Big Tech’s interest in nuclear power is no longer theoretical. Microsoft’s deal with Constellation Energy to restart a nuclear reactor at Three Mile Island puts the issue in plain view: data centers need large amounts of electricity, and the companies building them are under pressure to limit the climate impact of that growth.
The shift is happening against a difficult backdrop. Nuclear power in the U.S. has been moving in the wrong direction for years, with seven reactors decommissioned in the last decade and only two new ones switched on. At the same time, the digital infrastructure behind cloud computing and AI has expanded quickly, creating a fresh reason for technology companies to reconsider a power source many had treated as fading.
Data centers are changing the electricity equation
The scale of data center growth is central to the story. There are over 10,000 data centers worldwide, and half of them are in the U.S. As cloud computing expands, EPRI expects the sector’s energy demand to grow by anywhere from 29% to 166% by 2030.
Data centers already consume about 4% of U.S. electricity. By the end of the decade, that share might rise to 9%, even as overall demand grows. That matters because electricity demand is not just increasing inside one company or one region; it is becoming a structural issue for the technology sector.
Hyperscale data centers are a major driver. These are the large facilities operated by Microsoft, Google and Amazon, and relied on by startups such as OpenAI and Anthropic. According to EPRI, hyperscale data centers account for 60% to 70% of all data center energy use.
For companies selling cloud services and building AI systems, the power requirement is becoming harder to separate from the business model itself. More computing means more facilities, and more facilities mean more electricity.
Carbon targets make the problem harder
The energy issue is especially complicated for companies that have made public climate commitments. Microsoft has ambitions to eliminate its carbon emissions by 2030, but its emissions have grown some 40% over the last four years. The source article identifies expanding data center operations as a major reason.
Google faces a similar tension. Its carbon emissions have grown some 48% in the last five years. Amazon says all of its data centers’ energy use is matched by an equivalent amount of renewable power.
These figures explain why nuclear power is becoming attractive to technology companies. The appeal is not only that nuclear reactors produce electricity; it is that they can provide steady power for facilities that need to run continuously.
Fission reactors can operate without interruption for years and work at maximum capacity over 90% of the time. Maintenance outages are usually planned months or years ahead, which gives data center operators time to prepare. That reliability helps explain why Microsoft signed a 20-year agreement with Constellation.
Microsoft is not the only company looking at nuclear power
Microsoft’s agreement is the clearest recent example, but the wider pattern includes other major technology players and investors connected to them.
- Amazon recently bought a hyperscale data center that is directly connected to a nuclear plant.
- Amazon is hiring a nuclear engineer to help AWS develop and acquire nuclear power.
- Bill Gates co-founded TerraPower and has personally invested over $1 billion in the company.
- Former Microsoft CTO Nathan Myhrvold, through Intellectual Ventures, is also on TerraPower’s cap table.
- Sam Altman backed the small modular reactor startup Oklo before it merged with a special-purpose acquisition company.
These moves show two related strategies. One is to secure existing nuclear capacity where possible. The other is to support or watch new nuclear startups that promise future options for power-hungry computing infrastructure.
Microsoft’s Constellation deal suggests urgency. The company may be trying to secure electricity faster than newer nuclear projects can realistically deliver it. The current wave of nuclear startups includes many companies that are still young and have produced plans or concepts of plans rather than operating reactors.
New reactors still face major barriers
Nuclear startups face engineering and regulatory challenges, and even more mature companies have struggled. Two years ago, the Nuclear Regulatory Commission denied Oklo’s application to build a reactor for the Department of Energy in Idaho. Last year, the Air Force rescinded a $100 million cost-plus contract. NuScale Power, another fission startup that went SPAC, lost a big contract in 2023.
Even if those kinds of obstacles are eventually solved, nuclear companies still need places to build. Public acceptance remains uncertain. The source article notes that a majority of Americans now support nuclear power, but that nuclear still trails wind and solar in acceptance and that support may weaken once specific projects are proposed.
Three Mile Island also carries symbolic weight. The reactor involved in Microsoft’s deal was operational as recently as 2019, but the name still evokes concern for many people. That reaction matters because infrastructure decisions do not happen only on spreadsheets; they also depend on what communities are willing to accept.
Renewable power adds another pressure. Its cost has grown increasingly attractive, even when batteries are included to support 24/7 operation. That does not remove nuclear from the conversation, but it means nuclear must compete with other options as technology companies search for dependable electricity.
The near-term answer may not scale forever
Restarting older nuclear power plants can help technology companies meet rising demand while reducing climate impact. For Microsoft and others, that may be one of the fastest ways to obtain steady, low-carbon power for data centers.
But the number of mothballed nuclear plants is limited. That makes restart deals useful but not a complete long-term answer. If cloud computing and AI keep increasing electricity needs, companies will have to look beyond the small pool of existing nuclear assets that can be brought back into service.
The broader lesson is straightforward: energy has become a core constraint for AI and cloud computing. Big Tech is turning to nuclear power because reliability, growth and carbon targets are colliding. Whether nuclear can move from a useful near-term option to a larger solution will depend on reactors, regulation, siting and public acceptance.