The Startling Results of a New Study
An e-mail a few days ago from a long-time friend (I don't say "old friend" anymore!) alerted me to some new work he's done that I think has the potential to stir up a firestorm. Herb Inhaber has made a career of investigating conventional wisdom and poking holes in it--some may remember his past work on the comparative risk assessment of different energy sources--and now, it looks like he's done it again!
Herb's latest work looks at wind generation and comes to the counter-intuitive conclusion that increasing the use of wind energy could actually increase carbon dioxide emissions instead of decreasing them! The logic behind his analysis is the same as the reason automobiles get better mileage when driven on highways than in stop-and-go city traffic.
If the wind blew all the time and back-up power was not needed, of course the carbon emissions would be reduced. But according to Herb's analysis, every time back-up gas turbines are ramped up and down, they generate more CO2 than when they are operated alone at full power. The result is that much of the expected environmental benefit of wind power is lost.
The same logic applies for solar generation, although my own experience is that the wind usually varies more than solar insolation does, so I would expect the effect to be smaller for solar energy.
I should make it clear that I have not personally tried to analyze every step of his analysis. I'm certainly not an expert on the performance of gas turbines, so am unable to comment on the relative efficiency of gas turbines in different modes of operation. Nevertheless, it is significant that Herb cites data from the United States and several other countries that appears to support his argument.
Therefore, it appears there is enough evidence in this study to spur a very close look at the growing assumption in the minds of the public and many policymakers that global warming can be significantly reduced by converting to a greater use of solar and wind power.
Herb's full article on his research is available for purchase from Renewable and Sustainable Energy Reviews. A good summary of the Inhaber study has been published in the blog, Brave New Climate.