Most Renewable Growth Is in Wind
Almost all the growth in renewable energy over the last five years has been in wind capacity. Biomass (meaning mostly ethanol), geothermal and solar energy have barely changed. Solar may have doubled but it occupies such a minute portion of our energy budget that it hardly matters. It is bizarre that solar energy gets so much attention when it contributes almost nothing. Wind, on the other hand, has risen from producing just over 25 terawatt-hours per year in 2007 to almost 150 Twh last year. In a way this is unfortunate because wind is generally the most useless type of renewable energy. Unlike biomass and geothermal it is not dispatchable and other portions of the grid must be adjusted to compensate for its vagaries. It also tends to blow at night and in the spring and fall, when electrical demand is low. But the wind production tax credit has made it profitable to keep building windmills, even though they do not significantly lower dependence on other sources of power. And those giant windmills certainly are changing the American landscape.