For five years, Reactor 1 at the Three Mile Island Nuclear Power Plant in Pennsylvania has been mothballed, but the deal with Microsoft means the reactor will be restarted in 2028, this time to provide the company with large amounts of low-carbon electricity on an exclusive basis.
This is all part of Big Tech’s ongoing relationship with nuclear power. In March, Amazon Web Services agreed to buy a data center operating at the Susquehanna Nuclear Power Plant in Pennsylvania. At a Sept. 18 event at Carnegie Mellon University, Alphabet CEO Sundar Pichai mentioned the possibility of small modular nuclear reactors as a power source for data centers. And the connection doesn’t end there: OpenAI CEO Sam Altman serves as chairman of the board of directors for nuclear startups Oklo and Helion Energy.
The AI boom has tech companies scrambling to find low-carbon energy sources to power their data centers, with the International Energy Agency predicting that electricity demand from AI, data centers, and cryptocurrencies could more than double by 2026. Even conservative projections put the additional demand at roughly the amount of electricity consumed by Sweden, or Germany at higher usage levels.
The surge in energy demand is good news for the nuclear industry. U.S. electricity demand has remained roughly flat for decades, but the scale and intensity of the AI boom is changing that trend. A report published in December 2023 by a power industry consultancy declared that the era of flat electricity demand is over, due to increased demand from data centers and industrial facilities. The report predicts that peak electricity demand in the U.S. will increase by 38 gigawatts by 2028, roughly 46 times the output of Three Mile Island’s No. 1 reactor.
“AI is becoming very popular and has garnered a lot of attention in the energy industry,” says John Kotek, senior vice president of policy development and public affairs at the Nuclear Energy Institute, a trade group for the nuclear industry. There’s also a national security angle, Kotek says. “People are looking at AI as a competition between the U.S. and its global competitors.” That the U.S. is lagging behind in the AI race because it doesn’t have enough power, he says, “is really what’s garnering people’s attention.”
Nuclear power is attractive to technology companies because it can provide low-carbon electricity 24 hours a day, unlike solar and wind power, which only operate intermittently unless combined with some form of energy storage. Restarting Reactor 1 would give Microsoft 835 megawatts of low-carbon energy over the 20-year life of the contract. Microsoft has committed to being carbon negative by 2030, so the surge in power demand from AI poses a major threat to the company’s climate plans unless it can find a low-carbon power source. In 2023, Microsoft’s emissions increased 29% compared to 2020, but this was mainly due to the construction of new data centers.
Three Mile Island has two reactors. The second one infamously suffered a partial meltdown in 1979 and has been out of service ever since. The first, however, continued to operate without incident until 2019, when it was shut down for financial reasons (mainly competition from gas and wind power). Kotek said that the number of idled reactors is relatively small and could be restarted fairly quickly, but that many plant owners are interested in extending the operating licenses of existing plants in order to ride the AI wave.
