Despite the global economic recession, solar capacity in the U.S. increased by 37% last year to reach 2108 MW, according to figures from the Solar Energy Industries Association.

The annual industry report shows that 2009 was, in fact, a year of strong growth with revenues reaching $4 billion, up 36% on 2008.

The growth is being driven mainly by utilities, which tripled their solar photovoltaic capacity from 22 MW to 66 MW. Aggregating all of their solar technologies (e.g., adding in concentrating solar power), utilities have a generating capacity of 17 GW, sufficient to power 3.4 million homes.

Residential photovoltaic installations also showed particular growth, doubling in capacity from 78 MW to 156 MW. Nonresidential installations, however, lagged well behind growing 2% less than last year.

California continues to lead the way with 220 MW in new solar electric capacity, followed by New Jersey, Florida, Arizona, Colorado, Hawaii, New York, Massachusetts, Connecticut and North Carolina.

Despite the strong growth, the U.S. still ranks fourth in newly installed solar electric capacity (481 MW) well behind Germany, a nation that leads the way with a massive 3000 MW increase, followed by Italy and Japan. The total capacity of the U.S. is also well behind Germany’s total of 8877 MW, as well as Spain and Japan.

“We expect 2010 to be a breakout year for the US solar industry,” says SEIA president and CEO Rhone Resch. “The right policies and industry innovation continue to drive solar’s growth across America. Now we’re talking gigawatts of solar, not megawatts.”