A unit of Pennsylvania’s Three Mile Island nuclear plant will be restarted as part of a new energy-sharing agreement with Microsoft, which plans to use it to power the data centers it operates as part of its push into artificial intelligence.

In a joint release, Microsoft and Constellation Energy, Pennsylvania’s main utility, said Three Mile Island Unit 1, a unit separate from the one that sparked the infamous shutdown nearly five decades ago, will be used to provide clean energy to the tech giant as the artificial intelligence arms race heats up.

Constellation shut down Unit 1 in 2019 due to operating losses. Unit 2 was shut down in the wake of the 1979 incident that saw a partial core meltdown that led radioactive compounds to be released into the environment.

Studies have produced a range of estimates for the death toll over the course of 30 years as a result of the radiation release — but it is often cited as having set back America’s nuclear-energy push for a generation.

Today, energy has become the new coin of the realm for companies investing in artificial intelligence. That’s because the data centers tasked with running the complex calculations needed to power artificial intelligence applications require enormous amounts of power. Restarting Unit 1 will mean bringing 800 megawatts back onto the grid, greater than the amount of hydroelectric power supplied by the Hoover Dam.

Additional shuttered nuclear factories now being considered for reactivation amid the broader AI-data center push can be found in Michigan and Iowa, while a half-dozen other states are reversing moratoriums on new nuclear plants.

Microsoft’s vice president of energy touted the clean-energy benefits of reviving the facility in a statement.

“This agreement is a major milestone in Microsoft’s efforts to help decarbonize the grid in support of our commitment to become carbon negative,’ Bobby Hollis said. ‘Microsoft continues to collaborate with energy providers to develop carbon-free energy sources to help meet the grids’ capacity and reliability needs.”

Earlier this week, Microsoft and investment group BlackRock announced a new, $100 billion initiative to develop data centers for artificial intelligence. While analysts are still debating what the AI push has accomplished to date, companies worldwide see it as the next great business opportunity.

Microsoft CEO Satya Nadella recently shrugged off doubts about AI’s payoff, comparing it to the trajectory of the Industrial Revolution

‘There was not that much industrial growth, and then it took off,’ he said at a recent conference. ‘1817 in the United States to the 1940s was just one of those golden ages.’