Microsoft taps Three Mile Island nuclear plant to power AI

The data centers that train the large language models behind AI consume unimaginable amounts of energy, and the stakes are high for big tech companies to ensure they have enough power to run those plants. That’s why Microsoft is now throwing its weight behind nuclear power.

The tech giant on Friday signed a major deal with nuclear plant operator Constellation Energy to buy power for its data centers from the energy company’s Three Mile Island Unit 1 nuclear plant.

The plant is located right next to TMI-Unit 2, which infamously melted down in 1979. Unit 1 was shut down in 2019 as demand for nuclear energy waned amid competition from cheaper energy alternatives like natural gas, solar, and wind power. 

Constellation said it plans to spend $1.6 billion to revive the Unit 1 plant, pending regulatory approval, by 2028.

The financial terms of the deal were not disclosed. Microsoft has agreed to purchase all of the power from the reactor over the next 20 years, a Constellation spokesperson told TechCrunch. Once restored, the reactor promises a capacity of 835 megawatts.

The new plant will also be renamed the Crane Clean Energy Center (CCEC) after Constellation’s former CEO, Chris Crane, who died in April. The plant is expected to create 3,400 direct and indirect jobs, add $16 billion to Pennsylvania’s GDP, and generate more than $3 billion in state and federal taxes, according to an economic report commissioned by the Pennsylvania Building & Construction Trades Council.

“Powering industries critical to our nation’s global economic and technological competitiveness, including data centers, requires an abundance of energy that is carbon-free and reliable every hour of every day, and nuclear plants are the only energy sources that can consistently deliver on that promise,” said Joe Dominguez, president and CEO of Constellation, in a statement.

Microsoft did not immediately respond to a request for comment.

Microsoft isn’t the only tech company turning to nuclear energy to power AI data centers. OpenAI’s CEO Sam Altman has called for an energy breakthrough in the form of nuclear power, and Amazon in March bought a nuclear-powered data center in Pennsylvania for $650 million. 

Microsoft, Amazon, and Alphabet have all said they plan to run data centers entirely on green energy. Microsoft’s goal is to do so by 2030, but in May, the company admitted its AI push is putting that goal into jeopardy.

In June, Bloomberg reported that big tech’s upcoming data centers promise to consume a combined 508 terawatt hours of electricity per year if they run constantly. That would be more than the total electricity produced in Australia in a year. 

The demand for clean electricity to power not just data centers but also electric vehicles, factories, and more has spurred a renaissance of sorts around nuclear power. Investors are increasingly bullish on nuclear fusion startups, which have raised $7.1 billion to date, since it represents a cleaner and more powerful future for nuclear power. It uses hydrogen as fuel, whereas nuclear power plants and their fission process rely on hard-to-come-by elements like uranium and plutonium.