Helion Hits 150 Million Degrees in Fusion Push Toward 2028 Microsoft Deal
The startup’s Polaris reactor reaches a critical temperature milestone as it races to power the grid.
Helion has crossed a pivotal threshold in its bid to commercialize fusion energy.
The company’s Polaris prototype reactor has reached 150 million degrees Celsius, roughly three-quarters of the temperature it believes is required for a commercial power plant.
“We’re obviously really excited to be able to get to this place,” CEO and co-founder David Kirtley told TechCrunch.
A Temperature Milestone — and a First
Polaris is now running on deuterium-tritium fuel, a mix of two hydrogen isotopes.
Kirtley said Helion is the first fusion startup to operate a prototype this way.
- Fusion power output increased “dramatically” as heat.
- The milestone validates core plasma performance assumptions.
- It narrows the gap toward commercial-scale operation.
At 150 million degrees C, Helion stands within striking distance of its ultimate target: 200 million degrees C.
That level, Kirtley argues, represents the “sweet spot” for operating a fusion power plant.
Racing the Clock to 2028
Helion’s ambitions aren’t theoretical.
The Everett, Washington–based company has a contract to supply electricity to Microsoft starting in 2028. That power will come from Orion, a 50-megawatt commercial reactor now under construction — not Polaris.
Most competitors target the early 2030s for grid power. Helion’s deadline is closer, and fixed.
The broader fusion race is heating up alongside investor enthusiasm:
- Inertia Enterprises raised $450 million this week.
- Type One Energy is raising $250 million.
- Commonwealth Fusion Systems secured $863 million last summer.
- Helion raised $425 million last year from investors including Sam Altman, Mithril, Lightspeed, and SoftBank.
Fusion, long a scientific moonshot, now commands billions in venture capital.
A Different Reactor, A Different Bet
Helion’s approach diverges sharply from tokamak designs like Commonwealth’s doughnut-shaped reactors.
Its system uses a field-reversed configuration with an hourglass-shaped chamber.
- Fuel is injected at both ends and turned into plasma.
- Magnets accelerate the plasmas toward each other.
- Initial merge: 10–20 million degrees C.
- Magnetic compression pushes temperatures to 150 million degrees C.
- Entire process unfolds in under a millisecond.
Instead of converting fusion heat into steam and turbines, Helion extracts electricity directly from the reaction’s magnetic field. Each pulse induces electrical current in the reactor’s magnets.
It’s closer to charging a battery than boiling water.
That direct electricity recovery could, in theory, deliver higher efficiency than heat-based systems. Over the past year, Helion refined reactor circuits to improve electricity recovery rates.
Fuel Strategy: From Tritium to Helium-3
Today, Helion uses deuterium-tritium fuel.
Long term, it plans to shift to deuterium–helium-3.
Helium-3 reactions produce more charged particles, which interact strongly with magnetic fields — ideal for Helion’s direct electricity model.
There’s a catch: helium-3 is scarce on Earth.
- Helion will initially create helium-3 by fusing deuterium nuclei.
- Some deuterium-on-deuterium reactions will generate helium-3 during operations.
- The company plans to purify and recycle it internally.
Kirtley said helium-3 production has proven “easier to do than maybe we expected,” achieving high throughput and purity.
He even hinted Helion might one day sell helium-3 to rivals.
The Breakeven Question
Has Helion reached scientific breakeven — producing more fusion energy than required to initiate the reaction?
Kirtley sidestepped the milestone.
“We focus on the electricity piece, making electricity, rather than the pure scientific milestones,” he said.
That answer underscores Helion’s thesis: commercial viability matters more than laboratory bragging rights.
Still, 200 million degrees Celsius remains ahead. And Orion must deliver 50 megawatts to Microsoft in just two years.
Fusion has always been the energy source of tomorrow.
Can Helion make it the energy source of 2028?
TL;DR
Helion’s Polaris reactor hit 150 million degrees C, a key step toward its goal of 200 million degrees for commercial fusion. The company aims to supply Microsoft with 50 megawatts by 2028 using its Orion reactor, betting on direct electricity recovery and helium-3 fuel.
AI summary
- Polaris reached 150 million degrees C.
- Helion targets 200 million degrees for commercial ops.
- 50-MW Orion reactor under construction for Microsoft.
- Direct electricity recovery differentiates Helion.
- Long-term shift to helium-3 fuel planned.
