I have basic idea of working of hydrogen fuel cell but why just hydrogen? Isn’t there any better or maybe cheaper alternative?
(I know it’s bit complex for but I would appreciate your answers)
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Other fuels work too, but Hydrogen is the most abundant element in the universe. It’s like the opposite of oil, in that you can find it almost everywhere. No need to rely on foreign countries to buy your hydrogen from. Planning a long distance space journey? Stop and refuel on any celestial body, which is sure to be dripping with hydrogen.
Water is the product of using it as fuel. But I don’t know why it’s being touted so much. It’s difficult to store as a gas, much harder as a liquid, and it’s not very energy dense. Longer-term storage is especially difficult because those tiny molecules make their way through almost anything.
Methane is easier to store as gas or liquid, over three times as energy dense as a gas, and it produces CO2 and water. Yeah, yeah, I know, CO2, but if you make it using atmospheric CO2 using clean energy (as you should hydrogen in this same case), it comes out carbon neutral.
Hydrogen isn’t regarded as the “fuel of the future”, or any other time. It’s a terrible fuel.
Hydrogen is seen as the closest to an ideal fuel because both production and consumption of it can be (almost) 100% green and renewable.
Some have mentioned that you get mostly water when you consume hydrogen.
On the production side, the ideal pathway is to use electricity from solar energy (hence no emission) to break down water into hydrogen and oxygen (no unwanted emission too!)
There are also other similarly green fuel, known as e-fuel, but they are a long way away from being widely commercially available.
Hydrogen is the *element* of choice because the binding of hydrogen to oxygen releases energy and that’s what powers a fuel cell or a burning reaction. Hydrogen is also the most abundant element in the universe.
Pure hydrogen is seen, on top of it, as an environmentally friendly choice because after you bind all the hydrogen to oxygen you end up with water.
That said, renewable hydrocarbons might turn out to be better fuel because producing pure hydrogen and transporting it has significant costs and challenges. But even when hydrocarbons are used as fuel, most of the energy is coming from the reaction of the hydrogen in the hydrocarbon with oxygen, so you can think of them as a different way to package hydrogen.
Methanol is also pretty popular actually.
Maersk recently purchased ships that can run on methanol expecting this to become more abundant.
Good descriptions of draw backs and alternatives in this thread but haven’t seen the plain and simple answer: It’s not. That’s a marketing phrase.
Hydrogen only looks good if you compare it with carbon based fuels. The way it’s used is more akin to a battery. Even then a normal gas tank isn’t under a couple thousand psi pressure.
In a post-carbon future, hydrogen is just a fancy and portable way of recharging a battery. (Don’t everybody @ me; this is ELI5.) The problem is, it probably won’t be the obviously best way of doing that in most cases.
It’s better *in theory* than carbon-based fuels for, say, powering a car, because its emissions are less of a problem. Nothing else besides hydrogen or hydrocarbons that combusts comes close in terms of energy density—or at least nothing we can readily construct an engine around. (It’d be pretty neat to see a magnesium-burning car, but not very practical.)
A lot of reasons. An incomplete list:
1. A decent amount of fuel cell work was done by NASA because of space applications before this was seriously considered.
2. There’s a concept in this that is criminally understated, and it’s the necessity of a “primary” or “secondary” carrier to actually reasonably transport hydrogen without spending ridiculous sums. These are just chemicals with more favorable transit+storage properties that can be converted back to hydrogen cheaply at high efficiencies. Ammonia is the big and obvious solution there, and the conversion to and from ammonia is ridiculously optimized with high efficiency because ammonia is one of the most important chemicals made. It’s not impossible to use ammonia as the fuel directly, but it’s probably not going to ever get to high enough efficiency to beat hydrogen fuel cells directly.
3. Hydrogen has a pretty simple chemistry and closed cycle that doesn’t create long lived greenhouse gases. In a fuel cell you have a very tractable number of side products to deal with.
4. Batteries are a shitty solution for most things. It’s bad for grid scale energy storage, and it’s bad the second you try to use it for towing anything or to drive anything bigger than an ~F150. Either hydrogen or methane is going to happen in the trucking industry at some point because there’s just not an alternative. It’s also not clear that the current air cooled transformer strategy will actually work with a full EV transportation infrastructure. They currently assume that usage will be way down at night allowing them to cool.
5. Renewables are very geographically limited with very high long term drift no matter how much some apologists try to downplay this. Any serious renewable grid proposal requires something called a “dense energy carrier” to get power from areas of high generation (like the Texas panhandle for wind) to areas of low generation (like the north east in general) and to act as energy storage to get you through the months where solar irradiance is down 15% over the average year on your solar farm. Hydrogen is an obvious choice here because it can double as a fuel source for vehicles which will be needed no matter what. “Green methane” is another serious proposal, but I haven’t kept up with that much.
Hydrogen combustion is a pretty non serious proposal even though some car manufacturers are working on it so I don’t feel the need to address it much. THe grid balancing aspect of the renewable economy is also why I pretty heavily support a nuclear grid. It’s not impossible to make a renewable grid work, but man, it’s definitely a lot easier to just not fuck up nuclear power which is already a pretty high bar on the complexity side. It’s also just expensive because a renewable grid needs to be very, very, very overbuilt to be reliable.
Keep in mind green hydrogen is not a fuel source. It’s used as an energy storage. The goal is to use energy from renewable to produce hydrogen.
So really you have to compare hydrogen to batteries and other energy storages, not energy sources.
Compared to electric batteries, hydrogen has much higher energy density and is relatively cheaper. This allows it to be used in industries where the battery wouldn’t be able to viable, and to store much more electricity.
However, converting electricity into hydrogen, and then transporting that hydrogen, is super in efficient. So it’s far from certain that it will be the future.
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