6 ms·

The only other contender that is even worth mentioning is compressed gas, but it seems to have neither the capacity nor the efficiency of a large hydro deployme

The only other contender that is even worth mentioning is compressed gas, but it seems to have neither the capacity nor the efficiency of a large hydro deployment. The largest pumped storage station in the US has a storage capacity of 24,000 MWh: https://en.wikipedia.org/wiki/Bath_County_Pumped_Storage_Station https://en.wikipedia.org/wiki/Bath_County_Pumped_Storage_Sta... There's an underground hydrogen storage project underway in Delta, Utah with a capacity of 300,000 MWh: https://www.powermag.com/massive-utah-hydrogen-storage-project-garners-finalized-504m-doe-loan-guarantee/ https://www.powermag.com/massive-utah-hydrogen-storage-proje... It would take 22 Deltas to overtake the world's largest pumped storage plant, a massive Chinese installation with 6.6 terawatt hours of storage capacity: https://www.pv-magazine.com/2022/01/04/state-grid-of-china-switches-on-worlds-largest-pumped-hydro-station/ https://www.pv-magazine.com/2022/01/04/state-grid-of-china-s... Still, potential underground hydrogen capacity is tremendous, amounting to thousands of terawatt hours in Europe alone: https://www.preprints.org/manuscript/201910.0187/v1 https://www.preprints.org/manuscript/201910.0187/v1

cwkoss 4y ago
How does the energy in underground hydrogen get utilized? Is the capacity the combustive energy, or only the energy from the gas pressure?
- philipkglass 4y ago
  It's burned as fuel in a gas turbine to generate electricity. The process is similar to burning natural gas in turbines, but some equipment adjustments have to be made when running on hydrogen. The Delta project is starting with a 30/70 blend of hydrogen and natural gas, gradually stepping up to 100% hydrogen. Siemens currently has turbines that can burn up to 75% hydrogen and is targeting 100% hydrogen by 2030: https://www.siemens-energy.com/global/en/priorities/future-technologies/hydrogen/zehtc.html https://www.siemens-energy.com/global/en/priorities/future-t... General Electric has a variety of gas turbines, accepting 50% to 100% hydrogen in the fuel blend: https://www.ge.com/gas-power/future-of-energy/hydrogen-fueled-gas-turbines https://www.ge.com/gas-power/future-of-energy/hydrogen-fuele... Mitsubishi claims to offer turbine operation on up to 100% hydrogen: https://solutions.mhi.com/clean-fuels/hydrogen-gas-turbine/ https://solutions.mhi.com/clean-fuels/hydrogen-gas-turbine/
  - jakewins 4y ago
    Also used for direct industrial heat and as a feedstock! Eg. the Hybrit project produces iron sponge with electrolyzed hydrogen. So the process becomes > (electricity + H2O) + Fe3O4 [iron ore] => Fe + H2O instead of the usual > C [coke] + Fe3O4 => Fe + CO2
- WJW 4y ago
  No it's mostly the chemical energy in the stored hydrogen, pressure is only a small part of it (though they might insert some expander turbine somewhere in there). Pretty similar to how you'd rate a natural gas storage facility.
  - pfdietz 4y ago
    It should be noted that the energy stored in the pressure of gas is zero. All the energy of an ideal gas is the kinetic energy (and rotational/vibrational energy) of its molecules, which is thermal energy. Internal energy of an ideal gas is independent of pressure. What compressed gas storage does is (aside from combustion energy of a fuel gas) to provide not a store of energy, but a store of reduced entropy, enabling otherwise unusable amounts of heat to be converted to work.
_hypx 4y ago
The Delta facility is in its preliminary stages. It could be expanded by something like 50x that of current listed capacity.
ClumsyPilot 4y ago
You are confusing energy storage and fuel storage. I am talking about CAES, it uses electricity to compress air and feed that into a container, like a metal cylinder or caverns lined with impermeable material. When you need electricity, you release the air through a generator and produce electricity. Hydroelectric, compressed air and batteries have round trip efficiency of ~80%. https://www.sciencedirect.com/topics/engineering/compressed-air-energy-storage https://www.sciencedirect.com/topics/engineering/compressed-... The facility you linked produces and stores chemical fuel, and can't even convert it back into electricity. It is really easy to store insane quantity of fuel, just like we can store loads of oil. The kicker is that production of Hydrogen and other e-fuelds is less than 50% efficient, and converting them back to electricity is another 50% loss. Compression for storage and transportation mean further losses. So the overall round-trip efficiency is expected to be about 25% or lower. It is probably possible to build an economy based on e-fuels, and that's what many oil companies are pushing for. They are probably the only viable way to achieve seasonal storage. It's a different set of tradeoffs.
- philipkglass 4y ago
  The facility you linked produces and stores chemical fuel, and can't even convert it back into electricity. The project includes using Mitsubishi M501JAC combined-cycle gas turbines to turn the hydrogen back into electricity: https://www.powermag.com/aces-deltas-giant-utah-salt-cavern-hydrogen-storage-project-gets-504m-conditional-doe-loan-guarantee/ https://www.powermag.com/aces-deltas-giant-utah-salt-cavern-... https://power.mhi.com/products/gasturbines/lineup/m501j https://power.mhi.com/products/gasturbines/lineup/m501j This turbine has a rated combined-cycle efficiency of 64%. Production of hydrogen is more than 70% efficient in the best current commercial electrolyzers: https://www.nrel.gov/docs/fy04osti/36705.pdf https://www.nrel.gov/docs/fy04osti/36705.pdf Round-trip efficiency is much lower than 80%, but not as low as you have written here.
  - pencilguin 4y ago
    Industrial-scale electrolysers will soon be well over 90% efficient.
Manuel_D 4y ago
Such hydrogen storage facilities already exist, actually. But the hydrogen the store is produced via steam reformation which emits carbon. The big issue with hydrogen storage cheaply producing hydrogen without producing CO2.
- pencilguin 4y ago
  There is in fact no such issue because literally no one is even considering producing hydrogen for energy storage in that way.
  - Manuel_D 4y ago
    Then how is hydrogen going to be stored? Electrolysis remains either inefficient or expensive.
    - pencilguin 4y ago
      Storage method has exactly nothing to do with production method. Electrolysis efficiency and expense are entirely sufficient to requirements for the hydrogen storage projects are, in fact, proceeding.
    - Schroedingersat 4y ago
      Inefficiency doesn't matter if you are storing curtailed energy. If it makes more financial sense and uses less resources to overbuild solar 3x and curtail 60% of the energy than paying for fuel, then you have 2 units of energy you have already paid for spread out over 6-8hrs/day. As long as using your $300/kw electrolyser at reduced duty cycle is cheaper and less resource intensive than mining and shipping gas, you do it.
mjevans 4y ago
I thought it was missing from the list... https://en.wikipedia.org/wiki/Grand_Coulee_Dam#Irrigation https://en.wikipedia.org/wiki/Grand_Coulee_Dam#Irrigation However it seems that the pumped storage I recall hearing about as a kid has an extremely low storage capacity and is more focused on irrigation.

