A 
hydrogen gas generation 
system is provided for use in a 
mobile vehicle. The 
mobile vehicle may be for example, a car or 
truck or other vehicle such as a 
balloon, dirigible, airship, ship, or boat. The vehicle has an on-board 
hydrogen generator for generating 
hydrogen gas, preferably using an 
electrolysis process. The hydrogen produced by the 
electrolysis process is stored in an on-board 
hydrogen storage tank. 
Hydrogen from the 
storage tank is flowed into a vehicle propulsion 
system where the hydrogen gas is consumed to provide power to propel the vehicle. An on-board electrical generation 
system provides at least some of the 
electricity for the 
electrolysis process. In one example, the vehicle has an on-board electrical generator for providing 
electricity for the electrolysis process. The on-board electric generation system may be, for example, a solar photovoltaic 
cell system, a wind 
turbine generator system, or a regenerative braking generator, for example. Depending on the particular electrical 
generation process or processes used, the vehicle may generate hydrogen gas when moving, when coasting or braking, or when long-term parked.