As CleanTechnica’s readers are probably well aware, Toyota treats hydrogen the same way my cats treat their catnip. It’s an obsession, and maybe an addiction. On the other hand, the Japanese government seems to be favoring the use of hydrogen vehicles, and that’s playing a factor. What I didn’t expect was to see that Toyota is spending money to develop hydrogen combustion engines, which burn it instead of using a fuel cell. Let’s talk about Toyota’s racing/development program, why the company is doing this, and then look at the advantages and disadvantages of the technology.
A week or so ago, Toyota announced that it is developing a hydrogen combustion engine as part of its efforts to achieve a “carbon neutral mobility society,” and that a race car using the engine would start racing in May. Toyota says it feels the engine is under-developed, but that running it through the strain of racing would help the company improve it.
The basic idea behind a hydrogen combustion engine is pretty simple. You basically have a regular gas combustion engine and put hydrogen into it instead of gasoline vapor. To make it work as well as possible, a bunch of small changes need to be made, of course, but the combustion concept doesn’t change at all. Intake, compression, ignition, and exhaust (suck, squeeze, bang, blow) is how this works, just like most others.
Toyota put together a little animation showing all this:
Like the animation, it will be an inline 3-cylinder piston engine with a turbocharger, displacing 1.6 liters.
For people who love combustion engines, the experience is pretty much the same as driving any other combustion car (and, environmentally speaking, this could be an advantage as I’ll explain further below). The sound, vibration, feel, and every other aspect of actually driving a hydrogen-burner are all there.
A video floating around the internet (h/t to Jalopnik) shows what appears to be Toyota’s car in action:
“It’s not as different (from normal gasoline-powered vehicles) as I had expected.” said driver Hiroaki Ishiura. “It feels like a normal engine. (If I’m not told anything) I’d probably think that this is one normal engine.”
Why Is Toyota Doing This?
As I’ll explain in a bit, there are some serious drawbacks to hydrogen combustion, but Toyota does have some reasoning (even if somewhat flawed) behind the decision. In short, the company wants to take multiple approaches to cleaner vehicles. This has worked out much better in Japan than anywhere else because the government is pushing hydrogen, especially when it comes to infrastructure. Europe is pretty good, too. Hydrogen is flopping a lot harder in the US because the infrastructure is terrible.
Here’s a video of a Toyota rep explaining their thinking (both the good and the bad, too):
Advantages To Hydrogen Combustion Engines
Rather than just go straight to poo-pooing the idea like we’d usually do with hydrogen, I’m going to be fair and discuss the advantages, which do exist. I’m not saying they’re a good strategy for all, most, or even any significant number of vehicles to use (as I’ll explain in a bit), but for niche applications, they can do some good in the world that it wouldn’t be fair to ignore.
The big thing is that the emissions are cleaner than gasoline or diesel cars. Put in hydrogen and oxygen, and get water out of the reaction, in theory. In practice, it’s not perfect because atmospheric air also has a lot of nitrogen. The engine runs hot enough to burn some of that, too, which produces a small amount of nitrogen oxides, but they’re still a lot less than in other combustion vehicles.
Another advantage is that it can run on multiple fuels without adding much complexity. There are engines that run on both gasoline and hydrogen, and even a mix of the two in some cases. When hydrogen infrastructure sucks big like it does in the US (or doesn’t exist at all, which is the case anywhere but California), being able to burn another fuel during shortages or when out of range of a hydrogen station is a pretty big plus that you just can’t get with fuel cells.
For cars with an engine that only burns hydrogen, you don’t need expensive equipment like catalytic converters, which attract theft in some areas. You do need to build the exhaust in such a way that it doesn’t get rusted out by the water vapor, though.
The biggest advantage to the technology is that it can be used in applications where people cannot or just refuse to switch to electric.
One big example is people who are ICE enthusiasts and just refuse to switch. People who are set in their ways, people involved in some types of racing, and people who really do need to fill up super fast and go far (emergency vehicles, some commercial drivers) are all good examples. Sure, it would be better to switch all of that to electric, but getting them to adopt hydrogen is still better than just continuing to burn gas.
In applications like aviation, it’s going to be some time before batteries have the needed energy density to work out. The batteries are just too heavy and big, and don’t have enough range for things like airliners and large cargo planes. Even when better, the power requirements to quickly charge a plane to cross oceans will be astronomical. Having them burn hydrogen instead of kerosene would be a big improvement, even if it’s not perfect.
(Big) Disadvantages Of Hydrogen Combustion
The biggest problem at present, and for the near future is where the hydrogen comes from. Ideally, we’d use electrolysis to make clean hydrogen (green hydrogen), but most of it is made using steam reformed methane, which is pretty dirty and inefficient.
Also, it shares the same efficiency problems that hydrogen fuel cell cars have. You’d be far better off, whether you fuel cell it or burn it, to just charge a battery pack. Here’s a great video explaining this:
This is still better than burning fossil fuels, but it’s expensive and wasteful.
On top of the efficiency problems of hydrogen fuel cells, hydrogen combustion engines are only half as efficient once you get the hydrogen to the car. This means that for the same hydrogen tank, expect to get half the range. Thus, for every mile of driving, the fuel cost is double what a fuel cell vehicle is. Worse, you’ll want to have a tank about twice as big to get satisfactory range.
This becomes unbearable when you consider it costs about $85 to fill up a hydrogen fuel cell car to go only about 300 miles (500 km). To get the same range, you’d only pay about $10 to charge an EV. Now, since the hydrogen combustion car burns twice as much per mile, consider that you’re going to pay about $170 to go the same 300 miles. Ouch!
Finally, they could get in the way of doing better things if adopted too widely. If, say, a developing country adopts the technology because it’s cheap to build/sell, can be dual fueled with gasoline, and then they bring the hydrogen cost down to get people to buy hydrogen instead of gasoline, this would be an improvement over what happens now. However, that inertia would mean the country is going to be more resistant to changing to EVs when the cost comes down, which leaves them in a worse position in the long run.
For niche cases, where electric doesn’t work for whatever reason (physics, sport, stubbornness), hydrogen combustion is a valid option to consider. It sucks, and badly, but it’s better than the status quo and shouldn’t be dismissed outright.
For everything else, it’s not a good option. It’s wasteful, expensive, and requires infrastructure.
Featured image provided by Toyota.
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