A power generator includes a housing, a chemical hydride fuel block adapted to be removably placed within the housing, an air conduit disposed about the chemical hydride fuel block in the housing. The air conduit includes a fuel cell portion and a water vapor permeable, hydrogen impermeable membrane portion. The housing has an air intake opening to draw air into the housing and through the air conduit to provide oxygen to the fuel cell portion and to carry water vapor generated by the fuel cell portion past the permeable membrane portion such that water vapor passes through the membrane and causes release of hydrogen from the fuel block.