Hydrogen is the most abundant element in the universe and has great potential as an energy source. Unlike petroleum, it can be easily generated from renewable energy sources. It is also nonpolluting, and forms water as a harmless byproduct during use. Yet it is so difficult to store that its use as a fuel has been limited. Now it is stored in a hydride which uses an alloy that can absorb and hold large amounts of hydrogen by bonding with hydrogen and forming hydrides. A hydrogen storage alloy is capable of absorbing and releasing hydrogen without compromising its own structure. But it is possible to store 1.4 to 7.5% of hydrogen by weight of hydride. Hoever nanotechnology offers great scope for higher storage capacity. Researchers at Stanford have shown that have recently shown that carbon nanotubes could be a promising material for storing hydrogen safely. They studied the film with different x-ray spectroscopy techniques to see if any hydrogen atoms had formed chemical bonds with the carbon. By bombarding a film of carbon nanotubes with a hydrogen beam, they found that about 65 percent of the carbon atoms had bonded to hydrogen atoms.