Three Mile Island nuclear plant likely to come back online a year earlier than planned

Work to bring the Three Mile Island nuclear power plant in the US state of Pennsylvania back to life is gathering pace. According to the plant’s owner, Unit 1 could resume operation as early as 2027, a year earlier than originally expected. The Three Mile Island nuclear power plant became infamous for the 1979 accident, although Unit 1 continued operating until recently. In recent years, plans have emerged in the US to revive retired nuclear power plants amid expectations of rising electricity demand from data centers.

Unit 1 at the Three Mile Island nuclear power plant could be connected to the grid as early as 2027, according to its owner. Work to restore the plant to operation was made possible by an agreement between owner Constellation Energy and Microsoft, which plans to use its output to meet the electricity needs of its data centers. Microsoft’s role is crucial in this case, as it has committed to purchasing the plant’s full output for 20 years. This commitment provides the plant with financial stability and makes the project restart possible.

Unit 1 will also be renamed the Crane Clean Energy Center in honor of the late Exelon CEO Chris Crane. Unit 1 was not affected by the 1979 accident and continued operating until 2019. The reason it was shut down was not technical problems, but that it was operating at a loss. The long-term agreement with Microsoft is expected to address this issue.

“We made a mistake when we shut this plant down, but we’re not here to dwell on the past,” Constellation Energy CEO Joe Dominguez said, according to Reuters.

According to the owner, the 890 MW unit is in a similar condition to how it was before it was shut down in 2019. Since the restart was announced, most of the work has focused on planning and recruiting new employees, the company said. It has already ordered several key components needed to resume operations, including the main transformer and nuclear fuel.

Accelerating grid connection is expected to help bring operations back sooner

When Constellation announced the plant’s restart last autumn, it said it expected the process to be completed in 2028. Company representatives said the process could be slowed by the long wait for a connection to the regional transmission grid operated by PJM Interconnection.

The grid operator has nevertheless moved to accelerate the process for several selected projects, including Three Mile Island, now known as the Crane Clean Energy Center. One reason for accelerating the process—not only for the nuclear unit—is the expectation of rising electricity consumption by data centers.