"Residential continues to be the fastest-growing market segment in the U.S., with 2014 marking three consecutive years of greater than 50% annual growth," the report said.
California remains by far the dominant source of residential solar systems. But in the fourth quarter of last year, more than half of all residential solar in the U.S. came from other states -- an industry first.
SEIA CEO Rhone Resch said that without question the federal government's solar Investment Tax Credit (ITC) has helped fuel "remarkable growth."
"Today, the U.S. solar industry has more employees than tech giants Google, Apple, Facebook and Twitter combined," Resch said in a statement. "Since the ITC was passed in 2006, more than 150,000 solar jobs have been created in America, and $66 billion has been invested in solar installations nationwide.
There are now about 20GW of installed solar capacity in the U.S., which is enough to power 4 million homes, Resch said. That amount of clean energy can reduce carbon emissions by 20 million metric tons a year.
"By any measurement, the ITC has been a huge success for both our economy and environment," Resch said.
At the same time, 2014 marked the first time ever that more than half a gigawatt of residential solar installations came on line without any state incentive.
GTM Research is predicting that the U.S. PV market will grow 31% in 2015. The utility segment is expected to account for 59% of the forecasted 8.1 GW of PV to be installed this year.
"Solar PV was a $13.4 billion market in the U.S. in 2014, up from just $3 billion in 2009," Shayle Kann, senior vice president at GTM Research, said in a statement. "And this growth should continue throughout 2015 thanks to falling solar costs, business model innovation, an attractive political and regulatory environment and increased availability of low-cost capital."
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