North America · USA · Founded 2013
Sunday, October 18, 2026
Helion Energy
Magneto-inertial — Field-Reversed Configuration (FRC)
Magneto-Inertial
Deuterium-Helium-3 (D-³He)
$1B+ (Series F: $425M, 2025)
Microsoft PPA delivery 2028
Investor brief
Direct-electric fusion power for the hyperscaler era
Executive Summary
Helion Energy is the only fusion company in the world with a binding commercial power purchase agreement — Microsoft will buy 50 MW from Helion's first commercial plant starting in 2028. Helion's linear field-reversed-configuration (FRC) machine directly induces electricity into its capture coils as plasma is compressed and expanded, eliminating the steam cycle entirely.
Latest coverage — Helion Energy
- FundingSep 16, 2026Fusion funding
Helion funding round grows to $500M amid uncertainty over fusion startup’s Microsoft timeline
Helion Energy secured an additional $35 million in a Series E extension, bringing the total round to over $500 million as it works toward a 2028 power purchase agreement deadline with Microsoft.
- FundingSep 14, 2026Helion Energy
Helion Raises $465 Million Series G Funding Round To Accelerate Commercial Fusion Power Deployment
Helion Energy has secured a $465 million Series G funding round to advance its commercial fusion power systems and expand manufacturing capabilities.
- IndustrySep 14, 2026Helion Energy
OpenAI in talks with Helion Energy to secure fusion power supply
OpenAI is reportedly in discussions with Helion Energy for a future power purchase agreement, signaling a potential offtake market for commercial fusion driven by the energy demands of artificial intelligence.
- IndustrySep 14, 2026Helion Energy
With a headcount topping 800, Helion opens Seattle office in pursuit of fusion energy
Helion Energy has expanded its physical footprint with a new Seattle office to support a workforce that has now grown to 800 employees across its Washington state facilities.
- MilestoneAug 27, 2026Helion Energy
Sam Altman’s fusion startup Helion Energy hits 150 million degree plasma temperature—a milestone that could bring first grid power in 2028
Helion Energy reports achieving a plasma temperature of 150 million degrees Celsius in its Polaris prototype, a key step toward the conditions required for its planned deuterium-helium-3 fusion power plant.
- IndustryAug 26, 2026Helion Energy
OpenAI CEO Sam Altman exits Helion Energy's board as firms explore partnership
OpenAI CEO Sam Altman has resigned from the board of Helion Energy to manage conflicts of interest as the two companies begin to explore a potential power purchase agreement.
- MilestoneAug 24, 2026Helion Energy
Helion Energy starts construction on nuclear fusion plant to power Microsoft data centers
Helion has begun construction on a 30,000-square-foot facility in Everett, Washington, to house its seventh-generation fusion prototype, Polaris, which aims to demonstrate net electricity generation.
- FundingAug 21, 2026Helion Energy
Nuclear fusion startup Helion to build ‘world’s first’ power plant after raising $425 million
Helion Energy has secured $425 million in a new funding round to support the construction of what the company describes as the world's first fusion power plant.
Strategic Thesis
Convert plasma magnetic energy directly to electricity via induction, enabling a small, cheap, repetitively-pulsed power module that fits a hyperscaler campus.
Technical & Economic Profile
Architecture class
Magneto-Inertial, Pulsed & Alternative Cores
Pulsed compression schemes that explicitly avoid massive static superconducting magnets, prioritising upfront-capex reductions and modular replicability.
Reactor design
Magneto-Inertial / Field-Reversed Configuration (FRC)
Core tech focus
Direct Energy Conversion (induction; no steam cycle)
Key milestones
Microsoft 50 MW PPA (2028 delivery). Polaris commissioning 2025. Orion commercial facility breaking ground.
How Helion Energy sits vs peers
Holds the industry's singular commercial benchmark: a binding Microsoft 50 MW PPA for 2028 delivery. D-³He + direct induction allows compact high-rep modules suited to hyperscaler siting.
Class engineering bottlenecks
- Pulsed-rep-rate engineering: sustaining 1–10 Hz operation with millisecond-scale energy recovery.
- For aneutronic FRC (TAE), bremsstrahlung scales as Pbrems ∝ Tₑ^½, capping Pfus/Pbrems at ~0.2–0.3 without non-thermal ion distributions.
- For MTF (General Fusion), liquid-metal vortex stability under pneumatic shock and synchronisation of dozens of pistons.
- For sheared-flow Z-pinch (Zap), maintaining kink-stability at commercial pulse repetition rates.
LCOE drivers
- Elimination of large superconducting magnet assemblies removes the single largest capex line in tokamaks.
- Direct-conversion architectures bypass the 35–40% Rankine/Brayton thermodynamic ceiling, pushing net plant efficiency past 60–70%.
- Liquid-metal first-walls (General Fusion) eliminate first-wall replacement cycles entirely.
Sourced from the 2026 Global Fusion Energy Comparison — triple-product thresholds, direct-energy-conversion architecture, materials limits, and the LCOE / Qecon framework.
