Fusion's 2026 Scoreboard: Four Private Results, One Public Project and a Lot of Unfinished Business

Fusion energy research in 2026 came in two shapes. Private machines posted firsts on short timescales. The world's largest publicly funded reactor kept absorbing the cost of a defect found six years ago. That gap is the story of the year.

Start with Helion, the Everett, Washington company that announced on 13 February 2026 that its seventh-generation Polaris prototype had become the first privately developed fusion machine to demonstrate measurable deuterium-tritium (D-T) fusion and to reach plasma temperatures of 150 million degrees Celsius. Both were firsts for the private fusion industry, according to the company's newsroom post. Polaris began operating at the end of 2024, and Helion said it became the first and currently only private machine to run on D-T fuel this January. The temperature figure matters because of what it beat: Helion's own 100 million degrees Celsius record, set by its sixth-generation Trenta prototype.

Within the fusion industry, 100MºC is treated as the threshold temperature for a commercially relevant machine. Helion says it will keep pushing Polaris temperatures higher to show it can reliably run on deuterium-helium-3, the fuel it intends to use in commercial operations.

What was verified, and by whom

Helion's post includes comments from outside reviewers. Ryan McBride, an inertial confinement fusion and pulsed power specialist who has worked as a department manager at Sandia National Laboratories and as a professor at the University of Michigan, said he reviewed diagnostic data and called the evidence of D-T fusion and temperatures above 13 keV, or 150 million degrees Celsius, exciting. Jean Paul Allain, associate director for Fusion Energy Sciences at the Department of Energy's Office of Science, said the Polaris data indicated strong progress and that getting fusion on the grid requires approaches that enable rapid turnaround in design and testing.

Separately, Helion has said it began building in July 2025 on the site of Orion, its first commercial machine, in Malaga, Washington, which is intended to deliver electricity from fusion to the grid for Microsoft. That is a construction claim, not an operating result, and the dossier does not give an output figure for Orion.

Thea Energy took a different route. On 27 May 2026 the Kearny, New Jersey company announced a $100 million Series B led by US Innovative Technology Fund, with General Innovation Capital Partners, Linse Capital and a longer list of participants. Thea is commercializing the stellarator, a magnetic confinement design it says it has simplified by shifting complexity from precision mechanical fabrication to software-defined controls, using arrays of mass-manufacturable planar magnets.

The company says it built and operated the world's first superconducting magnet array capable of producing the complex fields commercial stellarator systems need, and that it received DOE certification of its Helios preconceptual design milestone, making it the first awardee to receive that distinction. The new money is meant to add a second magnet manufacturing facility in northern New Jersey and support siting and construction of Eos, a large-scale integrated stellarator. Thea says it will pick a site for Eos later this year and double its team.

Direct conversion, with the caveats attached

Realta Fusion's result is the most precisely bounded of the four. On 19 June 2026, working with the University of Wisconsin-Madison on the Wisconsin HTS Axisymmetric Mirror device, Realta demonstrated direct energy conversion of plasma kinetic energy into electricity, which it describes as the first time a commercial fusion company has done so with a fusion plasma. The converter replaces the center disk on WHAM's end-ring assembly and slows charged particles exiting the mirror's loss cone using an electrostatic potential.

The company is explicit about scale: the single-stage prototype, built from three meshed grids, draws multiple amps at around 100 volts, enough to light a few lightbulbs. Realta also states plainly what it has not shown. This is neither a demonstration of net electricity production nor large-scale conversion of fusion-born power, milestones it says it will pursue on future devices. WHAM runs on deuterium only, so most of the directly converted energy is input power the company supplied, not fusion power.

Working with the philosophy of "first make it work, then make it good," it's now on us to scale what we've done on WHAM to multi-kW and ultimately multi-MW capability in our future devices.

The context for that caution is arithmetic. Realta notes that in first-generation deuterium-tritium plants, 80 percent of the yield arrives as high-energy neutrons and 20 percent as charged alpha particles. Only the charged fraction can be captured directly; the rest goes through a thermal cycle. The company argues direct conversion can eventually cover the system's own input power requirement, but that is a design target, not a measurement.

Against all this, ITER. CNET reported in May 2026 that the International Thermonuclear Experimental Reactor in southern France carries an estimated cost of $22 billion and is designed to contain plasma at 150 million degrees Celsius, ten times hotter than the core of the Sun, using superconducting magnets kept a few degrees above absolute zero. Cracks in the piping of the heat shield were discovered in 2020, along with welding distortions and pandemic disruptions, leading to a years-long delay and the need for an additional $5 billion to cover repairs.

ITER's chief strategic advisor, Laban Coblentz, framed the collaboration bluntly: that China and Russia would collaborate with the US and Europe, plus Korea, India and Japan, is either genius or insane. Javier Artola, a scientist modelling ITER's plasma behaviour, said the project is publicly funded and belongs to the knowledge of the world. More than 30 countries are party to the ITER agreement, and every member state gets access to the science that comes out of it.

The pattern in the results

Read together, the 2026 results show private fusion advancing on narrow, checkable milestones: a temperature, a fuel, a funding round, a converter drawing amps. None of them is net electricity. Helion's D-T campaign is one step in a testing programme aimed at a different fuel. Thea's Eos has not been sited. Realta's converter is a prototype on a machine that does not burn fusion fuel at power-plant scale.

ITER, meanwhile, is doing something the private sector cannot: it is building the shared supply chain and publishing the physics that lowers risk for everyone else, as CNET's reporting notes. Every problem ITER solves is one fewer problem for a startup. The cost is measured in decades and billions, and the repair bill is already public.

So the honest scoreboard for fusion energy research results in 2026 is this: real hardware, real diagnostics, real money, and no one yet claiming a working power plant. The private companies are moving fast because they can fail cheaply on small machines. The public project is moving slowly because it has to succeed once, at scale, in front of more than 30 governments. Both are necessary. Neither is finished.