Can hydrogen fuel cells really be the future?
Some simple explanations of the nerdy number crunching. Oh, and the answer is also there, sort of...
Well, because it's everywhere, literally. It's the most abundant element in the whole universe, which is cool. What's no so cool about it, is that it's never single. Think of it like that annoying hot girl who's always with a boyfriend at the party, even when there are no other guys apart from you at that same party (a bit of a wishful thinking). We all know at least one such lady who seems to find a guy out of thin air and it's never available. Sooo . . to get the good stuff (the hydrogen, you pervs), we need to end that relationship. And in a way that won't cost us too much money, energy or health. Plenty of ways to do that, but all are costly in one way or another. Getting hydrogen from natural gas gets very gassy (pun intended) - carbon monoxide and carbon dioxide are a by-product. Even worse, some very potent methane is escaping when we drill or frack for natural gas. And if that's not enough, we're still dependant on those pesky fossil fuels the world is actively running out of, which makes no sense for production. Another way is to electrocute water, so there won't be greenhouse gasses as a by-product. But it's not very efficient as it uses a lot of energy and 25% is lost. We can use green energy, produced by the sun or the wind, but even then, the efforts will be somewhat pointless, because to compress the hydrogen to a liquid and store it means another 45% loss in energy. There is a cleaner way with with a proton exchange membrane, but that's still rare, expensive, and the efficiency gains are optimistically around 11% in total. Not great, but not terrible either.
Natural gas dependency is not ideal
Still, why hydrogen is the good stuff?
Because it's packing some sweet looking ju . . joules! I meant joules! It's very energy dense, compared to petrol, diesel and batteries. In fact, a single kilogram of hydrogen packs 236 times more energy than a single kilogram of batteries! The difference between hydrogen and petrol is not that enormous, but it's still two and a bit times in favour of the hydrogen. And it's as sweet as petrol to fill that tank - just put the hose in, wait a bit and you're ready to go. Well, wait a bit more than a petrol, but those are just semantics, compared to charging an EV, for instance. Even the fastest chargers can't top up a battery pack in 5-10 minutes (for now). And it's easy to out-range an EV by putting a bigger tank in the car. And a hydrogen fuel cells are way easier to recycle, compared to lithium batteries. No harmful residual chemicals to think about.
A diagram of how fuel cell convert a chemical reaction to electricity and water
What is a fuel cell and how does it work?
It's a very quiet place which harvest electricity from mixing hydrogen with oxygen. No V8 noise, unfortunately... But hey, it's still more efficient at turning hydrogen into kinetic energy (turning the wheels) than a petrol or diesel engine. Like nearly two and a half times more efficient. But still no match for those heavy batteries. It's not measurable in times, but 20-35% behind is significant! Think of the batteries as an Italian espresso - it turns that stored caffeine energy into a pure motion of your body (mostly your hands). Sometimes too much motion. Now compare the hydrogen to a drip coffee from a diner. It's still enough to move you, but not by that much. Now let's talk benefits. When hydrogen and oxygen mix, the by-products is a good old water. Hurray! But now think about it - to electrocute water, to get hydrogen, to mix it back with oxygen that makes electricity and water. It's a complete water cycle, minus some losses. And no batteries means no digging the earth for precious lithium.
Refuelling hydrogen is pretty straight-forward
Hydrogen? Batteries? Why not both?
No, seriously, why not both? I would love to have an answer to that, but I don't have one so far. And it makes me wonder why manufacturers don't sell plug-in hydrogen hybrids. Why not have the best of both worlds? Just imagine the punch of an EV with the range of a big-tank of H. The hydrogen will give you the freedom to go any distance and the batteries will make your neck hurts on acceleration. It's a win-win! And since both are pushing electric power to the wheels, you don't need extra motors, which would at least partly offset the extra weight of the fuel cell and hydrogen tank, on top of the batteries. Now this sounds more like a future and one without huge compromises from owners, manufacturers and fuel-producing companies. The biggest problem would be refuelling infrastructure, but it's not that big of an issue. You can install a hydrogen refuelling tank on a petrol station as easy as installing petrol, diesel or natural gas tanks.
Pictured below is a Hyperion XP-1 as a prime example of what hydrogen fuel cells can do on their own. 0-60 in 2.2 seconds, the top speed is 221 mph (356 km/h), it weighs just 1248 kg (2751 lb) and the range on a full tank is 1016 miles (1635 km). Still a concept from a small manufacturer in California, but it really shows the engineering possibilities.