The U.S. still derives the vast majority of its electricity from coal, natural gas and nuclear reactors, but the growth is all in renewables.

Approximately 90 percent of the new electrical capacity that will be brought on line in the U.S. in 2012 will come from renewables like solar, wind, geothermal, biomass and hydroelectric power, according to a new study from the Prometheus Institute.

The vast majority of the 18.6 gigawatts of renewable capacity that will come on line that year will consist of wind power. Wind capacity will grow by 15.9 gigawatts in 2012 while solar will trail with 2.1 gigawatts. Still, even solar should do better than fossil fuels in 2012, according to Travis Bradford, president of Prometheus. Fossil fuel capacity should grow by just over a gigawatt. (Disclosure: The Prometheus Institute and Greentech Media collaborate on several research projects but did not work on this one together.)

Although the growth rates may sound outlandish, they come as a result of pre-existing circumstances and trends. States, such as California, are mandating that utilities increase the power they harvest from renewable resources and a national renewable standard seems likely. By contrast, banks have pulled away from funding coal plants out of fears that carbon trading or taxing may come soon and increase the cost of power. Ironically, in the U.K., researchers are building wind turbine facilities on old coal mines.

Then there is simple construction time. Solar utility fields take time to permit and build, but not as long as nuclear or fossil plants.

The study, though, assumes wind will grow at 17.5 percent and biomass will grow by 10 percent annually.

Nonetheless, renewables have been growing rapidly. In 2000, renewables accounted for a whopping 1 percent, or 279 megawatts of new generation capacity. In 2005, it jumped to 2.7 gigawatts or 17 percent. Fossil fuel plants, meanwhile, dived in 2003 from 44 gigawatts of new capacity to 15.9 a year later.

The flip occurred last year. 9,015 megawatts worth of renewable capacity was added last year while only 8,407 megawatts worth of fossil fuel capacity was added. An additional 720 megawatts of "other" power, i.e., nuclear and fuel cells, was added to bring the total of new capacity to 18.1 gigawatts.

Overall, though, renewables account for only a small fraction of the U.S. energy diet. Renewables accounted for only 7 percent of all of the energy consumed in America in 2007, including petroleum, which clocked in a number one with 40 percent of the pie, according to the Energy Information Administration.

That 7 percent almost entirely consisted of hydroelectric power and biomass. Solar and wind together represented only 6 percent of the seven percent.