More than 80 of hydrogen generators, HHOG (High-purity Hydrogen and Oxygen Generator) with polymer electrolyte membrane, have already been delivered. HHOG has the following feature, 1) 99.999 % of purity of H₂, 2) simple operation, 3) maintenance free, 4) high safety.

Combination of water electrolysis and electric power generation by using renewable energy resources is investigated and there are many projects in progress in Japan. In Yaku-island, the HHOG was applied for the hydrogen station project by using hydraulic power generation for fuel cell vehicles.

Production of hydrogen from renewable energy sources is an important technology for achievement of the sustainable society. In this paper, hydrogen production from biomass using supercritical water gasification is discussed. Supercritical water is a state of water whose temperature is above its critical temperature, and whose pressure is above its critical pressure. When biomass is treated in supercritical water, decomposition of biomass takes place, resulting in hydrogen rich gas. Since the reaction takes place in “water”, the biomass feedstock is not needed to be dry. Since it is a thermochemical conversion, relatively quick and complete gasification is possible. The principle and current situation of the supercritical water gasification are introduced.

In this review, it is mainly described that the recent progress on fermentative hydrogen production from various kinds of sugar and renewable organic resources using a facultative anaerobe, Enterobacter aerogenes HU-101. Firstly, the reason anaerobic bacteria must produce hydrogen is briefly reviewed. Then, methodology and experimental results for improvement of hydrogen productivity considering with energy metabolism of E. aerogenes and redox state of substrates are demonstrated. Finaly, as one example of hydrogen production from actual organic wastes, it is introduced that simultaneous production of hydrogen and ethanol by E. aerogenes from glycerol-containing wastes discharged from bio-diesel manufacturing process.

‘BioHydrogen’, the photo production of H₂ by Photosynthetic microorganisms and Photosynthetic Bacteria, has been an massive stage of basic and applied R&D in the world. Even NEDO has begun to funding to this research area again from end of this fiscal year. Realization of practical processes for photo production of H₂ from water and organic wastewater using solar energy would result in a major, novel source of sustainable and renewable energy, without greenhouse gas emissions or environmental pollution. Furthermore, BioHydrogen by in vitro systems and construction of biological fuel cells, BioHydrogen in nano-technology and molecular handling technology are to be involved in this technological field. Also, the combined system with FC, especially PAFC and BioHydrogen should be put on emphasis as a new R&D field. As the rise of energy prices, new energy like BioHydrogen came up to the stage of realistic method.

Photocatalytic water splitting into H₂ and O₂ in a stoichiometric ratio, an uphill reaction, is an important topic from the viewpoint of ideal hydrogen production. Heterogeneous photocatalysts for hydrogen production by water splitting are reviewed. Many oxides consisting of d⁰ and d¹⁰ metal ions recently have been found as new photocatalyst materials for water splitting under UV irradiation. In particular, NiO/NaTaO₃ doped with lanthanum with a perovskite structure shows a remarkably high activity, and its apparent quantum yield is 56% at 270 nm. This photocatalyst proved that highly efficient water splitting is possible using a powdered photocatalyst. (Ga_1-xZn_x)(N_1-xO_x), (Zn_1+xGe)(N₂O_x) and Z-scheme type photocatalysts can decomposition water under visible light irradiation.

It is a matter of great urgency to develop Fuel Cell Vehicle(FCV) which has same safety, functional and economical level with existing gasoline vehicle and it is concerned that the most realistic Hydrogen storage method is to use high pressured Hydrogen. In other words, the performance improvement of high pressured vessel for FCV is required. And there is no doubt that safety issue is essential for the performance improvement.

Because “there is a long history of 25years”, “ there is actual result of 6 million vessels usage in this world” “ can be designed Leak Before Burst theory”, Samtech Corporation has been working, based on aluminum-carbon fiber composite vessel (hereinafter Type3) on development of vessel performance improvement by securing safety.

This time we set the target on the Hydrogen weight efficiency of high pressured vessel by using high performance aluminum liner , aimed at improvement of aluminum fatigue. Then we tested 4 types of aluminum liners with fatigue proof test and corrosion proof test on each liner. As a result, 6069 aluminum liner showed the best performance. This 6069 aluminum liner has also had good performance on Hydrogen embrittlement proof.

Therefore we decided to make 35MPa -6069 aluminum liner similar weight as 6061 liners. We performed burst test and cycle test on this vessel according to JARI S001 Hydrogen Standard and confirmed safety accordingly. Afterwards we tried cycle test on the same vessel with higher pressure and confirmed safety issue and possibility of weight efficiency improvement. Here we would like to present our report.

In practical hydrogen fueled engines where hydrogen gas at high pressure is directly injected into the combustion chamber and consequent burns, it is impossible to identify the contribution of the energy of the hydrogen gas pressure to the engine output power. And, it is very important to know theoretically the contribution because the pressure of the hydrogen gas affects the system of the engines. It is also significant to whether the work obtained only by the direct injection into the engine without combustion, namely only by the pressure energy of hydrogen injected into the combustion chamber, can compensate the work needed to pressurize liquid hydrogen in the pump or not. If not, the work of the pump driving is supplied from the engine, decreasing the engine output power and the thermal efficiency.

By varying the direct injection pressure from 5 to 35 MPa and the mixture strength, namely the air-fuel ratio or air excess ratio, a simple theoretical thermodynamic study was carried out to clarify the contribution of the pressure energy of the hydrogen injected, the balance of the work needed for the pump driving and the work obtained by the direct injection. As a result, the followings have been found. The injection pressure studied here is above the critical pressure of hydrogen.

(1) There is the contribution of the energy of the hydrogen gas pressure to the engine output power. The contribution is small, varying from 1.61 % to 1.68 % of the combustion energy when the injection pressure varies from 5 MPa to 35 MPa.

(2) The work obtained by the direct injection can compensate the work needed to drive a liquid hydrogen pump. But it depends on the conversion efficiency of the electric generator.

In addition, the simple estimation study carried out to obtain the results of this paper will be explained.

CO₂ capture and storage technology, now called CCS, is to sequestrate CO₂ in ocean and underground, which is one of the promising options for CO₂ mitigation. The present paper describes not only the outline of these sequestration technologies but also combination with hydrogen fuel-cell system, which shows an efficient CO₂ sequestration as compared with that of conventional case.