According to the DOE Solar Technologies Office, GTM Research and the Solar Energy Industries Association (SEIA) released the U.S. Solar Market Insight 2014 Year in Review report last week, which revealed another record-setting year for solar: the U.S. reached 20 gigawatts of total installed capacity, enough to power 4 million American homes. It’s the result of more than 30% more PV installations over last year and three CSP solar projects coming online. In 2014, solar accounted for 32% of the new electric generating capacity brought online in the United States.

Here are the key findings:

• The U.S. installed 6,201 MWdc of solar PV in 2014, up 30 percent over 2013, making 2014 the largest year ever in terms of PV installations.
• More than one-third of all cumulative operating PV capacity in the U.S. came on-line in 2014.
• By the end of 2014, 20 states eclipsed the 100 MWdc mark for cumulative operating solar PV installations, and California’s market alone is home to 8.7 GWdc.
• For the first time ever, more than half a gigawatt of residential solar installations came on-line without any state incentive in 2014.
• 32 percent of all new electric generating capacity in the U.S. came from solar in 2014.
• Growth remains driven primarily by the utility solar PV market, which installed 1.5 GWdc in Q4 2014, the largest quarterly total ever for any market segment.
• We forecast that PV installations will reach 8.1 GWdc in 2015, up 31 percent over 2014. Growth will occur in all segments, but will be most rapid in the residential market.
• 2014 was the largest year ever for concentrating solar power, with 767 MWac brought on-line. Notable project completions include the 392 MWac Ivanpah project. Genesis Solar project’s second phase of 125 MWac, and Abengoa’s Mojave Solar (250 MWac), which achieved commercial operation in December 2014.