In many ways, hydrogen is the perfect fuel. It is the cleanest burning and the most efficient. Hydrogen can produce electricity, and electricity can produce hydrogen, creating an energy loop that is renewable and harmless to the environment. Hydrogen combines chemically with most elements, so it has been utilized as an industrial chemical in a wide range of applications for many years. In vehicles, hydrogen is being used to produce electricity that powers a motor by combining it with oxygen in a fuel cell.