Fuel Abundance Across Sources

Fusion fuel starts with deuterium from water — effectively unlimited — though the burner's helium-3 is scarce and gates that machine.

Fuel abundance shapes how sustainable and secure an energy source is. Fossil sources burn finite reserves and depend on continuous extraction. Renewables use inexhaustible flows — sun, wind, water. Fusion sits with the abundant category on its primary fuel: deuterium is extracted from ordinary water and is effectively unlimited. The honest complication is the burner's second fuel, helium-3.

The fusion fuel picture

The breeder (Hyperion) fuses deuterium and tritium. Deuterium comes from water; tritium is bred inside the plant's lithium blanket, with the tritium breeding ratio treated as a design lever across 1.1, 1.5, and 1.8. The burner (Aegis / MetroVolt) fuses deuterium and helium-3. Helium-3 is extremely scarce on Earth, which is a genuine constraint discussed below.

The helium-3 gate — stated plainly

Helium-3 demand for a commercial burner unit is on the order of 400 times domestic terrestrial supply. This is a hard physics-and-supply fact: the burner is gated on a helium-3 supply that does not exist at terrestrial scale today. It is precisely why the breeder's in-situ helium-3 production (~1.97 kg/yr class) and, longer term, lunar helium-3 matter to the program. The breeder's deuterium–tritium cycle does not face this constraint.

• Deuterium: from water, effectively unlimited — fusion's primary fuel.
• Breeder tritium: bred in-situ, breeding ratio a design lever (1.1/1.5/1.8).
• Burner helium-3: scarce terrestrially, ~400x domestic supply per unit — a real gate.
• This gate motivates breeder-bred and lunar helium-3, stated honestly.

Design-and-simulation framing. The Kronos machines are today design and simulation studies: the breeder (Hyperion) and the burner (Aegis / MetroVolt). No hardware net-gain has been demonstrated. Breeder construction is planned to begin Q2 2027, with first-of-a-kind (FOAK) first tritium targeted around 2030. Comparisons on this page are qualitative and use only public, defensible figures; nothing here is a performance guarantee.

Fusion's fuel abundance is a strength for the breeder and an honestly flagged constraint for the burner — no overclaim, no economics.