Pennsylvania’s Data Center Boom Fails PJM’s Reliability Test

A Pennsylvania-commissioned study finds the largest U.S. grid missing its 2030 reliability target unless new data centers stop arriving. PJM Interconnection, which runs the bulk power system for 67 million people in 13 states and Washington, D.C., fails its own planning standard from 2027 through 2030 in every case that still adds those campuses.

Harrisburg is not closing the door. Weeks before the study landed, Gov. Josh Shapiro built a two-track permit system that still lets large projects move if they pay for new power and win local yes votes.

What the Pennsylvania PUC Study Found for 2030

The Synapse Energy Economics independent analysis of resource adequacy, released Sept. 14 by the Pennsylvania Public Utility Commission, tests PJM against a loss-of-load expectation of 0.1. That standard is meant to keep shortages to about one event every 10 years. Only a case with no new data centers meets it.

THREE FUTURES FOR 2030

Those readings do not say a given home will go dark on a given night. They measure how often the model expects supply to fall short if demand keeps outrunning plants that can actually be built. In the severe case, new data center demand across PJM in 2029 and 2030 alone exceeds the electricity Pennsylvania uses in a year.

PUC Chairman Steve DeFrank called the state an energy crossroads and said the status quo is not sustainable. “Time matters,” he said. “The changes highlighted in this report are not decades away. The reliability pressures emerge during the next several years, and the decisions being made now will determine how prepared we are to meet them.”

Harrisburg Still Wants the Campuses, With Strings

On Aug. 18 Shapiro signed Executive Order 2026-05, titled Protecting Pennsylvania Consumers from Data Center Impacts. It pulls every AI data center out of the PA Permit Fast Track program, bars state agencies from signing nondisclosure deals on these projects, and splits Department of Environmental Protection review into two tracks for projects with peak demand over 25 MW.

Developers who execute a consent order to meet the Governor’s Responsible Infrastructure Development rules keep rolling review after they show local approvals. Developers who refuse wait until every local approval is in and every construction permit has already been found compliant. The Department of Revenue will also withhold the Computer Data Center Equipment sales-tax exemption from applicants who skip those rules.

WHAT THE GRID PATH DEMANDS

• New power costs: Developers pay the full cost of new generation, transmission, distribution, and other gear their project needs, without shifting those bills onto households and other businesses.
• Local yes: They notify affected governments, hold public meetings, and consult early enough that residents can still change major design choices.
• Local hire: They train local workers and sign community benefit deals that put money into schools, infrastructure, or other town priorities.
• Water and air: They meet the order’s environmental floor, including strict water-conservation terms, and file annual energy and water use with DEP.

DEP has seen an unusual pile of proposals. Public databases list more than 100 projects. Fifty-eight have talked to the department at some formal level, 15 have applied for at least one permit, and five hold every permit they need for a first phase. Shapiro said many of the rest lack plans, money, power, or a tech tenant. “If you can’t agree to our strict requirements and get the community where you want to build to say ‘yes,’ you’re not going to have the Commonwealth’s support either,” he said.

That is a filter, not a freeze. The order is how Pennsylvania still tries to land the campuses the study says the regional grid cannot absorb on today’s plant schedule.

Who Loses Power First in an Emergency?

On Sept. 10 the PUC voted 5-0 for a Kimberly Barrow motion that tells staff to draft updates to emergency load control rules. The aim is a clearer order of who gets cut, under what tests, when PJM is already in a pre-emergency or emergency. Barrow said rapid load growth and tighter resource adequacy now force a hard look at whether the old playbook is enough.

THE HARRISBURG CLOCK

1. May 2026: The PUC issues a model large-load tariff so customers at 50 megawatts or more pay the system costs they add, rather than spreading them across other ratepayers.
2. August 18, 2026: Shapiro’s order asks his special counsel for energy affordability to push the PUC toward cutting data centers before other customers when the grid is stressed, and toward putting reliability-backstop auction costs on those campuses.
3. September 10, 2026: Commissioners vote 5-0 to rewrite curtailment rules and to call a fall technical conference on cost allocation for large computational loads.
4. September 14, 2026: The Synapse study is released, finding the regional standard missed from 2027 through 2030 unless new data centers stop arriving.
5. October 1, 2026: A tentative order on the new curtailment rules is due at the public meeting, then goes out for comment.
6. January 28, 2027: A final order is targeted at that public meeting.

The commission is also carrying out Act 45 of 2025, a second check on the load forecasts Pennsylvania utilities send to PJM, and it has told electric distributors that want offsets under PJM’s proposed Reliability Backstop Procurement to file those details for review. Last week’s companion vote on that backstop, the PUC said, restated that existing customers should be protected ahead of newly connecting large loads.

