Technology companies are increasingly looking to nuclear power plants to provide the emissions-free electricity needed to run artificial intelligence and other businesses.

Microsoft, Google and Amazon have recently struck deals with operators and developers of nuclear power plants to fuel the boom in data centers, which provide computing services to businesses large and small. The demand has accelerated because of the big investments these and other tech companies have made in A.I., which requires far more power than more conventional technology businesses like social media, video streaming and web searches.

Microsoft has agreed to pay an energy company to revive the shuttered Three Mile Island nuclear power plant in Pennsylvania. And this week, Amazon and Google said they were focusing on a new generation of small modular reactors. That technology has not yet been successfully commercialized but energy experts say it might be cheaper and easier to build than the large nuclear reactors that the United States has built since the 1950s.

Big technology companies, which previously invested a lot in wind and solar energy, are now gravitating toward nuclear energy because they want power that is available around the clock while producing no greenhouse gas emissions. Wind and solar don’t contribute to climate change but are not available at all times without the help of batteries or other forms of energy storage. The biggest tech companies have all made pledges to power their operations with emissions-free power by 2030, but those commitments came before the boom in artificial intelligence, which has demanded more energy.

“They have a desire to grow all this in a sustainable way, and at the moment the best answer is nuclear,” said Aneesh Prabhu, a managing director at S&P Global Ratings.

On Monday, Google said that it had agreed to purchase nuclear energy from small modular reactors being developed by a start-up called Kairos Power, and that it expected the first of them to be running by 2030. Then Amazon, on Wednesday, said it would invest in the development of small modular reactors by another start-up, X-Energy. Microsoft’s deal with Constellation Energy to revive a reactor at Three Mile Island was announced last month.