Elon Musk has never been a proponent of the universe's most abundant element, hydrogen. Well, at least in the context of a fuel source for an electric car. This is not a new stance for him, but it is one he reiterated last month at a press conference. So, why, exactly, is he such an H-phobe, and is he right?
There's been a good number of arguments for and against Musk's position. Let's try to get to the basic thrust of both sides so we can make sense of it. But before we do that, let's just quickly go over exactly how hydrogen is used in electric cars.
To run an electric car, you need a source of, duh, electricity. A conventional battery-powered electric car uses storage batteries that are capable of storing electricity provided by some outside source. The battery is charged by the outside source, and stores that energy with, generally, pretty minimal loss. The source of electricity can be absolutely anything: coal, solar, nuclear, dogs on treadmills, etc. Modern batteries have gotten pretty good, but they're still heavy, bulky, and take a long time to charge.
A fuel cell (again, I'm simplifying wildly) takes a source of hydrogen, oxygen from the air, and chemically combines the two to produce a flow of electrons (electricity) and water. Fuel cells were used on the Apollo spacecraft, since they were a great way to get both electricity and have a source of drinking water, eliminating the need to haul heavy water into space.
Now, hydrogen is the most abundant element in the universe, but most of it is out there, in interstellar space or inside some unpleasantly hot stars. On earth, it's trickier to get, and a fair amount of effort is needed to extract it from other sources, like methane or natural gas or other hydrocarbons. And that process takes energy. Hydrogen is also extremely flammable and tricky to transport and store, so all of that takes energy, materials, and effort as well.
And all of those caveats are at the heart of why Elon Musk thinks hydrogen is "bullshit" as a car fuel — he's looking at everything from an overall, systems-level viewpoint, and evaluating all the extra steps involved from the initial conversion of motion or nuclear reactions or combustion into electricity to storing and using it in a car. From a purely scientific standpoint, he's absolutely right — just storing the electricity in a battery is way, way more efficient.
All of the production and preparation of hydrogen — and then the transport and storage — is using energy that could otherwise be used to charge batteries that could just be driving the cars. Here's Musk explaining it himself:
"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."
That's pretty hard to argue with. And, really, you can't argue with that, because it's just cold, unfeeling science. But you hydrogenheads may be able to argue on some other, more real-world aspects.
The biggest issue is recharge time. Even if we accept that, all told, a fuel cell is about half as efficient as battery storage, that still doesn't change that even with Tesla's best Supercharger recharging stations, you're still looking at an hour recharge time. And that's best case.
If you're not near a supercharger, or are driving an electric car not compatible with a Supercharger, you're realistically looking at an overnight charge. It's slow, and that's a real issue, based on how most of us live and drive.
Hydrogen fuel cells, though, offer recharging/refueling times not too different from what we're used to with gasoline cars. That's a big deal, and it's easy to not give a shit that your electricity storage system is half as efficient as batteries when you can just refill your hydrogen tank in five or so minutes.
Both systems are bulky and heavy. Batteries are bulky and heavy, reinforced kevlar-weave hydrogen tanks are bulky and heavy. Let's call that one a draw. Sure, hydrogen is flammable and potentially explosive, but it's not like no Tesla has ever caught on fire (or that there's no safety risks with Li-ion batteries) and there's a risk of electrocution if you're not careful or extremely unlucky.
Things, of course, could change. Tesla could actually open those battery-swapping stations they've been teasing us with forever, or maybe a new, much energy-cheaper way of extracting or acquiring hydrogen will be found. That could also make hydrogen ICE engines more viable, too, for those of us that like being pulled along by lots of combustion events.
As it stands now, here's what I think is the rational way to view this debate: Elon Musk is technically correct. Some say that's the best kind of correct. Battery storage is a way, way more efficient use of energy, full-stop, no question.
But the problem is so much of the real world is a sloppy mess that, for the vast majority of drivers, the ability to rapidly recharge outweighs efficiency advantages most drivers can't even perceive. Is this better technology, or better for the environment? Nope. Will most people give a shit when you ask them to pick between a five minute recharge and a five hour recharge? Nope.
Both infrastructures, hydrogen and battery, are in their infancy. Battery swap stations could start popping up everywhere and become quick and easy (one attempt has already tried and failed). A hydrogen network could piggyback on our vast network of gas stations and become ubiquitous and easy. It's too early to tell.
So, when you hear Musk lambast hydrogen as being an idiot's fuel, just keep in mind that while that's true in the beautiful, clean world of science where Elon floats, arranging molecules with his bare hands, it's not the same as the shithole we're actually all going to be driving in.