If that hierarchy holds, some of the demand in the study never shows up. Campuses that can be cut first, and that have not locked down their own plants, have a reason to shop for another region. The reference case still fails without that brake working at scale, because it already uses PJM’s latest load forecast and still misses the standard.

A Net Exporter on a Shrinking Surplus

Pennsylvania still sells more electricity than it uses. In the study’s reference case that surplus shrinks from about 91 TWh in 2025 to about 69 TWh by 2035 and 38 TWh by 2040. In the high-load, low-supply case the state flips, becoming a net importer of 5 TWh by 2040. The report warns that a large block of unmet load from 2031 onward means some of that later demand will simply not be served, because the region will not have enough generation for PJM-wide need.

The new load is not evenly spread. Maryland People’s Counsel David Lapp, briefing from PJM’s 2026 forecast, put large-load growth at 41 percent in Virginia, 29 percent in Ohio, 12 percent in Illinois, and 9 percent in Pennsylvania, with the rest of the footprint at 9 percent. Northern Virginia remains the construction pit. An Amazon Web Services campus going up in Sterling sits on the same PJM system Pennsylvania is trying to keep in surplus.

That is the quiet export story inside the outage math. Neighbors who have long bought Pennsylvania power lose that spare capacity even if Harrisburg never hosts the biggest share of the campuses. Homes in the state still sit on a grid whose planning margin is being eaten by load a few zones away.

Two Capacity Auctions Missed the Reliability Target

The study did not arrive in a quiet market. PJM’s July 2026 capacity auction posted a system-wide reliability shortfall of 6,831 megawatts for the delivery year that runs from 2028 to 2029. The PUC said the auctions for both 2027/28 and 2028/29 came in below the regional requirement, which is why PJM is now stacking extra tools, including the reliability backstop and an Interim Resource Adequacy Service.

WHERE THE SHORTFALL ALREADY SHOWS

• Customers on the line: 67 million people across 13 states and Washington, D.C., take power from the PJM system that missed those two auctions.
• The plant gap: 6,831 megawatts is the July 2026 shortfall against what PJM said it needed for 2028 to 2029.
• The load forecast: PJM’s 2026 long-term load forecast files still point to a summer peak near 222,000 MW by 2036, about 66,000 MW above today’s level, even after a near-term trim for weaker large-load commitments.
• The state check: Pennsylvania’s August electric outlook flagged industrial load growth of 18.56 percent over five years, driven mainly by PPL Electric Utilities’ large-load forecast, while statewide usage fell from 2024 to 2025.

Jeff Shields, PJM’s senior manager of external communications, said the operator has moved to raise supply and manage new demand in line with the Ratepayer Protection Pledge that data center developers took, a pledge meant to keep reliability risk and extra costs off residential customers and other ratepayers. The Department of Energy has also kept some coal plants running past planned retirements to hold supply in the region, the study notes.

Paper Promises and a 2027 Supply Gap

The Ratepayer Protection Pledge, first signed in March by Amazon, Google, Meta, Microsoft, OpenAI, Oracle, and xAI, is a voluntary promise to build, buy, or fund enough generation for new data center load and to pay for the wires that connect it. The White House later folded in utilities, co-ops, other developers, and governors. It has no enforcement mechanism of its own. Retail rates are still set by state commissions, and PJM’s backstop design is already drawing protests from consumer advocates who say leftover plant costs can still land in zones where ordinary customers pay.

Data center development brings significant opportunities, but that growth cannot come at the expense of the families and businesses that already depend on reliable and affordable electric service. This analysis sends a clear warning: electricity demand and supply are moving out of balance, and the status quo is not sustainable. We need urgent action at PJM and a broader Pennsylvania energy strategy that makes sure our supply of electricity keeps pace with demand.

Steve DeFrank, Chairman, Pennsylvania Public Utility Commission

Synapse was hired to give Harrisburg its own forecast, not PJM’s. The firms on the work also included Mondre Energy and Aspen Technologies, and the commission sent the report to the General Assembly. The finding that survives every caveat is narrow and blunt. Under the loads already in the 2026 forecast, the region’s own 0.1 rule does not hold from 2027 through 2030 if new data centers keep connecting. It holds if they do not.

Shapiro’s order and the PUC’s tariff, curtailment rewrite, and fall cost conference are the state’s answer: host the boom only if the campuses bring plants, take the first cuts, and pick up the bill. Those rules are still paper on a 2027 clock. The next date that can change the order of who goes dark is the Oct. 1 public meeting, with a final curtailment order aimed at Jan. 28, 2027. Until new megawatts actually clear interconnection and run, the only modeled path that meets PJM’s standard is the one Pennsylvania’s permit system is still designed not to take.