MetroVolt is specified twice on purpose. The near-thermal posture (ion and electron temperatures equal) is the operating baseline the economics stand on; the hot-ion posture (Ti/Te = 1.9) is a physics upside held behind a pre-registered gate.
Hot-ion operation boosts fusion output — the deposited ceiling is 2.41 GW — but D-³He plasmas deposit fast-particle energy preferentially on electrons, taxing the very temperature split that makes hot-ion attractive. The completed Fokker–Planck gate (S26) and the channeling bound (S72: ≤30% tax redress) size that tax honestly, which is why the baseline is near-thermal: Ti = Te = 48 keV, 1.22 GW fusion, 486 MWe net on the exhaust-honest ledger, with its 2.28 profile-basis confinement requirement stated in the abstract.
The hot-ion case is retained as the P6-adjudicated ceiling — its 0.61/0.84 GWe ledgers labeled history — engineered now, credited only when the gate says so. A bonus, published with the rest: the near-thermal core is also the more turbulence-stable one (ITG threshold ≈1.3× higher).
Two postures give customers a floor they can bank and an upside they don't pay for until it is proven. It also tells reviewers something rarer: this team downgraded its own headline number when its own physics said to.
| Baseline (near-thermal, Mode D) | 1.22 GW fusion · 486 MWe exhaust-honest |
| Ceiling (hot-ion, gated history) | 2.41 GW fusion · 0.61–0.84 GWe |
| Hot-ion tax redress bound | ≤30% (S72) |
| Baseline confinement need | H98 = 2.28 (2.38 banking leg, stated) |
| Adjudication | gate P6, pre-registered |