The U.S. solar industry is on course for a new growth record in 2015, according to a new report that finds that solar photovoltaic installations now exceed 20 gigawatts in capacity and could surpass an unprecedented 7 gigawatts this year alone across all segments. A gigawatt is equivalent to 1 billion watts and can power some 164,000 homes, according to the Solar Energy Industries Association (SEIA).

The new report, from GTM Research and SEIA, covers the second quarter of 2015, which set a new record for residential rooftop solar installations in particular, a category that saw 70 percent year-over-year growth. 473 megawatts of residential solar capacity were installed, or nearly half a gigawatt.