How effective is wind energy?

Case van Kooten has an interesting working paper here showing that the impact of wind on C02 emissions is highly variable. First, the opportunity cost matters a great deal. If people are relying on hydro or nuclear power and they switch to wind, emissions decrease very little. Second, wind power tends to be intermittent, requiring other sources to be available when the wind's not blowing. If other flexible sources are going to turn out to be fossil fuels, and, worse, if those fossil fuel-burning plants are hard to start up and turn off, then again we'd expect to see only a small reduction in CO2 emissions from use of wind.

Natural Gas in Pennsylvania

Pennsylvania's Natural Gas reserves alone could power the US for 10-15 years, according to this article on the Chesapeake Bay Foundation's website. Like any kind of mining, extraction can be environmentally difficult, though it sounds like appropriate care can mitigate a lot of the problems. However nasty it might be, I'd much rather have it going on in this country where it can be carefully monitored instead of leaving it to be extracted in the Middle East or other places and then have it traveling here in tankers.