Interesting to see … and now some refueling stations.
While it would be nice to have one of these, in terms of the environment, hydrogen-powered vehicles are a mixed bag. It’s true that when you burn hydrogen, the only by-product is water vapor, which is non-polluting. That’s the good news.
And the bad news? Most hydrogen is obtained from stripping hydrogen atoms from natural gas (methane). Right now, hydrogen is cheap because it’s a waste product of producing ammonia and methanol. However, if everyone started buying hydrogen-powered cars or bikes, we’d have to start drilling for natural gas just to make hydrogen, and this would be environmentally ruinous.
The alternative is to make hydrogen from hydrolysis of water. You might have done that in your high school chemistry class (we did). However, this is awfully inefficient, with an energy loss of about 70%. As for how “green” this would be, a lot depends on how you generate the electricity. If you burn oil, coal or natural gas to produce the electricity to make the hydrogen, it would be more polluting than just burning fossil fuel directly in the vehicle’s engine to power the car or motorbike. If you produce the electricity from solar, wind, hydro or nuclear, than it should work out to be low-polluting.
Nevertheless, when you start talking about hydrogen refilling stations, you run into more issues. Hydrogen is an extremely light and leaky gas (indeed, the lightest and leakiest). It has a huge volume and can’t be compressed except by two methods: 1) In a catalyst, like in fuel cells, or 2) liquefied by lowering its temperature to -252.87 °C. Handling super-cold hydrogen is messy and dangerous, so fuel cells are better, but way more expensive. Don’t expect a hydrogen fuel cell vehicle to come cheaply. NASA can afford them for the space shuttle, but your average student looking to buy a moped is not likely to have the cash.
Just how expensive was that fuel cell shown in the video? I don’t know. I tried googling for an answer, and it wasn’t straightforward. Really tiny fuel cells capable of producing 2 watts can be had for around US$100. I tried doing some calculations based on battery-powered mopeds, and I admit that I my calculation method could be way off, but I came up with a price of about US$18,000 for a fuel cell than could give an electric bike a 20-mile range. Like I said, this might be very wrong, so if anybody here knows more about it, please raise your hand.
Harvesting methane from cow barns and garbage dumps and sewage farms is certainly feasible, and the resulting CO2 from steam reforming is carbon-neutral (as it’s organic in origin, and therefore pulled out of the atmosphere in the first place anyway).
it may not be a great source, but at least it’s a contribution, and one that reduces the amount of methane in the air, which is important as methane is 30 times more potent as a greenhouse gas.
[quote=“urodacus”]Harvesting methane from cow barns and garbage dumps and sewage farms is certainly feasible, and the resulting CO2 from steam reforming is carbon-neutral (as it’s organic in origin, and therefore pulled out of the atmosphere in the first place anyway).
it may not be a great source, but at least it’s a contribution, and one that reduces the amount of methane in the air, which is important as methane is 30 times more potent as a greenhouse gas.[/quote]
Feasible? Yes. Practical? Very doubtful. Rather than run through everything I think I know about this (which is based entirely on the experience of others, as I haven’t tried it myself), I refer you to this very thorough rundown of the complexity involved:
extension.missouri.edu/publicati … px?P=G1881
Note that the above study is just for using methane to burn directly, thus producing energy to actually run the farm operation. If you want to produce hydrogen from this methane, you can expect to lose about another 70% of the energy potential.
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Some key points I’m trying to make here (about the original topic, hydrogen-powered bicycle)…
Hydrogen IS an attractive fuel, because it’s non-polluting when you burn it. It’s also very energy dense if it’s liquid (if you can safely handle something at -252.87 °C), or if it’s absorbed by a catalyst (as in a fuel cell).
Super-cold liquid hydrogen is very hard to handle - terribly leaky and explosive. Because it’s so energy dense, it’s used as rocket fuel, sometimes with disastrous results:
youtube.com/watch?v=j4JOjcDFtBE
Thus, it would be insane to build cars and motorcycles powered by liquid hydrogen.
Hydrogen fuel cells, on the other hand, are pretty safe. They are just very expensive.
The other big problem is the production of hydrogen, which is very energy inefficient. If you’re using fossil fuels to make the hydrogen, you’re actually going to pollute more in the manufacturing process than if you just burned gasoline in the engine.
And that is basically why - after decades of discussions - hydrogen-powered cars are still not being sold. Yes, you can build them. In fact, first one I saw was built by Caltech in the 1970s. It was driven around the university parking lot to the oohs and ahhs of journalists who were there to record the event. It was the promised “car of the future.” And now more than 30 years later, it’s still the “car of the future.”
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If we are ever to have electric cars, they will most likely be battery powered. Actually, we do already have those. Main problems are: 1) limited range, and 2) long charging times. Those issues have been largely overcome with hybrids, the only real problem being that still doesn’t quite free us from fossil fuel dependency.
[quote=“Dog’s_Breakfast”]
Just how expensive was that fuel cell shown in the video? I don’t know. I tried googling for an answer, and it wasn’t straightforward. Really tiny fuel cells capable of producing 2 watts can be had for around US$100. I tried doing some calculations based on battery-powered mopeds, and I admit that I my calculation method could be way off, but I came up with a price of about US$18,000 for a fuel cell than could give an electric bike a 20-mile range. Like I said, this might be very wrong, so if anybody here knows more about it, please raise your hand.[/quote]
I think it’s pretty much right on.
