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At scale means with mining requirements as well. With current and projected reserves we can manage intra-day requirements for the whole world. This is the we m

At scale means with mining requirements as well. With current and projected reserves we can manage intra-day requirements for the whole world. This is the we mine it all option. But we need intra-year storage capacity. Nuclear is clearly the easier and only option (and the most environment-friendly to me, considering the mining requirements)

adrianN 4y ago
Mining of what? Hydrogen as storage medium for example doesn't require all that much mining. Are you assuming storage will be in the form of Lithium batteries?
- BenoitP 4y ago
  I'm assuming currently proven tech of batteries. And we need to act now for climate change, with current tech. Electricity to H2 to electricity has horrendous efficiency (about 20% at most IIRC). We'd be much better off CO2-speaking using it to replace coal in steel production, and replace gas in fertilizer production. Both of which are proven tech (but not globally deployed, as coal and gas are cheap)
  - pfdietz 4y ago
    Power2Gas2Power has low round trip efficiency (say 40%), but as only a fairly small fraction of the energy flow goes through it that doesn't matter that much at the end of the day. If it did, that just means heavy industries would migrate to less seasonally variable places.
  - ncmncm 4y ago
    Inefficiency just requires extra capex, not opex. And the capex is capex is still falling at an exponential rate. So, no.
  - Sinidir 4y ago
    Where are you getting that 20% number from? https://www.irena.org/-/media/Files/IRENA/Agency/Publication/2019/Sep/IRENA_Power-to-Hydrogen_Innovation_2019.pdf?page=11 https://www.irena.org/-/media/Files/IRENA/Agency/Publication... https://www.sciencedirect.com/topics/engineering/round-trip-efficiency https://www.sciencedirect.com/topics/engineering/round-trip-... The round trip efficiency is 30% or more and rising with better electrolysis and reverse electrolysis being developed.
- marcosdumay 4y ago
  Personally, I expect something made with iron or sodium to take over. For hydrogen, we have to solve the horrible cycle efficiency of its storage. It's not so bad for use as a fuel (e.g. for airplanes), but as static storage hydrogen is currently a very bad choice.
  - ncmncm 4y ago
    Cycle efficiency is trivially resolved by feeding in more zero-opex power. But hydrogen efficiency is improving as fast as all renewable tech.
    - megaman821 4y ago
      I agree that hydrogen efficiency doesn't matter here, but the capital expenditure to build a giant electrolyzer with 5% utilization doesn't really make sense. The cost of the electrolyzer is the things that needs to greatly fall if hydrogen is going to be used for long-term storage.
      - pfdietz 4y ago
        Electrolyzers driven by otherwise curtailed renewables would have a capacity factor much higher than 10%. If I go to https://model.energy/ https://model.energy/ and solve for the optimal solution for the US for 2011 weather and 2030 cost assumptions, the capacity factor of the electrolyzers is 43%.
        megaman821 4y ago
        That is more of a what-if. If there was more wind and solar built out there would be enough curtailed energy to run electrolyzers at 43% capacity factor. I am saying today it doesn't make sense because there isn't a lot of over-provisioning taking place. There should be but what investors are going to jump first with a curtailed energy electrolyzer when curtailed energy is low.
        4y ago

adrianN 4y ago

Mining of what? Hydrogen as storage medium for example doesn't require all that much mining. Are you assuming storage will be in the form of Lithium batteries?

BenoitP 4y ago
I'm assuming currently proven tech of batteries. And we need to act now for climate change, with current tech. Electricity to H2 to electricity has horrendous efficiency (about 20% at most IIRC). We'd be much better off CO2-speaking using it to replace coal in steel production, and replace gas in fertilizer production. Both of which are proven tech (but not globally deployed, as coal and gas are cheap)
- pfdietz 4y ago
  Power2Gas2Power has low round trip efficiency (say 40%), but as only a fairly small fraction of the energy flow goes through it that doesn't matter that much at the end of the day. If it did, that just means heavy industries would migrate to less seasonally variable places.
- ncmncm 4y ago
  Inefficiency just requires extra capex, not opex. And the capex is capex is still falling at an exponential rate. So, no.
- Sinidir 4y ago
  Where are you getting that 20% number from? https://www.irena.org/-/media/Files/IRENA/Agency/Publication/2019/Sep/IRENA_Power-to-Hydrogen_Innovation_2019.pdf?page=11 https://www.irena.org/-/media/Files/IRENA/Agency/Publication... https://www.sciencedirect.com/topics/engineering/round-trip-efficiency https://www.sciencedirect.com/topics/engineering/round-trip-... The round trip efficiency is 30% or more and rising with better electrolysis and reverse electrolysis being developed.
marcosdumay 4y ago
Personally, I expect something made with iron or sodium to take over. For hydrogen, we have to solve the horrible cycle efficiency of its storage. It's not so bad for use as a fuel (e.g. for airplanes), but as static storage hydrogen is currently a very bad choice.
- ncmncm 4y ago
  Cycle efficiency is trivially resolved by feeding in more zero-opex power. But hydrogen efficiency is improving as fast as all renewable tech.
  - megaman821 4y ago
    I agree that hydrogen efficiency doesn't matter here, but the capital expenditure to build a giant electrolyzer with 5% utilization doesn't really make sense. The cost of the electrolyzer is the things that needs to greatly fall if hydrogen is going to be used for long-term storage.
    - pfdietz 4y ago
      Electrolyzers driven by otherwise curtailed renewables would have a capacity factor much higher than 10%. If I go to https://model.energy/ https://model.energy/ and solve for the optimal solution for the US for 2011 weather and 2030 cost assumptions, the capacity factor of the electrolyzers is 43%.
      - megaman821 4y ago
        That is more of a what-if. If there was more wind and solar built out there would be enough curtailed energy to run electrolyzers at 43% capacity factor. I am saying today it doesn't make sense because there isn't a lot of over-provisioning taking place. There should be but what investors are going to jump first with a curtailed energy electrolyzer when curtailed energy is low.
        4y ago