A report this week from the U.S. Energy Information Administration (EIA) shows coal-fired power was still the major source of generation on a state-by-state basis in 2017, though natural gas-fueled electricity production slightly outpaced coal overall

The EIA’s report, published September 10, said 18 states relied on coal for the bulk of their power generation last year, while 16 states primarily relied on natural gas. Nuclear power led in nine states and hydropower led in six. Petroleum was the primary source of generation in Hawaii.

Natural gas-fired units provided 32% of the nation’s power in 2017, with coal-fired power at 30%. The EIA report noted the decrease in coal’s share of generation over the past decade—it paced generation in 28 states in 2007—contributed to the increase in states where nuclear and natural gas now lead. Of the 10 states where coal led generation in 2007, five are now paced by natural gas, and five are led by nuclear.

Just one new nuclear reactor has come online in the U.S. over the past 20 years—Watts Bar Unit 2 in Tennessee, POWER’s Top Plant for 2018—though other reactors have completed uprates in recent years, increasing their generating capacity.

The report noted that while hydropower is the only renewable energy source leading statewide generation in 2017, wind power is likely to take the top spot in some states in the near future, including Kansas and Iowa. In those states, and four others, wind power ranked second in generation last year.

Solar power ranked second in just one state, Nevada, where it accounted for 11% of generation while natural gas provided 69%. Biomass—including wood, wood waste, landfill gas, and other biogenic material—had the second-largest amount of generation in three states: Maine, Vermont, and Rhode Island.

Of the 11 states where natural gas led generation in 2007, all but Maine were still led by gas-fired generation in 2017. The EIA said hydropower surpassed natural gas in Maine last year due to lower utilization of the state’s gas-fired units.

Darrell Proctor is a POWER associate editor (@DarrellProctor1, @POWERmagazine).