Why can hydrogen be used as a fuel source in the future?
Hydrogen is available in plenty on earth and space.On earth we have to get it from water which is H ^2 O.
Hydrogen burns with oxygen and only water is produced.No pollution.
Hydrogen can be used in fuel cells (based on earlier technology developed by NASA during the Apollo years) to power cars and buses. However, after nearly 20 years of research, hydrogen powered fuel cells are still struggling to become commercially viable. Its now not clear whether or not hydrogen fuel cells will ever become economic although research breakthroughs are always possible.