Those interested in a direct comparison of efficiency between hydrogen fuel cell vehicles and battery electric ones will probably appreciate a pretty in-depth stab at the subject that recently came to our attention.
The comparison in question includes discussion of the wider process behind producing hydrogen fuel — the production itself, the compression/storage, the transportation of the fuel, and associated factors.
As a bit of a sidestep here — while we’re on the subject, Elon Musk recently went off on hydrogen cars (in pretty humorous fashion) when asked about them during a Q&A session in Detroit. Some of the better bits include referring to the technology as “extremely silly” and “terrible.” Lmao. Can’t say that I disagree myself, but then the technology certainly does have some proponents.
It’s a rule of thumb that every operation you do when handling energy is made with costs. This rule is true for electricity, hydrogen, and even gasoline. Since you can’t use energy right away, you have to store it and transport it. And that’s where the big trouble really is. You can’t compress or liquefy hydrogen with 100% efficiency – energy is being lost through the energy spent by the very compressors that liquefy hydrogen. It is being put in at compression/liquefaction and lost at decompression. You can experience that first-hand when you use a spray – you feel it getting cold as it decompresses, because decompression sucks heat out of the environment – that’s the trouble even with compressed air energy storage – but that’s another story.
Well, these days they carry oil with diesel-powered trucks, and the same is going to be happening to hydrogen. The theoretically clean-burning, carbon-free energy carrier (for hydrogen is not an energy source, it’s only a carrier) is going to be transported with losses from the production site to the delivery stations. Trucks are going to lose energy, pipes are going to lose energy, accidents can happen with disastrous circumstances.
Here’s a snippet of what Elon Musk has said about hydrogen cars:
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.
Tony Seba recently wrote a good article on hydrogen cars vs battery-electric cars as well. One key point he made in that was: “Electric Vehicles are at least three times more energy efficient than Hydrogen fuel cell vehicles.” He added: “But not all hydrogen vehicles are made alike. You can use compressed or liquefied hydrogen. You can also use either internal combustion engine of fuel cells to power the car. The following chart shows that whatever choice of type of hydrogen and engine results in the electric vehicle going three to six times more miles for the same energy when compared to hydrogen-powered cars.” He also included some good diagrams. Check out the article!
And then, if you haven’t read this yet, there’s this giant takedown of hydrogen cars that Julian Cox wrote for CleanTechnica: Time To Come Clean About Hydrogen Fuel Cell Vehicles.