Founding Team
Operating at the convergence of aerospace engineering and plasma physics, the Helion founding team spent over a decade conducting rigorous, low-profile research before entering the commercial spotlight. Dr. David Kirtley, Chris Pihl, and Dr. George Votroubek originally collaborated within the innovative laboratories of the University of Washington's aerospace program, building on the foundational Field-Reversed Configuration (FRC) physics pioneered by Dr. John Slough. Their deep academic cohesion enabled them to buck industry trends, eschewing giant steam-turbine designs in favor of a sleek, linear magneto-inertial device designed to directly capture electricity via inductive magnetic coils.
David Kirtley
PhD in Aerospace Engineering, University of Michigan
John Slough
PhD in Plasma Physics, Princeton University; Professor Emeritus, University of Washington
Chris Pihl
MS in Aeronautics & Astronautics, University of Washington
George Votroubek
PhD in Plasma Physics, University of Washington
The Problem
Global electricity demand is entering an unprecedented growth phase driven by AI infrastructure, data centers, transport electrification, industrial decarbonization, water desalination, and advanced manufacturing. Solar suffers intermittency, wind capacity-factor variability, natural gas carbon emissions, conventional nuclear cost and deployment speed, and batteries energy-density and duration limits. The world requires a new source of clean, dispatchable baseload energy. Fusion represents the ultimate energy source — the challenge is making it commercially practical.
Pulsed FRC Direct-Electric Architecture
Helion uses a linear acceleration-and-merging architecture: two FRC plasma rings are formed at opposite ends of the machine, accelerated toward the center at over 1 million mph, and merged. The compressed plasma's expanding magnetic field induces current directly into the device's coils — Faraday's law as a power plant.
Field-Reversed Configuration (FRC)
A compact, self-organised plasma ring with closed magnetic surfaces. FRCs naturally accept advanced fuels and exhaust plasma along the device's open ends.
Pulsed Operation
Helion's reactor pulses roughly once per second. Each pulse forms, merges, compresses and recovers a plasma — capacitor banks store and release the energy.
Direct Energy Recovery
Most of the energy delivered to the plasma plus the fusion energy itself is recaptured electrically through induction, dramatically simplifying the balance of plant relative to thermal-cycle reactors.
Polaris Prototype
Polaris (the seventh-generation prototype) is commissioning in Everett, Washington and is designed to demonstrate the first measurable electricity from fusion.
Orion Commercial Plant
Orion is Helion's first commercial machine — a ~50 MWe pulsed fusion plant currently under construction in Washington State, contracted to supply Microsoft from 2028.
Fuel Strategy
Deuterium–Helium-3 (D-³He)
Helion's primary fuel cycle. The reaction's charged-particle products couple naturally to direct electrical conversion.
On-site Helium-3 Synthesis
Helion produces its own ³He from D-D side reactions inside the machine — eliminating the world-supply bottleneck that has historically blocked D-³He fusion.
Product Platform
Polaris
Seventh-generation prototype demonstrating electricity from fusion.
Orion
First commercial 50 MWe pulsed fusion plant contracted to deliver power to Microsoft from 2028.
Energy Conversion
Direct (Inductive)
Low-neutron
~60% wall-plug electrical (target)
Magneto-inertial FRC compression with direct inductive energy recovery — the expanding plasma's changing magnetic field induces current in the surrounding coils, recovering electricity directly.
Conversion chain
- 1D-³He plasma in FRC
- 2Magnetic compression by capacitor banks
- 3Plasma expansion → changing B-field
- 4Faraday induction in coils → AC electricity
No thermal cycle. The same magnets that compress the plasma also harvest the energy on expansion. Compatible with pulsed operation at high repetition rate. Critical dependency: ³He production via D-D side reactions inside the same machine.
Economic Vision
By eliminating steam turbines, cooling towers and most balance-of-plant, Helion targets a small-footprint, factory-built power module compatible with data-center campuses and industrial sites. The pulsed architecture allows rapid iteration: each generation has been built and tested in roughly two years.
Vision
A world where electricity is so abundant and inexpensive that desalination, direct air capture and universal compute become economic by default.
Mission
Build the world's first fusion power plant that delivers electricity to the grid — on contract — by 2028.
Engineering Bottlenecks
- Plasma-ring merging stability at full energy
- Helium-3 fuel sourcing (Helion synthesises its own from D-D side reactions)
- Capacitor-bank lifetime under repetitive discharge
Milestone Timeline
2023
Signed Microsoft PPA — 50 MW from 2028
2025
$425M Series F; Polaris commissioning
2025
Broke ground on Orion commercial facility
Late 2026
Tiny Merge agile testbed online
2028
First electricity to Microsoft (contractual deadline)
The description above reflects Helion Energy's publicly stated technology goals, roadmap and architecture. Many elements — particularly net-energy gain at scale, advanced fuel cycles, and grid-relevant economics — remain ambitious objectives that have not yet been demonstrated commercially anywhere in the fusion industry. Forward-looking statements should be treated as engineering targets, not certainties.
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Citations & Sources
Academic & financial rigor- [01]
Helion–Microsoft 50MW PPA
Microsoft · 2023
- [02]
Series F $425M
Helion Energy · 2025
- [03]
The Global Fusion Industry in 2025
Fusion Industry Association · Jul 2025
- [04]
Company disclosures and press releases
Helion Energy
- [05]
Peer-reviewed plasma physics literature
Journal of Plasma Physics / Nuclear Fusion