Leno was interviewed by James May (Top Gear) in a segment about the Honda Clarity FCX. They concluded that hydrogen car will replace the gasoline for general use and that gasoline vehicles will be used only for recreational purposes; just as the automobile and truck replaced horses, carriages, and wagons for general use - horses now being used more for sport than as beasts of burden.
I believe he also said it was quite hypocritical how many Celebs talk about saving the Earth and then jump into their private jets.
“They concluded that hydrogen car will replace the gasoline for general use...”
Again, more fantasy until somebody comes up with a useful source of hydrogen. Right now, if you want levels of H2 sufficient to dent our transportation needs, you’ll get it from . . . petroleum. There’s a brilliant thought - convert oil to CO2 and H2, and burn the H2, instead of just burning the damn gasoline.
Hydrogen will become a major player, and solar will matter for things like transportation, when we learn to use the energy of sunlight to cleave water to hydrogen and oxygen (which could then be recombined to give water and electricity).
Photochemical (solar) cleavage of water is hypothetically possible, but it’s hellishly difficult to make the process practical. There are numerous researchers working on that technical problem - that’s where we need to put some serious funding.
Hydrogen as a fuel is a farce. Hydrogen is more akin to the acid in a battery than gasoline in a tank, that is, it is an energy storage medium, not an organic or refined fuel.
Hydrogen exists in nature almost exclusively as part of chemical compounds (hydrocarbons and water). In the case of water, you have to separate the Hydrogen atoms from the Oxygen atoms, only to then combine them into water again through combustion. Thermodynamics says this will never net an increase in energy, in other words, with perfect efficiency, you would only get out of the Hydrogen "fuel" the energy you used to make the "fuel".
Like charging a battery.