Three Mile Island nuclear plant to restart for Microsoft

The site known for America’s worst ever nuclear power plant disaster is poised for a revival as a clean energy hub to power Microsoft’s ambitious push into artificial intelligence.
Constellation Energy, the owner of the shuttered Three Mile Island nuclear plant in Pennsylvania, has said it will invest about $1.6 billion to revive one of the plant’s units, which it plans to open in 2028. It has agreed to sell all of the energy from the plant to Microsoft for two decades.
It comes decades after a separate unit of Three Mile Island suffered a partial meltdown in 1979 in one of the biggest industrial accidents in the country’s history. Small radioactive releases had no detectable health effects on plant workers or the public. However, the incident prompted sweeping changes around emergency response planning, reactor operator training and radiation protection.
The revival of the plant will require federal, state and local approvals.
The tie-up with Microsoft comes as big technology companies’ appetite grows for US electricity which powers the data centres needed for technologies such as artificial intelligence and cloud computing.
Nuclear energy, which is nearly carbon-free and broadly considered more reliable than energy sources such as solar and wind, is particularly in demand among technology companies who have made climate pledges and need stable energy sources.
“This agreement is a major milestone in Microsoft’s efforts to help decarbonise the grid in support of our commitment to become carbon negative,” Bobby Hollis, vice-president of energy at Microsoft, said in a statement. The unit will provide 835 megawatts of energy to the tech giant.
Constellation’s shares were up 16 per cent at $242.62 in early afternoon trading, and have risen 111 per cent so far this year.
The company plans to revive Unit 1 of the Three Mile Island facility that was retired in 2019 owing to economic reasons. Unit 2, which had the meltdown, will not be restarted.
Microsoft has also signed a power purchase agreement with the Washington-state fusion company Helion.
The deals come after technology leaders including Sam Altman, chief executive of the ChatGPT developer OpenAI, and Bill Gates, the co-founder of Microsoft, have backed nuclear energy as a solution to the growing power needs of data centres.
Altman has backed and is the chairman of Oklo, a nuclear power start-up which went public through a blank-cheque merger in May. TerraPower, a startup co-founded by Gates, broke ground on a nuclear facility in June.
Power supply deals with AI data centres have raised concerns over the risks of causing spikes to customer costs or damaging grid reliability. Nuclear plants generated about 18.6 per cent of the total electricity in the US last year, according to Energy Information Administration data.