It’s generally been recognized that using wind to generate electricity is inefficient, costly, and unreliable.
Now the news is getting out that it’s even worse than previously thought.
The report, The Performance of Wind Farms in the United Kingdom and Denmark, issued by the Renewable Energy Foundation in London, established that capacity factors for on-shore wind farms decline from 24% in the first year of operation to 15% in year ten, and 11% in year 15.
These results are amazing, in that the literature usually indicates a consistent capacity factor of 30%, which is what financial projections are typically based on.
The report holds even worse news for off-shore wind farms.
In Denmark, output declined from 40% in the first year of operation to less than 15% in year 10.
Wind Turbines off-shore Copenhagen, Denmark. Picture by D. Dears
Another source indicates that capacity factors decline by 1 to 2% annually.
A report by Lawrence Berkeley National Laboratory said that because developers received grants, rather than tax credits for the amount of electricity produced, they built wind farms where wind conditions were less favorable.
Now a new report by Amanda S. Adams from the University of North Carolina at Charlotte and David W. Keith from Harvard University, published in the journal “Environmental Research Letters”, indicates that the capacity of wind farms is overstated.
The report concludes that the shadowing effect of wind turbines on each other in a wind farm reduces the effective wind speed for turbines shadowed by other turbines.
The report suggests that wind power production is 25% to 50% of what has been previously assumed for wind farms of over 100 square kilometers. This is a huge reduction in what has been estimated for the potential electricity production from wind energy.
Smaller wind farms were also affected by the shadow effect.
One conclusion resulting from the decline in electricity production by wind farms came from a study done by Edinburgh University. Its study concluded it would be uneconomic to run wind turbines for more than 12 to 15 years, which is far less than the predicted life span of 20 to 25 years.
All of these studies bode ill for wind energy and the taxpayer dollars used to support their construction.
Read more of Donn’s columns at his blog, Power For USA.