Large scale and effective utilization of renewable energy including hydroelectric power, photovoltaic power, and wind power which are abundant on the earth can contribute to the solution of global environmental issues as well as the release of energy demand and supply. Hydrogen can be produced from the renewable energy, and is converted, transferred and stored if necessary. Such hydrogen can be used in various fields for power generation, fuel for transport, and city gas. In order to establish the technology by which worldwide energy network can be introduced for wide range of fields, conceptual design of a total system has been conducted, and elemental core technologies have been developed. Conceptual design of a practical scale system (total system) including a wide range from production of hydrogen to its utilization has been conducted, and its constitution has been illustrated. In addition, the energy balance and cost of hydrogen have been calculated and analyzed as a trial. Hydrogen production technology, transport and storage technology, and hydrogen utilization technology are introduced as individual elemental technologies. Research results of innovative and leading technologies obtained in FY 1996 are reviewed. 80 figs., 56 tabs.