How do hydrogen cars work?
I twist the grip and the fuel cell whooshes like a Hoover somewhere beneath me. The car glides along the path through the grassy suburban park, a gleaming silver vision of the future. I peer past my feet through a window where a normal car’s grille would be, watch the smooth blacktop pass under us. The car is a greenhouse on wheels, a sleek assmeblage of curved panes suspended in a sleek, mercurial frame. The windshield is huge, stretching up and over our heads, reaching down to the tips of my toes. The nearly unobstructed view ahead makes us feel like we’re hovering above the tarmac.
This is the 2002 General Motors Hy-Wire concept vehicle, a hydrogen fuel cell car built to represent the future of GM—and automobiles in general. I got to drive the thing way back in 2002 during a press event at a park in midtown Sacramento, California. The Hy-Wire represented decades and millions of dollars of research and development by engineers in Europe and the US. The car was incredibly cool and daring, a blank-slate design based on everything the automotive giant had learned during 80 years of making cars. It was based on a “skateboard” chassis, which looks exactly like it sounds. Imagine a big flat skateboard with four wheels. All the drive components, including the motor, hydrogen cell, battery, and suspension, are housed within the skateboard’s “deck.” The car’s body sits on top of the skateboard.
GM envisioned dropping virtually any kind of vehicle design on top of that skateboard: sedans, sport coupes, trucks, minivans, whatever. The modular design was reminiscent of the old mid-century body-on-frame designs.
Back in the ‘50s, ‘60s, and ‘70s car manufacturers built their cars on ladder frames. The frames held the engine, transmission, suspension, brakes, fuel lines, pretty much everything mechanical. The body was dropped onto the frame, which meant that they could put different cars on the same frame. It saved a lot of time and money, and let manufacturers offer a wide variety of vehicles.
Today cars are built on unibody chassis, which means the frame is integrated with the body. Sometimes they bolt structural subframes to the unibody, but for the most part the car is kind of like one big hunk of metal. That makes them stronger and lighter than body-on-frame cars.
Manufacturers can still build multiple models based on the same unibody platform, but the process is much more sophisticated.
Unlike body-on-frame or modern unibody cars, the Hy-Wire is hot swappable. That means owners could swap their car’s four-door body for a minivan body if they needed to. Just undo a handful of bolts, lift the four-door body off the skateboard, and plop the new minivan body down onto it. This would let people upgrade or change their vehicles at a much lower cost than they can now. Hell, you could even switch bodies with your neighbor. If you’re into that sort of thing.
This hot-swapping setup made the interior of Hy-Wire pretty weird. The floor is completely flat from front to back, and is pretty tall compared to other cars. But the weirdest thing about the Hi-Wire is its steering wheel. Or control module. Or yoke? It’s shaped like an airplane steering wheel with two vertical grips on either side of a rectangular screen. And that’s it. No pedals. To accelerate you twist the grip, like a motorcycle. To stop you squeeze it. It’s bizarre at first, but I quickly get used to it and the car responds to the smallest of movements. After a few minutes it becomes just as intuitive as a gas pedal and brake, only more precise. The engineers told me that people have a much faster reaction time with their hands, so it would actually be safer than a brake pedal. That’s assuming the driver doesn’t have arthritis, of course. I’m only allowed to drive the car at 20 miles per hour, but it’s enough to get a feel for it. It feels… like a video game. I know a lot of reviewers say that about modern computer-controlled cars, but this really did. Remember, zero physical connection between driver controls and car. Even if your 2018 MINI Cooper has electric steering, there’s still a physical steering shaft between the steering wheel and the front wheels. With the Hy-Wire, there isn’t.
When you turn the wheel, electrical signals zip down some wires and tell the motors attached to the steering system to turn. It is completely and totally like driving a full-sized remote-control car. And from what I can remember—17 years, half a dozen jobs, five different homes, and a child later—it was pretty great. I’ve owned many cars over the years, and I’ve driven plenty of go-karts. Though I’ve never raced and I wouldn’t say I’m a hyper sensitive person when it comes to cars. So it didn’t really bother me that I couldn’t feel the road through the Hy-Wire’s wheel. I could still feel the road in the seat of my pants and that was enough to orient myself in space. Now on a race track the lack of direct feedback might be a problem. With a race car or go-kart, there’s a high-fidelity analog connection between your hands and the steering wheel, which is directly connected to the road through the steering column, suspension, and finally the tires. In a go-kart you can really feel it. You can feel the tiny bumps in the track, and when the tires start to lose traction. A tremendous amount of information is relayed through the steering wheel. With a totally digital interface much of that info would be missing. It would feel like one of those Logitech driving simulator steering wheels, which is cool, but not like the real thing.
