Abstract
A long-term energy system in the future is expected to be based on the ideal circulation system between water and hydrogen in the sense that the hydrogen prepared from water eventually returns to water again after its use. Currently, with respect to the hydrogen energy system, it is predicted that the turning-point at which the production cost of hydrogen will become to be lower than that of fossil fuels would be after 2010. However, fuel cell technology would be able to be practically used for the applications to the transportation vehicles and small-scale power sources from 2004, and therefore, an efficient construction of the infrastructure covering hydrogen production and supply systems would be required with short-/mid-term technologies for the $CO_2$ reduction associated with fossil fuel utilization. In this paper, the hydrogen quantity available in domestic market has been estimated focusing on the hydrogen by-produced from domestic industries, and also the infrastructure for hydrogen-driven vehicles like fuel cell cars has been reviewed.
