Solar panels aren't born green. Their manufacture uses power, often generated in plants that burn coal or oil, and releases pollutants (including greenhouse gases) into the environment. The extent of this original sin depends on the kind of solar technology involved, but it's not trivial. According to Peter Owen of Linde Electronics, four years pass before the U.S. industry's typical solar panel has generated enough electricity to make up for the power used to make it.
As for wind power, its carbon "footprint" doesn't end when the turbine comes out of the factory. In order to guarantee a steady supply of electricity, windmills have to be backed up with an alternate source of power, which kicks on when the wind dies down. To be reliable, this backup power has to be generated constantly, whether or not it will be needed (you can't shut a coal-fired plant on a breezy morning and flip it on when the wind dies at lunchtime). Here's how that case was made this morning, by an industry front group on the West Coast.
For the Cascade Policy Institute the story ends with the point that wind power has a "dirty secret." But the more important point is that "greening" our power can't be done by changing only hardware. It requires psychological and social change as well.
Notice, for example, what the Cascade Policy Institute presumes: That wind power must be used just like coal-fired power. If, instead, people changed their expectations—if they accepted that their electricity supply would vary with the weather—then wind power would need less backup from other sources, and its footprint would be smaller.
"Green" change often is presented as a simple and painless substitution, as if it were all about going from one kind of lightbulb to another, and otherwise keeping on with the life you know. What's coming down the road, though, is systemic change. Not just new sources of power, but new ways of using it and thinking about it.
Sustainability isn't achieved by changing something; it's achieved by changing everything. That's why it's a psychological issue as well as a political and economic one.