Helion Energy, Inc.

Overview

Helion Energy, Inc. is a Delaware corporation headquartered in Everett, Washington, developing pulsed fusion generators that it says will convert fusion energy directly into electricity. Its Forms D give 2013 as the year of incorporation. The company's About page says Helion was founded in Washington State by David Kirtley, Chris Pihl, John Slough and George Votroubek; the same page lists Anthony Pancotti as a co-founder, and Y Combinator's company page names only Kirtley and Pihl. TechCrunch reported in 2014 that the founders came from MSNW, a University of Washington spinoff in Redmond.

Kirtley is chief executive, Pihl chief technology officer, Votroubek chief scientist and Prag Jain chief financial officer. Slough is no longer with the company; NEI Magazine reported in June 2026 that he left in 2018, and he now disputes Helion's physics in public. Sam Altman, listed as a director on the 2015 Form D and described as executive chairman in Helion's 2021 Series E release, stepped down from the board in March 2026. Helion publishes no board list.

Headcount figures disagree. Scientific American put staff at about 600 in May 2026; GeekWire reported in September 2026 a headcount "topping 800" as the company opened a Seattle office. Helion moved its headquarters from Redmond to Everett in 2022.

Two customer agreements are public: the Microsoft PPA for Orion and a 2023 agreement with Nucor to develop a 500 MW plant at a Nucor steel mill. A Helion spokesman said in March 2026 that the company had announced no customer agreements beyond those two. The OpenAI arrangements reported by the Wall Street Journal and Reuters (see below) have not been announced by either company.

Pulsed FRC design

Helion's machines use field-reversed configurations (FRCs), self-contained rings of plasma that carry their own current. According to the company, an FRC is formed at each end of the machine, driven magnetically into a central chamber, merged with the other and compressed by pulsed magnets. As the fusing plasma expands, it pushes back on the magnetic field, and the current this induces is recovered directly as electricity, with no steam turbine. The design is pulsed and does not aim for ignition, a self-sustaining burn. Kirtley wrote in February 2025: "We don't need high yields, we can design and operate a system that doesn't require the most demanding physics in fusion: ignition."

What the prototypes have shown

Helion lists a line of prototypes on its About page: Grande in 2014, at 4 T of compression; Venti in 2018, built with ARPA-E support; Trenta in 2020, compressing FRCs above 8 T; and Polaris, with first plasma in 2024. The ARPA-E award, DE-AR0000563, provided $3,971,263 from 2015 to 2018 for "staged magnetic compression of FRC targets to fusion conditions," according to USASpending. It is the only federal award to Helion located. Helion was not among the eight companies selected in May 2023 for the Department of Energy's Milestone-Based Fusion Development Program.

Helion's June 2021 Trenta release reported "9 keV total bulk plasma temperatures with operation above 8 keV ion temperature and 1 keV electron temperature" over a 16-month campaign, and said Helion was the "first private company to announce exceeding 100 million degrees Celsius." The results were presented at the 2021 IEEE Pulsed Power Conference. Kirtley's October 2023 blog post on ending Trenta operations gives the same result as "9 keV (< 100 million degrees Celsius)" and says Trenta "saw evidence of bulk deuterium-helium-3 fusion." Neither document gives a fusion yield.

Polaris began operating at the end of 2024. Helion's website lists it at 19 m long, with more than 50 MJ of stored bank energy and a peak field above 15 T. A February 13, 2026 release says Polaris is the "first privately developed fusion energy machine to demonstrate measurable deuterium-tritium (D-T) fusion and achieve plasma temperatures of 150 million degrees Celsius," and that it began using D-T fuel in January 2026. The only outside party quoted in the release is Ryan McBride of the University of Michigan, who reviewed Helion's diagnostic data and cites "evidence of D-T fusion and temperatures exceeding 13 keV." The release gives no neutron yield, no gain, no split between ion and electron temperature, and no electricity recovered. Kirtley declined to confirm scientific breakeven to TechCrunch the same day and put the commercial temperature target at about 200 million degrees.

The Polaris page still says the machine is "designed to demonstrate electricity production from fusion," in the future tense. No peer-reviewed Polaris results were located. "They don't publish, and that's a stance they take," Carter told Scientific American.

The schedule has moved repeatedly. In 2014 Kirtley told TechCrunch that Helion could reach break-even in three years for "just a few tens of millions of dollars." In 2015 he told Vox that Helion could reach scientific gain within three years, as MIT Technology Review later recounted. Helion's November 2021 Series E release was headlined as targeting 2024 for demonstrating net electricity from fusion, and the May 2023 Microsoft release said Polaris would "demonstrate the ability to produce electricity in 2024." In January 2025 the Series F release said Polaris was "expected to demonstrate the first electricity produced from fusion." Helion has since replaced "net electricity" with "electricity from fusion"; its FAQ says "the term 'net' didn't align with the commercial-driven goals."

