The Coal-to-Gas Transition at the State Level: 15 Years of EIA Data

U.S. coal-fired electricity generation in 2007 reached its all-time peak at roughly 2,016 billion kilowatt-hours, about 49 percent of total U.S. electricity. By the early 2020s, coal generation had fallen to roughly 900 to 950 billion kilowatt-hours, around 20 to 23 percent of total electricity. The transition reflects a roughly 50 percent reduction in coal generation over 15 years — one of the most significant energy transitions in U.S. history. The state-by-state pattern revealed by the EIA Form 923 generation data is uneven and tells the underlying story.

The early-2010s drivers were three. First, natural gas prices fell substantially as shale-gas production expanded, making gas-fired electricity cheaper than coal-fired electricity in most U.S. markets. Second, the Mercury and Air Toxics Standards (MATS), finalized in 2011 and effective in 2015, required coal plants to install pollution-control equipment that was uneconomic for older plants. Third, state-level air quality and renewable portfolio standards added additional pressure to retire coal plants. The combination drove a wave of coal retirements starting around 2010 and continuing.

The state-by-state pattern is uneven. Mid-Atlantic and Northeast states (Pennsylvania, Ohio, West Virginia, Kentucky, Indiana) had the largest absolute coal generation declines because they had the largest coal fleets to begin with. Southeastern states (Georgia, Alabama, Mississippi, Tennessee) shifted aggressively to natural gas combined-cycle plants. Texas combined modest coal-to-gas with substantial renewable build-out. Mountain West states (Montana, Wyoming, Utah, Colorado) reduced coal more slowly because of regional grid economics and political factors.

Some states have essentially exited coal. California has not generated meaningful coal-fired electricity in years; the state's small remaining coal share comes from imported electricity. Several New England states (Massachusetts, Rhode Island, Connecticut) retired their coal plants over the last decade. New York retired the last operating coal plant in the state in 2020. The Pacific Northwest has very little coal generation because of abundant hydroelectric capacity.

Some states remain heavily coal-dependent. Wyoming, West Virginia, Kentucky, Indiana, and Missouri still rely on coal for substantially more than half of their in-state generation. These states have lower electricity rates than the national average because coal generation has been built out and depreciated, and the variable cost of operation is competitive with natural gas at current fuel prices. The coal-dependent states are also coal-producing states; the political economy of coal reduction is harder there than in non-producing states.

The replacement fuel pattern shows in the EIA data. About 60 percent of the coal-generation reduction has been replaced by natural gas; about 35 percent has been replaced by wind and solar; the remainder has been replaced by efficiency gains (less total generation needed) and nuclear (steady share). The pattern varies by state: gas-rich states replaced more coal with gas, wind-rich states replaced more coal with wind, and California replaced essentially all coal with renewables-plus-gas.

Three caveats. First, the coal share figures are based on generation, not consumption; some states import coal-fired electricity from neighboring states. Second, the transition pace has slowed in recent years as the most economic coal retirements have already happened and the remaining coal plants are either more competitive or in states where retirement faces more political resistance. Third, the post-2022 natural gas price increases temporarily slowed the coal-to-gas transition in some markets, though the longer-term direction is unchanged.

The coal-to-gas transition is the largest single change in the U.S. electricity sector in the last 50 years. The EIA Form 923 data is the authoritative federal record of how it has played out at the state level.

Source: U.S. Energy Information Administration, 2026.