3 ms·

Its actually around 70-80% efficient depending on method. https://en.wikipedia.org/wiki/Electrolysis_of_water#Efficiency https://en.wikipedia.org/wiki/Electrol

Its actually around 70-80% efficient depending on method. https://en.wikipedia.org/wiki/Electrolysis_of_water#Efficiency https://en.wikipedia.org/wiki/Electrolysis_of_water#Efficien... Not that this changes the picture of hydrogen powered personal vehicles. Still the only viable option for grid level seasonal storage.

ncmncm 4y ago
Hydrogen is very, very far from the only viable long-term storage. Liquified ammonia will also be popular. But we don't need any seasonal storage at all, just as we don't have seasonal storage of oil. We only need enough storage to hold out until a shipment of LH2 or LNH3 arrives from the tropics. Efficiency of H2 needs to fold in the cost of getting the power back out: Cf. "round-trip efficiency". But as I said, it doesn't matter very much, anymore, since generation is getting so cheap. Gasoline engines were never efficient, but few have cared much about that. Hydrogen won't, in any case, be "transported to the fuel station". It will be made right on the spot, or just down the street. And, won't be compressed, but will be poured in and allowed to boil up to pressure. That said, cars will be using batteries for the foreseeable future. In 20 years, H2 might get another chance, if batteries don't improve enough. Which seems unlikely.
- ClumsyPilot 4y ago
  "It will be made right on the spot, or just down the street. And, won't be compressed, but will be poured in and allowed to boil up to pressure." Are the efficient machines you are talking about affordable and portable enough to be locally owned? Also you are talking about hydrogen being poured in - so that would be cryogenic cooling, right? that incurrs an energy cost as well?
  - ncmncm 4y ago
    Yes, liquifying hydrogen also consumes energy. But by the time we are doing that on every street corner, the whole grid will be driven from renewables, and joules will be very cheap vs. other concerns. In particular, the LH2 will be banked during peak generation time, so almost free.

ncmncm 4y ago

Hydrogen is very, very far from the only viable long-term storage. Liquified ammonia will also be popular. But we don't need any seasonal storage at all, just as we don't have seasonal storage of oil. We only need enough storage to hold out until a shipment of LH2 or LNH3 arrives from the tropics. Efficiency of H2 needs to fold in the cost of getting the power back out: Cf. "round-trip efficiency". But as I said, it doesn't matter very much, anymore, since generation is getting so cheap. Gasoline engines were never efficient, but few have cared much about that. Hydrogen won't, in any case, be "transported to the fuel station". It will be made right on the spot, or just down the street. And, won't be compressed, but will be poured in and allowed to boil up to pressure. That said, cars will be using batteries for the foreseeable future. In 20 years, H2 might get another chance, if batteries don't improve enough. Which seems unlikely.

ClumsyPilot 4y ago
"It will be made right on the spot, or just down the street. And, won't be compressed, but will be poured in and allowed to boil up to pressure." Are the efficient machines you are talking about affordable and portable enough to be locally owned? Also you are talking about hydrogen being poured in - so that would be cryogenic cooling, right? that incurrs an energy cost as well?
- ncmncm 4y ago
  Yes, liquifying hydrogen also consumes energy. But by the time we are doing that on every street corner, the whole grid will be driven from renewables, and joules will be very cheap vs. other concerns. In particular, the LH2 will be banked during peak generation time, so almost free.