A hydrogen producing fuel comprises a chemical hydride and metal hydride. In one embodiment the chemical hydride evolves hydrogen spontaneously upon exposure to water vapor, and the metal hydride reversibly absorbs/desorbs hydrogen based on temperature and pressure. The hydrogen producing substance may be formed in the shape of a pellet and may be contained within a hydrogen and water vapor permeable, liquid water impermeable membrane. The hydrogen producing substance may further be soaked in a hydrophobic material.