Scientists at the Technical University of Denmark have invented a technology they believe may be an important step towards the hydrogen economy: a hydrogen tablet they say effectively stores hydrogen in an inexpensive and safe material. If manufactured through clean means, hydrogen can be a non-polluting fuel, but since it is a light gas it occupies too much volume, and it is flammable. Consequently, effective and safe storage of hydrogen has challenged researchers worldwide for almost three decades. At the Technical University of Denmark (DTU), an interdisciplinary team has developed a hydrogen tablet that enables storage and transport of hydrogen in solid form. "Should you drive a car 600 km using gaseous hydrogen at normal pressure, it would require a fuel tank with a size of nine cars. With our technology, the same amount of hydrogen can be stored in a normal gasoline tank," says Professor Claus Hviid Christensen, Department of Chemistry at DTU. The hydrogen tablet is safe and inexpensive, according to the researchers. You can literally carry the material in your pocket without any kind of safety precaution. The reason is that the tablet consists solely of ammonia absorbed efficiently in sea salt. Ammonia is produced by a combination of hydrogen with nitrogen from the surrounding air, and the DTU tablet therefore contains large amounts of hydrogen. Within the tablet, hydrogen is stored as long as desired, and when hydrogen is needed, ammonia is released through a catalyst that decomposes it back to free hydrogen. When the tablet is empty, you merely give it a "shot" of ammonia and it is ready for use again.