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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The energy density of hydrogen is almost 3 times better than gasoline by mass, it’s the absolute best you can get for chemical energy. That means it’s something like 300 times better than current production batteries. It’s non-toxic and burns to form water which is pretty much harmless. It’s quite easy to produce it from water and electricity.
The problem is to store it you either need huge volume tanks to store the gas, hugely strong and therefore heavy and espensive tanks to store it as a liquid or even just pressurised gas, which are going to explode if they fail. Or you need to freeze it close to absolute zero and keep it there to liquify it. If we could solve these problems then hydrogen would absolutely be the fuel to use but we don’t even know if it’s possible.
Generally disolving it in a liquid or metal and using it to power a fuel-cell looks more promising than burning a tank of hydrogen.
Cause its easy to refine from water and relatively abundant practically anywhere on earth and throughout the universe. People that invoke hydrogen as the future fuel however neglect the extra steps toward cleanly and efficiently using it. While you can burn it, its a horribly inefficient way of utilizing it and the efficient way, fuel cells, are expensive and fiddly technologies.
I know we’re talking about hydrogen as a fuel for internal combustion. But it’s also considered the nuclear fuel of the future. Hydrogen is (relatively) incredibly easy to fuse into heavier elements like helium and it potentially has energy densities that are orders of magnitude above any other fuel source. Combined with its effectively unlimited supply here on earth and you have a fuel that can effectively end energy shortages, although distribution will still be a big expense.
Per weight, H2 gas has the single highest chemical potential energy possible. (or more ELI5, it can do a lot of stuff while not weighing a lot)
Burning hydrogen releases a lot of energy, and Hydrogen (having no neutrons and very few protons) is also incredibly light.
Also, burning H2 with O2 just makes Water. No other nasty byproducts.
A couple of reasons.
Burning hydrogen only produces water as a waste product.
Hydrogen is the most abundant element in the universe.
And this is a fringe benefit that only really applies to rocketry:
Under sufficient temperatures and pressures, hydrogen can be compressed into a metallic form allowing you to store more mass of hydrogen in a smaller space
Hydrogen is extremely common* and can be produced in gigantic amounts. Hydrogen then can scale, especially if you have a lot of very cheap electricity to work with to ‘crack’ it from water and provide it to compress it. (From, for example, fusion reactors).
It’s sort of a ‘race’ between hydrogen and better battery chemistry to see what will be the energy storage of the future.
*As far as we know most of the universe is hydrogen, by a fairly large margin.
Out of the renewable-electricity-to-chemical-fuel options, hydrogen is generally seen as the least bad. It is the easiest and least energy inefficient to produce, requiring just electrolysis of water, while other “green fuel” options generally start with hydrogen and combine it with carbon dioxide (or nitrogen, in the case of ammonia), which causes some further efficiency losses as well.
Using hydrogen to produce electricity in a fuel cell is also fairly efficient compared to using an internal combustion engine to drive a generator (or just a mechanical load directly), and unlike combustion, produces no toxic or environmentally harmful byproducts.
Hydrogen of course also has downsides compared to the other options: For useful storage, it needs to be either chilled to extremely cold temperatures or compressed to extremely high pressure, which takes a lot of energy and compensates for the efficiency loss of other hydrogen-derived fuels somewhat. Also, hydrogen itself has a fairly high short-term global warming potential, about a third as large as that of methane, so the (inevitable, especially with how hydrogen can diffused through a solid metal container) leaks in hydrogen infrastructure could contribute significantly to global warming – though that is an issue that it shares with synthetic methane as well.
Also, if you want to be a bit cynical about it, since most hydrogen currently is produced by reacting natural gas with steam, one could argue that fossil fuel companies are pushing hydrogen (as an alternative to direct electrification) in order to be able to keep running their infrastructure and make mooney from it for longer.
The endgame for power might be nuclear fusion. We are still a few breakthroughs away though, but once we have efficient nuclear fusion, we can make huge amounts of power anywhere, removing the geographical limitations of green power sources (solar, wind, hydro) and also the radioactive waste issue of nuclear fission.
Hydrogen can be generated cleanly from water with electrolysis using a clean power source to be green hydrogen. However, the efficiency of converting electrical power to hydrogen chemical power, and then back into electricity, is much lower than simply charging a battery. Therefore, in most cases, it makes more sense to use BEVs, or mass rail transit system directly hooked to the power grid. However in the case of airplanes and long distance freight trucks, batteries aren’t all that practical, so some amount of hydrogen can be produced for those use cases to replace kerosene and diesel. Spaceships will also be in need of hydrogen to provide the amount of lift power needed to escape into orbit and beyond.
As long as hydrogen was produced from clean electricity, the only byproduct of consuming it is water. If it was also made from water, then everything remains in balance, no new greenhouse gas is added to the atmosphere.
Because nuclear fusion (which powers the sun) is the holy grail of energy production.
Also because natural gas producers are desperate to con the world into paying 3X as much to travel the same distance they could have gone in an EV, and they are investing heavily in propaganda and projects that require huge public subsidies to be competitive.
Allow me to introduce you to the Nitrogen Economy: https://scitechdaily.com/replacing-carbon-fuel-with-nitrogen-chemists-discover-new-way-to-harness-energy-from-ammonia/
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