US Offers Constellation $5 Billion for Nuclear Upgrades
The US Department of Energy has offered Constellation Energy a conditional loan commitment of up to $5 billion to expand output from its existing nuclear plants, the agency announced October 27. The financing would support uprates and modernization at eight plants in Illinois, Maryland and Pennsylvania.
Constellation, based in Baltimore, Maryland, is the largest nuclear power company in the United States. It operates 21 nuclear reactors, more than any other American company, and became an independent company in 2022 when it separated from Exelon. Across all fuels, including natural gas, wind, solar and hydro, its plants total 55 gigawatts of capacity, enough electricity for the equivalent of 27 million homes, or about 10 percent of the nation’s clean energy, according to the company.
Six of its nuclear plants sit in Illinois, at Braidwood, Byron, Clinton, Dresden, LaSalle and Quad Cities. Calvert Cliffs is in Maryland, and three are in New York, at FitzPatrick, Ginna and Nine Mile Point. In Pennsylvania, it runs Limerick and Peach Bottom, and it is also restarting the Crane Clean Energy Center, the former Three Mile Island Unit 1, with backing from Microsoft, with a return to service expected in 2027.
An uprate raises the output of an existing reactor by adding new and more efficient equipment, allowing the same plant to produce more megawatts. The projects across the eight plants, which run 15 reactors, would add nearly 1.1 gigawatts of electricity, enough to power more than 930,000 homes, according to the Energy Department. The power would serve the PJM Interconnection, the grid operator covering 13 states and Washington, D.C., and the Midcontinent Independent System Operator grids, and the department estimates the work would support more than 10,000 project-related jobs.
The commitment is conditional, not a completed loan. The financing remains subject to due diligence, negotiation of definitive agreements and other conditions, and Constellation has said the commitment is not a final investment decision on any individual project. The company has not said which plants could move forward first or by how much.
Pennsylvania’s stake is the Limerick plant. It is the only Pennsylvania facility in the portfolio, and Constellation has said its output would rise by 348 megawatts. The added power lands in the PJM grid at a moment of rising strain: PJM expects peak demand to grow by 32 gigawatts by 2030, with about 94 percent of that growth from data centers.
The offer is part of the Energy Department’s Utility Power Reactor Incremental Scaling Effort, known as UPRISE, launched in March 2026 under an executive order calling for 5 gigawatts of uprates from existing reactors. The department said about 95 percent of that goal, or roughly 4.7 gigawatts, has now been identified.
It was the department’s second major nuclear uprate financing offer this month. On October 5 it offered Vistra up to $4.2 billion for uprates and modernization in Pennsylvania and Ohio that would add 433 megawatts while preserving nearly 4 gigawatts of existing capacity.
Private investment is moving in the same direction. Twenty-year power agreements with Google and Amazon support more than $7 billion of investment for about 1,080 megawatts of added nuclear capacity, according to Constellation. Google’s share, announced October 6, is an 890-megawatt uprate program across Illinois, Pennsylvania and New Jersey backed by more than $4.3 billion. Amazon signed a 20-year agreement in September supporting a 190-megawatt expansion at Calvert Cliffs in Maryland, and a separate agreement with Meta supports another 30 megawatts at Clinton in Illinois.
Energy Secretary Chris Wright announced the commitment during a visit to Constellation’s Byron Generating Station in Illinois, calling uprates an example of the administration’s approach to affordable, reliable and secure energy. What happens next depends on which projects clear the loan’s conditions and on the company’s own investment decisions, neither of which has a public timeline.
