Three Mile Island nuclear site to reopen in Microsoft deal

America’s Three Mile Island energy plant, the site of the worst nuclear accident in US history, is preparing to reopen as Microsoft looks for ways to satisfy its growing energy needs.

The tech giant said it had signed a 20-year deal to purchase power from the Pennsylvania plant, which would reopen in 2028 after improvements.

The agreement is intended to provide the company with a clean source of energy as power-hungry data centres for artificial intelligence (AI) expand.

The plan will now go to regulators for approval.

The owner of the plant, Constellation Energy, said the reactor it planned to restart was next to, but “fully independent” of, the unit that had been involved in the 1979 accident.

It caused no injuries or deaths but provoked widespread fear and mistrust among the US public, discouraging the development of nuclear power in the US for decades.

However, there is renewed interest in nuclear as concerns about climate change grow – and companies need more energy due to advances in artificial intelligence.

Constellation chief executive Joe Dominguez told analysts on Friday that the deal was a “powerful symbol of the rebirth of nuclear power as a clean and reliable energy resource”.

“Before it was prematurely shuttered due to poor economics, this plant was among the safest and most reliable nuclear plants on the grid, and we look forward to bringing it back with a new name and a renewed mission,” he said in a statement announcing the deal.

He said nuclear plants were the “only energy sources” that could consistently deliver an “abundance” of carbon-free energy.

Microsoft also called it a “milestone” in its efforts to “help decarbonize the grid”.

On 28 March, 1979, a combination of mechanical failure and human error led to a partial meltdown at the nuclear power plant in central Pennsylvania.

The accident occurred at about 04:00 in the Three Mile Island plant’s second unit.

The plant’s Unit 1 – which would reopen under the Microsoft deal – continued to generate power until closing in 2019.

Its owner at the time, Exelon, which spun out Constellation as an independent business in 2022, said the low cost of natural gas extraction had made nuclear-generated electricity unprofitable.

Constellation said it would invest $1.6bn (£1.2bn) to upgrade the facility, which it would seek approval to operate until at least 2054.

Reopening the plant would create 3,400 direct and indirect jobs and add more than 800 megawatts of carbon-free electricity to the grid, generating billions of dollars in taxes and other economic activity, according to a study by The Brattle Group cited by Constellation.

Local media reported earlier this month that word of its possible revival had drawn some protesters.

Microsoft is not the only tech company that is turning to nuclear power as its energy needs expand.

Earlier this year, Amazon also signed a deal which involves purchasing nuclear energy to power a data centre. Those plans are now under scrutiny by regulators.