The fuel cell is widely regarded as a key technology for tomorrow's energy supply infrastructures. By using this technology in vehicles and in decentralized combined heat and power plants, it is hoped that over the long term it will be possible to achieve significant reductions in fossil fuel consumption and the associated pollutant emissions. The major efforts being undertaken by science and industry throughout the world to develop and commercialize fuel cell systems leave little doubt that a serious market breakthrough can be expected in the relatively near future. But there is still a need for suitable instruments capable of stimulating more rapid and efficient development.