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As long as you don't get your hydrogen from natural gas it's just energy storage like batteries. You can make it from electricity or directly via solar-powered
by the8472 7y ago
As long as you don't get your hydrogen from natural gas it's just energy storage like batteries. You can make it from electricity or directly via solar-powered reactions.
- i_am_proteus 7y agoHow efficient is hydrogen as an energy storage medium compared to e.g. Li-Ion batteries?
- barrkel 7y agoHydrogen is 3x more energy dense than diesel, and diesel is about 5 to 10x more energy dense than lithium ion batteries.
- murkle 7y agoBy mass or volume?
- Avshalom 7y agotrying to split the difference between https://en.wikipedia.org/wiki/Toyota_Mirai https://en.wikipedia.org/wiki/Toyota_Mirai https://en.wikipedia.org/wiki/Tesla_Model_S https://en.wikipedia.org/wiki/Tesla_Model_S https://en.wikipedia.org/wiki/Tesla_Model_3 https://en.wikipedia.org/wiki/Tesla_Model_3 I mean different shaped/sized cars and all but probably a bit worse? range vs weight seems about on par with the S but worse HP? but also https://en.wikipedia.org/wiki/Fuel_cell#Theoretical_maximum_efficiency https://en.wikipedia.org/wiki/Fuel_cell#Theoretical_maximum_... so ?
- peteradio 7y agoEfficiency as in energy/kg? Tesla batteries: 207 watt-hours per kilogram (per google search) Hydrogen: 120-142 MJ per kilogram (per google search) Conversion from MJ to watt-hours: 277.778 watt-hours per MJ 120*277.778/207 ~ 161 more compact. Assuming energy conversion losses are equal.
- i_am_proteus 7y agoEfficiency in terms of watts out from the medium divided by watts into the medium over a normal duty cycle.
- tigershark 7y agoAs I said in another comment with some napkin calculations is about 30%. Another user gave a 22% number compared to 73% for batteries. The difference is hugely in favour of batteries.
- rcMgD2BwE72F 7y ago>As long as you don't get your hydrogen from natural gas (...) And that's the problem: hydrogen production is a huge waste of energy. Well to wheel efficiency of fuel cells is 22% vs 73% for battery EV (source: https://twitter.com/transenv/status/899976235794788352/photo/1 https://twitter.com/transenv/status/899976235794788352/photo...)
- usrusr 7y agoBut BEV cannot really use intermittent energy sources. Not without severely inconveniencing drivers and that's impossible. Hydrogen could be made from intermittent energy sources.
- darksaints 7y agoI can't speak to well to wheel, but at the very least current research tech electricity to hydrogen to electricity round trips are 75% efficient. https://www.nature.com/articles/s41560-019-0333-2 https://www.nature.com/articles/s41560-019-0333-2
- barrkel 7y agoThat's pretty much irrelevant, though. The infrastructure for energy distribution is decoupled from its production. Even if hydrogen is split from water via gas today, it can be done by solar or wind tomorrow with no changes to the distribution network.
- donaltroddyn 7y agoCurrent hydrogen production is largely from cracking methane, where natural gas is the feedstock (and also energy source) - it is much cheaper than production from electrolysis.
- samfisher83 7y agoMining and processing Lithium isn't that clean either.