Three Mile Island Restarts to Power Microsoft’s AI Data Centers in Historic Nuclear Revival

The Three Mile Island nuclear power plant is being restarted. Its mission is now to power Microsoft’s artificial intelligence data centers. Energy Secretary Chris Wright visited the Pennsylvania site to confirm a summer 2027 restart timeline. This marks a dramatic turnaround for the facility.

This move is a cornerstone of a national strategy. The goal is to secure carbon-free electricity for the exploding AI industry. A federal loan of $1 billion has already been secured to fund the historic reboot of the dormant reactor.

A $1.6 Billion Rebirth for a Nuclear Landmark

Constellation Energy is leading the $1.6 billion restart project. The company closed the landmark federal loan in November. According to Reuters, this financial backing was crucial for moving the project forward.

The reactor, known as Unit 1, was shut down in 2019. At the time, it could not compete with cheap natural gas. The plant’s entire output is now pledged to Microsoft under a 20-year agreement.

This deal is worth an estimated $16 billion. It provides the stable, clean power Microsoft’s cloud and AI services desperately need. The reactor will produce 835 megawatts of electricity upon its return.

The AI Industry’s Insatiable Appetite for Power

The restart is a direct response to a looming energy crisis. Data centers powering AI require massive, reliable electricity 24 hours a day. Intermittent renewable sources like wind and solar often cannot meet this constant demand alone.

Nuclear power operates at over 90% capacity. It provides the perfect “always-on” backbone for AI infrastructure. The PJM grid operator forecasts a need for 30 gigawatts of new capacity by 2030, largely for data centers.

This project positions Three Mile Island as a national model. Other tech giants are seeking similar nuclear partnerships. The race to power AI is fundamentally changing America’s energy landscape.

The restart of Three Mile Island is more than a power project; it is a symbol of the new energy reality, where historic nuclear assets are being revived to fuel the nation’s technological future.

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Why is Three Mile Island being restarted now?

The primary driver is the huge electricity demand from artificial intelligence data centers. Companies like Microsoft need vast amounts of reliable, carbon-free power, which nuclear energy uniquely provides. The economics now support restarting dormant plants.

Is it safe to restart the Three Mile Island plant?

Officials and the operator state it will meet all modern Nuclear Regulatory Commission safety standards. The reactor being restarted, Unit 1, was not involved in the 1979 accident. Extensive upgrades and inspections are part of the restart process.

When will the plant be fully operational?

The accelerated target for the Three Mile Island restart is summer 2027. Key steps before then include reactor fuel loading and final approvals from grid operators and nuclear regulators. The timeline has been moved up by one year.

How will this affect local electricity prices?

Analysts are watching closely. While new demand can pressure prices, officials argue that adding steady, large-scale generation to the grid can ultimately help stabilize costs for other users by increasing overall supply.

What was the 1979 Three Mile Island accident?

It was a partial meltdown in the plant’s Unit 2 reactor. It is considered the most significant accident in U.S. commercial nuclear power history. However, official studies concluded it led to no direct deaths or identifiable long-term health effects in the public.

Are other closed nuclear plants being restarted?

The Three Mile Island project is seen as a major test case. Its success could inspire similar efforts at other recently retired nuclear sites across the country, especially those located near major data center hubs needing clean, firm power.