Helion Energy
🇺🇸 Everett, US · Founded 2013 · Active
Helion Energy is a US fusion company founded in 2013 and based in Everett, Washington. Its machines form two rings of plasma called field-reversed configurations, fire them at each other, and compress the merged plasma with pulsed magnets; as the plasma expands it pushes back on the magnetic field, and Helion aims to recover that energy directly as electricity rather than through a steam turbine. It plans to use deuterium and helium-3 fuel, making its own helium-3 from deuterium reactions. Its seventh prototype, Polaris, was completed in 2024, and in February 2026 Helion reported that Polaris had produced measurable deuterium–tritium fusion. In May 2023 Microsoft agreed to buy electricity from Helion's first plant from 2028; that plant, Orion, is planned near Malaga, Washington. In June 2026 Helion raised a $465 million Series G.
- Sector
- Fusion
- Fuel
- Deuterium–helium-3
- Role
- Fusion developer
It is the operator of record for POLARIS (operating) and TRENTA (shut down).
Its recorded equity, $1.4bn, is the 6th largest of the 25 organisations with a priced round here. Not every round is on record, so this is not its total raised.
It also holds one award or agreement with no cash figure, which is not added to any total.
Terms
- Field-reversed configuration
- A self-organised plasma ring that generates its own confining field, with no central coil. Compact and high-beta, but stability over long timescales is the open question.
- Pulsed magnetic compression
- Repeated compression of a plasma by pulsed magnetic fields, recovering energy directly from the expansion rather than through a steam cycle. The main open problem is hardware lifetime: the compression coil and switching electronics must survive millions of repeated pulses for a power plant to be economic.
- Deuterium–helium-3
- Deuterium with helium-3. Most of the energy is released as charged particles rather than neutrons, which allows direct electrical conversion, but deuterium also fuses with itself in the same plasma, so some neutrons are still produced. Helium-3 is vanishingly scarce on Earth.
Funding
- 2026-06-04Equity roundSeries G announced 4 June 2026 at $465 million and closed in September 2026 at $500 million, led by Thrive Capital, at a stated $15.5 billion post-money valuation. One round: the $465 million initial close is part of the $500 million, never a separate deal. The vocabulary has no Series G term, so no round label is recorded. The release's "total invested to date ... $1.5 billion" is the company's cumulative figure.$500m
- 2025-01-28Equity roundSeries F of $425 million announced 28 January 2025, led by Lightspeed Venture Partners and SoftBank Vision Fund 2, at a stated $5.425 billion post-money valuation. Neither lead has an organisation record yet. The vocabulary has no Series F term, so no round label is recorded.$425m
- 2023-05Offtake or power purchase agreementPower purchase agreement announced 10 May 2023: Microsoft to buy electricity from Helion's first plant, targeting "50 MW or greater" after a one-year ramp, online 2028. Constellation is power marketer. Recorded as binding on the word of Helion's CEO ("a binding agreement that has financial penalties"); the terms and penalties are undisclosed.Unpriced
- 2021-11Equity round · Series ESeries E of $500 million, led by Sam Altman, announced 5 November 2021. The same release describes "the opportunity for an additional $1.7 billion" tied to performance milestones; that option is contingent and is not recorded as raised.$500m
Design values
| Device | Parameter | Value | Unit | Status |
|---|---|---|---|---|
| TRENTA | On-axis magnetic field | 10 | T | design valueclaimed |