Elon Musk is many things, but reserved is not among them. Even by his standards, though, his vocal and colorful criticism of hydrogen fuel cells stands out. He’s not alone either; major automakers like Ford and GM have also voiced criticism, albeit more calmly, of fuel-cell tech.
On the face of it, they seem to have a point. Hydrogen is difficult to produce, hard to store, and, with current extraction processes, not all that efficient. Meanwhile, electric cars are improving every day and appear to be serious competitors to internal combustion.
Actual production of fuel cell vehicles is less energy intensive than that of EVs.
So if all that were the case, companies would have to be crazy to pursue hydrogen fuel cells. But major automakers like Toyota and Honda have devoted tons of time and treasure to fuel cell-powered vehicles. If the rep at Honda with whom we spoke is to be believed, they’re not crazy; fuel cell detractors are just looking at the technology in the wrong way.
Not ones to take Musk’s word as gospel, we decide for this week’s Road Rave to explore the potential of hydrogen technology, as well as its future for ourselves.
What the heck is a hydrogen fuel cell?
For all of the attention that gets paid to hydrogen, the technology is actually not well understood. As it turns out, that is a problem because that misunderstanding gives people the wrong idea about the technology’s purpose and benefits. So, with that in mind, let’s look at how it works.
In a lot of important ways, hydrogen fuel-cell vehicles (FCV) work just like electric vehicles (EVs). The wheels on Honda’s Clarity and Toyota’s Mirai FCV are both turned entirely by electric motors. Further bridging the gap between EVs, FCVs even feature battery packs and regenerative braking. The differences between the two breeds start in the battery pack itself, which is on par with those found in gasoline hybrids rather than the massive chassis-breakers found in EVs.
That size difference is down to the fact that, while hydrogen cars are driven by electric motors, that electricity is generated by the onboard fuel cell rather than fed in from an electric grid-connected wall outlet. On the face of it, fuel cells seem like black magic; hydrogen and oxygen go in and electricity and water come out. As it turns out, the process of turning hydrogen into electricity is a deceptively simple one that involves no warlocks at all — at least according to Honda.
Though there are many kinds of hydrogen fuel cell, automotive fuel cells are almost exclusively the Proton Exchange Membrane (PEM) type. These PEM fuel cells consist of a stack of extremely thin membranes. Each membrane has flow channels on either sides, one for hydrogen and the other for air.
The membrane uses a catalyst — typically platinum — to strip protons from the hydrogen, which then pass through the membrane creating electric current. The protons then bind with oxygen in the air to form a fuel cell’s only exhaust: water vapor.
The more of these membranes there are, the more electricity is produced. The beauty of this design is that it is almost infinitely scalable and requires no moving parts.
Fuel cells themselves are brilliant. However, they come with more baggage than a crazy sex partner. The big problem is hydrogen.
Honda’s next-gen fuel-cell vehicle will offer a fuel cell that is not only a third smaller but also 60 percent more powerful.
Yes, it is the most common element in the universe. It, however, is almost never found in its pure state. This means that any hydrogen that goes into cars must first be refined from a natural source before it is pumped into the onboard tank.
The most common method is steam reformation of natural gas, a process by which extremely high temperature steam is added to natural gas in the presence of a metal catalyst. The subsequent reaction breaks natural gas into hydrogen and carbon monoxide.
This method is already a big business, but it has problems. For starters, it requires natural gas, which slightly defeats the purpose of moving away from fossil fuel-powered vehicles. Further, it isn’t actually that efficient. While Honda’s representatives told me that it beats out internal combustion in terms of efficiency, other sources estimate more conservative efficiency figures.
The main alternative production method is hydrolysis of seawater. There is a plethora of different ways to do this and, while each is fascinating in its own right, I don’t have the 10,000 words needed to describe them in detail. Suffice it to say that current methods require either high temperatures or high pressures to operate and thus a great deal of energy.
These factors make the criticism of hydrogen seem reasonable, even unapproachable. After all, why spend all that energy and money on hydrogen when you could just generate electricity directly, which could be used to power an EV?
Barking up the wrong tree
According to Steve Ellis, the head of fuel cell vehicle marketing for Honda, the criticisms of hydrogen are missing the point. Hydrogen isn’t an alternative to battery powered EVs, it is a complement.
As it stands, battery-powered vehicles are still subject to the vicious cycle of energy density. The more range required, the bigger the batteries need to be, which in turn increases the weight, further increasing the battery demand. The only company to even partially address this has been Tesla. And it has done it at the cost of, well, cost.
Honda itself has developed a solar-powered home station that is capable of generating hydrogen for use in cars.
Hydrogen cars already in production, like the Honda Clarity or the Toyota Mirai already offer range competitive with gas-powered vehicles, as well as similar refueling times. The latter comes as a result of industry standard fuel pressures and the increasing use of carbon fiber composite hydrogen tanks, which are at least as safe as the tanks on gasoline- and diesel-powered vehicles.
There is another hidden advantage to hydrogen technology. While the production of hydrogen creates its own pollution footprint, the actual production of fuel cell vehicles is less energy intensive than that of EVs, thanks to the reduced need for battery capacity. As we have explored in the past, EVs have large hidden energy costs in production — especially the toxic and costly nature of lithium refining and battery production. Toyota’s Mirai is able to use cheaper, less environmentally problematic nickel hydride batteries.
These factors may not make hydrogen vehicles a replacement for EVs in a city setting, especially where small vehicles are concerned. However, hydrogen is a far more viable for larger, long-distance vehicles akin to gas vehicles. Hydrogen vehicles also have simple architecture, which can be easily shared with other types of powertrains. In theory, this should make it easy for automakers to offer hydrogen power in models alongside traditional hybrid drive, or even pure battery EVs.
Speaking of batteries, advances in battery and electric drive technology won’t so much leave hydrogen in the dust as bring it along for the ride. Because hydrogen vehicles use electric motors and small battery packs, they benefit from any advances made in those technologies, too. In fact, Ellis acknowledged that plug-in hybrid hydrogen cars could happen in the future.
The technology for fuel cells is also improving at a more rapid pace than battery tech. According Ellis, the next-generation Honda fuel-cell vehicle will offer a fuel cell that is not only a third smaller but also 60 percent more powerful. This will translate to better efficiency and range.
These developments are happening in parallel with new hydrogen refining techniques. Honda itself has developed a solar-powered home station that is capable of generating hydrogen for use in cars. There are also interesting developments in using algae to break water into hydrogen and oxygen that could be commercially viable in the next five to ten years.
In some respects, hydrogen fuel-cell advocates have done themselves and the technology a disservice by claiming that it is a silver bullet that will provide the world with pollution-free transportation. The stance taken by Honda and other companies currently trying to make money from fuel cells is far more sensible, in that it acknowledges the technology’s limitations as well as its potential.
Hydrogen may not be a substitute for EVs, but, by the same token, EV advocates would do well to acknowledge that the technology they champion isn’t a silver bullet either. There may well be room for, as Steve Ellis says, “everyone to get along.”
Whatever we may think now, the next decade will do a lot to determine which technology will succeed and in what ways.
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