Abstract
Development of alternative fuel is urgent issue because of expectation of fossil fuel termination. Ammonia has advantages for high density of hydrogen fuel, and stop of global warming due to carbon-free fuel. However, the handling of ammonia must be careful of safety specifically, because toxicity of ammonia affects a human body and a fuel cell. On the other hand, urea can be easily changed into ammonia and dealt with safety. A hydrogen generation system fueled with ammonia from urea for fuel cells is described in this paper. The authors have studied urea properties, new recycle processes, system possibilities theoretically calculated, and appropriate applications. Furthermore, they have tested and proved urea decomposition by urease catalyst of enzyme without conventional high heat energy. By these studies, conditions of the appropriate urea decomposition could be achieved. The possibility of urea was examined as an energy career of hydrogen and a renewable energy without exhaustion of energy source in the future.