In response to rising electricity demand driven in part by growth in artificial intelligence applications, U.S. energy companies are increasingly investing in upgrades to existing nuclear power plants to boost their output capacity. These efforts, known as “power uprates,” involve refurbishing or replacing key components such as controls, turbines, and pumps to enable older reactors to generate more electricity without the lengthy process of constructing new plants.

Constellation Energy, the country’s largest nuclear operator, recently announced plans to invest over $4.3 billion to enhance 11 reactors across six plants located in Illinois, Pennsylvania, and New Jersey. These upgrades are expected to add approximately 890 megawatts (MW) of power, sufficient to supply roughly 700,000 homes. Google has entered into a power purchase agreement to buy electricity from these facilities, though the contract price was not disclosed.

The Department of Energy (DOE) has also taken steps to support similar projects, committing a $4.2 billion loan to Vista Energy to increase generation at three plants in Pennsylvania and Ohio, potentially adding another 430 MW. Meanwhile, Amazon and Google have separately struck agreements to upgrade other reactors, including Constellation’s Calvert Cliffs plant in Maryland and four reactors in Georgia.

Proponents view power uprates as a relatively rapid and cost-effective method to increase clean, reliable electricity supply. Building new nuclear reactors typically takes over a decade and costs tens of billions of dollars, while uprates can be completed within five years at a fraction of that cost. According to Amanda Peterson Coprio, global head of energy and power at Google, these projects offer a “fastest way to get new additional clean capacity online confidently and reliably.”

Upgrades may include modern digital controls, higher capacity turbines, or the use of more potent nuclear fuel to optimize reactor performance. Although power uprates are not a new concept—they were common in the 1990s and early 2000s—interest had waned during periods of flat electricity demand and financial challenges in the nuclear sector. The recent surge in data center construction and companies’ climate commitments, however, have revived enthusiasm for expanding output at existing facilities.

Industry leaders emphasize the importance of securing premium pricing for electricity during such capital-intensive projects. Joe Dominguez, CEO of Constellation, noted that projects like these require financial arrangements beyond standard market rates to be viable. The planned upgrades are expected to be completed in stages through 2032.

Nuclear safety experts express confidence that uprates generally pose no significant safety risks given the extensive operational experience with the reactors involved. Koroush Shirvan, a professor of nuclear engineering at MIT, highlighted the comprehensive knowledge of plant performance but cautioned that increased wear on equipment could lead to more frequent maintenance outages, potentially offsetting some generation gains.

Some industry stakeholders see potential for even larger uprates in the future, noting that many reactors have not yet reached their maximum operational capacities. James Krellenstein, CEO of the startup Alva Energy, described current uprates as “on the tinier side” but considers them an important step to rebuilding industry expertise and execution capabilities. Alva is exploring innovative approaches, such as installing additional turbines and generators alongside operating reactors to minimize downtime during upgrades.

While uprates offer immediate capacity gains, experts agree that substantially expanding nuclear energy in the long term will require building new plants. However, significant financial, regulatory, and logistical challenges remain. Recent ventures into next-generation small modular reactors have faced sharp declines in stock valuations, and large-scale projects like the Vogtle Vogtle nuclear expansion in Georgia have experienced significant delays and cost overruns.

For now, the focus on maximizing output from existing infrastructure serves as both a practical response to growing power needs and a means of revitalizing the nuclear workforce and technical capabilities needed for future development. As Krellenstein summed up, power uprates are effectively a “training ground” for the nuclear industry’s next phase.