For forty-five years the name Three Mile Island has meant one thing: the morning of 28 March 1979, when a stuck valve and a misread gauge led to the partial meltdown of Unit 2 at the plant on the Susquehanna River in Pennsylvania — the worst nuclear accident in American history, though one that killed nobody. This month the name acquired a second meaning. Microsoft has signed a twenty-year agreement to buy every megawatt from the plant’s other reactor, Unit 1, which its owner, Constellation Energy, will bring back from the dead.
The deal
Unit 1 was undamaged in 1979 and ran safely for another forty years, closing in 2019 not for safety reasons but because cheap gas made it unprofitable. Constellation will spend about $1.6 billion restoring it — turbine, generator, cooling systems, transformers — and expects it back on the grid in 2028, subject to regulatory approval. Its output, about 835 megawatts, enough for 800,000 homes, will go entirely to Microsoft’s data centres in the regional grid. The plant is being renamed the Crane Clean Energy Center. “Before it was prematurely shuttered, this plant was among the safest and most reliable nuclear plants on the grid,” said Constellation’s chief executive, Joe Dominguez, “and we look forward to bringing it back with a new name and a renewed mission.”
Why now
Because AI eats electricity. A data centre full of GPUs training and serving models draws power continuously, day and night, in a way that wind and solar cannot supply alone; Microsoft, Google and Amazon have all found that their climate pledges — Microsoft’s is to be carbon-negative by 2030 — collide with the power needs of the AI race. Nuclear is the one carbon-free source that runs around the clock. Amazon bought a data-centre campus next to a Pennsylvania reactor in March; Google is talking to small-reactor developers; and now Microsoft has done the most striking thing of all, paying to restart a plant at the most infamous nuclear site in the country. Nothing says more about how the arithmetic of AI has changed the energy debate.
What it does not solve
Restarting a closed reactor is cheaper and faster than building one, but there are only a handful of recently closed plants in the US to restart, and 2028 is the optimistic date. The electricity is also not new capacity for the public: Microsoft is taking all of it, which is why the deal has drawn criticism that Big Tech is buying up the clean power everyone else needs.
The Bangladesh angle
Bangladesh’s first reactor, Unit 1 of the Rooppur plant in Pabna, is due to start generating in 2025 — a 1,200 MW Russian VVER-1200, one of two. It was planned as baseload for a grid short of gas, and for a long time it was the only new nuclear build in South Asia outside India. The world that Rooppur enters is one in which the largest technology companies on earth are competing for exactly the kind of steady, carbon-free power it will produce. That is a better market to be selling into than the one it was planned for.
Source: BBC, via Prothom Alo.
