“Hydrogen is an energy storage mechanism. It is not a source of energy. So you have to get that hydrogen from somewhere. if you get that hydrogen from water, so you’re splitting H20, electrolysis is extremely inefficient as an energy process…. if you say took a solar panel and use the energy from that to just charge a battery pack directly, compared to try to split water, take the hydrogen, dump the oxygen, compress the hydrogen to an extremely high pressure (or liquefy it) and then put it in a car and run a fuel-cell, it is about half the efficiency, it’s terrible. Why would you do that? It makes no sense.”
In fact, Musk was being generous. In a 2006 Scientific American article I wrote with advanced-hybrid guru Andy Frank, we explain that “The entire process of electrolysis, transportation, pumping and fuel-cell conversion would leave only about 20 to 25 percent of the original zero-carbon electricity to drive the motor.” But in an EV or plug-in hybrid, “the process of electricity transmission, charging an onboard battery and discharging the battery would leave 75 to 80 percent of the original electricity to drive the motor.” So the hydrogen car is more like one third as efficient as the EV.
Put in more basic terms, the plug-in or EV “should be able to travel three to four times farther on a kilowatt-hour of renewable electricity than a hydrogen fuel-cell vehicle could”!
http://thinkprogress.org/climate/2015/0 ... ign=tptop3