your mark. Toyota, let’s go places.

Hydrogen-powered cars are hitting the road this year, and eventually one will be in a

crash. What... would happen? Would it explode?

When you think of hydrogen you probably think of the SUN or the HINDENBURG EXPLOSION, but

hydrogen does so much more than go up in flames, especially when looked after properly.

Hydrogen is atomic number 1. The bestest element. It burns efficiently resulting only water

vapor and tiny amounts of nitrates when done at high temperatures. It's made by electrolysis[1],

which is essentially using electrical energy to split water into hydrogen and oxygen. The

first ideas of using hydrogen gas as a fuel cell were published in the late 1830s, and

now[2], 185 years later, fuel-cell cars are heading onto the roads. We already use it

for rocket engines, so why not for cars?

When we think of hydrogen on the road, we might worry about tiny little Hindenburgs

driving around out there, which couldn't be further from the truth. Hydrogen gas is very

explosive, it's true, even more so than natural gas[3] which is also used in moving vehicles;

gasoline VAPOR is ALSO explosive. Hydrogen can alite with airborne concentrations as

low as 4-percent or as HIGH as 75 percent! Thats a lot! Even so, gasoline burns at even

lower concentrations of 1.1 to 3.3%.[4] I read documents from specialists in hydrogen

storage and transportation safety, and they say the concern is if the gas is trapped in

an enclosed space; otherwise, you're probably alright.

Hydrogen is way lighter than air, which is why it was (theoretically) great for airships.

If you were to fill three balloons with natural gas, hydrogen and helium, [a]and let them

all go, hydrogen is going to rise at 45 mph (20m/s) - twice as fast as helium and six

times natural gas[5].

When a movie needs to make a car crash, even more terrible than car crashes really are…

they add a small fire and a HUGE tank of leaking gasoline. Sidebar: Everyone always has a full

tank of gas in movies, you ever think about that? Anyway… What about hydrogen? Well,

gasoline evaporates slowly so when a crash does occur, it CAN drip out, but hydrogen

fuel is stored pressurized, because it doesn't WANT to be a liquid. Tanks onboard the newest

hydrogen cars to enter U.S. highways store hydrogen at 10,000 psi[6]! This means, if

a crash were to occur between a gasoline car, and a hydrogen car where BOTH of their fuel

reservoirs were punctured, the hydrogen car would be safer, fuel-wise. If there WAS a

fire, the hydrogen would burn completely and rapidly, whereas gasoline would burn more

slowly as it vaporizes. But at that point, it would be difficult to tell which wasn't

as fun. And its heavier than air vapors would pool around the crash site, providing vapors

for any resulting fires to consume.

But when you combine a pressurized tank and a lighter-than-air gas like hydrogen, the

result will likely be dissipation rather than combustion. Which means it would almost instantaneously

escape into the atmosphere. That’s hardly a Hindenburg.

BUT TRACE! What about the FUELING STATIONS! Hydrogen fuel infrastructure is relatively

new, but people catch their cars on fire at gas stations all the time -- 3,000 times a

year[7]! NASA has used liquid hydrogen since the middle of the last century to lift astronauts

into orbit, and so far it's been pretty okay. If a leak is detected, they use helium to

flush the liquid hydrogen out into the air, so it quickly dissipates. Helium is a noble

gas, which means it's SUPER stable and doesn't really combust. With the right safety precautions

in place, maybe hydrogen fueling stations will adopt this too? Then if a leak happens

we'll all sound like chipmunks! ADORBZ.

We'd like to take a second and give a shout out to Toyota for supporting DNews. They were

at CES this month and released their patents for new fuel-cell technology, and revealed

THEIR fuel cell car to the world, the Mirai. They’re hoping these royalty-free patents

will spurn a hydrogen-fuel-based future and spent the last decade reducing the cost of

fuel cell production 95 percent.