NOVELTY - Water is electrolyzed using an electric power obtained from predetermined energy source. The water electrolysis process (1) separates and generates hydrogen and oxygen. The water soluble organic compound aqueous solution preparation process (3) involves mixing water soluble organic compound and water. Then, the obtained aqueous solution is electrolyzed and carbon dioxide is recovered. The water soluble organic aqueous solution is used as a medium for storing and transporting hydrogen.    USE - For supplying hydrogen used as fuel for fuel cell, electric vehicle e.g. hydrogen fuel battery motor vehicle, and also used for portable apparatus such as notebook-type personal computer, and mobile phone.    ADVANTAGE - The hydrogen has high energy density, storage stability for long time, and haul, and is supplied without loss of density.    DETAILED DESCRIPTION - Water is electrolyzed using an electric power obtained from predetermined energy source. The water electrolysis process separates and generates hydrogen and oxygen, and the water soluble organic compound synthesis process (2) synthesizes a water soluble organic compound recovered from carbon dioxide and hydrogen. The water soluble organic compound aqueous solution preparation process involves mixing water soluble organic compound and water, and generating water soluble organic aqueous solution of predetermined concentration, using electric power. Then, the obtained aqueous solution is electrolyzed using water soluble organic compound aqueous solution electrolysis process (4), and carbon dioxide is recovered by carbon dioxide collection process (5). The water soluble organic aqueous solution is used as a medium for storing and transporting hydrogen.    DESCRIPTION OF DRAWING(S) - The figure shows a process diagram of hydrogen supply method. (Drawing includes non-English language text)    Water electrolysis process (1)    Water soluble organic compound synthetic process (2)    Water soluble organic compound aqueous solution preparation process (3)    Water soluble organic compound aqueous solution electrolysis process (4)    Carbon dioxide collection process (5)    Water soluble organic compound aqueous solution synthetic process (6)