Helion Energy Hits 150 Million °C in Polaris Reactor, Races Toward 2028 Fusion Power

Helion Energy has crossed a threshold that the fusion industry has chased for decades. Its seventh-generation Polaris reactor reached 150 million degrees Celsius — 50% hotter than the previous private-sector record — and became the first privately built machine to achieve measurable deuterium-tritium fusion. The company is now on a direct path to delivering commercial fusion electricity to Microsoft by 2028.

The milestone, announced in February 2026 and confirmed through independent review, marks a decisive moment in the race to prove that fusion power can move from laboratory curiosity to grid-scale reality.

What Polaris Actually Did

Polaris is a 19-meter machine housed inside Helion's "Ursa" facility in Everett, Washington. It uses 2,500 capacitor banks delivering 100 GW of peak power per pulse to compress plasma at extreme temperatures. Over 3,800 diagnostic sensors monitor every pulse in real time.

How Helion's Approach Is Different

Most people picture fusion reactors as giant donut-shaped tokamaks — the design behind ITER, the $22 billion international project in France that has been under construction since 2010 and still hasn't produced first plasma. Helion took a radically different path.

Helion's Field-Reversed Configuration creates a "smoke ring" of plasma that gets compressed by magnetic fields. When the plasma expands after fusion, it pushes back against those fields and generates electricity directly — no steam, no turbines, no boiling water. It is the electrical equivalent of regenerative braking in an electric vehicle.

This direct conversion approach is why Helion believes it can build reactors roughly the size of a shipping container that produce 50 megawatts — enough to power approximately 40,000 homes.

The Money and the Pressure

Helion has raised over $1.1 billion across multiple funding rounds, with its January 2025 Series F of $425 million valuing the company at $5.4 billion. The investor list reads like a who's who of tech capital.

The Skeptics Have a Point

Fusion has broken more promises than any other energy technology. The joke — "fusion is always 30 years away" — exists because it has been true for 70 years.

What Comes Next

Helion's immediate roadmap has three critical milestones:

Remaining challenges

• Demonstrate net electricity from Polaris (more energy out than in) — expected 2026-2027
• Transition from D-T fuel to deuterium-helium-3, which is cleaner but harder
• Complete construction of Orion, the first commercial-scale generator in Malaga, WA
• Meet the 2028 Microsoft deadline — the credibility test for the entire company

What's working

• 150M°C achieved — well above the 100M°C commercial threshold
• D-T fusion demonstrated in a private machine for the first time
• Independent data verification builds scientific credibility
• Commercial contracts (Microsoft, Nucor) create accountability
• Over $1.1B in funding with $1.7B in milestone bonuses available ::/proscons

The Department of Energy is watching closely. Jean Paul Allain, Associate Director for Fusion Energy at the DOE, said private-sector milestones like Polaris are "de-risking" the path to commercial fusion — language that suggests government support could follow if Helion continues delivering.

Why This Time Might Be Different

The fusion industry has cried wolf before. But several things distinguish this moment from previous false dawns.

First, there is commercial accountability. Microsoft's PPA means Helion faces real financial consequences if it fails to deliver — not just reputational damage, but contractual liability. Second, the speed of iteration is unprecedented. Helion has built seven prototypes in 13 years, each dramatically more capable than the last. Third, the capital is private. Unlike government megaprojects that can absorb decade-long delays without consequence, Helion's investors expect returns.