Wednesday
Jan022013
by 
Bishop Hill
Bishop Hill Message to Clive
Jan 2, 2013 Blogs This is a message to Clive, who emailed my last night re setting up a user account at BH. I replied but got a bounce from your email. This is probably why your account is unverified.
Reader Comments (4)
Thanks B-H,
I was intending to draw further attention to the Prof. Hughes report on the performance of wind farms in the UK. see: http://www.ref.org.uk/publications/280-analysis-of-wind-farm-performance-in-uk-and-denmark.
Basically it overturns the government's plans to extend wind power by 2020. The show stoppers are:
1. The lifetimes of on-shore wind turbines are 10 years less than that assumed. They are only 15 years rather than the 25 years assumed in economic forecasts. The lifetimes for off-shore turbines are probably even shorter.
2. The measured load factors averaged over their lifetime is just 17%. Prof. David Mackay was using 30% load factors for more optimistic assessments of wind farms.
The government plans to increase "total capacity" from 4,500 MW to 10,000 MW by 2020. The cost of this is now predicted to be 40% higher - since plant will need replacing 10 years earlier. Even worse the amount of electricity generated will only give an effective generation capacity of 1.7 Gw ! So in reality the costs per Gw have now also doubled !
For comparison the single DRAX coal power station generates 4 GW continuously - 7% of UK demand !
To replace DRAX by wind generated electricity would require wind turbines covering 4000 square kilometers of British countryside ! At some point politicians have to face up to physical reality.
This report cannot be ignored.
Clive Best
The URL you give did not work but I found a pdf at
http://www.ref.org.uk/attachments/article/280/ref.hughes.19.12.12.pdf
On your point 2. The figures for UK load factor seem to be: after one year 24%, after 10 years 15% and after 15 years 11%. This means that on average about 5% of the initial load factor is lost every year. Interpolating these figures, an approximate equation, to the nearest whole number, is
load factor in % = 25 x (0.95) ^ y, where y is the age in years.
Hi Mark
I was just averaging the load factor over the 15 year period assuming a linear decline in performance over the 15 years. So I get the average load to be 11 + (24-11)/2 = 17.5 .
In either case it doesn't really look too good.
People forget the very low power densities of wind energy. Optimistically it was 2 watts/m2, but with these figures it looks more like 1.2 watts/m2. IMHO, wind is a non starter as a replacement for fossil fuel. It might produce a maximum of 5% of UK energy needs - excluding transport, but at 3 times the cost. Even then it must solve the energy storage problem when the wind doesn't blow.
Biofuels are even more daft.
Britain hit "peak wood" crisis as a fuel in the 17th century. I suppose we could deforest the rest of the world and burn their crops and wood, but that doesn't seem very sustainable to me.
worthy of note is this blasting of prof hughes
https://s3.amazonaws.com/s3.documentcloud.org/documents/468709/imperial-college-supp-evidence-to-eec-wind.pdf
Also DRAX has availability of 80% not 100%
Also using the REF site and looking at turbine data from 2002 to 2011 the worst farm is losing <2% per year the average is 0.3% per year (approx) giving quite reasonable load factors after 10 years. certainly not as hughes states.