A monthly report from the U.S. Department of Energy indicated utility-scale solar generating capacity will grow from 10 GW at the end of 2014 to 27 GW in 2017, which is an annual growth rate of 39 percent.
That growth rate makes solar the fastest-growing renewable energy source for utilities.
The report indicated natural gas will supply 35 percent of all utility-grade electricity in the U.S., with coal at 30 percent. Last year, both supplied 33 percent.
For 2017, natural gas and coal are expected to generate 34 percent and 31 percent of electricity respectively, due to an anticipated rise in natural gas prices.
Non-hydropower renewable energy sources will grow from eight percent in 2016 to nine percent in 2017. Nuclear and hydropower are expected to remain unchanged.
Carbon emissions for the first half of 2016 reached the lowest levels for that period since 1991. 2016 as a whole should see emissions declining by 1.4 percent, though they will increase 0.6 percent the next year.