Over the past few years, fusion power has disappeared from the joke's ass – always 10 years away! – An increasingly concrete and intriguing technique that pulls investors from the bystanders.
This technology is challenging to challenge today's mastery, and fusion promises to use the nuclear reaction that drives the sun to generate almost infinite energy on Earth. If startups are able to complete commercially viable fusion power plants, they could promote the trillion dollar market.
The bullish waves supporting the fusion industry are driven by three advancements: stronger computer chips, more refined AI and powerful high temperature superconducting magnets. Together, they helped to provide a more sophisticated reactor design, better simulations, and more complex control schemes.
At the end of 2022, a U.S. Energy Agency lab announced that it had produced a controlled fusion reaction that produced more power than the lasers provided to the fuel pellets. The experiment, which goes beyond what is known as the scientific break-even, still a long way from a commercial break-even point where more reactions are generated than the entire facility consumes, was a much-anticipated step that proved the underlying science was sound.
The founders have built on that momentum in recent years, and have rapidly moved the private fusion industry forward.
Federal Fusion System
With a $1.8 billion Series B, Commonwealth Fusion Systems was cut to pole position in 2021. Since then, the company has been quiet in terms of fundraising (no surprise), but “works at Massachusetts Building Sparc, the first clean power plant aimed at generating what happens at the commercial level.
SPARC's reactors use Tokamak designs that resemble donuts. The D-shaped cross section is wrapped with high-temperature superconducting tape, and upon energy it creates a strong magnetic field that encloses and compresses the overheated plasma. In the commercial scale arc, which succeeds SPARC, the heat generated from the reaction is converted into steam and powers the turbine. CFS designed the magnets in collaboration with MIT, where co-founder and CEO Bob Mumgaard worked as a researcher in Fusion Reactor Designs and high-temperature superconductors.
Supported by breakthrough energy ventures, engines, Bill Gates and others, Massachusetts-based CFS expects ARC to operate in the early 2030s. According to Pitchbook, the company has raised a total of $2 billion.
Te
Founded in 1998, TAE Technologies (formerly known as Tri Alpha Energy) was spin-out from the University of California Irvine by Norman Lost Car. Use an inverted configuration to the field, but with a twist, after two plasma shots collide in the center of the reactor, they continue to spin the cigar shape by firing the plasma with a particle beam. This improves the stability of the plasma, increases the time it takes for fusion to occur, allowing more heat to be extracted and the turbine can be rotated.
The company raised $150 million in June from existing investors, including Google, Chevron and New Enterprise. According to Pitchbook, Tae has raised a total of $1.79 billion.
Hellion
Of all fusion startups, Hellion has the most offensive timeline. The company plans to produce electricity from nuclear reactors in 2028. Your first customer? Microsoft.
Based in Everett, Washington, Hellion uses a type of nuclear reactor known as a field-inverted configuration. Here, the magnet surrounds a reaction chamber that looks like an hourglass with a bulging at a point where both sides are combined. At each end of the hourglass, spin the plasma into the shape of a donut that is shot at each other for over a million miles. When they collide in the middle, additional magnets help induce fusion. When fusion occurs, the unique magnetic field of the plasma is improved, induced current within the magnetic coil of the reactor. That electricity is harvested directly from the machine.
The company raised $425 million in January 2025, roughly the same as turning on the prototype reactor Polaris. According to the Pitchbook, Helion raised $1.03 billion. Investors include Sam Altman, Reid Hoffman, KKR, BlackRock, Peter Thiel's Mithril Capital Management and Capricorn Investment Group.
Pacific fusion
Pacific Fusion exploded from the gate with a $900 million Series A. The company uses inertial confinement to achieve fusion, but instead of lasers compressing the fuel, it uses tuned electromagnetic pulses. The trick is timing. All 156 impedance matches Marx generators should generate 2 terawatts in 100 nanoseconds, and those pulses must converge to the target simultaneously.
The company is led by Eric Lander, scientist who led the human genome project, and Will Regan, president. Pacific Fusion's funding may be massive, but startups don't get it all at once. Rather, the investor pays in a tranche when the company achieves a certain milestone. This is a common approach in biotechnology.
Shine Technology
Shine Technologies takes a careful and perhaps practical approach to generating fusion capabilities. Selling electronics from fusion power plants for years has been apart, so instead starts with neutron testing and medical isotopes. Recently, we have been developing methods to recycle radioactive waste. Shine has not chosen a Fusion Reactor approach of the future. Instead, he says he is developing the skills he needs when the time comes.
According to Pitchbook, the company has raised a total of $778 million. Investors include the energy venture group, Koch's disruptive technology, nuclear-forming capital, and the Wisconsin Alumni Research Foundation.
