The Everett, Washington-based fusion energy startup Helion announced Friday that it has hit a key milestone in its quest for fusion power. Plasmas inside the company’s Polaris prototype reactor have reached 150 million degrees Celsius, three-quarters of the way toward what the company thinks it will need to operate a commercial fusion power plant.
“We’re obviously really excited to be able to get to this place,” David Kirtley, Helion’s co-founder and CEO, told TechCrunch.
Polaris is also operating 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 startup is locked in a race with several other companies that are seeking to commercialize fusion power, potentially unlimited source of clean energy.
That potential 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 are targeting the early 2030s to put electricity on the grid, Helion has a contract with Microsoft to sell it electricity starting in 2028, though that power would come from a larger commercial reactor called Orion that the company is currently building, not Polaris.
Every fusion startup has its own milestones based on the design of its reactor. Commonwealth Fusion Systems, for example, needs to heat its plasmas to more than 100 million degrees C inside of its tokamak, a doughnut-shaped device that uses powerful magnets to contain the plasma.
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Helion’s reactor is different, needing plasmas that are about twice as hot to …