Hydrogen gas at a hydrogen refueling site is cooled below liquid nitrogen temperature (e.g., about 80K) for more efficient adsorption of hydrogen on hydrogen adsorbent particles in the fuel storage of a hydrogen powered vehicle. When compressed hydrogen gas is available it may be cooled with liquid nitrogen and then sub-cooled below about 70K by a Joule-Thompson expansion. When liquid hydrogen provides hydrogen gas it may be cooled below liquid nitrogen temperatures by mixing with liquid hydrogen or by heat exchange with liquid hydrogen.