Google and Constellation Energy have signed a twenty-year power purchase agreement worth $4.3 billion. The goal is to add 890 megawatts of nuclear capacity to the PJM Interconnection grid — the largest in the United States — by upgrading 11 currently operating reactors in Illinois, Pennsylvania, and New Jersey. The announcement sent Constellation’s stock up more than 12% on the day of the news.
The work will involve plants including Braidwood, Byron, LaSalle, and Quad Cities in Illinois, Limerick in Pennsylvania, and a stake in Salem in New Jersey. Upgrades will cover turbines, steam generators, and digital control systems. The additional capacity will be fed into the grid in phases between 2028 and 2032, totaling the equivalent output of a brand-new reactor. The two companies also signed a second, 15-year agreement covering an additional 2,700 megawatts of energy within the same PJM footprint.
The rationale behind the deal is straightforward. Building new reactors takes decades. Uprating existing ones delivers additional capacity far more quickly, without the permitting risks associated with new sites. Constellation gains the revenue certainty it needs to invest in already-operational assets, while Google secures a stable, carbon-free source of power for its energy portfolio. The agreement is aligned with the U.S. Department of Energy’s UPRISE program and the Trump administration’s Ratepayer Protection Pledge, which explicitly commits to not passing additional costs on to consumers’ electricity bills.
This deal is taking shape against the backdrop of a broader nuclear race among major American tech companies, driven by the surge in energy demand from AI data centers. Amazon closed a similar transaction with Constellation in Maryland the previous week. Meta has agreements to keep plants running in Ohio, Pennsylvania, and Illinois. Microsoft purchases power from the restart of Three Mile Island, also operated by Constellation. The pattern is consistent: tech giants are bankrolling the existing nuclear fleet in exchange for guaranteed electricity supply over the coming decades.
There is also a significant regulatory shift in the background. Illinois — home to the largest number of utility-scale reactors in the United States, with eleven units across six sites — lifted its thirty-year moratorium on new nuclear construction in 2025 through the Clean and Reliable Grid Affordability Act, signed by Governor JB Pritzker. The state had already opened the door to SMRs in 2023. Now, with the ban on large reactors removed, Illinois can once again become a full-spectrum hub for nuclear development. The Google-Constellation deal fits squarely into this context as a concrete signal: private capital is ready to move wherever policy has cleared the way.
If the planned uprates are completed on schedule over the coming years, the PJM grid will gain nearly 900 megawatts of additional nuclear power without a single foundation being laid. It is a pragmatic approach that could become the dominant model for expanding nuclear capacity in the United States in the near term — complementing, rather than replacing, new-build projects and the rollout of SMRs.
