Hydrogen was converted to such a material as coal or oil with a low specific gravity so that it could be stored for a longer period and transported for a long distance at room temperature and under atmospheric pressure; which is sodium metal or sodium hydride. Sodium metal is produced with molten-salt electrolysis from seawater by wind power and transported to a thermoelectric power station in the consumption place for hydrogen-fueled combustion power generation. Sodium hydroxide, a waste, is re-electrolyzed to produce sodium for hydrogen generation; which constructs a hydrogen fuel cycle. This hydrogen fuel cycle is a clean, environmentally friendly recycle system that never requires repeated supply of raw materials in the same manner as the nuclear fuel cycle. Sodium or sodium hydride is an alternative energy.