Helion Energy
| Company type | Private |
|---|---|
| Industry | Fusion energy, Clean energy technology |
| Founded | 2013 |
| Founder | David Kirtley, John Slough, Chris Pihl, George Votroubek |
| Headquarters | Everett , United States |
Key people | Sam Altman (Executive Chairman) |
| Products | Fusion power technology, Helium-3 production |
Helion Energy, Inc. is a fusion research enterprise headquartered in Everett, Washington, United States. The company focuses on developing magneto-inertial fusion technology aimed at generating helium-3 and fusion power through aneutronic fusion. Its goal is to provide affordable, clean electricity derived solely from water-based fuel sources.
History
Established in 2013 by David Kirtley, John Slough, Chris Pihl, and George Votroubek, Helion Energy quickly gained recognition by winning the 2013 National Cleantech Open Energy Generation competition and receiving accolades at the 2014 ARPA-E Future Energy Startup event. The team also participated in the 2014 Y Combinator accelerator program and was awarded a 2015 ARPA-E ALPHA contract focused on "Staged Magnetic Compression of FRC Targets to Fusion Conditions."
In 2022, Helion was shortlisted as a finalist for the innovation of the year award in the fusion startup category at the GeekWire Awards. The following year, it earned finalist status again for GeekWire's Best Workplaces of the Year.
On May 10, 2023, Helion announced a landmark agreement with Microsoft as its inaugural customer, committing to supply fusion-generated electricity beginning in 2028—representing the first commercial fusion energy contract ever secured.
Technology
Helion employs a linear fusion device utilizing pulsed magnetic compression, setting it apart from conventional fusion reactors based on tokamak designs.
Operating at a frequency of 1 Hz, the system cycles through plasma injection, compression to fusion conditions, expansion, and energy recovery to produce electricity. This pulsed-fusion technique is designed to enable continuous power generation around the clock. Its compact footprint offers the potential to replace existing fossil fuel plants without extensive capital expenditures.
Fuel
The fuel mixture consists of deuterium combined with [[helium-3|Template:Chem]], facilitating primarily aneutronic fusion that emits only about 5% of its energy as fast neutron radiation. Due to the scarcity and high cost of commercial 3He, Helion intends to generate it internally via side reactions from deuteron–deuteron (D–D) fusion alongside D–3He fusion. The D–D process produces equal quantities of 3He and tritium (3H), with tritium naturally decaying into additional 3He over time. Helion plans to capture and recycle this 3He for reuse as fuel—a method safeguarded by patents.
Confinement
Fusion plasma confinement is achieved using a magnetic field generated by a field-reversed configuration (FRC) plasmoid. Control is maintained through solid-state electronics adapted from power switching technology originally developed for wind turbine applications, minimizing energy losses from the plasma. The FRC design features closed magnetic field lines and high beta, without internal structural penetrations, which enhances plasma containment efficiency.
Compression
Two FRC plasmoids are propelled at velocities exceeding 300 km/s using pulsed magnetic fields before merging into a single plasmoid under high pressure. Published objectives include compressing fusion plasmas up to 12 tesla (T).
Energy generation
Energy extraction occurs through direct energy conversion, where plasma expansion induces currents in magnetic compression and acceleration coils, while energetic fusion products such as alpha particles are converted directly into electrical power. The 3He produced via D–D fusion carries energy of 0.82 MeV, tritium decay products have 1.01 MeV, and protons deliver 3.02 MeV.
This approach eliminates the need for steam turbines and cooling towers, thereby reducing energy losses significantly. Helion reports achieving round-trip efficiencies above 95%, enabling substantial recovery of input energy.
Development background
The Fusion Engine technology originates from the Inductive Plasmoid Accelerator (IPA) experiments conducted between 2005 and 2012. These trials utilized deuterium–deuterium fusion, which produced neutrons at 2.45 MeV in approximately half of the reactions. The experiments succeeded in reaching ion velocities of 300 km/s and deuterium ion temperatures near 2 keV. Helion and MSNW LLC have also documented work involving a deuterium–tritium fusion approach, which is simpler to achieve but results in higher energy neutrons at 14 MeV. In 2011, the Helion team published peer-reviewed research confirming D–D neutron generation.
Fourth prototype, 'Grande'
In 2014, Helion introduced its fourth fusion prototype, Grande, designed to evaluate high magnetic field operation. Grande achieved magnetic field compression up to 4 tesla, generated field-reversed configurations (FRCs) on a centimeter scale, and attained plasma temperatures of 5 keV. The company asserts that Grande surpassed performance benchmarks set by other private fusion ventures at that time.
By 2015, Helion demonstrated direct recovery of magnetic energy from a smaller-scale pulsed magnetic system utilizing high-voltage insulated gate bipolar transistors (IGBTs). This system achieved over 95% round-trip efficiency through more than one million pulses. Additionally, a compact apparatus produced over one billion FRCs.
