Tech
How fusion power works and the startups pursuing it
For decades, humans have sought to harness the power of the stars to generate electricity here on Earth. And for nearly as long, achieving that goal always seemed just a decade away.
Now, a slew of startups are closer than ever before and rushing to build fusion reactors capable of putting power on the grid.
Fusion startups have drawn more than $10 billion in investment, with more than a dozen raising over $100 million. Many large funding rounds have closed in the last year, with investors drawn to the industry as energy demand from data centers ramps up and as fusion startups draw closer to the finish line.
At its core, fusion power seeks to use the energy released from the fusing of atoms to generate electricity. Humans have known how to fuse atoms for decades, from the hydrogen bomb — an example of uncontrolled nuclear fusion — to any of the myriad fusion devices built in labs around the world. Experimental fusion devices have been able to control nuclear fusion, and one has been able to generate more energy than was required to spark the reaction.
But none of them have been able to produce enough of a surplus to make a power plant possible.
To solve that problem, fusion startups are trying a number of different approaches. Experts have varying opinions on which have the best chance of success, though the industry is still in its infancy, so nothing is guaranteed.
Here is a brief overview of the main approaches to fusion power.
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Magnetic confinement
Magnetic confinement is one of the most widely used techniques, using strong magnetic fields to confine plasma, the soup of superheated particles that’s at the heart of a fusion device.
The magnets must be tremendously powerful. Commonwealth Fusion Systems (CFS), for example, is assembling magnets that can generate 20 tesla magnetic fields, which is about 13 times stronger than a typical MRI machine. To handle the amount of electricity required, the magnets are made out of high-temperature superconductors, which still need to be cooled to –253˚ C (–423˚ F) using liquid helium.
CFS is currently building a demonstration device called Sparc on a much more accelerated timeline in Massachusetts. The company anticipates turning it on sometime in late 2026, and if all goes well, it will begin construction on Arc, its commercial-scale power plant, in Virginia in 2027 or 2028.
There are two main types of fusion devices that use magnetic confinement: tokamaks and stellarators.
Tokamaks were first theorized by Soviet scientists in the 1950s, and since then, they’ve been widely studied. Tokamaks come in two basic shapes — a doughnut with a D-shaped profile and a sphere with a small hole in the middle. The Joint European Torus (JET) and ITER are two notable experimental tokamaks; JET operated in the UK between 1983 and 2023, while ITER is expected to begin operations in France in the late 2030s.
UK-based Tokamak Energy is working on a spherical tokamak design. Its ST40 experimental machine is currently undergoing upgrades.
Stellarators are the other main type of magnetic confinement device. They’re similar to tokamaks in that they keep the plasma contained within a doughnut-like shape. But unlike tokamak’s geometric sides, stellarators twist and turn. The irregular shape is determined by modeling the plasma’s behavior and tailoring the magnetic field to work with its quirks rather than force it into a regular shape.
Wendelstein 7-X, a large stellarator with modular superconducting coils that is operated by the Max Planck Institute for Plasma Physics. has been operating in Germany since 2015. Several startups are also developing their own stellarators, including Proxima Fusion, Renaissance Fusion, Thea Energy, and Type One Energy.
Inertial confinement
The other main approach to fusion is known as inertial confinement, which compresses fuel pellets until the atoms within fuse.
Most inertial confinement designs use pulses of laser light to compress fuel pellets. Several laser beams fire at once, and their pulses of light converge on the fuel pellet from all angles simultaneously.
So far, inertial confinement is the only approach that has broken a milestone known as scientific breakeven, which is when the reaction releases more energy than it consumed. Those experiments have occurred at the National Ignition Facility (NIF) at the Lawrence Livermore National Laboratory in California. Notably, measurements to determine scientific breakeven do not include things like the electricity required to power the experimental facility.
Still, nearly a dozen startups see enough promise in inertial confinement that they’re designing reactors around it. Focused Energy, Inertia Enterprises, Marvel Fusion, and Xcimer are some notable examples using lasers.
