Three of the largest U.S. power producers have spent the past year signing twenty-year supply contracts with the hyperscalers building out AI infrastructure, locking in revenue visibility that spans two decades. Constellation Energy, Vistra, and Talen Energy each control nuclear fleets that run at capacity factors above ninety percent, a reliability metric that now commands a premium over intermittent generation. The contracts coincide with a federal target to quadruple domestic nuclear capacity by 2050, a policy tailwind that turns existing plants into scarce assets.
Constellation holds the fleet advantage
Constellation operates fifty-five gigawatts of total generation, twenty-two gigawatts of it nuclear, giving it the largest reactor fleet in the country. Its plants ran at a ninety-three percent capacity factor in the second quarter, a figure that translates directly into more megawatt-hours sold under fixed-price agreements. The company has already secured twenty-year power purchase agreements with Microsoft and Meta Platforms, anchoring a contracted revenue base that scales with every additional hour of reactor uptime.
Vistra builds a Texas and PJM portfolio
Vistra controls forty-four gigawatts of capacity, with six-point-six gigawatts of nuclear split between the ERCOT and PJM regions. Its ERCOT units posted a ninety-two-point-nine percent capacity factor and its PJM units ninety-one percent, trailing Constellation but still in the top tier of U.S. operators. In September 2025 Vistra signed a twenty-year PPA with Amazon Web Services for output from the Camanche Park plant in Texas. Four months later it agreed to sell twenty-six-hundred-nine megawatts from its PJM nuclear stations to Meta Platforms under another twenty-year deal. A third arrangement, announced in June, made Vistra the preferred power supplier to Helix Digital Infrastructure, a ten-billion-dollar data-center venture backed by KKR, Nvidia, and the Kuwait Investment Authority.
Talen leans on a single reactor complex
Talen’s fifteen-point-seven gigawatts of generation include two-point-two gigawatts of nuclear through a ninety-percent stake in the Susquehanna plant in Pennsylvania. That single site supplies the bulk of the company’s clean output and underpins its major supply agreement with AWS. The concentration creates a different risk profile: one refueling outage or regulatory action at Susquehanna affects a larger share of contracted volumes than a comparable event across Constellation’s geographically dispersed fleet.
The policy floor and the next catalyst
The White House goal of four-times current nuclear capacity by mid-century does not guarantee new builds, but it raises the replacement cost of every operating reactor. For the three incumbents, the immediate catalyst is not policy but contract execution: each hyperscale deal converts baseload reliability into predictable cash flows at a time when wholesale power prices remain volatile. Investors will watch whether Vistra’s Helix partnership expands beyond the initial ten billion dollars, whether Constellation adds a third hyperscaler to its roster, and whether Talen can diversify away from a single plant without diluting the premium its Susquehanna output already commands.