General fusion
According to Pitchbook, the third year General Fusion raised $440.53 million. The Richmond, British Columbia-based company was founded in 2002 by physicist Michel Bellage. He wanted to prove another approach to fusion known as magnetized target fusion (MTF). Investors include Jeff Bezos, Temasek, BDC Capital and Chrysalix Venture Capital.
In a typical fusion reactor, a liquid metal wall surrounds the chamber where the plasma is injected. The wall-surrounding piston pushes it inward, compressing the internal plasma, causing a fusion reaction. The resulting neutrons heat the liquid metal. This allows the turbine to rotate through the heat exchanger to generate steam.
General Fusion hit a rough patch in spring 2025. The company was building the LM26, the latest device it had hoped to hit Breakeven in 2026, so it didn't take away any cash. Just a few days after hitting a key milestone, we unlocked 25% of our staff.
Tokamak Energy
Tokamak Energy takes a regular Tokamak design (the shape of a donut), squeeze it out, and reduces its aspect ratio to make the outer boundary resemble a sphere. Like many other Tokamac-based startups, the company uses high-temperature superconducting magnets (rare earth barium oxide, or REBCO, variety). Its design is more compact than traditional tokamacs, which means fewer magnet methods are supposed to reduce costs.
The UK-based startup ST40 prototype looks like a large steampunk Far Berge egg in 2022. Tokamak Energy raised $125 million in November 2024, continuing its reactor design efforts and expanding its magnet business.
In total, it raised $336 million from investors, including Future Planet Capital, In-Q-Tel, Midven and Capri-Sun founder Hans-Peter Wild, according to Pitchbook.
ZAP Energy
ZAP energy does not limit the plasma using high temperature superconducting magnets or super-strong lasers. Rather, it uses current to zap the plasma (get it?), which generates its own magnetic field. The magnetic field compresses about a millimeter of plasma, at which point an ignition occurs. The neutrons released by the fusion reaction bomb the liquid metal blanket surrounding the reactor and heat it. Liquid metal circulates through a heat exchanger where it generates steam and drives the turbine.
Like Helion, Zap Energy is based in Everett, Washington, and according to Pitchbook, the company has raised $327 million. Backers include Bill Gates' groundbreaking energy ventures, DCVC, Low Carbon, Energy Impact Partners, Chevron Technology Ventures and Bill Gates as Angels.
Proximal Mfusion
Most investors support large startups pursuing the design and taste of inertia confinement in Tokamac. However, Stellareter has high hopes for science experiments involving the German Wendelstein 7-X reactor.
However, Proxima Fusion fell into this trend, attracting a Series A of 130 million euros, bringing the total to over 185 million euros. Investors include Balderton Capital and Cherry Ventures.
The Stellarator is similar to Tokamaks in that it uses a powerful magnet to limit the plasma to a ring-like shape. But they do it with a twist – literally. Rather than pushing the plasma into a human-designed ring, the space star twists and bulges out, responding to the habits of the plasma. The result should be a plasma that will remain stable for longer and increase the likelihood of a fusion reaction.
Marvel Fusion
Marvel fusion follows the inertial confinement approach, the same basic technique used by the National Ignition Facility, which was used to prove that fusion reactions were able to produce more force than is necessary to kick off them. Marvel fires a powerful laser at a target embedded with silicon nanostructures cascaded under bombing, compressing the fuel to the ignition point. Because the targets are made using silicon, they must be relatively easy to manufacture, leaning towards decades of experience in the semiconductor manufacturing industry.
The inertial confinement fusion startup is working with Colorado State University, which is operational by 2027, to build demonstration facilities. Munich-based Marvel has raised a total of $161 million from investors including B2Venture, Deutsche Telekom, Earlybird, HV Capital, Taavet Hinrikus and Albert Wenger As Angels.
The first light
First Light dropped its pursuit of fusion capabilities in March 2025 and instead pivoted to become a technology supplier for fusion startups and other companies. Startups previously followed an approach known as inertial confinement. This approach is compressed until the fusion fuel pellets are ignited.
According to Pitchbook, First Light, based in Oxfordshire, UK, has raised $140 million from investors such as Investors, IP Group and Tencent.
xcimer
While fusion cannot be described as simple, Xcimer takes a relatively simple approach. Following the basic science behind National IgnitionFacility's groundbreaking net-positive experiments, we will redesign the technology that supports it from scratch. The Colorado-based startup aims to be a 10-megajoule laser system five times more powerful than the NIF setup that made history. The molten salt wall surrounds the reaction chamber, absorbing heat and protecting the initial solid wall from damage.
Founded in January 2022, Xcimer has already raised $109 million from investors including Hedosophia, Breakthrough Energy Ventures, Emerson Collective, Gigascale Capital and LowerCarbon Capital.
This story was originally released in September 2024 and will be updated continuously.