Source: U.S. Energy Information Administration, U.S. Energy Information Administration, Electric Power Monthly

Electricity generators that use fossil fuels continue to be the most common sources of electricity generation in most states. In all but 15 states, coal, natural gas, or petroleum liquids were the most-used electricity generation fuel in 2017. Since 2007, the number of states where coal was the most prevalent electricity generation fuel has fallen as natural gas, nuclear, and hydroelectricity have gained market share.

In 2017, coal provided the largest generation share in 18 states, down from 28 states in 2007. Natural gas had the largest share in 16 states, up from 11 in 2007. Petroleum remained the largest generation share in only one state—Hawaii—providing 62% of the state’s electricity generation in 2017. For the United States as a whole, natural gas provided 32% of total electricity generation in 2017, slightly higher than coal's 30% share.

Beyond fossil fuels, nuclear power plants provided the largest electricity share in nine states, up from six in 2007. Hydroelectricity is the most prevalent electricity generation source in six states, up from four in 2007. Hydro is the only renewable energy source with the largest share in any state, but that may soon change with the continued addition of wind turbines in states such as Kansas and Iowa.

The shares in this article reflect portions of the total utility-scale electricity and small-scale solar photovoltaic electricity generated in each state. Because the electric system in the Lower 48 states essentially operates as three large interconnections, the electricity generated in one state may be consumed in another.

Source: U.S. Energy Information Administration, U.S. Energy Information Administration, Electric Power Monthly

In the 10 states that were primarily generating electricity from coal in 2007 but not 2017, 5 of those states are now primarily generating electricity from natural gas and 5 primarily from nuclear. These changes have occurred as coal-fired power plants have retired or been used less and as natural gas-fired power plants have been built and used more nationwide. Only one nuclear power plant was built in those years—Watts Bar Unit 2 in Tennessee—but some other nuclear power plants across the country have completed uprates to their existing nuclear generators.

Source: U.S. Energy Information Administration, U.S. Energy Information Administration, Electric Power Monthly

In 2007, nuclear power provided 81% of Vermont’s electricity generation. Following the 2014 retirement of the state’s sole nuclear power plant, Vermont Yankee, the state’s nuclear share fell to zero, and hydro and biomass became the top two generation sources in the state.

In New Jersey, the addition of natural gas-fired generators led natural gas to surpass nuclear in 2015. More than a quarter of New Jersey’s currently operating natural-gas fired capacity came online from 2009 through 2016.

Among the 11 states where natural gas was the most prevalent electricity generation fuel in 2007, all were still using mostly natural gas in 2017, except Maine. In Maine, lower utilization of the state’s natural gas-fired generators resulted in hydroelectricity surpassing natural gas as the state’s most common electricity generation source in 2017.

More information on electricity generation by state—both annual data through 2017 and monthly data through June 2018—is available in EIA’s Electric Power Monthly.

Principal contributor: Owen Comstock