TL;DR · 30-second read

The Short Version

The organization that runs the electric grid for 67 million people across 13 states, including Pennsylvania, held its auction to line up power plants for 2028 and 2029. The price hit the maximum allowed, again. Even at that price, it could not secure as much power as it wanted.

Data centers, giant buildings full of computers, are one big reason demand is climbing fast. A Pennsylvania consumer advocate says higher power costs already add $220 to $320 a year to a typical household’s bill. Paying top dollar is not fixing it, because new power plants cannot be built and connected fast enough.

PJM Interconnection, the Valley Forge, Pennsylvania-based nonprofit that operates the largest electricity grid in the United States, announced on July 14, 2026 that its latest capacity auction cleared at $325 per megawatt-day for the 2028-2029 delivery year. That is the maximum allowed under a price cap first negotiated by Pennsylvania Governor Josh Shapiro’s administration after the 2024 auction set a record of $269.92, and later extended at the request of PJM-state governors and the Trump administration. The Pennsylvania Capital-Star reported that the auction also fell 6,831 megawatts short of PJM’s capacity goal, a larger deficit than in last year’s auction.

PJM President and CEO David Mills said the results show “demand for electricity continues to grow faster than electricity supply.” PJM’s peak demand forecast has risen by 66,000 megawatts through 2036, driven by retiring fossil fuel plants, electrification of transportation and industry, and proposed data center development.

Executive Summary

PJM’s capacity auction, the mechanism it uses to pay power plants to be available on the hottest and coldest days of the year, hit its price ceiling again. At $325 per megawatt-day, the 13-state grid still came up 6,831 megawatts short of its target. The cap will also apply to the next auction, scheduled for December and covering 2030 and 2031.

This matters beyond the price. When an auction clears at its maximum and still falls short, the shortfall shows how much supply the highest permitted price could not attract. Consumer advocates and the generators’ own trade association disagree on a lot, but both point to the same near-term obstacle: getting new plants built and connected to the grid. The main limit on power for data centers in the largest US grid is construction and interconnection, not willingness to pay.

For households, the cost is already visible. Pennsylvania’s former consumer advocate estimates the last two auctions added about $16 billion in reliability costs, and $220 to $320 a year to the average Pennsylvania residential bill.

At the Ceiling, the Price Signal Runs Out of Room

A capacity auction is supposed to work like any market. If the grid needs more standby power, the price rises until enough generators commit to being available. The price is quoted per megawatt-day, the payment for one megawatt of capacity held ready for one day. In this auction that mechanism hit its limit. The clearing price of $325 is the cap itself, and even at that price PJM ended up 6,831 megawatts below its capacity goal, a wider gap than last year’s.

This is the key point for anyone planning around PJM power. A market that clears below its cap tells you what supply costs. A market that clears at its cap and still comes up short only tells you that the maximum permitted price was not enough. Two years ago the record was $269.92. Prices are now pinned at the ceiling, and the ceiling has been extended through the December auction for 2030 and 2031. Patrick Cicero, the former Pennsylvania consumer advocate now with the Pennsylvania Utility Law Project, described what that looks like: “These are flat prices that are going to remain high. It’s not necessarily another spike, but it’s really, really high prices remaining.”

Why the Constraint Is Construction, Not Capital

Robert Routh of the Natural Resources Defense Council blames data center load for the price pressure, and Todd Snitchler of the Electric Power Supply Association, which represents competitive generators, defends the price as a healthy investment signal. The two still converge on where the bottleneck sits. Routh said a lack of money is not among the problems: “Tech companies, data center customers that have a need for power have deep pockets. Any power plant that can get built these days should have no problem finding buyers and arranging financing.” He named the real obstacles as supply chain delays, long construction timelines, and siting and permitting hurdles. Snitchler said “new supply is coming; the issue now is to address getting it connected to the system as quickly as possible.”

That connection step is PJM’s responsibility. The grid operator vets proposed power plants and transmission lines before approving them to connect, and it has faced intense criticism for a years-long backlog of projects waiting in that line, often called the interconnection queue. Some projects dropped out while they waited. PJM says it has made significant progress by prioritizing shovel-ready projects.

There is one honest caveat. Because the cap is binding, this auction cannot show how much supply an uncapped price might have drawn in, and EPSA’s argument that years of record-low prices discouraged investment deserves weight. Still, even the generators’ trade group names connection rather than compensation as the near-term limit. For data center developers, the implication is plain: a higher bid does not produce a megawatt that has not been built. The scarce resources are deliverable, connected capacity and the time it takes to create it.

Who Carries the Cost, and the Proposal to Separate It

The link between auction prices and retail bills is indirect, but it is real. Cicero said the last two auctions added about $16 billion to the cost of ensuring reliability. Some Pennsylvania utilities have raised default rates, the rate paid by customers who do not shop for an electricity supplier, by up to 20%. He put the added cost to the average Pennsylvania residential customer at $220 to $320 per year.

The policy response under discussion is a separate auction, sought by PJM-state governors and the Trump administration, in which data centers and other large-load customers would buy long-term power commitments that fund new capacity. Routh described it as a matchmaking venue to build new supply “without raising prices for everyone else.” By his own account, though, that process faces the same supply chain, timeline and permitting hurdles as everything else. It could change who pays for new generation. On its own, it does not shorten the time it takes to build and connect that generation, which is what closes a 6,831-megawatt gap.

Weighing the Competing Explanations

Each camp’s framing captures part of the picture. NRDC’s Routh attributes the pressure to data centers directly: “Data center load growth is degrading grid reliability, and it’s raising prices to the Governor Shapiro-negotiated cap.” PJM’s 66,000-megawatt forecast increase through 2036, nearly 80 times the output of the Three Mile Island nuclear plant, bundles three drivers into one number: retiring fossil plants, electrification, and proposed data centers. How much of that number belongs to data centers is the question that decides whether large-load cost allocation addresses most of the problem or only part of it.

The Three Mile Island example shows how the pieces fit together. That plant is set to reopen next year to serve data centers exclusively, a sign that large tech buyers are already securing dedicated supply outside the shared pool. Snitchler’s point that new supply is coming is plausible given that buying interest. Until it is connected, however, the region is running on the capped price and a growing shortfall, and the costs fall largely on customers who did not create the new load.

Background

PJM Interconnection coordinates electricity supply across 13 states, including Pennsylvania, for 67 million customers. Alongside real-time grid operations, it runs capacity auctions years in advance to ensure enough generators are on standby for peak demand. It also reviews and approves new power plants and transmission lines seeking to connect, a process that has drawn criticism for a years-long backlog.

Capacity prices in PJM were low for years, which the generators’ trade association says discouraged investment. The 2024 auction broke that pattern with a record $269.92 per megawatt-day. Pennsylvania’s governor then negotiated a price cap, and PJM later extended it at the request of state governors and the Trump administration. Demand forecasts have risen sharply since, as fossil plants retire, transportation and industry electrify, and data center proposals multiply.

Sources

Source: PJM Interconnection electricity price hits cap again in latest auction (Pennsylvania Capital-Star): PJM’s 2028-2029 capacity auction clears at the $325 cap and falls 6,831 megawatts short of its goal.