scotland. Based on the data, for one third of the time wind output is less than 10% of capacity, compared to the 30% that is commonly claimed”.
This report will be welcomed by those who argue that there’s too much emphasis placed on wind power and that it will not fill the energy gap in years to come. However, RenewableUK criticised the report saying it was incomplete. The industry body said onshore wind farms worked at 27.6% capacity between 2006 and 2009 and offshore at 31.1% capacity.
It’s difficult to know who to believe in situations like this because statistics as we know can be used to provide a positive and a negative view on any given situation.