Neutron-source stellarator based on planar coil technology. Generates revenue through tritium and medical isotope production before Helios power plant.
ProtoStage 2 of 5
Design phase; construction and operations targeted around 2030.
Checked 10 Oct·0 updates this week
Milestones
Next · Eos site selection and construction start
Series A fundingJan 2024Complete.
Series B funding completeMay 2026Complete.
DOE certification of Helios pilot plant preconceptual designJan 2026Complete.
Headquarters opens in Kearny, New JerseyJan 2025Complete.
Eos site selection and construction startTarget 2027Not yet reached.
Eos first plasmaTarget 2029Not yet reached.
Eos tritium production beginsTarget 2030Not yet reached.
Upcoming
2026Eos site selection finalized (next)
2027Eos site selection and construction start
2029Eos first plasma
2030Eos tritium production begins
Current obstacles
Tritium breeding blanket performanceAchieving consistent net tritium breeding at sustained neutron flux requires validated blanket materials and geometry.
Planar coil manufacturing precisionCoil positioning must meet strict tolerances to maintain proper field geometry. Manufacturing variability could degrade plasma confinement.
Software-magnetic feedback loop latencyPlasma instabilities evolve on millisecond timescales. Sensor, control electronics, and magnet response delays must be minimized.
Physics limits
HTS superconductor critical fieldHigh-temperature superconductors lose superconductivity above a critical magnetic field (~20 Tesla for commercial HTS). Magnet field strength is thus limited by coil geometry and material.
Neutron damage to structural materials14 MeV neutrons activate and embrittle steel and other structural materials. Material lifetime and replacement costs scale with neutron fluence.
Plasma stored energy and confinement timeStellarators naturally confine particles well but heat addition and energy storage remain engineering challenges. Increasing confinement time drives up operating temperature and fuel consumption.
How it works
4 parts
Plasma shape
Planar-coil stellarator
Planar HTS coil arrays create a twisted magnetic field that confines plasma in a doughnut shape without external current.
Field control
Software-driven field adjustment
Real-time software adjusts coil currents to maintain confinement. Eliminates hand-wound 3D coils and reduces manufacturing cost.
Neutron generation
Fusion produces fast neutrons
Deuterium-tritium reactions release 14 MeV neutrons. These breed tritium in a lithium blanket and enable isotope production.
Revenue business
Tritium and medical isotopes
Eos sells tritium to fusion programs and medical isotopes (Mo-99) to hospitals, generating revenue before Helios power plant.
Founded in 2022, Thea Energy is a Princeton Plasma Physics Lab spinout developing planar HTS coil stellarators with software-controlled magnetic fields for fusion power.
Raised $130M total ($20M Series A in early 2024, $100M Series B in May 2026); headquarters in Kearny, New Jersey.
Eos neutron source targets 2030 operations, selling tritium and medical isotopes before Helios power plant.
Planar HTS coils with dynamic software control simplify magnet design. DOE certified Helios pilot plant design in January 2026.
