Solar power has grown dramatically over the last decade. The Solar Energy Industries Association reports that the U.S. added another 878 megawatts of solar installation in 2010, more than double the 435 megawatts from 2009 and more than 10 times the 79 megawatts added in 2006. This brought the U.S. to a total capacity of more than 2.6 gigawatts.
Yet, the country was entirely eclipsed last year by Germany, the global leader in solar installations. Research In Germany reports that the European nation added more than 7 gigawatts of solar capacity, bringing its total to more than 17 gigawatts. Germany has managed to match the U.S.' dramatic growth, nearly doubling its added capacity in 2010 and more than doubling it in 2009, according to the SEIA.
A recent report from the German Association of Energy and Water Industries (BDEW), Germany accomplished the somewhat more remarkable feat of drawing more than 20 percent of its electricity from renewable sources in the first half of 2011, according to Spiegel Online International. With 76 percent growth in output, solar energy actually replaced hydroelectric power as the third largest renewable source.
The stunning success of the German solar industry, however, proves somewhat counter-intuitive and, rather than reflecting the weakness of the American market, illustrates the massive potential for solar power in the U.S.
In 2009, the National Renewable Energy Laboratory produced a map of solar energy potential in the U.S., Germany and Spain. Because of their different latitudes and climates, these countries receive drastically different amounts of solar energy, which is measured in kilowatt-hours per square meter per year. The U.S. Energy Information Administration lists 6 kWh/m2/day as its definition for "solar potential," or around 2,190 kWh/m2/year.
According to the NREL map, only the barest sliver of Germany receives even 1,600 kWh/m2/year, while only the western third of Washington state and Alaska falls notably below Germany's highest point. The vast majority of Germany falls in a range between 1,000 and 1,200 kWh/m2/year, around half of the EIA's cutoff. Meanwhile, the U.S. boasts substantial regions in the southwest that reach well above that cutoff and the majority of the country receives at least 1,800 kWh/m2/year.
The United Nations Environment Programme reports that regions such as Africa, South America, Australia, and Central Asia could see even greater benefits than the U.S., but when compared the dramatic success of the Germany it seems apparent the potential for American solar power remains strong.