Abstract
It is generally considered that use of hydrogen in energy system is attractive because it produces no matters to cause air pollution or water pollution. Following this recognition, research to develop a car with low temperature fuel cell or hydrogen engine is extensively performed. The future energy system where hydrogen is used as the key material is shown in the figure below. To realize this system we must develop 1) the reasonable way to produce electricity or heat by using hydrogen as fuel, 2) the infrastructure to supply hydrogen to whole society, 3) energy sources and methods to produce huge amount of cheap hydrogen with minimum impact on nature, 4) together with assurance of resources to construct the system and 5) establishment of understanding about the basic behavior of hydrogen in various materials.
