3 ms·

Does 100% efficiency here mean that the energy of the hydrogen equals the energy used to produce it?

by teruakohatu 4y ago

JonChesterfield 4y ago
Unlikely. What with thermodynamics. I'd guess it's something like "nearly" hides some sins and ignoring things other than oxygen that result hide the rest.
- MBCook 4y ago
  I would think it means that (nearly) 100% of the energy input is used in useful chemical reactions doing work as opposed to generating waste heat or something else.
onlyrealcuzzo 4y ago
My understanding is that a perfectly efficient device would take ~39 kWh to produce 1 kg hydrogen [1]. So I'm imagining this is close to that? IIUC, 1 kg hydrogen = ~33.6 kWh. [1] https://wernerantweiler.ca/blog.php?item=2020-09-28#:~:text=How%20much%20electricity%20is%20needed,kWh%20per%20kg%20of%20hydrogen https://wernerantweiler.ca/blog.php?item=2020-09-28#:~:text=....
- onlyrealcuzzo 4y ago
  Current battery storage costs are $143/kWh. The LCOE of solar is <$0.04 now. A hydrogen powered combined cycle peaker plant would have ~60% efficiency. Meaning, you should be able to produce solar-hydrogen fuel for $0.04/0.6/(33.6/39) = <$0.08 per kWh. Why isn't anyone doing this? Natural gas costs >$3.45/MMBTU = $0.01 per kWh. That sounds like it's 8x more expensive. But the wholesale cost of Natural Gas electricity is $0.18 per kWh - meaning going to Hydrogen shouldn't even increase that by 40%. But in the EU, it's already higher than that!
  - _hypx 4y ago
    There are short-term issues like capital costs and a need for contracts to be set up first. These things can't happen instantly. But beyond that, it is entirely backwardness in thinking that is driving the opposition. Many people simply reject the evidence and are convinced that such low costs are impossible. It is a repeat of those who thought wind and solar could never be cheap. They will be embarrassed in the same way too.

3 ms·

Does 100% efficiency here mean that the energy of the hydrogen equals the energy used to produce it?

by teruakohatu 4y ago

Does 100% efficiency here mean that the energy of the hydrogen equals the energy used to produce it?

JonChesterfield 4y ago
Unlikely. What with thermodynamics. I'd guess it's something like "nearly" hides some sins and ignoring things other than oxygen that result hide the rest.
- MBCook 4y ago
  I would think it means that (nearly) 100% of the energy input is used in useful chemical reactions doing work as opposed to generating waste heat or something else.
onlyrealcuzzo 4y ago
My understanding is that a perfectly efficient device would take ~39 kWh to produce 1 kg hydrogen [1]. So I'm imagining this is close to that? IIUC, 1 kg hydrogen = ~33.6 kWh. [1] https://wernerantweiler.ca/blog.php?item=2020-09-28#:~:text=How%20much%20electricity%20is%20needed,kWh%20per%20kg%20of%20hydrogen https://wernerantweiler.ca/blog.php?item=2020-09-28#:~:text=....
- onlyrealcuzzo 4y ago
  Current battery storage costs are $143/kWh. The LCOE of solar is <$0.04 now. A hydrogen powered combined cycle peaker plant would have ~60% efficiency. Meaning, you should be able to produce solar-hydrogen fuel for $0.04/0.6/(33.6/39) = <$0.08 per kWh. Why isn't anyone doing this? Natural gas costs >$3.45/MMBTU = $0.01 per kWh. That sounds like it's 8x more expensive. But the wholesale cost of Natural Gas electricity is $0.18 per kWh - meaning going to Hydrogen shouldn't even increase that by 40%. But in the EU, it's already higher than that!
  - _hypx 4y ago
    There are short-term issues like capital costs and a need for contracts to be set up first. These things can't happen instantly. But beyond that, it is entirely backwardness in thinking that is driving the opposition. Many people simply reject the evidence and are convinced that such low costs are impossible. It is a repeat of those who thought wind and solar could never be cheap. They will be embarrassed in the same way too.