Long lasting Fuel cells depend on very expensive and rare materials.
Something like platinum. Unless they find some cheaper solution the fuel cell revolution won’t happen ever.
I think it’s more likely that graphene will give battery performance another three fold boost.
Yeah graphene is cheap and we know all about how to handle it in large pieces.
Sorry I don’t get what you are trying to say.
it will be a long time till we can use it effectively.
at the moment it is not cheap, and it is very hard to make consistently in anything larger than micron scale in controllable fashion. (My comment was a sarcastic reverse of the true situation).
Sre, it’s early days and it has lots of potential. Carbon nanotube escalators to low earth orbit à la A C Clarke are much more feasible: there’s even a Japanese company started to develop that already. I think you should put your investment money elsewhere than graphene batteries for a while.
The Japanese are making massive investments in fuel cell technology. Never write off the Japanese.
That being said. electric cars will surely dominate the market for the next few decades as their range increases and they get cheaper and the infrastructure builds out. Fuel cell cars offer some advantages but its hard to get away from the fact you need to refine the hydrogen, compress it and ship it around a lot. It seems a bit pointless for this reason. Also, nobody mentioned it yet but fuel cell powered cars still need large electric batteries! Basically the car makes its own electricity which it needs to store and pass to the motor. It would need a smaller battery for a longer range compared to a pure electric car. the energy conversion from H2 to motor power is excellent and non polluting, but the source and cost of H2 will always be the question mark.
[quote=“headhonchoII”]The Japanese are making massive investments in fuel cell technology. Never write off the Japanese.
That being said. electric cars will surely dominate the market for the next few decades as their range increases and they get cheaper and the infrastructure builds out. Fuel cell cars offer some advantages but its hard to get away from the fact you need to refine the hydrogen, compress it and ship it around a lot. It seems a bit pointless for this reason. Also, nobody mentioned it yet but fuel cell powered cars still need large electric batteries! Basically the car makes its own electricity which it needs to store and pass to the motor. It would need a smaller battery for a longer range compared to a pure electric car. the energy conversion from H2 to motor power is excellent and non polluting, but the source and cost of H2 will always be the question mark.
timescolonist.com/toyota-bet … -1.1465510[/quote]
Hydrogen is made with water and electricity.
It doesn’t have to be shipped around. It can be produced where it is sold right in place.
Something that needs to be clarified - hydrogen gas cannot be compressed. Any attempt to compress it and put it into a propane bottle (like the kind we use for our stoves here in Taiwan) will almost certainly lead to an explosion. Note that when you compress any gas, it heats up, and the more you compress it, the hotter (and more explosive) it gets. So don’t try it at home.
Indeed, methane (natural gas) also cannot be compressed. Those bottles we buy (that are sometimes delivered on the back of a motorcycle) are filled with propane, not methane. Cigarette lighters are filled with butane which is even easier to compress.
Both methane and hydrogen can be liquefied at extremely low temperatures. When that’s done with methane, it’s called LNG (liquefied natural gas). It’s fairly dangerous stuff to handle, but it’s way less dangerous than liquefied hydrogen. The safety of storing flammable gases has a whole lot to do with the boiling point:
butane, boiling point -0.5ºC
propane, boiling point -42ºC
methane, boiling point -164ºC
hydrogen, boiling point -253ºC
absolute zero: -273.15°
As you can see, liquid hydrogen is barely above absolute zero. It’s not easy to get it down to that temperature, or to hold it there.
It’s true that some experimental cars have been built with a conventional internal combustion engine and a modified fuel injection system, and then run on a tank of liquefied hydrogen. I remember reading that BMW built such a car, for demo purposes only - don’t expect to buy one anytime soon. It would be insane to drive it on the highway, or even park it in a garage, since hydrogen leaks very easily (due to being the smallest atom that exists), and thus your garage would soon have an explosive mixture of air+hydrogen that one spark could set off. It was a hydrogen leak that blew up the space shuttle Challenger in 1986, killing everyone aboard - a powerful demonstration that liquid hydrogen is serious stuff.
But you can store hydrogen safely in a fuel cell. That’s a chemical process involving a catalyst. I don’t know enough chemistry to describe it, though I imagine if you’re diligent enough, you can drag the info out of google. Anyway, fuel cells are really expensive, and the energy loss associated with creating hydrogen is around 70%. And for those reasons, I suspect that hydrogen-powered cars are never going to prove practical, although I’d be happy to be proven wrong.
[quote=“Hamletintaiwan”]
Hydrogen is made with water and electricity.
It doesn’t have to be shipped around. It can be produced where it is sold right in place.[/quote]
That’s true, and it would be way safer to do that than to ship liquid hydrogen around on tanker trucks. However, these days most hydrogen is made by stripping it from natural gas, and that’s probably not going to be done at your local filling station. Of course, if we really had hydrogen fuel cell vehicles on the road, we probably would have filling stations making hydrogen on site with electricity and water.
It wouldn’t seem to make much sense to have filling stations making hydrogen on site with only 70% or less energy conversion when commuters could simply charge up their cars directly. The costs would go up astronomically compared to simply charging the battery with electricity. Safety concerns alone would probably make the project nonviable. If there was some type of remote site production of hydrogen that might come in handy for some industries I guess or as a store of energy for times.
Chloroalkali chemistry also produces hydrogen by the way, but the amount of hydrogen produced is very little. It is the process by which bleach is produced by the way.