Fifth prototype, 'Venti'
The fifth prototype, Venti, developed in 2018, reached magnetic fields of 7 tesla and ion temperatures of 2 keV at elevated plasma densities. Helion reported neutron production from D–D fusion experiments during the U.S. Department of Energy’s ARPA-E ALPHA program meeting. That year’s tests yielded plasma temperatures in the multi-keV range and a triple product value of , marking notable advancement toward viable commercial fusion power.
In 2021, Helion announced that after a rigorous 16-month testing period involving more than 10,000 pulses, their sixth prototype—Trenta—achieved plasma temperatures of 100 million degrees Celsius, the threshold required for commercial fusion energy generation. This accomplishment positioned Helion as the first private fusion company to reach such temperatures. Magnetic compression fields exceeded 10 tesla; ion temperatures surpassed 8 keV; electron temperatures were above 1 keV. The company also reported ion densities reaching up to , with confinement durations lasting as long as 0.5 milliseconds.
Seventh prototype, 'Polaris'
Helion’s seventh-generation device, Polaris, has been under development since 2021 and is projected for completion in 2024. Its objectives include increasing pulse frequency from one every ten minutes to one per second for brief intervals and elevating fusion plasma temperatures beyond 100 million degrees Celsius. Polaris is designed to be approximately 25% larger than Trenta to mitigate ion-induced damage to vessel walls. In August 2024, Helion obtained a Large Broad Scope license from the Washington Department of Health authorizing possession and utilization of byproduct materials essential for Polaris operations.
Eighth prototype
As of January 2022, the eighth prototype was still in the design phase.
Summary table
| Prototype | Year developed | Key characteristics | Milestones |
|---|---|---|---|
| Inductive Plasmoid Accelerator (IPA) experiments | 2005–2012 | Deuterium–deuterium fusion process | Achieved ion velocities of 300 km/s, neutron production from deuterium fusion, and deuterium ion temperatures near 2 keV. |
| Grande (4th) | 2014 | High-field operation with magnetic compression up to 4 tesla; generated cm-scale FRCs; plasma temperatures reaching 5 keV | Surpassed contemporary private fusion efforts.
Demonstrated first direct magnetic energy recovery from subscale pulsed magnetic system with over 95% round-trip efficiency across more than one million pulses. |
| Venti (5th) | 2018 | Magnetic fields at 7 T; high-density plasma with ion temperature of 2 keV | Conducted detailed D–D neutron-producing fusion experiments.
Produced multi-keV plasma temperatures and achieved a triple product of 6.4 × 1018 keV·s/m3. |
| Trenta (6th) | 2021 | Magnetic compression exceeding 10 T; ion temperatures above 8 keV; electron temperatures over 1 keV | Reached thermal conditions of 100 million degrees Celsius after extensive testing involving over 10,000 pulses.
Reported ion densities up to 3 × 1022 ions/m3 and confinement times up to half a millisecond. |
| Polaris (7th) | Expected operational start in January 2025 | Designed for pulse rates up to one per second temporarily; plasma heating beyond 100 million degrees Celsius; size increased by ~25% compared to Trenta | Currently under development. |
| Ursa Major (8th prototype) | Design underway as of 2022 | Projected to be twice as large as Polaris | Design phase ongoing. |
Funding
Helion Energy obtained $7 million in funding from NASA, the U.S. Department of Energy, and the Department of Defense, followed by an additional $1.5 million investment from private backers via Y Combinator and Mithril Capital Management in August 2014.
By 2021, the company’s valuation reached $3 billion, with total investments amounting to $77.8 million by the end of that year. In November 2021, Helion secured $500 million through a Series E funding round, accompanied by milestone-based commitments totaling $1.7 billion. This financing round was predominantly led by Sam Altman, CEO of OpenAI and Helion’s executive chairman.
Criticism
Daniel Jassby, a retired researcher from Princeton Plasma Physics Laboratory, criticized Helion Energy in the April 2019 issue of the American Physical Society newsletter Physics & Society, categorizing it among fusion startups accused of engaging in "voodoo fusion" rather than sound scientific practices. He pointed out that the company repeatedly promised "power in 5 to 10 years" but had yet to generate any D–D fusion reactions. Contrarily, Helion published peer-reviewed studies confirming D–D neutron generation as early as 2011. Moreover, according to the independent JASON review team, Helion’s Venti prototype demonstrated initial results in 2018 including ion densities of 8 × 1022 ions/m3, energy confinement times of 4 × 10−5 seconds, and temperatures reaching 2 keV. In 2020, Helion became the first private enterprise to produce thermonuclear fusion plasmas exceeding 9 keV with anticipated D–D fusion reactions and neutron emissions, achieving a triple product above 1 × 1020 keV·s/m3, thereby satisfying the Lawson criterion.
The MITRE/JASON report from 2018, commissioned by ARPA-E under the U.S. Department of Energy, highlighted that for commercial success Helion would require a magnetic field strength of 40 tesla, while their prototype demonstrated an 8 tesla capability at that time. The report anticipated breakeven by 2023 but identified the principal obstacle as maintaining plasma stability during high compression. As of 2023, Helion’s prototype operates at a magnetic field strength of 10 tesla and aims for breakeven in 2024.