[manche]

That's true, but batteries are for storing energy. Separating water into Hydrogen & Oxygen is for producing energy. You'd need to have a battery on board to do it and you might as well use it to run the electric motor since it'd be more efficient.

[rdl]

Actually, people have been talking about the "hydrogen economy" for a long time, and whenever it's about electrolysis of water, it's about hydrogen as a way to transport and store energy.

You put electrolysis near a "stranded" source of energy (a hydro dam in BFE where costs/losses to run electrical lines to users is high), produce hydrogen, then ship it out. One of the more interesting (kooky or technologically interesting, your choice) is "Ocean Thermal Energy Conversion" (OTEC), where differentials in water temperature at different depths are exploited to generate electricity, which then is used to make hydrogen, which is then exported from a platform in the open ocean to users elsewhere.

I think there are a lot better ways to get hydrogen than electrolysis (right now, steam or kvaerner processes, and eventually, a biological or biocatalyzed process), and I'd prefer current liquid fuels to hydrogen, but it's not utter kookiness.

http://en.wikipedia.org/wiki/Hydrogen_economy

I find it inspiring if someone in a position of power in the economy like Tata is actually talking about things like that, although cynically I guess it's probably just feel-good posturing.

I'd like a world in 2050+ with 50-100x more energy production, and all of that from nuclear, hydro, solar, wind, etc., with a mix of electrical consumption and synthetic fuels for transportation.

[randallsquared]

I wouldn't expect anyone thinks it's a good idea to do the separation in the car. You'd do it at a plant somewhere to take advantage of economies of scale.

[mgedmin]

In which case why call them cars that run on water?