a hydrogen production system for use in connection with stirling engines . the production system generates hydrogen working gas and periodically supplies it to the stirling engine as its working fluid in instances where loss of such working fluid occurs through usage through operation of the associated stirling engine . the hydrogen gas may be generated by various techniques including electrolysis and stored by various means including the use of a metal hydride absorbing material . by controlling the temperature of the absorbing material , the stored hydrogen gas may be provided to the stirling engine as needed .