# Constellation Energy The largest nuclear fleet operator in the United States and, following its January 2026 acquisition of Calpine, the largest overall power producer in the country with roughly 60 GW of generation capacity. Constellation was formed in February 2022 as a spinoff of Exelon's competitive power generation and retail energy business. Headquartered in Baltimore, Maryland, the company trades on NASDAQ as CEG. CEO Joe Dominguez was elected board chairman in August 2026. Constellation's nuclear fleet -- approximately 32 GW of largely carbon-free baseload power across 21 reactors at 13 sites -- is the centerpiece of the company's value proposition in the [[Artificial Intelligence]] era. As hyperscalers race to secure firm, zero-carbon electricity for data centers, Constellation's existing nuclear capacity has made it the single most important energy company in the AI-nuclear convergence tracked across this knowledge base. ## Calpine Acquisition In January 2025, Constellation announced its intent to acquire Calpine Corporation for approximately $16.4 billion in equity (roughly $22 billion enterprise value). The transaction closed on January 7, 2026, with Calpine shareholders receiving 50 million shares of newly issued Constellation common stock and $4.5 billion in cash. Calpine brought roughly 26 GW of modern natural gas capacity and the largest geothermal complex in the world, creating a combined fleet of approximately 60 GW -- dwarfing any other U.S. power producer. The deal was expected to deliver more than 20% immediate accretion to adjusted operating earnings per share. ## Three Mile Island: Crane Clean Energy Center The most symbolically significant energy deal of the AI era. In September 2024, Constellation signed a 20-year power purchase agreement with [[Microsoft]] to restart Three Mile Island Unit 1, which had been shut down in 2019 for economic reasons. The $1.6 billion project will deliver 837 MW of carbon-free nuclear power dedicated to [[Microsoft]] data center operations, with a target restart of 2028. The facility was renamed the Christopher M. Crane Clean Energy Center in May 2025 (NRC-approved), honoring the late Exelon CEO. Unit 2 -- the reactor that suffered a partial meltdown in the 1979 accident, the worst nuclear incident in American history -- remains permanently shut down and is undergoing separate decommissioning. The restart involves only Unit 1, which operated safely for decades before its 2019 closure. As of mid-2026, the restart is progressing through NRC environmental review. FERC granted a waiver in early 2026 allowing expedited grid interconnection. The NRC released a draft environmental assessment in June 2026, with a final assessment projected for September 2026 and nuclear fuel receipt expected by year-end. America's most infamous nuclear disaster site becoming the dedicated power source for [[Artificial Intelligence]] is a potent symbol of the energy-AI convergence -- and a template that competitors are racing to replicate. ## Meta PPA: Clinton Clean Energy Center In June 2025, Constellation signed a second landmark 20-year PPA with [[Meta]] for the full 1,121 MW output of the Clinton Clean Energy Center in Illinois. Beginning June 2027, the deal supports relicensing and continued operation of the Clinton reactor for two decades beyond the expiration of Illinois's ratepayer-funded zero emission credit program. The agreement includes a 30 MW uprate (expected complete by 2029) and preserves 1,100 local jobs and $13.5 million in annual tax revenue. Investment bank Jefferies valued the deal at roughly $70/MWh -- a ~$20/MWh premium over Illinois energy-plus-capacity market rates. The Clinton and Three Mile Island deals together establish the template of dedicated nuclear power plants for dedicated data centers. ## Stock Performance Constellation's stock roughly tripled between 2023 and early 2025, making CEG one of the best-performing energy stocks in the market as investors priced in the AI data center demand thesis. The Calpine merger and Three Mile Island restart approvals drove further gains. By mid-2026, the stock had pulled back approximately 20-25% from its highs alongside a broader AI-power sector correction, trading around $274 with a market capitalization of roughly $98 billion. ## KB Relevance Constellation is the bridge between the nuclear renaissance and AI infrastructure buildout. The Three Mile Island restart -- America's most infamous nuclear site repurposed to power [[Microsoft]] AI -- is the most symbolically loaded energy deal in [[The Quest for 90 Gigawatts]]. The [[Meta]] Clinton PPA extends the model. Together these deals establish the pattern of dedicated nuclear plants for dedicated data centers, a structural shift in how [[Big Tech]] sources power. Constellation connects to the [[Stargate Project]] ecosystem indirectly through the demand dynamics it reflects: the same hyperscaler hunger for firm, carbon-free power that drives the Abilene buildout also drives the nuclear PPA wave Constellation leads. ## See Also - [[Microsoft]] - [[Meta]] - [[Nuclear Energy Debate]] - [[The Quest for 90 Gigawatts]] - [[Stargate Project]] - [[Artificial Intelligence]] - [[Energy Sector]] - [[Climate Change]] - [[Inflation Reduction Act]] - [[Big Tech]]