Depresion wrote:

"Steven M. O'Neill" wrote:

Where does the hydrogen come from?

Water most of our hydrogen is pre-oxidised at present, the conventional
way to split it is to use electricity that could be developed in an
environmentally friendly way, or we could throw away hundreds of years
worth of science and use billions of years worth of evolution and algae.
Algae happens to be very good at splitting hydrogen and oxygen using
little more than water space and a bit of "free" energy from the sun. All
that remains is the collection, storage and distribution of the gasses.

AIUI algae is a lot better at making diesel than it is at making
hydrogen! Plus diesel's a lot easier to collect. I'd expect diesel
production to be more economically efficient than hydrogen production
but I don't have the figures. Do you?