Wind Energy Supply, and Science on Decarbonization

While thinking about the large-scale wind issue, I ran into this interesting report from the European Wind Energy Association.

This has a lot of data which I've been trying to absorb. In part the writing is rather defensive about wind's variability (they repeatedly refer to it as "variable" and not "intermittent"). One thing it's telling us is that over regions the size of Denmark or England (200x200 to 400x400 km) and over short time periods (seconds to 30 minutes) experience with wind supply shows it to be fairly constant, with variations of perhaps 5% at most. Little modification to existing grid management systems seems necessary to handle this even if wind provides a large percentage of supply.  

However, on longer time-scales, supply can drop as much as 90% in a matter of hours, due to large storm systems for instance. So you need backup capacity to stabilize supply (or the ability to drop load - that may become more of an option if battery-powered vehicle systems grow significantly). Nuclear power is unfortunately not a good option for this, because it also has high capital costs, and start-up and shut-down times are at least hours in themselves. Fossil fuel plants can of course provide this supply, but unless they include carbon sequestration they aren't a this-century solution, and fossil fuels simply aren't an option for the longer term. And none of the other on-demand options (biofuels, hydro, geothermal) scales far enough to provide the large-scale backup capacity needed if wind is to be a major power option. So this is a serious issue. It's not clear that storage is the only solution though - extending grids beyond 400x400 km regions may be enough to reduce the variability significantly. Using more stable wind sources (high atmosphere) may also help a lot... But it's a problem that does need attention.

So I just ran across a second article (actually I haven't seen the full article yet, just a synopsis): "A Road Map to U.S. Decarbonization", by Reuel Shinnar and Francesco Citro, Science, 1 Sep 2006, p. 1243 They strongly advocate concentrating solar thermal power, with attached storage. They also look at the other options and favor most of them, but are doubtful on carbon sequestration. The cost estimate to do this in 30-50 years seems to be $5-6 trillion: that's just for the U.S. A $45-50/ton(CO2) carbon tax would pay for it, they claim. If the technologies proposed are actually capable of doing what is claimed, the main problem, it seems to me, is the US could perhaps do this, but is this a transition the rest of the world could afford? Research into alternatives is still essential, but at least some people seem to be starting to look at the full scope of the problem...

Created: 2006-09-08 11:27:27 by Arthur Smith
Modified: 2006-09-08 11:28:02 by Arthur Smith