Everyday drivers wouldn’t notice, or care. The Hy-Wire’s controls were quick and ultra responsive, maybe even easier than old analog controls. I guess I’m saying the GM engineers really fricking nailed it, even without any AI or complex computing. Remember, this was 2002. We’re talking Pentium 4, pre-iPhone era. Today there’s enough computing power in your iPhone to faithfully simulate steering feel, no problem.
And because the controls are totally digital, you can do some really cool things with them. Like move the entire steering wheel from driver to passenger with the push of a button. They demoed this for us. They stopped the car, moved the steering wheel over to the passenger side, and we zoomed off. Can you imagine being on a long road trip and switching drivers without switching seats? Also GM wouldn’t have to make two different versions of their cars for right-hand and left-hand-drive markets.
The Hy-Wire was powered by a hydrogen fuel cell and an electric motor. Hydrogen fuel cells work by oxidizing hydrogen to make good old H20. The chemical reaction produces an electrical current and heat. Feed a fuel cell a steady stream of hydrogen and it’ll produce an electrical current, heat, and water vapor. The first fuel cells were developed way back in the ‘30s by Sir William Grove and Francis Thomas Bacon. NASA has used them for years in the space program, and commercial fuel cells have been used to power buildings in remote locations for decades. They sound like miracle technology, a black box that eats plain old hydrogen and spits out electric pixies while producing nothing but water vapor as a byproduct. And they are, kinda. But until recently fuel cells were crazy expensive. The cells in the Hy-Wire used a lot of platinum and other precious metals and they wore out over time, requiring expensive rebuilds.
Today hydrogen fuel cells are still made with platinum, but also advanced polymers, carbon fiber, and even carbon nanotubes. Toyota says the Mirai’s cells use an all-new micro mesh that makes them the most efficient fuel cells ever. The car company has also developed a fuel cell recycling system—when the fuel cell in your Mirai wears out, you can turn it in for a new one. Toyota will take the old one apart, scrape all the precious metals out of it and use them to build a new one. The company has really though this whole hydrogen fuel cell thing through, and while the gigantic company moves slowly, its ideas tend to stick around.
So why did Tesla’s Elon Musk famously call hydrogen fuel cells the stupidest idea ever? Because he sells battery-powered electric cars, of course. But no, the main reason is that hydrogen is extremely difficult to store. It’s the smallest, least dense element. To give you an idea of how hard it is to store pure hydrogen: The stuff will permeate glass. That’s right, hydrogen atoms are so small that they’ll go right through glass if you give them enough time. Any hydrogen tank will leak a little bit, and over time will empty itself out. The engineers at GM told me back in 2002 that they worked with an acceptable amount of hydrogen leakage. Just a tiny, tiny slow trickle of the stuff, and they made sure it was vented away from the vehicle and didn’t collect anywhere. I’m not sure if the Miria’s fuel tanks leak, they may be so precise that only a few atoms of it gets out. They’re made of an all-new blend of carbon fiber and plastic that Toyota says can easily hold up to 10,000 psi of hydrogen. That’s a lot of pressure, and the new Mirai coming out in 2021 is supposed to hold even more—though Toyota isn’t saying how much.
So it seems like Toyota, the world’s largest automaker, has this whole hydrogen fuel thing figured out. Except the stations. Yeah, that’s kinda important. There are only a handful of places you can fill up a Mirai, mostly in California and Hawaii. And that’s only because those states funded development of hydrogen fuel stations. Right now there really isn’t much demand for them, so big companies like Shell or Chevron aren’t keen on retrofitting their gas stations to sell hydrogen. If the Mirai takes off and people start demanding hydrogen fuel cell vehicles, they might. Or if trucking companies start thinking about switching to hydrogen. It makes a lot of sense for long-range zero-emissions vehicles. It’s faster to fill up a hydrogen tank than it is to charge a huge battery pack—at least for now. And it would be possible to retrofit regular gas stations with hydrogen tanks.
