Hydrogen in fueled systems and the significance of hydrogen in vehicular transportation

Hydrogen is not a primary fuel; it must be manufactured from water with either fossil or nonfossil energy sources. Benefits include cleaner air, cleaner water, and better health. Hydrogen can be used as a engine fuel, whereas neither nuclear nor solar energy can be used directly. It has good properties as a fuel for internal combustion engines in automobiles. The main disadvantages of using hydrogen as a fuel for automobiles are huge on-board storage tanks which are required because of hydrogen's extremely low density. Hydrogen will also solve air pollution and planet-warming problems in the future. The combustion of hydrogen does not produce CO2, CO, SO2, VOC and particles, but entails emission of vapor and NOx.