4. Mobile applications

With the exception of the space applications discussed in § 4.5 , all mobile hydrogen applications are currently under development, or in a demonstration phase on a limited scale. These applications capitalize on the lower calorific value of dihydrogen by oxidizing it and converting the chemical energy released into mechanical energy. Oxidation does not always take place by combustion. In fact, with the exception of spacecraft propulsion, for which there are only a few alternatives, it is generally not advisable to use thermal conversion. Indeed, this approach would considerably limit the conversion efficiencies...