Both utility-scale and non-residential photovoltaics grew by over 100 percent in 2011 in the U.S. That’s according to the Interstate Renewable Energy Council’s (IREC’s) 2011 Solar Market Trends Report. It’s an annual report that looks at solar installations throughout the country to better understand how and where solar is being deployed.

The report found that the increase in solar installations to 64,000 in 2011 was driven in part by falling photovoltaic prices, consumer demand and financial incentives offered by the federal government, states and utilities. State renewable portfolio standards also played a large role in the expansion of utility-scale PV. That led to a total of more than 1.8 DC gigawatts of photovoltaics being installed, according to the report.

Growth in solar was most dramatic in utilities (145 percent) and non-residential systems (132 percent), compared with 2010. Residential solar also continued to grow, but at a lower rate, 24 percent. “The relative growth of residential and non-residential installations has varied from year-to-year. The trend has been for increasing non-residential growth rates and decreasing residential growth rates,” said report author Larry Sherwood, president of Sherwood Associates.

The report looked at all solar electric projects installed in the U.S. that generate electricity for the grid,Said Sherwood. “It includes mostly PV but also included concentrating solar power (though there were no CSP projects in 2011),” he said. “It does not include non-electricity producing solar thermal projects or PV for off-grid applications,” he added.

While California remained the largest overall market and grew 29 percent over last year, other states continued to gain ground. The amount of solar capacity installed in 2011 doubled over 2012 in Arizona, California, Hawaii, New Jersey, New Mexico and New York, the report said.

That growing trend’s likely to be bigger in 2012 despite reductions in solar incentives, like the end of the 1603 Treasury Grant Program, according to Sherwood. “So far the trends are that the number of installations will increase in 2012, not decrease. The reduction in utility, state, and local incentive programs is offset by the reductions in the cost of solar installations. Other policies (such as renewable portfolio standards) are also important,” he said.