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Types of Hydrogen Technology for Engines

"Hydrogen" covers four very different product categories with different capital costs, infrastructure needs and risk profiles. Confusing them is the most common source of bad procurement decisions.

The four categories

Category	What it is	Infrastructure
Fuel cell EV	Hydrogen converted to electricity, electric drivetrain	Refueling network, full drivetrain replacement
H₂ dual-fuel conversion	Stored hydrogen substituted for part of the diesel	Onboard storage, refueling, ECU work
Stored-hydrogen injection	Bottled hydrogen metered into intake	Cylinder handling and refill logistics
On-demand electrolytic enrichment	H₂/O₂ generated from water as the engine runs	None — water and DC power only

Where HydroHub™ sits

HydroHub systems are the fourth category. There is no storage, no refueling infrastructure and no drivetrain change. That constrains the size of the effect — enrichment is a combustion modifier, not a fuel substitution — but it also removes the capital and logistics burden that stops the other three categories from scaling on existing fleets.