No, the biggest problem with hydrogen is getting the stuff. Sure, you can split it out of water, but that takes a lot of energy and there are no large-scale hydrogen facilities. About 95 percent of the hydrogen we have now comes from fossil fuels, either oil or natural gas. In fact, refineries have been making hydrogen out of oil and natural gas for ages and they’re really really good at it. Breaking hydrogen out of water molecules is relatively new in comparison and hasn’t been done on a giant industrial scale. But it could be. Here’s how it would work, on a very, very basic level: Use energy generated from solar, wind, geothermal, or any other carbon-neutral source to split water molecules into hydrogen and oxygen. Then you can use that hydrogen in a fuel cell to pop down to the grocery story for a box of Captain Crunch. That process, however, is really inefficient because it has so many steps. First, energy is lost turning sunlight into the electricity you need to split water into hydrogen. Then some energy is lost in actually compressing the hydrogen into tanks. Then you lose some more energy in the fuel cell itself, which isn’t 100 percent efficient. Finally, you lose some power in the electric motor. The more steps you add between the sunlight (or power source) and the motion, the less efficient the process is. This is a big reason Elon doesn’t like hydrogen fuel cells.
Battery-powered electric vehicles remove two steps from that process. Sunlight can be used to generate electricity to charge batteries that move cars down the road. It’s a slightly simpler process, and theoretically more efficient. Battery-powered electric cars are also easier to make—there aren’t any super-high-pressure tanks or tubes to deal with and batteries don’t wear out as quickly as hydrogen fuel cells.
So is there a place for hydrogen in transportation? Probably. Toyota has put billions of dollars of research into it and doesn’t appear to be giving up anytime soon. And remember, Toyota is the largest car company on the planet. VW, the second-largest, is also exploring hydrogen fuel cell technology, though its latest electric vehicles are battery powered.
And General Motors didn’t just throw away all the tech that went into the awesome Hy-Wire. The company has continued to develop fuel cells and even worked with the US Army to develop a fuel cell pickup for the troops. The company also plans to build and sell some fuel cell vehicles to the public in the early 2020s. The Hy-Wire’s skateboard chassis concept is currently being used in a few heavy truck and construction equipment projects. And the famous Rivian electric pickup uses a similar skateboard chassis design. So it looks like the Hy-Wire was just way ahead of its time.
I would love a Hy-Wire. Of course the concept vehicle probably wouldn’t pass any crash tests, and it’s probably insanely noisey with all that glass, but still. I want one. It was just such a great thing to drive. Even today I find myself wishing I had hand controls for my regular car, and a steering wheel that I could pass over to the passenger.
To me the Hy-Wire was one of the last American out-of-this-world concept cars, a bold vision of the future that would be right at home in the ‘50s and ‘60s World Fairs, an almost completely new reinterpretation of the automobile. Man, it was so cool.
In the last episode I said that cars probably won’t be sustainable in the long run. They’re just super inefficient. Unless we unlock the secrets of fusion power, I don’t think there will be enough energy to give everyone their own personal vehicle. But maybe autonomous cars will be a thing, or shared cars. Hey, my car sits in the driveway most of its life. Somebody else could be driving it—just as long as they don’t spill any soda in it. Or get it dirty. Or drive it too hard. Or crash it. But seriously, car sharing will probably become a reality in the future. Personal car ownership will also still be around, but it might not make a lot of sense for most people. Hell, everyone may be zipping around on hoverboards or riding winged cyber horses. Or shambling along a dusty, dead, heat-blasted wasteland. We’ll see.
That’s it for this one. I wanted to keep it nice and short. In the future I’d like to explore some awesome public transportation tech—like bullet trains. In America we’re all about cars because this country is huge and there are millions of miles of roads. In other countries they have the cool things called trains that run on metal tracks or even hover above the ground on a cushion of magnetic repulsion. Seriously, if you don’t think public transportation is cool, take a ride on a Japan’s 200-mile-per-hour Shinkansen bullet train.
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And hey! I’ve been thinking about steering this podcast directly into climate change and sustainability. We’re facing some really tough challenges and we’re gonna have to science the crap out of stuff to survive. I’d switch focus to surviving climate change and thwarting environmental disaster. I think I’d re-name it something like “Don’t Die, Humanity!” or “Hey, Let’s Talk About Maybe NOT Ruining the Environment!” Or maybe, “Check Out The Awesome Cool Science Stuff We’re Doing to Make the Earth Cleaner and More Sustainable.” Or something like that. Let me know what you think. Find me on Twitter dustin_driver and let me know what you think. About the show. Not about my face.