Eos is Thea Energy's planned large-scale integrated stellarator built from arrays of planar HTS magnets, meant to demonstrate power-plant-relevant steady-state fusion ahead of its 'Helios' power plants. Thea raised a $100 million Series B in May 2026 (extended in August) and was evaluating sites for Eos.
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Current state
| Status | Design |
| Country | United States |
| Developer | Thea Energy |
| Developer type | Private |
| Concept | Stellarator |
| Fuel | D-T |
| Purpose | Demonstration |
| Site | Multiple sites under evaluation; selection expected in 2026 |
| Public funding | DOE Milestone-Based Fusion Development Program awardee (Helios preconceptual design certified); $20M ARPA-E SCALEUP award; six DOE INFUSE awards |
Notes
Cumulative funding not disclosed (Series B $100M plus undisclosed extension), so private funding raised not recorded. Thea aims to start construction of the first Helios plant before 2030. Secondary reports suggest Eos completion around 2030, unconfirmed by Thea.
Timeline
- 2026-05-27 — Thea Energy raised a $100 million Series B led by Thomas Tull's USIT to expand magnet manufacturing and fast-track Eos, after DOE certified its Helios preconceptual design milestone. (source)
- 2026-08-18 — Thea closed a Series B extension, received a $20 million ARPA-E SCALEUP award and said Eos-spec magnets met field and precision requirements. (source)
The timeline is append-only: corrections are added as new entries. Stated targets appear in the current-state table, never as milestones.
Related projects
- Alpha (Proxima Fusion) Design · Germany
- ARC (Commonwealth Fusion Systems) Design · United States
- Athena (Xcimer Energy) Concept · United States
- Century (Zap Energy) Operating · United States
- Copernicus (TAE Technologies) Under construction · United States
- Da Vinci / first utility-scale plant (TAE Technologies) Concept · United States
- Demonstration System (Pacific Fusion) Under construction · United States
- FLARE fusion neutron source (SHINE Technologies) Operating · United States
See all 51 projects in the Fusion Energy Companies & Projects Tracker →
Sources
- Thea Energy Raises $100 Million Series B Funding to Build Scalable Fusion Power Plants — Thea Energy (primary), checked 2026-10-11
- Thea Energy Extends Series B Funding to Deploy Efficient and Economical Fusion Power — Thea Energy (primary), checked 2026-10-11