Microsoft Wants to Reboot Three Mile Island to Power Its AI Data Centers

Microsoft announced on Friday that it has signed an agreement with Constellation Energy to purchase electricity from the infamous Three Mile Island nuclear plant in order to power its AI data centers.

The "Unit 1" nuclear station has been out of commission since 2019, when it was shuttered due to low demand and increased competition from greener alternatives like solar, hydro, and wind. Unit 2 has been offline since 1979 when it partially melted down in what would become the single worst commercial nuclear accident in American history. The Three Mile Island disaster effectively sealed nuclear power's fate in the U.S., the accident setting off waves of opposition to the technology, leading to stringent new regulations, and accelerating the decline in developing new nuclear plants.

Nearly 50 years later, that calculus has changed as hyperscalers like Microsoft, Google, and Oracle race to build ever more powerful and capable language models. Constellation plans to spend $1.6 billion to get Unit 1 back online. The company expects to do so by 2028, assuming they can get regulatory approval.

While the particulars of the deal have not been confirmed, Microsoft has disclosed that it plans to purchase the entirety of Unit 1's 843 megawatt output for the next 20 years. Per a report commissioned by the Pennsylvania Building & Construction Trades Council, the deal is expected to generate 3,400 jobs in the region, more than $3 billion in state and federal taxes, and add $16 billion to Pennsylvania’s GDP.

“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," Constellation CEO Joe Dominguez said in a press statement. "Nuclear plants are the only energy sources that can consistently deliver on that promise."

While this is Microsoft's first foray into dedicated nuclear power for its AI data centers, the idea is not a new one for the industry. This past March, Amazon purchased a 960MW power plant, and the 1,200-acre Pennsylvania campus it sits upon, from Talen Energy for $650 million. It, too, plans to use that energy to power its AI data centers in the region.

“Several years ago, Amazon set an ambitious goal to reach net-zero carbon by 2040—ten years ahead of the Paris Agreement. As part of that goal, we’re on a path to power our operations with 100 percent renewable energy by 2025—five years ahead of our original 2030 target,” an Amazon spokesperson stated at the time. “To supplement our wind and solar energy projects, which depend on weather conditions to generate energy, we’re also exploring new innovations and technologies and investing in other sources of clean, carbon-free energy."

Source: Bloomberg, TechCrunch