Constellation Energy will spend $4.3 billion to add 890 megawatts of nuclear capacity at eleven existing plants across the PJM Interconnection, the grid operator serving thirteen states from Virginia to Illinois.

The deal, signed Tuesday with Google, runs for twenty years and ranks as the largest hyperscaler-backed power uprate program in the United States. It moves the Trump administration closer to its goal of adding 5 gigawatts of carbon-free nuclear capacity by 2029 without building a new reactor.

What does the uprate actually entail?

Uprates replace turbines, steam generators and digital control systems inside plants that already hold operating licenses, sidestepping the multi-year Nuclear Regulatory Commission approvals required for greenfield reactors. Constellation expects to finish the first Google-backed uprate by 2028 and complete the entire batch in the early 2030s, spokesperson Paul Adams told reporters.

The 2,317-megawatt Limerick Generating Station near Philadelphia will absorb the largest addition at 348 megawatts. The 2,327-megawatt Salem plant in southern New Jersey will take a 97-megawatt boost.

"Each plant is different, so the scale of the projects and what is being done varies plant to plant," Adams said. "The generic way to describe it is that we will be adding new and more efficient equipment and technology that will allow us to get more megawatts from the same plant."

At roughly $4,800 per kilowatt, the program costs more than utility-scale solar with storage, a new combined-cycle gas plant, or Constellation's $1.6 billion effort to restart the Pennsylvania reactor formerly known as Three Mile Island. It runs less than half the per-kilowatt expense Georgia Power and Southern Company incurred on Plant Vogtle Units 3 and 4, which arrived seven years past schedule.

Why does PJM want the power?

PJM expects electricity demand to climb more than 5 percent annually over the next decade across its 67-million-customer footprint, with retail prices rising as much as 60 percent by 2030. Tens of gigawatts of data center load drive that trajectory.

"We need all the megawatts of electricity supply we can get to meet growing demand," PJM spokesperson Jeff Shields wrote in an email. "Additional supply addresses both the reliability needs of the system and eases upward price pressure."

U.S. nuclear plants posted a 92.3 percent capacity factor last year, the Department of Energy reports, against 59.9 percent for combined-cycle gas, 34.3 percent for wind, 23.4 percent for solar and 17.2 percent for gas peakers. That round-the-clock profile drove hyperscalers to underwrite the uprates.

Who else is doing similar deals?

The day before Constellation's announcement, the Department of Energy issued a $4.2 billion loan to Vistra to extend operating licenses at three Pennsylvania and Ohio nuclear plants and complete 433 megawatts of previously announced uprates, with Meta as the offtaker.

"For the near term, uprates are the fastest, most practical and cost-effective ways to add reliable, clean nuclear capacity," said Judi Greenwald, president and CEO of the Nuclear Innovation Alliance.

Hyperscalers are also funding two reactor restarts: Microsoft at the 835-megawatt Crane Clean Energy Center, formerly Three Mile Island Unit 1, and Google at the 615-megawatt Duane Arnold Generating Station in Iowa. Both aim to return before 2030.

What does this change for generators and developers?

PJM renewables developers, often cast as nuclear competitors, have welcomed the long-tenor revenue contracts. Twenty-year power purchase agreements resemble the structures that have financed utility-scale wind, solar and storage for years.

"Long-term revenue agreements like this are essential to deploy new generation across all resource types: nuclear, solar, wind, storage, gas, and so on in PJM," said Evan Vaughan, executive director of MAREC Action, a mid-Atlantic renewables trade group. "Solar, wind, and storage continue to represent a large share of greenfield deployment in PJM."

Jefferies senior analyst Julien Dumoulin-Smith told clients the Constellation and Vistra commitments cover most of the 3 to 5 gigawatts of uprate potential in PJM and a meaningful slice of the same range nationwide.

What decides what happens next?

The Trump administration wants to bring 300 gigawatts of new nuclear capacity online by 2050. Uprates and restarts alone cannot deliver that figure, leaving greenfield reactors at uneconomic unit costs as the only remaining path.

The next milestone sits with the Nuclear Regulatory Commission, which must clear the license amendments and component qualifications for each uprate site before crews can move from engineering to installation.