Fill'er Up-with Hydrogen

This article highlights that researchers are developing new technologies to carry H₂ in gas, liquid, or solid state. The advantages of hydrogen fuel for cars and trucks keep driving efforts to develop ways of handling it. Hydrogen has the highest energy content by weight of any fuel—52,000 Btu per pound. As the simplest and most common element in the universe, though never found naturally in pure form, hydrogen can be produced from a host of available sources, including water, natural gas, coal, biomass, municipal solid waste, or scrap tires. Compressed gas tanks store hydrogen as a gas, and their cryogenic counterparts store it as a liquid. A less familiar method of storing hydrogen is a solid in metal hydrides, alloys of rare earth, transition metal, and magnesium. These granulated materials absorb hydrogen. Researchers feed hydrogen directly into the tanks, where it is absorbed by the powdered alloy. As the hydrogen gas is absorbed during charging, the metal hydrides generate heat that is removed by water.