Originally Posted by barit1
The thing to remember is that hydrogen is not a natural fuel like coal or oil or natural gas. You create hydrogen by using some other energy source to break down water or another hydrogen compound.
Thus hydrogen should be regarded only as an energy storage medium.
True enough, but...
- it is possible to move your hydrogen production to a ground installation where the use of hydrocarbon (or other) fuels can be made as clean as you possibly can. Then, if you (hypothetically) burn hydrogen in an aircraft, all you are producing should be water vapour - which should be harmless to the environment. This offers a huge, although still largely theoretical, benefit compared to our current habit of burning hydrocarbons in the lower stratosphere.
G