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Batteries are >95% efficient round trip. Hydrogen is: 70% Gibbs Free Energy Efficiency, 70% electrolysis efficiency, 50% fuel cell efficiency, 93% compression

Batteries are >95% efficient round trip. Hydrogen is: 70% Gibbs Free Energy Efficiency, 70% electrolysis efficiency, 50% fuel cell efficiency, 93% compression efficiency = 23% round trip efficiency.

Retric 4y ago
Fuel cells are only useful for automotive applications, on the grid you want combined cycle gas turbines which are cheaper and more efficient. That still only gets round trip efficiency to about 25%.
- kergonath 4y ago
  > on the grid you want combined cycle gas turbines which are cheaper and more efficient You don’t want gas turbines anywhere near the grid. It is a terrible strategic choice besides the obvious ecological effect.
  - Retric 4y ago
    You are thinking of natural gas fueled turbines, you can also burn hydrogen in gas turbines. If that hydrogen was produced domestically via electrolysis using clean sources there isn’t any strategic issues. Also, from a strategic perspective burning domestic natural gas and burning natural gas from a different country are very different things. Europe becoming dependent on Russian natural gas was stupid, but America burning it’s domestic natural gas is mostly just an environmental issue.
_hypx 4y ago
A fuel cell is a battery. It has the same fundamental efficiency as any other battery. Of course, this is not how it works in the real world, but people who cite "efficiency" are usually greatly exaggerating how it works. Most batteries cannot reach 95% efficiency, especially if they need to store energy for long periods of time. Round trip efficiency of hydrogen will beat any ICE doing the same thing, and with heat recapture will basically match a li-ion battery. In situations where li-ion is poorly suited, such as cold weather or long-term storage, hydrogen will often be more efficient.
taneq 4y ago
How is 93% compression efficiency calculated?

Batteries are >95% efficient round trip. Hydrogen is: 70% Gibbs Free Energy Efficiency, 70% electrolysis efficiency, 50% fuel cell efficiency, 93% compression efficiency = 23% round trip efficiency.

Retric 4y ago

Fuel cells are only useful for automotive applications, on the grid you want combined cycle gas turbines which are cheaper and more efficient. That still only gets round trip efficiency to about 25%.

kergonath 4y ago
> on the grid you want combined cycle gas turbines which are cheaper and more efficient You don’t want gas turbines anywhere near the grid. It is a terrible strategic choice besides the obvious ecological effect.
- Retric 4y ago
  You are thinking of natural gas fueled turbines, you can also burn hydrogen in gas turbines. If that hydrogen was produced domestically via electrolysis using clean sources there isn’t any strategic issues. Also, from a strategic perspective burning domestic natural gas and burning natural gas from a different country are very different things. Europe becoming dependent on Russian natural gas was stupid, but America burning it’s domestic natural gas is mostly just an environmental issue.

_hypx 4y ago

A fuel cell is a battery. It has the same fundamental efficiency as any other battery. Of course, this is not how it works in the real world, but people who cite "efficiency" are usually greatly exaggerating how it works. Most batteries cannot reach 95% efficiency, especially if they need to store energy for long periods of time. Round trip efficiency of hydrogen will beat any ICE doing the same thing, and with heat recapture will basically match a li-ion battery. In situations where li-ion is poorly suited, such as cold weather or long-term storage, hydrogen will often be more efficient.

taneq 4y ago

How is 93% compression efficiency calculated?