"Steve Firth" wrote in message
...

The trouble with hydrogen is that it is manufactured from hydrocarbons,
not by electrolysis of water. Thus using hydrogen as a fuel actually
increases CO2 emissions compared to burning those hydrocarbons in the
engine.

There is another route, used to produce hydrogen for barrage balloons during
WW2. This involves having a heated bed of Iron over which steam is passed,
and the steam is reduced to hydrogen by the iron. Of course, energy is
needed to preheat the iron and to produce the steam. Not to mention to
reduce the iron ore to iron in the first place.
--
Terry Harper
http://www.terry.harper.btinternet.co.uk/