Cryogenic hydrogen SCG Boot off

Trying to race 1,200 miles (1,931 km) of notoriously harsh, prickly desert is difficult in itself. Developing a first-of-its-kind zero-emissions fuel cell off-roader to complete the task is more difficult still. Skipping common compressed-gas hydrogen in favor of cryogenic liquid hydrogen so bleeding edge you can't even source it for testing, let alone pump it into your 4x4 ... well, that's just lunacy. But if your resume already includes an entry titled "Frankenhooker," your screws are probably loose enough to give it a go. Or that's the case at Scuderia Cameron Glickenhaus (SCG), anyway. The company's plans now call for its hydrogen-powered Boot Baja racer to run on liquefied hydrogen, which stores at -423 ºF (-253 ºC) and ignites with the tiniest of sparks.

Last time we looked in on it, SCG's fuel cell Boot was a fairly nondescript crew cab pickup truck with its rear seats swapped for hydrogen equipment. Half a year later, it's an absolute beast of a thing with a front-mounted spare tire, exo-cage, headlamps pulled back nearly to the windshield and a bed filled up with a rendered-in hydrogen tank.

We emphasize "rendered" not merely because we're looking at early renderings instead of photos, but because Glickenhaus hasn't yet figured out how exactly it's going to carry the liquefied hydrogen on board. So it's basically just coloring in a cool-looking metal tank protected by a gnarly bed cage.

"There are no FIA regulations for off-road hydrogen safety, no NHTSA regulations for road vehicle safety, only four or so labs that can even test at cryogenic hydrogen temperatures in the entire United States, no existing onboard tanks that meet our needs, no refueling infrastructure," SCG admitted bluntly in a creative Q&A-style announcement this week. "Hell, we have not yet been able to source cryogenic hydrogen for testing."

So why on earth is the company pursuing cryogenic hydrogen to power a vehicle that's going to smash its way through open desert? From what we can glean from the announcement, SCG sees its role as being a small, race- and high-end road focused shop that pushes boundaries and comes up with new ideas that mainstream auto won't touch – in this case developing the knowledge and means for using cryogenic hydrogen as a viable automotive fuel.

"Glickenhaus Zero builds the future of transportation, so we don't make existing things," the company emphasizes.

The advantage in using liquid hydrogen lies in its superior energy density, at least by weight. Liquid hydrogen has a density of 120 Megajoules per kilogram, whereas gasoline packs just over a third of that at 44 MJ/kg. Way down the scale, lithium-ion batteries have a fractional energy density under 1 MJ/kg.

But as we've all known since school age, hydrogen is the lightest of all elements. Liquid hydrogen is, of course, denser than gaseous hydrogen, but it still takes a large volume of liquid hydrogen to get to that kilogram, so its energy by volume drops off significantly. The Hydrogen Storage and Fuel Cells Technologies Office in the US Department of Energy points out that liquid hydrogen has a quarter of gasoline's energy per liter at 8 MJ/L compared to 32 MJ/L for gasoline. That's why liquid hydrogen tends to be stored in huge stationary tanks and transported on tanker trucks ... not two-door Baja pre-runners.

And storage space is just one among a list of major obstacles facing this project, a list that also includes flammability, energy losses during liquefaction and boil-off during storage. Such obstacles have so far stood in the way of liquid hydrogen becoming the hydrogen fuel of choice for small race cars or street-legal light vehicles, though past efforts have been made. SCG will also need to develop its own refueling infrastructure in order to refill the cryo tank during the Baja race.

Long story short, it sounds like SCG has a world of work ahead of it, especially since it previously indicated it wants to run the hydrogen Boot at the 2022 Baja 1000. It has teamed up with what sounds to be the perfect boundary-pushing engineering partner in Australian-American firm First Mode, which brings experience in working on massive (quite literally) hydrogen challenges.

"Today if you consider a hydrogen vehicle, it runs on gaseous hydrogen. The industry kind of just adopted that," Tomás Lafferriere, First Mode's SCG Boot project manager, said after SCG ran the V8-powered Boot in last year's Baja 1000. "There's not a great engineering reason for that. Liquid hydrogen provides quite a bit more energy but running it at any racetrack has never been done before. This is brutally cutting-edge."

Brutally cutting edge, indeed. But what's the point of having an experimental global adventure 4x4 like the Boot if you can't shear off some edges with it?

Source: SCG