Microsoft just made a huge, far-from-certain bet on nuclear fusion

Microsoft just signed a jaw-dropping agreement to purchase electricity from a nuclear fusion generator. Nuclear fusion, often called the Holy Grail of energy, is a potentially limitless source of clean energy that scientists have been chasing for the better part of a century.

A company called Helion Energy thinks it can deliver that Holy Grail to Microsoft by 2028. It announced a power purchase agreement with Microsoft this morning that would see it plug in the world’s first commercial fusion generator to a power grid in Washington. The goal is to generate at least 50 megawatts of power — a small but significant amount and more than the 42MW that the US’s first two offshore wind farms have the capacity to generate today.

To say that’s a tall order would be the understatement of the year. “I would say it’s the most audacious thing I’ve ever heard,” says University of Chicago theoretical physicist Robert Rosner. “In these kinds of issues, I will never say never. But it would be astonishing if they succeed.”

Experts’ optimistic estimates for when the world might see its first nuclear fusion power plant have ranged from the end of the decade to several decades from now. Helion’s success depends on achieving remarkable breakthroughs in an incredibly short span of time and then commercializing its technology to make it cost-competitive with other energy sources. Nevertheless, Helion is unfazed.

“This is a binding agreement that has financial penalties if we can’t build a fusion system,” Helion founder and CEO David Kirtley tells The Verge. “We’ve committed to be able to build a system and sell it commercially to [Microsoft].”

How might a fusion system work? Simply put, nuclear fusion mimics the way stars create their own light and heat. In our sun, hydrogen nuclei fuse together, creating helium and generating a tremendous amount of energy. 

Scientists have been trying to replicate this process in a controlled way since the 1950s. (They’ve been able to replicate it in an uncontrolled manner, aka a hydrogen bomb.) This is the opposite of nuclear power plants we have today that release energy through fission, or splitting atoms apart. A major downside of fission is that it leaves behind unstable nuclei that can stay radioactive for millions of years. Fusion avoids the radioactive waste problem because it’s essentially just creating new helium atoms.

The most advanced attempts at generating electricity through nuclear fusion involve shooting powerful laser beams at a tiny target or relying on magnetic fields to confine superheated matter called plasma with a machine called a tokamak.

Helion uses neither of those methods. The company is developing a 40-foot device called a plasma accelerator that heats fuel to 100 million degrees Celsius. It heats deuterium (an isotope of hydrogen) and helium-3 into a plasma and then uses pulsed magnetic fields to compress the plasma until fusion happens. (The company has a Youtube video that illustrates the process in much more detail.)

Helion claims that the machine should eventually be able to recapture the electricity used to trigger the reaction, which can be used to recharge the device’s magnets. “We electrically recover all the energy we put into fusion so that we can actually build systems that are smaller and cheaper and we can iterate on them a lot quicker,” Kirtley says.

“This is an exciting announcement and many in the community will be keen to see the technical details,” MIT School of Engineering distinguished professor Anne White says in an email to The Verge. “Forthcoming publications and results will help clarify the approach and understand the timeline.”

Figuring out how to be energy efficient is crucial to make fusion power a reality. After all, you need extreme heat and pressure to force atoms to fuse together. And until recently, researchers hadn’t been able to do this without burning through more energy than the fusion reaction actually produced. In December, lasers achieved a huge breakthrough called “fusion ignition” — meaning that for the first time, researchers were able to trigger a fusion reaction that resulted in a net energy gain. That’s a major milestone Helion has yet to accomplish.

Getting enough helium-3 fuel could be another big challenge, Rosner says, without a way of producing commercial quantities of it. It’s a very rare isotope that’s used in quantum computing and medical imaging. Helion, however, says that it has patented a process to make helium-3 itself by fusing deuterium atoms together in its plasma accelerator. Part of the appeal of nuclear fusion in the first place is that it can run on hydrogen, the simplest and most abundant element in the universe. 

Assuming Helion can pull this all off, it still has to ensure that it can do so in an affordable way. The cost of the electricity it generates for consumers would need to be comparable to or cheaper than today’s power plants, solar, and wind farms. The company isn’t sharing what price it agreed to in its power purchase agreement with Microsoft, but Kirtley says the company’s goal is to one day get costs down to a cent a kilowatt hour.

Helion’s funders include OpenAI CEO Sam Altman. Microsoft has made a multibillion dollar investment in OpenAI to boost its development of popular tools like ChatGPT. Altman is Helion’s board chair and largest investor, The Washington Post reports, and may have been involved in brokering Helion’s power purchase agreement with Microsoft. Kirtley tells The Verge his company has been working closely with Microsoft’s data center group for the past few years to better understand their energy needs and get Microsoft comfortable with its technology.

“Helion’s announcement supports our own long term clean energy goals and will advance the market to establish a new, efficient method for bringing more clean energy to the grid, faster,” Brad Smith, vice chair and president at Microsoft, said in a press release.

But as has been the case with dreams of nuclear fusion for decades — we’ll have to wait and see.

Update May 10, 10:00AM ET: This story has been updated with information about Sam Altman’s involvement with Helion and its deal with Microsoft and to clarify that the US’ offshore wind farms have the capacity to generate 42 MW.