Orion, Microsoft and Nucor

Helion announced the Microsoft agreement on May 10, 2023: a plant online by 2028, delivering 50 MW or more after a one-year ramp. Constellation is the power marketer and will manage transmission. Price, term and volume beyond 50 MW are not disclosed. Kirtley told POWER Magazine that the contract carries financial penalties if Helion fails to deliver; their size has not been disclosed. Scientific American described the commitment in May 2026 as 50 MW by 2029, without giving the basis for that year.

The language around 2028 has shifted. Helion's October 2025 release said Orion would begin delivering electrons to the grid "before the end of this decade" and described the PPA as providing electricity "to Microsoft by the end of 2028." In February 2026 Kirtley told Fortune: "We're on schedule to still have first electrons to the grid in 2028. It is an aggressive milestone." The Orion web page now says the plant will begin "initial operations" in 2028 and does not define the term.

At the FusionX:Americas conference in Boston in June 2026, Helion public affairs director Jackie Siebens said: "We will not, in no universe, have 50 megawatts hit full operation in 2028," and put full power in 2029 or 2030, The Fusion Report and Axios reported in September. Axios reported on September 28, 2026 that Helion had removed a website prediction of electricity by 2028, and that the Microsoft contract requires Orion to "be connected to the grid and begin operations by the end of 2028."

Orion sits on land Helion leases from Chelan County PUD near Rock Island Dam in Malaga. KPQ reported that PUD commissioners approved the lease in June 2025: a 20-acre parcel for a "100 megawatt generator facility," up to 60 more acres reserved through 2038, a 50-year operating term, about $600,000 in ground-lease revenue, and a first right of refusal for the PUD on power from the parcel. No source reconciles the lease's 100 MW with the contract's 50 MW or more. The PUD's lease document was not read.

Site work began in July 2025. Chelan County issued a mitigated determination of non-significance under the State Environmental Policy Act on May 30, 2025, describing an office, an assembly building, a fusion generation building of about 100,000 sq ft and an on-site substation; no environmental impact statement was required. The county hearing examiner heard the conditional use permit for Helion One, LLC on October 1, 2025, and Helion announced its approval on October 15. The Wenatchee World reported that several members of the public raised concerns about untested technology; no appeal was located.

Helion said in June 2026 that the assembly and office buildings were complete, earthwork on the generator building had begun that spring, and it was working toward a transmission interconnection agreement with Chelan PUD. No executed interconnection agreement was located. Helion has not disclosed Orion's cost, E&E News reported in July 2025, and no later figure was located.

The Nucor agreement, announced in September 2023, covers a 500 MW plant at a Nucor steel facility in the US. A joint Nucor-Helion fact sheet said Nucor was investing $35 million and that "2030 or after seems like a realistic target, depending on the final site selection." No site has been announced. Nucor's 10-Q for the quarter ended July 4, 2026 records a $61 million non-cash increase in its Helion investment after Helion's second-quarter financing round; the Nucor filings reviewed do not state the original amount.

OpenAI is a reported prospect. Altman, OpenAI's chief executive, left Helion's board in March 2026. TechCrunch and other outlets reported that Kirtley said the change "enables Helion and OpenAI to partner on future opportunities," and that Altman said he keeps a financial interest and remains recused from negotiations. Axios reported the same day that the companies were discussing OpenAI taking 12.5% of Helion's output, framed as 5 GW by 2030 and 50 GW by 2035.

The Wall Street Journal reported in April 2026 that Altman had proposed OpenAI invest about $500 million in Helion at roughly a $35 billion valuation. The Journal also reported that OpenAI declined to invest but struck a separate agreement giving it the right to buy up to 50 GW of Helion power by 2035. Reuters, covering the Musk v. Altman trial in May 2026, reported that Helion first signed an agreement in 2024 "to secure future energy for OpenAI"; Altman testified he was "recused from it on both sides." Neither Helion nor OpenAI has announced an agreement or published terms, and Helion's newsroom lists none.

Funding

The two Forms D are the only primary record of Helion's fundraising. The 2014 filing reports $1,499,986 sold to three investors, matching the $1.5 million seed from Y Combinator and Mithril Capital reported by TechCrunch. The 2015 filing reports $10,614,202 sold of $21,228,400 offered, to six investors.

Later rounds are company-reported. In September 2020 Helion announced a $40 million Series D led by Dustin Moskovitz at a $1.25 billion valuation, bringing its total since 2013 to $77.8 million. In November 2021 it announced a $500 million Series E led by Altman, with "the opportunity for an additional $1.7 billion dollars tied to Helion reaching key performance milestones"; no source says whether any of that $1.7 billion has been paid, and this profile does not count it. Nucor invested $35 million in 2023. In January 2025 Helion announced a $425 million Series F at a $5.425 billion post-money valuation, with Lightspeed and SoftBank Vision Fund 2 among new investors.

