Initiate fusion energy Helium announced on Friday that it had achieved a key milestone in its quest for fusion power. Plasmas inside the company’s prototype Polaris reactor have reached 150 million degrees Celsius, three-quarters of the way to what the company believes will be needed to operate a commercial fusion power plant.
“We’re obviously very excited to be able to get to this place,” David Kirtley, co-founder and CEO of Helion, told TechCrunch.
Polaris also operates using deuterium-tritium fuel — a mixture of two hydrogen isotopes — which Kirtley said makes Helion the first fusion company to do so. “We were able to see the fusion power output increase dramatically as expected in the form of heat,” he said.
The Everett, Washington-based startup is locked in a race with several other companies seeking to commercialize fusion power, a potentially limitless source of clean energy.
This possibility has investors rushing to bet on the technology. This week, Inertia Enterprises announced a $450 million Series A round that included Bessemer and GV. In January, Type One Energy told TechCrunch it was in the midst of raising $250 million, while last summer Commonwealth Fusion Systems raised $863 million from investors including Google and Nvidia. Helion itself raised $425 million last year from a group that included Sam Altman, Mithril, Lightspeed and SoftBank.
While most other fusion startups aim for the early 2030s to put electricity on the grid, Helion has a contract with Microsoft to sell electricity starting in 2028, though that power will come from a larger commercial reactor called Orion that the company is currently building, not Polaris.
Each fusion startup has its own milestones based on its reactor design. Commonwealth Fusion Systems, for example, needs to heat its plasma to more than 100 million degrees C inside its tokamak, a doughnut-shaped device that uses powerful magnets to hold the plasma together.
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Helion’s reactor is different, requiring plasma that is roughly twice as hot to operate as predicted.
The company’s reactor design is what is called an inversion field configuration. The inner chamber is shaped like an hourglass and at the wide ends, fuel is injected and converted into plasma. The magnets then accelerate the plasma towards each other. When they first merge, it’s about 10 million to 20 million degrees Celsius. Powerful magnets then further compress the fused ball, raising the temperature to 150 million degrees C. It all happens in less than a millisecond.
Instead of extracting energy from fusion reactions in the form of heat, Helion uses the magnetic field of the fusion reaction itself to generate electricity. Each pulse will push back the magnets of the reactor itself, causing an electrical current that can be collected. By harvesting electricity directly from fusion reactions, the company hopes to be more efficient than its competitors.
Over the past year, Kirtley said Helion had improved some of the circuits in the reactor to boost the amount of electricity they recover.
While the company uses deuterium-tritium fuel today, it plans to use deuterium-helium-3 next. Most fusion companies plan to use deuterium-tritium and extract energy as heat. Helion’s choice of fuel, deuterium-helium-3, produces more charged particles, which push hard against the magnetic fields that confine the plasma, making it more suitable for Helion’s approach to direct electricity generation.
Helion’s ultimate goal is to produce plasma reaching 200 million degrees C, far higher than other companies’ goals, a function of reactor design and fuel selection. “We think at 200 million degrees, that’s where we hit that optimal sweet spot where you want to run a power plant,” Kirtley said.
When asked if Helion had reached the scientific ceiling — the point where a fusion reaction produces more energy than it needs to start — Kirtley demurred. “We focus on the electricity part, the electricity generation, rather than the pure scientific milestones.”
Helio-3 is common on the moon, but not here on Earth, so the Sun has to make its own fuel. First, it will fuse deuterium nuclei to produce the first batches. In normal operation, while the main source of energy will be deuterium-helium-3 fusion, some of the reactions will still be deuterium-to-deuterium, which will produce helium-3 that the company will purify and reuse.
Work is already underway to improve the fuel cycle. “It was a pleasant surprise, as a lot of this technology was easier than we expected,” Kirtley said. Helion was able to produce helium-3 “in very high yields both in terms of yield and purity,” he added.
While Helion is currently the only fusion startup using helium-3 in its fuel, Kirtley said he believes other companies will do so in the future, hinting that he would be open to selling it to them. “Other people — as they come along and recognize that they want to do this direct electricity recovery approach and see the efficiency gains from that — will also want to use helium-3 fuel,” he said.
Alongside its experiments with Polaris, Helion is also building Orion, a 50-megawatt fusion reactor it needs to fulfill its contract with Microsoft. “Our ultimate goal is not to build and deliver Polaris,” Kirtley said. “This is a step on the way to scalable power plants.”
