Metal hydrides can act as energy conversions, for example from thermal to chemical energy, from thermal to mechanical energy, and are expected to be applicable to heat storage system, heat pump and chemical actuater.

In this paper, we explain the energy of metal hydride, the necessity of long—term heat storage technology in terms of effective utilization of solar heat and operating results of heat storage system metal hydride.

High performance gas-diffusion electrodes are essencial for practical fuel cells. Our efforts approaching to high performance have been devoted to the improvement of micro-structure in the porous reaction layer, based on the fundamental requirements to the electrode processes, i,e, high utilization of catalyst clusters and enough gas-supply to the clusters so that an electrochemical reaction on catalyst sites becomes the rate-conrolling process. It was found that a hot-pressing is very important to achieve these requirements resulting from the formation of fine and continuous electrolyte, gas and carbon black networks, respectively. Two preparation methods of high performance electrode were explained in the text, in which one uses a single powder of semi-hydrophobic catalysed carbon black and another one uses a mixed powder of a hydrophilic, catalysed carbon black and a wet-proofed carbon black. Resulting electrodes exhibited larger values both in the utilization and the performance than that prepared by the conventional method by a factor more than 3.

A plan on the hydrogen fuel system for domestic transportation (cars, ships,aircrafts) in Japan is investigated.

Hydrogen is produced with solar energy on huge rafts on the South Pacific Ocean and transported by liquefied hydrogen tankers or by metal hydride carriers. Futhermore, one example of domestic supply planning is proposed.

Finally, the quantities of facilities over total systems (numbers of rafts, tankers,storage tanks, offshore tankers, tank-rollys) is summed up and outline of systems is obtained.