There are two companies that aren’t using lasers, though: First Light Fusion, which proposes using pistons, and Pacific Fusion, which plans to use electromagnetic pulses instead of lasers.
More to come
Those are the two main approaches to fusion power, though they aren’t the only ones. Soon, we’ll add more details about alternative designs including magnetized target fusion, magnetic-electrostatic confinement, and muon-catalyzed fusion.
Tech
Sam Altman-backed fusion startup Helion in talks to sell power to OpenAI
OpenAI CEO Sam Altman is stepping down as board chair of the Helion — the fusion startup he backs — amid reported talks between the two companies.
The deal, which was reported by Axios, is in early stages, and it could guarantee OpenAI 12.5% of Helion’s production — five gigawatts by 2030 and 50 gigawatts by 2035. OpenAI partner Microsoft signed a similar deal with Helion in 2023 to buy power starting in 2028.
If the figures in Axios’ report prove to be accurate, it suggests that Helion expects to be able to rapidly scale production of its fusion power plant. The startup has said that each of its reactors will generate 50 megawatts of electricity, meaning it will need to build and install 800 reactors by 2030 and an additional 7,200 by 2035.
Helion wouldn’t confirm if talks with OpenAI were underway. A spokesman told TechCrunch the company has not announced any new customer agreements beyond those it already has with Microsoft and Nucor. However, the company did confirm to TechCrunch that Altman is leaving the board chair of Helion, suggesting that the two companies may eventually work together.
“Sam is stepping down from Helion’s Board of Directors after more than a decade. This decision enables Helion and OpenAI to partner on future opportunities to bring zero-carbon, safe electricity to the world,” David Kirtley, co-founder and CEO of the company, told TechCrunch in statement. “We look forward to continuing to work with him in this new capacity.”
Helion is racing to build its first commercial-scale reactor by that time. If the startup is successful, it would place it years ahead of the competition, which is mostly targeting early 2030s for commercial operations.
The startup raised $425 million last year from investors, including Altman as well as firms Mithril, Lightspeed, and SoftBank.
Most fusion startups are pursuing one of two approaches — harvesting heat from the fusion reactions and using a steam turbine to turn it into electricity. Helion is taking a different tack, developing a reactor design that would use magnets to convert fusion energy into electricity.
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Inside the hourglass-shaped reactor, fusion fuel is first turned into plasma at either end and then shot toward each other using magnetic fields. When they collide in the middle, another set of magnets compresses the merged plasma ball until fusion occurs. The reaction pushes back on the magnets, which can convert that energy directly into electricity.
Helion is currently operating its Polaris prototype in advance of its push to commercial power. In February, the company generated plasmas inside the reactor that hit 150 million degrees Celsius, almost to the 200 million degrees Celsius the company thinks will be required for commercial operations.
Though Altman has stepped down from his position as chair of Helion’s board and reportedly recused himself from the discussions, his fingerprints are all over the matchmaking.
Last year, Altman stepped down as board chair of Oklo, a small modular nuclear reactor startup that had merged with his acquisition company, AltC. The move was intended to allow Oklo to explore strategic partnerships with leading AI companies, including potentially with OpenAI,” Caroline Cochran, Oklo’s co-founder and chief operating officer, said in a statement given to CNBC at the time.
Update 1:30 pm ET: Added confirmation from Helion regarding Altman stepping down as board chair.
Tech
FBI says Iranian hackers are using Telegram to steal data in malware attacks
Iranian government hackers are using Telegram as a way to steal data from hacked dissidents, opposition groups, and journalists who oppose the regime around the world, according to an FBI alert published on Friday.
In the first stage of the attack, the hackers contact their targets and pretend to be a known contact or tech support, and are tricked into accepting a link to a malicious file masquerading as legitimate apps, such as Telegram and WhatsApp. Once the target installs the malware, the second stage of the attack connects the infected victim with Telegram bots that allow the hackers to remotely command and control the victim’s computer. This allows the hackers to gain remote control of victims’ devices to steal files, take screenshots, and record Zoom calls, according to the FBI.
