Effects of Altitude on Photovoltaic Production of Hydrogen

This paper compares hydrogen production by photovoltaic powered electrolysis of water at sea level and at low stratospheric altitudes up to 21 km. All the hydrogen production process has been considered from catchable solar radiation to storage technologies. The evaluation has been performed for 1 m² of flat horizontal plane. It has been considered the electric energy amount produced considering variations in equilibrium temperature and in solar. Hydrogen production through electrolysis has been evaluated too. Two different methods of hydrogen storage have been evaluated: high pressure compression up to 20 MPa and liquefaction process. The energetic cost of both production processes has been evaluated. The comparison is presented in terms of effective energy deliverable to final users considered in terms of HHV. This evaluation considers also, in the case of liquefaction process the energy which can be recovered by the rigasification process.