THE QUARTERLY REVIEW OF BIOLOGY 2

Abstract

inflammability limits (4-75% in air), and is difficult (sometimes dangerous) to store as a liquid. Its principal benefits are that it would allow the storage of energy in a post-fossil-fuel era, when electricity is expected to play a major role; it can be converted to electricity cleanly and efficiently, using fuel cells; and, in liquid form, it can be burned in jet aircraft. Hydrogen can also be burned in internal combustion engines, though less efficiently than in fuel cells.