Three Mile Island, located in Middletown, Pennsylvania, was the site of the most significant nuclear accident in U.S. history. On March 28, 1979, the Unit 2 reactor suffered a partial meltdown, leading to widespread public concern and transforming the landscape of nuclear safety regulations. After years of closing, the Three Mile Island plant is set to reopen its Unit 1 reactor in 2030. 

The restoration project will be overseen and funded by Constellation Energy directly, the nation’s largest operator of nuclear power plants, with 21 reactors out of 94 reactors across the country. Constellation, which spun off from Exelon in 2022, is investing in the revival of Three Mile Island, and in doing so, is expected to produce roughly 3,400 new jobs in the area. Constellation plans to rebrand the plant, renaming it the Crane Clean Energy Center in honor of Chris Crane, the late CEO of Exelon. The restart of Unit 1 will generate 835 megawatts of carbon-free electricity—enough to power over 600,000 homes—helping to address the growing demand for clean and reliable energy. 

A key factor in the plant’s revival is a major 20-year contract with Microsoft, which will purchase the entire electricity output from the plant. This deal is part of Microsoft’s ambitious strategy to power its data centers with 100% carbon-free energy. As the tech giant expands its operations, including a significant push into artificial intelligence, access to reliable and sustainable energy has become critical to maintaining its operations. Microsoft has also stated that the electricity purchased will feed into the grid, to stabilize it and will not directly into data centers. 

While the project faces challenges, especially since nuclear projects have a history of cost overruns and construction delays, Constellation remains confident in meeting its target date. Bryan Hanson, Constellation’s chief generation officer, is optimistic, noting that the plant’s overall structure is largely intact and requires minimal upgrades, “Not an ounce of concrete needs to be poured, not one piece of rebar needs to be tied, not one cable needs to be pulled. The infrastructure is here.” 

The reopening of Three Mile Island’s Unit 1 comes at a time when energy demand in the U.S. is expected to surge. According to PJM Interconnection, which manages the electricity grid for 13 states, demand could rise by nearly 40% by 2039, driven by the increasing reliance on data centers, electric vehicles, and electrified industrial processes. Experts agree that nuclear energy will play a crucial role in meeting this demand, particularly as the nation seeks to transition away from fossil fuels and ensure a zero-emissions green economy.