Pennsylvania has retired more than 5,000 megawatts of coal-fired generation capacity since 2019. That is roughly the equivalent of five nuclear reactors worth of always-available power, gone from the grid.
The closures have not caused blackouts. The lights still turn on. But the economics of electricity have shifted. When fewer power plants bid into PJM's capacity auction, prices rise. Those prices flow directly into the supply charges on every Pennsylvania electricity bill.
What coal retirements mean for the grid
Pennsylvania's electric grid is part of PJM Interconnection, the regional transmission organization serving 13 states and 65 million people. PJM ensures enough power plants are available to meet peak demand, even during summer heat waves when air conditioners run full blast.
The mechanism is the capacity auction. Power plant owners bid to supply capacity — the promise to be available when called upon. When more plants bid, competition keeps prices low. When plants retire, fewer megawatts compete, and prices rise.
Coal plants were once the backbone of this capacity market. They ran reliably, generated large amounts of power, and provided the kind of always-available baseload the grid depends on. Their retirements leave gaps that other sources must fill.
Why this matters for your electricity bill
The PJM capacity auction cleared at $329.17 per megawatt-day for the 2026/2027 delivery year. In 2023, that same auction cleared at $28.92. The 833% increase in a single year reflects, in part, the tightening supply margins created by plant retirements.
Capacity costs are distinct from energy costs, but both appear on your bill. When capacity auction prices spike, utilities incorporate those costs into the Price to Compare. Every Pennsylvania utility's PTC has risen over the past two years.
PECO's PTC jumped to 11.024 cents per kWh. Duquesne Light reached 13.75 cents. These increases are not arbitrary — they reflect wholesale market conditions shaped by supply and demand fundamentals.
Where Pennsylvania coal plants have closed
The major Pennsylvania coal plant closures since 2019:
Bruce Mansfield Power Station
Located in Shippingport, Beaver County, Bruce Mansfield was one of the largest coal plants in the eastern United States. Its three units totaled 2,490 megawatts of capacity. The plant closed in November 2019, citing unfavorable market economics and environmental compliance costs.
Cheswick Generating Station
The Cheswick plant in Springdale, Allegheny County, operated 565 megawatts of coal capacity. It closed in September 2022 after decades of operation. Like other coal plants, it faced competition from lower-cost natural gas generation.
Homer City Generating Station
Homer City in Indiana County was Pennsylvania's largest remaining coal plant at the time of its closure in July 2023. Its three units totaled 1,884 megawatts. The plant had operated since 1969 and employed hundreds of workers in the rural community.
Smaller closures and conversions
Several smaller coal units across Pennsylvania have also retired or converted to natural gas. The cumulative effect is a generation fleet that looks dramatically different from a decade ago.
What is replacing coal generation
Pennsylvania's generation mix has shifted substantially since 2010.
Natural gas dominance
Natural gas now generates more than 50% of Pennsylvania's electricity, up from roughly 15% in 2010. The state's position atop the Marcellus Shale has made natural gas cheap and abundant. Many retired coal plants have been replaced by combined-cycle natural gas plants that produce fewer emissions and operate more flexibly.
Nuclear remains stable
Pennsylvania's nuclear fleet — Limerick, Peach Bottom, Susquehanna, and Beaver Valley — generates roughly 35-40% of the state's electricity. Nuclear provides carbon-free baseload power that capacity markets reward heavily. Three Mile Island Unit 1, which shut down in 2019, is currently in restart preparation. Constellation Energy announced a 2024 deal with Microsoft to supply data center power from the plant, now renamed the Crane Clean Energy Center. The restart is targeted for 2027 — a notable example of how data center demand is bringing retired generation back online.
Renewables growing but modest
Wind and solar have grown in Pennsylvania but remain a small share of total generation, likely under 5% combined. The state's capacity factors for solar are moderate, and wind development has faced siting challenges. Renewable growth has not offset coal retirements in capacity terms.
Imports from neighboring states
PJM's interconnected grid allows electricity to flow across state lines. When Pennsylvania plants retire, generation from Ohio, West Virginia, and other states can fill gaps. This provides reliability but does not reduce capacity prices — the auction reflects the entire PJM footprint.
The reliability question
When large coal plants close, a natural question follows: is the grid becoming less reliable?
The short answer is that PJM has maintained reliability through the transition, but margins have tightened. The grid has enough generation to meet current demand. The concern is whether supply will keep pace with demand growth, particularly as data centers and electrification add load.
PJM's reserve margin — the buffer between available capacity and peak demand — has declined from comfortable levels in the 2010s to tighter margins today. The capacity auction price increases reflect this tightening. Higher prices are supposed to incentivize new generation investment, but building power plants takes years.
The grid is not in crisis. Blackouts from insufficient generation have not occurred. But the economics have shifted from a surplus environment to one where every megawatt matters.
How customers can offset rising costs
Coal plant retirements and capacity auction increases affect the wholesale market that underlies all Pennsylvania electricity rates. Both utility default rates and competitive supplier rates reflect these market conditions.
The difference is that competitive suppliers price their plans in various ways. Some offer rates below the current Price to Compare. Shopping for a plan priced below your utility's PTC saves money on the supply portion of your bill regardless of what is happening in wholesale markets.
Check current rates in your territory:
- PECO (southeastern PA)
- PPL (Lehigh Valley, central PA)
- Duquesne Light (Pittsburgh area)
- Met-Ed and Penelec (northern and central PA)
Fixed-rate plans lock in a rate for the contract term, protecting against future quarterly PTC increases. The switching process is free and takes about five minutes.
For more on Pennsylvania's deregulated market structure, see our guide to Pennsylvania electricity deregulation.
FAQ
How much coal capacity has Pennsylvania retired?
Pennsylvania has retired more than 5,000 megawatts of coal-fired generation capacity since 2019, including major plants like Bruce Mansfield (2,490 MW), Homer City (1,884 MW), and Cheswick (565 MW). Additional smaller units have also closed.
Are any coal plants still operating in Pennsylvania?
Yes. Pennsylvania still operates several coal-fired power plants, including Conemaugh and Keystone in Indiana County. However, the coal fleet is a fraction of its former size, and additional retirements may occur as plants age and economics shift further.
Do coal plant closures cause blackouts?
No. PJM Interconnection manages the grid to ensure reliability through plant retirements. The retirements have not caused blackouts. However, they contribute to tighter reserve margins and higher capacity auction prices, which flow into electricity bills.
Why are coal plants closing?
Coal plants close for economic reasons: natural gas is cheaper, environmental compliance is costly, and older plants require expensive maintenance. Market conditions have made many coal plants unprofitable. The decisions are made by plant owners based on business economics, not by government mandate.
Will my electricity bill go down if new power plants are built?
New generation that bids into PJM's capacity auction would increase supply and put downward pressure on capacity prices. However, building power plants takes years, and current prices reflect existing supply-demand conditions. Bills may stabilize as new generation comes online, but a return to pre-2024 price levels is unlikely in the near term.