U.S. Naval Research Laboratory (NRL) has prototyped a Hydrogen Small Unit Power (H-SUP) system to reduce detectability and improve readiness of Marine Corps in expeditionary warfare operations.
This "The Hydrogen Small Unit Power (H-SUP) prototype offers a low-signature solution for electric power production, up to 1.2 kW of continuous power, in a ruggedized package." was originally found on https://www.navy.mil/Press-Office/News-Stories/Term/3087/