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>Hydrogen makes sense for that use case, burned in turbines. And where's hydrogen going to come from? You need to overprovision renewables so that they not onl

>Hydrogen makes sense for that use case, burned in turbines. And where's hydrogen going to come from? You need to overprovision renewables so that they not only provide power for now, but also store enough power (via batteries or hydrogen or whatever) to get around daily, seasonal and inter-seasonal variability. And by the way, hydrogen from renewables is massively inefficient.

pfdietz 6y ago
It would come from electrolysis of water, using renewable energy when that's in oversupply. Overprovisioning renewables for immediate consumption works in tandem with hydrogen, since it means there will be times excess power is available to make the hydrogen. The round trip efficiency of power->hydrogen->power through turbines will be maybe 33%. But this is FINE, if the capital cost of storing hydrogen in underground caverns is low enough and renewables are otherwise cheap enough (low LCoE).
- Manfredo_1 6y ago
  If you're using caverns to reduce the capital cost of storing hydrogen, then you're ignoring a substantial amount of the real cost. Caverns are a geographically dependent feature, you might as well just say that we should use hydroelectricity as our main source of power.
  - pfdietz 6y ago
    Geological formations suitable for storage of hydrogen are quite widespread. They're basically identical to the formations that are already used to store natural gas.
    - Manfredo_1 6y ago
      Storing hydrogen is much more complicated than storing methane. Not to mention the challenge of moving hydrogen from the production location (probably close to a river), to the storage site. Hydrogen rapidly corrodes metals, turning them into metal hydrides. Hydrogen molecules are small, and they permeate through metals effectively increasing surface area. Even if storage is widespread, transport is challenging. Hydrogen gas would be useful for things like shipping. Such gas would likely be produced close to the port through thermochemical means, powered by a nuclear plant. This would minimize the amount of pipeline that needs to be built to transfer the gas to ships.
      - pfdietz 6y ago
        > Storing hydrogen is much more complicated than storing methane. Not really. It has lower energy/mole. There is the possibility that if CO2 is present that microorganisms could react the two to make methane. But aside from that, where is this much greater complexity coming from? The equipment required for storing either is similar. Hydrogen is already dealt with on a very large scale. If expanded to STP, the amount of hydrogen produced every year globally would occupy 700 cubic kilometers. This is not Power Point technology of the kind you find in pro-nuclear arguments.
        Manfredo_1 6y ago
        > But aside from that, where is this much greater complexity coming from? Did you read my post? Because I explain how it's permeability and corrosion make it challenging to build long lasting containers to store hydrogen. It's not the same technology to store methane. Methane can be liquified and kept as a liquid at room temperature. Hydrogen cannot, it must either be kept as a gas (drastically reducing it's energy density per liter) or cryogenically cooled. The scale at which it is produced, stored, and transported is not even remotely close to natural gas. Show me where you get this figure that 700 cubic kilometers of hydrogen is produced yearly? And even if it is, using it for energy storage is much more challenging than using it for things like chemical production because the latter doesn't involve storing hydrogen for long periods of time. The amount of hydrogen produced yearly doesn't hold a torch to Methane. 3.9 trillion cubic meters of natural gas are consumed yearly [1]. This works out to 2.7 trillion KG or 297 billion tons. By comparison, 70 million tons of hydrogen are produced annually [2]. We produce over 4000 times as much natural gas as hydrogen annually. I have no idea where you getting this idea that the hydrogen economy and natural gas economies are remotely close to the same scale. > This is not Power Point technology of the kind you find in pro-nuclear arguments. You're right, pro-nuclear arguments don't need to hand-wave away severe technological limitations. Because it actually works, and there are real-world examples of it working. 1. https://www.statista.com/statistics/282717/global-natural-gas-consumption/ https://www.statista.com/statistics/282717/global-natural-ga... 2. https://en.m.wikipedia.org/wiki/Hydrogen_production#:~:text=As%20of%202019%2C%20roughly%2070,as%20a%20fuel%20in%20transportation https://en.m.wikipedia.org/wiki/Hydrogen_production#:~:text=....

pfdietz 6y ago

It would come from electrolysis of water, using renewable energy when that's in oversupply. Overprovisioning renewables for immediate consumption works in tandem with hydrogen, since it means there will be times excess power is available to make the hydrogen. The round trip efficiency of power->hydrogen->power through turbines will be maybe 33%. But this is FINE, if the capital cost of storing hydrogen in underground caverns is low enough and renewables are otherwise cheap enough (low LCoE).

Manfredo_1 6y ago
If you're using caverns to reduce the capital cost of storing hydrogen, then you're ignoring a substantial amount of the real cost. Caverns are a geographically dependent feature, you might as well just say that we should use hydroelectricity as our main source of power.
- pfdietz 6y ago
  Geological formations suitable for storage of hydrogen are quite widespread. They're basically identical to the formations that are already used to store natural gas.
  - Manfredo_1 6y ago
    Storing hydrogen is much more complicated than storing methane. Not to mention the challenge of moving hydrogen from the production location (probably close to a river), to the storage site. Hydrogen rapidly corrodes metals, turning them into metal hydrides. Hydrogen molecules are small, and they permeate through metals effectively increasing surface area. Even if storage is widespread, transport is challenging. Hydrogen gas would be useful for things like shipping. Such gas would likely be produced close to the port through thermochemical means, powered by a nuclear plant. This would minimize the amount of pipeline that needs to be built to transfer the gas to ships.
    - pfdietz 6y ago
      > Storing hydrogen is much more complicated than storing methane. Not really. It has lower energy/mole. There is the possibility that if CO2 is present that microorganisms could react the two to make methane. But aside from that, where is this much greater complexity coming from? The equipment required for storing either is similar. Hydrogen is already dealt with on a very large scale. If expanded to STP, the amount of hydrogen produced every year globally would occupy 700 cubic kilometers. This is not Power Point technology of the kind you find in pro-nuclear arguments.
      - Manfredo_1 6y ago
        > But aside from that, where is this much greater complexity coming from? Did you read my post? Because I explain how it's permeability and corrosion make it challenging to build long lasting containers to store hydrogen. It's not the same technology to store methane. Methane can be liquified and kept as a liquid at room temperature. Hydrogen cannot, it must either be kept as a gas (drastically reducing it's energy density per liter) or cryogenically cooled. The scale at which it is produced, stored, and transported is not even remotely close to natural gas. Show me where you get this figure that 700 cubic kilometers of hydrogen is produced yearly? And even if it is, using it for energy storage is much more challenging than using it for things like chemical production because the latter doesn't involve storing hydrogen for long periods of time. The amount of hydrogen produced yearly doesn't hold a torch to Methane. 3.9 trillion cubic meters of natural gas are consumed yearly [1]. This works out to 2.7 trillion KG or 297 billion tons. By comparison, 70 million tons of hydrogen are produced annually [2]. We produce over 4000 times as much natural gas as hydrogen annually. I have no idea where you getting this idea that the hydrogen economy and natural gas economies are remotely close to the same scale. > This is not Power Point technology of the kind you find in pro-nuclear arguments. You're right, pro-nuclear arguments don't need to hand-wave away severe technological limitations. Because it actually works, and there are real-world examples of it working. 1. https://www.statista.com/statistics/282717/global-natural-gas-consumption/ https://www.statista.com/statistics/282717/global-natural-ga... 2. https://en.m.wikipedia.org/wiki/Hydrogen_production#:~:text=As%20of%202019%2C%20roughly%2070,as%20a%20fuel%20in%20transportation https://en.m.wikipedia.org/wiki/Hydrogen_production#:~:text=....