How do you know that it is only capacity. From "Approximately 100,000 turbines will be required to produce 20% of the nation's electricity in 2030." in one of the blue boxes I would guess it is 'energy'.

And if it is only capacity, how would that likely relate to 'energy'

Lich King/Caribou Barbie 08
Pain brings Katharsis

The diary was getting rather long, so I left out a great many issues and details. Yes, 20% refers only to capacity. The 20% figure is a riff off of the speeches Bush gave - and Bush probably pulled 20% out of his butt hole, so I agree that 20% is a very weak goal. If I were leader of the free world, I would set a goal of 100%. At 100% of capacity right this minute, wind would provide about a third of electricity consumed - if there's no wind, or too much wind, you can't get electricity out of 'em. One of the speakers at the AWEA workshop mentioned that we can expect to get up to the mid-40s, with a theoretical upper limit of the high-40s or low-50s. The people in the wind industry are very forthright that wind is not an answer all by itself; there must be a portfolio of energy sources of which wind is only one.