Microsoft is reviving Three Mile Island for AI power

Microsoft is turning to America's most infamous nuclear site to satisfy its bottomless thirst for AI power.

Microsoft inked a massive 20-year power purchase agreement with Constellation Energy to resurrect a shuttered reactor at Pennsylvania's Three Mile Island. If regulators give the green light, the tech giant will buy 100 percent of the plant's output exclusively for its data centers.

A $1.6 billion nuclear comeback

The Unit 1 reactor in question was shut down in 2019 due to financial hurdles. It sits right next to Unit 2, which suffered the most severe commercial nuclear accident in US history back in 1979.

Constellation plans to invest 1.6 billion dollars to restore the facility, rebranding it as the Crane Clean Energy Center. The reactor is expected to generate between 835 and 837 megawatts, which is enough electricity to power more than 800,000 homes.

Constellation is aiming to bring the reactor back online by 2028, pending approval from the Nuclear Regulatory Commission along with state and local authorities. The energy company is also pursuing a license extension to keep the plant humming through at least 2054.

According to Bloomberg, this dedicated nuclear pipeline will power Microsoft data center expansions across Virginia, Ohio, Pennsylvania, and Chicago, helping offset emissions that have spiked sharply since the generative AI boom began.

Why it matters

AI is hitting an energy wall, and the frontier tech race is rapidly transforming into a high-stakes power land grab.

For enterprise customers and developers, you will not see immediate UI changes tomorrow, but this deal helps guarantee the long-term uptime of the cloud infrastructure running Copilot and OpenAI models. Reliable, zero-carbon base-load power is the only way hyperscalers can keep training larger clusters without crashing regional grids.

Across the industry, Microsoft's move will likely force rivals like Amazon and Google to pursue similar dedicated nuclear contracts. Wind and solar alone simply cannot support data centers that demand relentless, uninterrupted electricity 24 hours a day, 7 days a week.

We think locking up an entire reactor is a clever tactical flex, essentially buying grid insurance while defending climate targets. However, reviving a retired nuclear facility carries serious regulatory, political, and public relations friction, and any permitting delays could easily puncture Microsoft's 2028 timeline.