The hydrogen energy system using renewable energies as primary energies has the low environmental factor compared to the fossil energy system. In order to get a sustainable growth of our human society we have to get the green hydrogen energy system where hydrogen is produced from water using renewable energies. In the system the green hydrogen and electric energy are used for secondary energies and the conversion between hydrogen and electric energy is very important. The fuel cell and water electrolysis should be technically advanced further.

Water electrolysis seems to be well established technology with high energy conversion efficiency, but new technologies will be required to combine renewable energies. This paper reviews thermodynamics, energy conversion efficiency, and materials such as electrocatalyst and separator for water electrolysis, and discusses subjects for the combination with renewable energies.

Wind-Hydrogen system is one of the ultimate renewable energy for human being. There are many good wind areas around the world, but no transmission lines being exist even today. This report describes Wind-Hydrogen Systems today and future with collaboration each other and indicates final goals. This paper also introduces some new design concept and business idea about wind-hydrogen systems.

I introduce “The Kitakyushu Smart Community Creation Project”, “The Kitakyushu hydrogen town” and the cooperation policy.

A PEM-type unitized reversible cell (URC) is a device combined the functionality of water electrolyzer (WE) and a fuel cell (FC) in one electrochemical cell. URC can work as either of WE or FC by switching operation depending on the demand, so that URC has the potential to reduce device cost, installation space, and to raise operating rate compared to the dedicated use of WE and FC. Therefore, URC should become a key energy conversion device for a distributed energy system or emergency power supply if it is used with a hydrogen storage system such as high pressure tank or metal hydride Alloy. For practical use, it is necessary to improve the performance and durability of the URC up to the level of the dedicated cells. In this paper, development state of URC system is described.

Studies of stationary hydrogen storage using metal hydrides are introduced. A recent study about the totalized hydrogen energy utilization system that consists of fuel cells, water electrolysis, metal hydride tanks and their auxiliaries is reviewed. In this system, the metal hydride tank system and its arrangement was developed for reaction heat recovery. The research on the hydrogen gas refinement by metal hydrides is also introduced.

IEA (International Energy Agency)/HIA (Hydrogen Implement Agreement) is an organization which secure the R&D activities in the field of the Development of Technologies for Hydrogen Production, Delivery and Storage Systems. The final vision of IEA/HIA is “Hydrogen future based on a clean, sustainable energy supply that plays a key role in all sectors of the economy” and the following are the themes. 1) Designing and conducting collaborative R&D that address basic research needs; 2) Undertaking independent analyses of hydrogen science, technology, systems and economics that support its RD&D and outreach programs; 3) Increasing membership participation; 4) Involving a broad range of industry partners; 5) Raising the level of hydrogen awareness, understanding, knowledge and support throughout all sectors of economy to foster confidence with hydrogen.