US solar generating capacity quadrupled over the four-year period that ended in February 2014, according to a report by the US Energy Information administration.
In 2010, total solar capacity was 2,326 MW, which accounted for only 0.22 percent of US electric generating capacity. By February 2014, this capacity increased 418 percent to 12,057 MW, a 9,731 MW gain. That accounts for almost 1.13 percent of total US capacity. Even with this growth, a recent research report says the EIA underestimates solar’s growth potential. Other reports suggest high growth as well.
EIA tracks three principal types of solar-electric generating, including residential and commercial rooftop photovoltaic (PV) capacity, utility level PV greater than 1 MW and utility level solar thermal capacity.
Net metered solar has increased each year since 2010 at an annual rate of about 1,100 MW and now totals 5,251 MW. California has the largest net metered solar capacity (38 percent of the total), but state incentives have helped New Jersey and Massachusetts together snag an additional 21 percent of the net-metered total.
Utility scale PV currently account for 5,564 MW. In 2013 utility scale solar exceeded the capacity of net metered applications. Sunny states like California (2,702 MW, 49 percent of the total utility scale PV) and Arizona (960 MW, 17 percent) lead, the report says.
The thermal solar sector expanded significantly in 2013 when three large plants, Solano, Genesis and Ivanpah, went on line adding a total of 650 MW of capacity. Solano has storage capability that extends the daily operating period and cushions sudden drops in output due to interruptions from passing clouds.
Currently, there are 6,459 MW of proposed utility scale PV and 1,841 MW of proposed thermal solar. Many of the same factors driving utility-level solar are expected to push net metered capacity as well.