cwkoss 4y ago

How does the energy in underground hydrogen get utilized? Is the capacity the combustive energy, or only the energy from the gas pressure?

philipkglass 4y ago
It's burned as fuel in a gas turbine to generate electricity. The process is similar to burning natural gas in turbines, but some equipment adjustments have to be made when running on hydrogen. The Delta project is starting with a 30/70 blend of hydrogen and natural gas, gradually stepping up to 100% hydrogen. Siemens currently has turbines that can burn up to 75% hydrogen and is targeting 100% hydrogen by 2030: https://www.siemens-energy.com/global/en/priorities/future-technologies/hydrogen/zehtc.html https://www.siemens-energy.com/global/en/priorities/future-t... General Electric has a variety of gas turbines, accepting 50% to 100% hydrogen in the fuel blend: https://www.ge.com/gas-power/future-of-energy/hydrogen-fueled-gas-turbines https://www.ge.com/gas-power/future-of-energy/hydrogen-fuele... Mitsubishi claims to offer turbine operation on up to 100% hydrogen: https://solutions.mhi.com/clean-fuels/hydrogen-gas-turbine/ https://solutions.mhi.com/clean-fuels/hydrogen-gas-turbine/
- jakewins 4y ago
  Also used for direct industrial heat and as a feedstock! Eg. the Hybrit project produces iron sponge with electrolyzed hydrogen. So the process becomes > (electricity + H2O) + Fe3O4 [iron ore] => Fe + H2O instead of the usual > C [coke] + Fe3O4 => Fe + CO2
WJW 4y ago
No it's mostly the chemical energy in the stored hydrogen, pressure is only a small part of it (though they might insert some expander turbine somewhere in there). Pretty similar to how you'd rate a natural gas storage facility.
- pfdietz 4y ago
  It should be noted that the energy stored in the pressure of gas is zero. All the energy of an ideal gas is the kinetic energy (and rotational/vibrational energy) of its molecules, which is thermal energy. Internal energy of an ideal gas is independent of pressure. What compressed gas storage does is (aside from combustion energy of a fuel gas) to provide not a store of energy, but a store of reduced entropy, enabling otherwise unusable amounts of heat to be converted to work.

