DOE Offers $5B Conditional Loan for Nuclear Uprates

By Olivia Hart

The U.S. Department of Energy has conditionally committed up to $5 billion to raise output by a combined 1.1 gigawatts across 15 reactors at eight nuclear power plants in Illinois, Maryland and Pennsylvania.

The money targets uprates at facilities that Constellation Energy operates as part of the country’s largest commercial nuclear fleet. Constellation said the commitment “builds on billions of dollars in private-sector investment already supporting Constellation’s efforts to increase nuclear output,” while stressing that it “does not, by itself, represent a final Constellation decision to proceed with any individual uprate or at every facility under consideration.”

This is the third multibillion-dollar uprate announcement in one month linked to Constellation. It follows an Amazon power agreement at Calvert Cliffs, a Google investment partnership and a Meta uprate deal. None of those private commitments establishes which DOE-financed projects will proceed.

What does the federal commitment cover?

An uprate generally adds new and more efficient equipment and technology so the same plant can produce more megawatts, Constellation spokesman Paul Adams said. At least six of the eight DOE-backed plants could draw funding from multiple sources:

• Calvert Cliffs, Maryland: On Sept. 30, Constellation finalized a power purchase agreement with Amazon supporting a 190-MW uprate at the 1,790-MW nuclear plant.
• Google partnership: On Oct. 6, Constellation said it would spend $4.3 billion with Google to increase generating capacity at 11 nuclear plants by a combined 890 MW.
• Limerick, Pennsylvania: Adams said earlier in October that the 2,317-MW plant would increase output by 348 MW. Limerick is among the facilities that could receive support from several sources.
• Illinois plants: Braidwood, Byron, LaSalle and Quad Cities could also receive multiple funding sources. Clinton, a fifth DOE-backed Illinois plant, already had a 30-MW uprate lined up under a 2025 agreement between Constellation and Meta.

The DOE may finance the hyperscaler-backed work or support separate increases at the same stations. Constellation did not answer a request for clarification before publication. The announcement identifies a capacity target, not a final plant-by-plant work plan.

The federal support opens a financing path, but it does not decide which uprates proceed.

Can existing plants close the capacity gap faster?

Nuclear power already serves as the country’s largest existing source of carbon-free electricity that does not vary with weather conditions. Uprates also offer a faster route to additional output than new reactors.

If the projects at all eight plants advance, Constellation would expand its nuclear generating capacity by about as much as one new AP1000 reactor, but at significantly lower cost. The United States has built only two AP1000s, both in Georgia, at a combined cost of more than $30 billion.

The Trump administration wants 10 new large reactors under construction by 2030, most or all probably AP1000s, as part of its goal of quadrupling national nuclear generating capacity by 2050. Late last month, the administration said it would back six new AP1000s and two South Korean-designed reactors of similar scale as part of a $350 billion trade deal with South Korea.

Separately, a startup staffed by veterans of the Georgia builds said it could construct six reactors at a Kentucky site beginning in 2028. Experts expect AP1000 construction costs to decline as more projects begin and thousands of engineers, tradespeople and laborers gain experience. They cited the second Georgia reactor, which cost about 30% less to build than the first.

Industry allies argue that uprating existing plants and restarting recently retired reactors remain the fastest and most affordable ways to add capacity in the near term. Given long development timelines for large plants, they say both approaches will be needed to meet the administration’s goal of adding 5 GW of new nuclear capacity by 2029.

Existing uprates can add capacity sooner; new reactors remain necessary for the larger target.

Who carries the financing risk?

The DOE unit now called the Office of Energy Dominance Financing, formerly the Loan Programs Office, made the conditional commitment.

“DOE thinks investing in uprates to existing facilities will be a cost-effective way to increase our domestic nuclear energy capacity,” said Erik Cothron, manager of research and strategy at the Nuclear Innovation Alliance. He said the agency also believes there is a reasonable prospect of repayment on the loan.

Cothron called external financing essential for capital-intensive uprates. He described the Google-Constellation partnership and the public loan support as complementary: private investment in uprates is increasing, while federal backing can make the projects easier to finance.

The deciding milestone is a final Constellation investment decision for each plant and confirmation that federal and hyperscaler financing can be combined; until then, the 1.1-gigawatt increase remains conditional.