The problem with using hydrogen as a fuel is not in finding an engine that will run on it. A conventional internal combustion engine will do that almost as well as a fuel cell. The difficulties are in carrying the fuel, and making it in the first place.
Hydrogen is a gas. The only way to carry a useful quantity of gas around is to liquefy it, as in the familiar butane and propane "bottles", in which the gas is liquefied under pressure. But hydrogen cannot be liquefied under pressure. That can only be done by cooling it to the sort of low temperatures normally found only in specialist laboratories. To carry a reasonable quantity under pressure only would require a huge, very heavy, vessel that required regular inspection, certification, and insurance against explosion.
And hydrogen is not a natural resource waiting to be tapped: it has to be made using electrical energy, and more than will be got out of it when it is used as a fuel. That electricity has to be generated, and the power station will produce pollution.
Powerful interests would like us to believe that a near-miraculous technological breakthrough will turn up to solve environmental problems. We need to be wary of these siren voices.
Market Rasen, Lincolnshire