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.