_hypx 4y ago

The Delta facility is in its preliminary stages. It could be expanded by something like 50x that of current listed capacity.

ClumsyPilot 4y ago

You are confusing energy storage and fuel storage. I am talking about CAES, it uses electricity to compress air and feed that into a container, like a metal cylinder or caverns lined with impermeable material. When you need electricity, you release the air through a generator and produce electricity. Hydroelectric, compressed air and batteries have round trip efficiency of ~80%. https://www.sciencedirect.com/topics/engineering/compressed-air-energy-storage https://www.sciencedirect.com/topics/engineering/compressed-... The facility you linked produces and stores chemical fuel, and can't even convert it back into electricity. It is really easy to store insane quantity of fuel, just like we can store loads of oil. The kicker is that production of Hydrogen and other e-fuelds is less than 50% efficient, and converting them back to electricity is another 50% loss. Compression for storage and transportation mean further losses. So the overall round-trip efficiency is expected to be about 25% or lower. It is probably possible to build an economy based on e-fuels, and that's what many oil companies are pushing for. They are probably the only viable way to achieve seasonal storage. It's a different set of tradeoffs.

philipkglass 4y ago
The facility you linked produces and stores chemical fuel, and can't even convert it back into electricity. The project includes using Mitsubishi M501JAC combined-cycle gas turbines to turn the hydrogen back into electricity: https://www.powermag.com/aces-deltas-giant-utah-salt-cavern-hydrogen-storage-project-gets-504m-conditional-doe-loan-guarantee/ https://www.powermag.com/aces-deltas-giant-utah-salt-cavern-... https://power.mhi.com/products/gasturbines/lineup/m501j https://power.mhi.com/products/gasturbines/lineup/m501j This turbine has a rated combined-cycle efficiency of 64%. Production of hydrogen is more than 70% efficient in the best current commercial electrolyzers: https://www.nrel.gov/docs/fy04osti/36705.pdf https://www.nrel.gov/docs/fy04osti/36705.pdf Round-trip efficiency is much lower than 80%, but not as low as you have written here.
- pencilguin 4y ago
  Industrial-scale electrolysers will soon be well over 90% efficient.

Manuel_D 4y ago

Such hydrogen storage facilities already exist, actually. But the hydrogen the store is produced via steam reformation which emits carbon. The big issue with hydrogen storage cheaply producing hydrogen without producing CO2.

pencilguin 4y ago
There is in fact no such issue because literally no one is even considering producing hydrogen for energy storage in that way.
- Manuel_D 4y ago
  Then how is hydrogen going to be stored? Electrolysis remains either inefficient or expensive.
  - pencilguin 4y ago
    Storage method has exactly nothing to do with production method. Electrolysis efficiency and expense are entirely sufficient to requirements for the hydrogen storage projects are, in fact, proceeding.
  - Schroedingersat 4y ago
    Inefficiency doesn't matter if you are storing curtailed energy. If it makes more financial sense and uses less resources to overbuild solar 3x and curtail 60% of the energy than paying for fuel, then you have 2 units of energy you have already paid for spread out over 6-8hrs/day. As long as using your $300/kw electrolyser at reduced duty cycle is cheaper and less resource intensive than mining and shipping gas, you do it.

mjevans 4y ago

I thought it was missing from the list... https://en.wikipedia.org/wiki/Grand_Coulee_Dam#Irrigation https://en.wikipedia.org/wiki/Grand_Coulee_Dam#Irrigation However it seems that the pumped storage I recall hearing about as a kid has an extremely low storage capacity and is more focused on irrigation.