And 2013, according to a new report from GTM Research and the Solar Energy Industries Association (SEIA), was a landmark year for the alternative energy source. A full 29 percent of all new electricity installations were solar, with developers installing 4.75 gigawatts worth of photovoltaic panels — a growth of 41 percent over 2012. By the end of the year, there were a total of 440,000 operating solar electric systems in the U.S., generating enough electricity to power 2.2 million homes.

This graphic from the report shows how solar breaks down across the U.S. — worth noting is how, after California, red states Arizona and North Carolina were way up there for new solar energy installations: