The US electric grid continued to transform in 2016. No new coal plants were added, and solar became the top new source of generating capacity. Combined with wind, a small bit of hydro, and the first nuclear plant added to the grid in decades, sources that generate power without carbon emissions accounted for two-thirds of the new capacity added in 2016.

These numbers come from the US Energy Information Administration, which asked utilities about what sources they expected to have online at the end of the year. These numbers typically show a burst of activity in December, as projects are raced to completion to take advantage of the tax benefits of reaching operational status in the current year.

Overall, the EIA recorded 26 GW of new capacity added to the grid in 2016. This includes a small amount (0.3GW) of new hydropower and a smattering of projects collected under "other" that produce a similar magnitude. Notably absent from the list is coal. Also absent is distributed solar, meaning panels installed on homes and other small-scale projects. Distributed solar accounted for about 2GW of new capacity in 2015, and the EIA notes that the incentives for these projects haven't changed considerably in 2016.

Even without that 2GW, solar comes out on top, with 9.5GW of new additions this year. At 8GW, natural gas comes in second place on the EIA's list, followed by wind at 6.8GW. Thanks to the opening of a new reactor at Watts Bar in Tennessee, nuclear also joins the list for the first time in years, adding 1.1GW of capacity. Combined, wind, nuclear, hydro, and solar account for 68 percent of the new additions, making 2016 a low-carbon year for the US grid. Assuming distributed solar this year is similar to its 2015 levels, the percentage of new non-fossil generation goes up above 70.

It's important to note that no energy source runs at full capacity. Utilization typically ranges from the low 30 percents for solar up to about 90 percent for nuclear; for gas, utilization typically depends on how often the local grid needs a rapid response to demand. So, predicting precisely what these installations will mean for future generation is difficult, other than the fact that all of these sources produce less carbon per unit of electricity than coal.

The focus of new solar installations is shifting a bit from the Southwest as well. While California installed more than the next four states combined, the top-five include states like North Carolina, Texas, and Georgia. This may indicate that the continued drop in the cost of utility-scale solar is making it competitive across a broader geographic region.

The changing economics of renewables may make President-elect Trump's decision to pack his cabinet with fossil-fuel fans irrelevant. Various estimates indicate that the leveled, subsidy-free cost of wind and solar have approached or dropped below that of coal (as has natural gas). Between that and the risk that a future president could reverse any decisions made in the Trump administration, it's unlikely that the next few years will see any radical changes from 2016.