The Wall Street Journal reported in April 2026 that Helion was running short of cash and, without OpenAI, had cut its target to $250 million at a $15 billion valuation. The Series G was announced on June 4, 2026 at $465 million, led by Thrive Capital at a $15.5 billion post-money valuation, and the release said it brought total investment to $1.5 billion. Helion later updated the release to say the round closed oversubscribed at $500 million in September 2026, without restating the total.

Reported valuations span $1.25 billion (2020), $5.425 billion (2025), $15.5 billion (2026), and the roughly $35 billion attached to the proposed OpenAI investment that, per secondary accounts, did not proceed. A September 2026 Form D for HII Helion Energy-01, a third-party vehicle, reports $4,552,131 sold to 53 investors; it buys exposure to Helion and is not company funding.

Competitive position

Of the private fusion developers reviewed for this profile, Helion has the earliest date attached to grid power. The Fusion Industry Association, whose figures are company-reported, counted five companies with a power purchase agreement, offtake agreement or "similar commercial commitment" as of July 2026. Commonwealth Fusion Systems has raised about $4 billion, targets first plasma and net energy gain at its SPARC tokamak in 2027, and plans its roughly 400 MW ARC plant in Virginia for the early 2030s. Type One Energy targets full startup of its Infinity Two stellarator by 2034.

TAE Technologies also uses FRCs, sustained by neutral beams, with hydrogen-boron fuel and a steam cycle for its first plant. Its investor materials put initial power operations in 2031. TAE agreed in December 2025 to an all-stock merger with Trump Media & Technology Group valued at more than $6 billion, which had not closed as of October 6, 2026. General Fusion, which uses magnetized target fusion, listed on Nasdaq in July 2026 through a SPAC merger and targets its next technical milestones in 2028. TAE publishes in peer-reviewed journals, including a 2025 Nature Communications paper on FRC formation; no comparable Helion paper on Polaris was located.

Regulation and permitting

Washington is a Nuclear Regulatory Commission Agreement State, so its Department of Health licenses fusion machines under existing radioactive-materials rules. The NRC chose the byproduct material framework for fusion in 2023, the ADVANCE Act of 2024 added a definition of "fusion machine" to the Atomic Energy Act, and the NRC published a proposed rule on February 26, 2026 that Agreement States would have to match once final. No Washington fusion-specific rule was located.

The Department of Health granted Helion a Large Broad Scope byproduct-material license for Polaris in Everett in July 2024. On June 16, 2026 it issued a Radioactive Materials License and a Radioactive Air Emissions License for Orion; Helion called itself "the first company in the world with the regulatory approvals in place for fusion power plant operations." Tennessee issued Type One what it called the state's first fusion-specific license on August 31, 2026, under a fusion rule Washington does not have; the two claims rest on different bases. No license numbers, tritium possession limits or authorized fuels for Helion have been published.

State law has added fusion in two steps. HB 1924 (2024) added fusion to the technologies Washington law counts as clean energy. HB 1018, law from May 13, 2025 and effective July 27, 2025, lets fusion facilities seek state siting through the Energy Facility Site Evaluation Council. Orion's environmental determination came on May 30, 2025, before HB 1018 took effect, and the project went through county permitting.

Key considerations

The physics basis is contested in peer-reviewed literature. A February 2026 comment in the Journal of Fusion Energyby Karl Lackner of the Max Planck Institute for Plasma Physics and co-authors argues that at reactor-relevant conditions, collisional power transfer from ions to electrons exceeds the fusion power "by more than an order of magnitude," eroding the temperature ratio Kirtley and Milroy assumed and implying "much tighter requirements on plasma lifetime, anomalous losses, and direct-conversion efficiency." A paper published in March 2026 by Timothée Nicolas of École Polytechnique and co-authors finds that "confinement times exceeding 10 ms are required for peak magnetic fields below 25 T." Helion's FAQ responds that its system is pulsed, so "the relevant question is whether enough fusion and energy recovery occur before full equilibration," and cites published projections of recovery efficiencies "exceeding 95% for optimized burn cycles." No formal reply by Kirtley and Milroy was located.

Slough, the co-founder, told Scientific American that the heat and confinement D-He3 requires are implausible with Helion's design and that he "can't see anything in the physics" that would allow it; Kirtley said Slough relies on "dated" one-dimensional models. Polaris has reached 150 million degrees by Helion's account, short of the roughly 200 million degrees Helion says D-He3 needs, and without published yield or gain.

Helion's targets for break-even, scientific gain and net electricity have each passed without a published result. The 2028 Microsoft milestone has moved from a plant online to initial operations, with full output in 2029 or 2030 according to a Helion spokesperson. The size of the contract penalties is not public.

Helium-3 is scarce, and Helion's plan to breed it has no published production figure.

The governance questions concern Altman, now off the board but keeping a financial interest, and OpenAI as a possible customer; a May 8, 2026 House Oversight Committee letter to Altman on OpenAI's conflict-of-interest procedures cites the proposed Helion investment. No source located alleges wrongdoing by Helion.

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