- Helion has raised $465 million in a Series G led by Thrive Capital, valuing the company at $15.5 billion — nearly triple its $5.425 billion valuation from the Series F just 17 months ago.
- Polaris, Helion’s 7th-generation prototype, became the first privately funded fusion machine to operate with deuterium-tritium fuel and exceed 150 million °C — ten times the temperature at the Sun’s core.
- Orion, the company’s first commercial fusion power plant, is under construction in Malaga, Washington, targeting delivery of 50MW of electricity to Microsoft by 2028 under the world’s first fusion power purchase agreement.
On a flat stretch of land in Malaga, Washington — apple country, 130 miles east of Seattle, next to a bend in the Columbia River — the world’s first commercial fusion power plant is being built. Orion is not a concept or a rendering. It broke ground in July 2025. Two miles away, Microsoft is constructing the data centres it expects to power.
Everett, Washington-based Helion has raised $465 million in a Series G led by Thrive Capital, bringing total funding to $1.5 billion and valuing the company at $15.5 billion post-money. New investors include Alta Park Capital, Anti Fund, BoxGroup, Lux Capital, Peak XV Partners, and Ford Motor Company Executive Chairman Bill Ford. Returning investors include Capricorn Technology Impact Funds, Lightspeed Venture Partners, Mithril Capital, Dustin Moskovitz through Good Ventures Foundation, SoftBank Vision Fund 2, and a university endowment fund. The round nearly triples Helion’s $5.425 billion valuation from its Series F in January 2025, making it the fastest valuation step-up in the private fusion sector.
The founders and the company
Helion was founded in 2013 by David Kirtley (CEO), John Slough, Chris Pihl, and George Votroubek, all with backgrounds in plasma physics and aerospace engineering. The company has now built seven generations of fusion prototypes, each more powerful than the last — a build-test-iterate philosophy that Kirtley credits for outpacing rivals who rely primarily on simulation. Helion is headquartered in Everett, Washington, with the Orion construction site in Malaga. Sam Altman — who personally invested $375 million in Helion (his largest personal investment ever) and serves as executive chairman — is not listed as a participant in the Series G. His prior stake and board role remain unchanged.
How Helion’s approach differs
Most fusion companies plan to extract electricity from the intense heat of fusion reactions using conventional steam turbines — the same method used in nuclear fission plants. Helion uses a fundamentally different architecture: its Field Reversed Configuration (FRC) approach harvests electricity directly from magnets, converting fusion energy without steam. If it works at scale, this eliminates a major layer of thermal conversion inefficiency and dramatically simplifies the plant’s design and cost structure.
Helion’s ultimate commercial fuel is deuterium-helium-3 — a combination that produces fewer neutrons and fits the direct electricity extraction architecture. The company used deuterium-tritium fuel in Polaris as a stepping stone, since DT fusion is easier to ignite, to validate temperatures and plasma behaviour before moving to the commercial fuel cycle.
The milestones behind the raise
In February 2026, Helion announced that Polaris — a 19-metre device with capacitor banks capable of storing 50 megajoules of energy per pulse — had achieved two industry firsts: the first privately funded fusion machine to operate with deuterium-tritium fuel, and plasma temperatures of 150 million degrees Celsius. That is ten times the temperature at the Sun’s core and surpasses the 100 million °C threshold physicists consider the minimum for commercially relevant fusion. The milestone was independently verified by Dr. Ryan McBride of the University of Michigan and Jean Paul Allain of the US Department of Energy’s Office of Science.
“Fusion is no longer a future idea, but a path to clean, reliable, affordable always-on electricity at scale. This funding accelerates our ability to deliver on that promise. Helion is best positioned to generate electricity from fusion for customers this decade, not the next.” — David Kirtley, co-founder and CEO, Helion.
“We believe Helion has the technical ambition, pace of execution, and commercial orientation to define a new category of energy.” — Vince Hankes, Partner, Thrive Capital.
“As power capacity becomes central to AI and industrial competitiveness, Helion is moving fusion from a scientific milestone to commercial reality and building one of the most important companies for America’s energy and AI future.” — Brandon Reeves, Partner, Lux Capital.
The commercial pipeline
In 2023, Helion signed the world’s first fusion power purchase agreement — with Microsoft, to deliver electricity from a 50MW plant starting in 2028. Constellation serves as the power marketer and will manage transmission. Helion also signed a customer agreement with Nucor, the US steelmaker, to develop a 500MW plant in the 2030s. These are binding commercial agreements with penalty clauses if targets are missed — making Helion the only private fusion company with contractual delivery obligations on a defined timeline.
The competition
The private fusion sector is crowded but fragmented by approach. Proxima Fusion, the Munich-based stellarator startup, secured €400M from Bavaria to build a €2B fusion test facility. Commonwealth Fusion Systems — an MIT spin-off that has raised nearly $3 billion — is building SPARC, a tokamak targeting net energy gain in 2027, followed by its ARC commercial plant in Virginia in the early 2030s. Marvel Fusion closed €113M for a laser-based approach. What differentiates Helion is its combination of the most aggressive commercial timeline, the only binding PPA in the industry, and the only approach that extracts electricity directly from the fusion process rather than via steam.
Market context
According to Grand View Research, the global nuclear energy market was valued at $382.4 billion in 2024 and is projected to reach $754.2 billion by 2030, growing at a CAGR of 12%. Fusion is not yet a line item in that figure — but Helion’s 2028 delivery target, if met, would make it one. The more immediate driver is AI infrastructure: Goldman Sachs estimates US data centre power demand will triple by 2030, creating a structural power shortage that makes any credible source of always-on clean electricity commercially valuable before it is technically perfect.
The question Helion’s $15.5 billion valuation forces the energy market to answer is not whether fusion will work. Polaris has already demonstrated the physics. The question is whether a 50MW plant in Malaga can be online, reliable, and commercially operating by 2028 — two years away — while the rest of the fusion industry is still building demonstration machines.
