Microsoft Powers Up Three Mile Island’s Nuclear Future

September 25, 2025

In a significant development for the nuclear energy sector, Microsoft has inked a deal with Constellation Energy to purchase the entire electrical output of the Three Mile Island Unit 1 nuclear reactor for the next 20 years. This agreement aims to restart the plant, which was shut down in 2019, and rebrand it as the Crane Clean Energy Center. The move signals a growing trend of major tech companies investing in nuclear power to meet escalating energy demands, particularly for data centers supporting AI.

Key Takeaways

Microsoft will buy all electricity from Three Mile Island Unit 1 for 20 years.
The plant, formerly associated with a 1979 nuclear accident at Unit 2, will be renamed the Crane Clean Energy Center.
The deal is driven by the increasing energy needs of tech companies, especially for AI data centers.
Federal tax credits from the Inflation Reduction Act are crucial for the plant’s restart.
Constellation Energy expects the reactor to be operational again by 2028.

A New Chapter for Three Mile Island

Three Mile Island, a site indelibly marked by the 1979 partial meltdown of its Unit 2 reactor, is poised for a remarkable comeback. Unit 1, which operated safely for decades after the accident, ceased generating electricity in 2019 due to economic pressures, including low natural gas prices and subsidized renewables. However, a shifting energy landscape, coupled with federal incentives like the Inflation Reduction Act’s tax credits for nuclear power, has created an opportunity for its revival.

Big Tech’s Energy Appetite

The burgeoning demand for electricity, largely fueled by the energy-intensive nature of artificial intelligence and data centers, is driving tech giants like Microsoft to seek reliable and consistent power sources. Microsoft’s agreement to purchase all of Three Mile Island Unit 1’s output is a substantial commitment, estimated to power approximately 800,000 homes annually, which will be directed towards the company’s regional data center infrastructure.

This move mirrors similar trends, such as Amazon’s recent acquisition of a data center site adjacent to the Susquehanna nuclear power plant in Pennsylvania. Unlike Amazon’s partial purchase, Microsoft’s deal secures the entirety of the plant’s generation.

Financial Backing and Future Prospects

Constellation Energy CEO Joe Dominguez has stated that ratepayers will not bear the costs of restarting the facility, nor will the company seek state subsidies. However, federal support through tax credits is considered essential for the project’s viability. Analysts estimate these credits could amount to around $100 million annually, contingent on meeting wage and pricing requirements.

The potential restart of Three Mile Island Unit 1, with an expected operational date by 2028, could be a precursor to a broader nuclear resurgence. Other recently shuttered plants, such as the Duane Arnold nuclear plant in Iowa, are also being considered for restarts. This trend highlights the growing recognition of nuclear power’s role as a source of "firm power"—consistent electricity generation unlike intermittent renewables—in meeting the grid’s increasing demands.