this post was submitted on 26 Aug 2024
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Currently, hydrogen production requires more energy to produce the equivalent amount of hydrogen.
Which is why it should not be produced on a fossil fuel based grid, but is perfect for stored portable energy on renewable grids. For example, converting excess wind and solar power to hydrogen fuel.
It sounds like Estonia is on the right track, and intending to leverage their access to water and other renewables to generate "green" hydrogen. This sounds great, I hope they can pull it off.
I'm not sure what you meant by your first sentence. There are words missing. But any energy conversion will have efficiency losses. That includes for lithium batteries too.
Hydrogen should be used for portable energy, like you said. Are electric cars also not considered green unless they are charged with non-fossil fuel sources? I think everyone understands that they enable us to use other energy sources but they don't in and of themselves reduce dependence.
“Green Hydrogen” is made by using electricity to split water into hydrogen and oxygen. There’re no carbon emissions in that process, but to be truly “green” the electricity must come from a carbon free source like wind, solar, nuclear, or hydroelectric.
The process of electricity to hydrogen to compressed hydrogen to fuel cell to electricity is about half as energy efficient as electricity to li ion battery to electricity. As a form of electricity storage green hydrogen is significantly less efficient than batteries.
Green hydrogen only makes sense as a fuel in situations where batteries are not feasible.
And right now making green hydrogen at all does not make sense because if you build a new low carbon source of electricity it will make a larger impact if you use it to displace fossil fuel based electricity generation rather than using it to create green hydrogen.
What you wrote is essentially true of Li+ ion batteries (not truly green unless the electricity is too). The part I was missing was the efficiency of electrolysis being half that of Li+ charging.
Fuel cells can also run cars, and refilling is much faster than recharging. So you can build cars which can go long ranges with quick stops. But of course the infrastructure for hydrogen fuel is well behind even car chargers, let alone gasoline.
It's usually faster, yeah. But honestly I'm not sure which I'd rather have in my cars, explosive Li batteries or explosive highly pressurized hydrogen. Or are we storing liquid hydrogen? Because that seems like an even worse idea.
It sucks that high density energy storage systems are by definition able to release a lot of energy (explosive).
Only for the first few cars. I had a Toyota Mirai through work for a while (contractor company for Toyota, chose the Mirai as a work car, which made my manager think I was crazy. I just wanted something a bit different, and I recognised that this may be the only chance in my life to drive a HFC-EV)
But yeah, back on topic, only for the first few cars at a station. After that, you need to wait for the tank at the refuelling station to repressurise. I was waiting at the station for 5-10 mins before I could even start refuelling a lot of the time. Now imagine if the stations were as busy as petrol stations.
If I recharge a car, I can just plug it in in 5s on my driveway, or spend a couple of minutes paying another charger, then walk off. Refuelling the Mirai was often a 15 minute ordeal of me standing around at a fuel station, not including the out-of-the-way journey to even get to one in the first place.