CEG

Drive 90 minutes south of Harrisburg, Pennsylvania, and you reach Three Mile Island — the nuclear plant that became infamous for the 1979 partial meltdown of Unit 2. Unit 1, which operated safely for decades, was shut down in 2019 for economic reasons. In 2024, Microsoft signed a landmark agreement to restart it — now called the Crane Clean Energy Center — a 20-year power purchase agreement that secures 835 MW of carbon-free, 24/7 electricity for Azure AI data centers. In January 2026, the DOE awarded a $1 billion loan to support the restart, citing Constellation's financial strength as a key factor.

That is the physical reality of AI power: hyperscalers need so much electricity that they are restarting nuclear plants. Not building new ones (which takes 10-15 years) — restarting existing ones (which takes 3-5 years) because it is the fastest path to gigawatt-scale clean power.

Constellation operates nuclear plants across Pennsylvania, Illinois, New York, Maryland, and other states. Each reactor generates 1,000-1,400 MW of constant power — enough to run 2-4 hyperscale AI data centers simultaneously. The plants run at 90%+ capacity factors (the percentage of time they generate at full power), compared to 25-35% for solar and wind. For AI workloads that run 24/7, the capacity factor difference is decisive. The company produces nearly 300 million megawatt-hours annually, with two-thirds carbon-free — more clean firm power than any other competitive-market producer in the US.

The $16.4 billion Calpine acquisition, which closed in January 2026, transformed Constellation from a nuclear-focused generator into the largest private-sector power producer in the world. The combined fleet adds 19 GW of natural gas generation — efficient combined-cycle and cogeneration assets that provide the peaking power and grid flexibility that complement nuclear's baseload. Constellation now serves over 80% of the Fortune 100 and has executed deals for over 10,000 megawatts of its fleet across multiple customer types, technologies, and regions. FY2025 revenue was approximately $26.85 billion, with 2026 projected at roughly $30 billion.

The US electrical grid was not built for concentrated, growing, 24/7 power demand in specific regions. Grid interconnection queues in key markets stretch 5-10 years. Hyperscalers are solving this by going directly to power generators — Microsoft's Crane deal, Meta's 1.1 GW Clinton nuclear PPA, CyrusOne's 380 MW agreement — bypassing the grid queue entirely. This direct PPA model is now being replicated across the industry, and Constellation still has 147 million megawatt-hours of clean firm output available for contracting — more than all other competitive-market nuclear operators combined.