Using Telegram as a way to remotely control a victim’s device is a common technique by hackers to hide malicious activity among legitimate network traffic, which makes it harder for cybersecurity defenders and anti-malware products to identify.
According to the FBI, the hackers responsible for these attacks are allegedly working for Iran’s Ministry of Intelligence and Security (MOIS). The FBI said these attacks are an example of Iranian government hackers’ attempts to push the regime’s “geopolitical agenda.”
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In the alert, the FBI mentioned the pro-Iranian and pro-Palestinian fake hacktivist group Handala, although it’s not clear if the attacks referenced in the alert were carried out by this group.
Earlier this month, Handala claimed responsibility for an attack on medical tech giant Stryker, which resulted in wiping tens of thousands of employee devices.
In an 8-K filing with the U.S. Securities and Exchange Commission on Monday, Stryker said it is still recovering from the hack.
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Last week, the U.S. Justice Department accused Handala of being a front for Iran’s government, specifically the MOIS, and for being behind the Stryker hack. At the same time, the FBI took down and seized two websites linked to Handala, and two other sites linked to another Iranian hacktivist group called “Homeland Justice.” In the recent FBI alert, the bureau said the two groups are linked and controlled by the MOIS.
An FBI spokesperson said in an email that the bureau “has nothing additional to add.”
Telegram’s spokesperson Remi Vaughn said that the platform’s “moderators routinely remove any accounts found to be involved with malware.”
Updated to include the FBI’s and Telegram’s response.
Tech
Elizabeth Warren calls Pentagon’s decision to bar Anthropic ‘retaliation’
Anthropic is attracting an increasing number of supporters in its fight against the U.S. Department of Defense, which last month designated the AI lab as a supply-chain risk after it refused to make concessions on how its AI could be used by the military.
In a letter to Defense Secretary Pete Hegseth, U.S. Senator Elizabeth Warren (D-MA) equated the DOD’s decision with “retaliation,” arguing that the Pentagon could simply have terminated its contract with the AI lab, CNBC reports.
“I am particularly concerned that the DoD is trying to strong-arm American companies into providing the Department with the tools to spy on American citizens and deploy fully autonomous weapons without adequate safeguards,” Warren wrote, per the report, adding that the barring of Anthropic “appears to be retaliation.”
Warren’s words echo many other organizations that have spoken out against the Defense Department’s treatment of Anthropic. Several tech companies and employees — including from OpenAI, Google, and Microsoft — as well as legal rights groups, have filed amicus briefs in support of Anthropic and denouncing the designation, which is usually applied to foreign adversaries and not U.S. firms.
The dispute arose after Anthropic told the Pentagon that it did not want its AI systems to be used for mass surveillance of Americans and that the technology wasn’t ready for use in targeting or firing decisions of lethal autonomous weapons without human intervention. The Pentagon contested that a private company shouldn’t dictate how the military uses technology, and soon after designated the company as a “supply-chain risk.” The label requires any company or agency that does work with the Pentagon to certify that it doesn’t use the designated company’s products or services — effectively barring Anthropic from working with any company that also works with the U.S. government.
The letter from Warren comes a day before a hearing in San Francisco on Tuesday, when District Judge Rita Lin will decide whether to grant Anthropic a preliminary injunction that seeks to preserve the status quo while its case against the DOD is litigated.
While Anthropic is suing the DOD for infringing on its First Amendment rights and for punishing the company based on ideological grounds, the Defense Department has maintained that Anthropic’s refusal to allow all lawful military uses of its technology was a business decision, not protected speech, and that the designation was a straightforward national security call and not punishment for the company’s views.
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The AI lab last week submitted two declarations to the court that claim the government’s logic is flawed as they depend on technical misunderstandings as well as points of concern that were not raised during the company’s negotiations with the DOD.
Warren has also written to OpenAI CEO Sam Altman, asking for details of the company’s agreement with the DOD, which came just a day after the Pentagon blacklisted Anthropic.
Anthropic and the Defense Department did not immediately respond to requests for comment.
