Hydrogen Hydrogen is a second key potential alternativeenergy source for transport. In the early 2000s, hydrogen was being viewed as a panacea for the future and in 2003 the International Partnership for the Hydrogen Economy established by the US Department of Energy with signatories from aroun the world, aimed to accelerate the transition to a hydrogen(see www.iphe net). The impetus towards this shift has, however, slowed as problems have emerged. To date, much of the research into hydrogen as an AF has focused on passenger cars and buses rather than freight vehicles, although there is considerable interest in the potential for hydrogen use in the light goods vehicle(LGV) sector. As the technology improves, and as long as it is viewed as being successful, transferral of this energy source to larger vehicles is likely The main form of hydrogen to be used in transport is the hydrogen fuel cell. This is a device that converts hydrogen gas and oxygen into water via a process that generates electricity. Fuel cell vehicles are generally powered by pure hydrogen which comes in the form of compressed hydrogen gas, metal hydrides stored in cylinders or as liquid hydrogen, though any hydrogen-containing feedstock(such as petrol and diesel oil) could be used(Dff, 2000). Proton exchange membrane fuel cells(PEMFC) are being developed for both transport and stationary applica tions(such as power for warehouses). PEMFCs are not new; they were invented in the 1950s by General Motors and were used by NASA in the Gemini space project. The PEMFC works by harnessing the chemical energy that results from the reaction of hydrogen and oxygen and