Work to restart US nuclear unit at Three Mile Island is ahead of schedule

The process of restarting the retired first unit at the Three Mile Island nuclear power plant in Pennsylvania is gathering pace. Constellation, which is preparing to resume generation at the 835 MW unit, has reached its first milestones ahead of schedule. Preparatory work on the Crane Clean Energy Center project began after Constellation agreed to sell electricity to Microsoft.

US energy company Constellation announced that the initial phase of bringing the retired Three Mile Island 1 nuclear unit back online had exceeded expectations. The company reached the first milestones in the preparatory phase earlier than planned. The project, which will see the plant renamed the Crane Clean Energy Center, is focused on hiring staff, inspecting equipment, upgrading buildings, and securing the permits and licences needed for the restart.

"Every new milestone reinforces our belief that the Crane Clean Energy Center can be brought back online better than ever. Our goal is to restore 835 megawatts of emissions-free electricity to the grid at a critical time for Pennsylvania and our country," said Joe Dominguez, Constellation’s president and CEO.

The Three Mile Island power plant had two pressurised water reactor (PWR) units, commissioned in 1974 and 1978. The second unit, however, generated electricity for just three months before an accident struck, after which it never returned to service. The first unit generated electricity for 45 years, and Constellation shut it down in September 2019 because operating it was unprofitable.

"Major maintenance and upgrades are underway ahead of schedule. We have also ordered new equipment and are making tremendous progress in hiring and training the next generation of skilled workers to operate the plant to world-class standards of safety and performance, just as before," Dominguez added.

Microsoft partnership

The idea of bringing the retired nuclear unit back online was backed by US software company Microsoft, which agreed with Constellation to purchase electricity from the plant. Specifically, the 20-year contract will provide financial stability and allow the operator to invest around $1.6 billion (about CZK 37 billion) in bringing the technology back into operation.

In addition to Microsoft, other IT companies, including Google, Amazon and Meta, are also involved in restoring nuclear power plants to operation. The main reason is to secure emissions-free electricity for data centres and meet their growing consumption as artificial intelligence takes off.

"Pennsylvania’s nuclear energy sector plays a crucial role in providing safe, reliable and clean electricity. That is why my administration has engaged in plans to launch the Crane Clean Energy Center, with the aim of creating thousands of jobs, ensuring the reliability of our energy grid and cementing the Commonwealth (editor’s note: "US Commonwealth" – the states of Kentucky, Massachusetts, Pennsylvania and Virginia) as a national energy leader," said Pennsylvania Governor Josh Shapiro.

Constellation says it has already hired 200 employees and will need another 400 during the start-up phase. According to an independent economic impact study, the restart will create 3,400 direct and indirect jobs and generate $16 billion in GDP. Under current plans, the unit is expected to restart in 2028.