4 ms·

This works because electrolysis equipment is cheap, so shutting it down half time barely increases total cost of ownership compared to the input electricity.

ZeroGravitas 5y ago
I don't think electrolysis equipment is particularly cheap, there's some excitement about cheaper alternatives coming to market and mass production that use cheaper materials. But overall it's going to be the cheapest way to make hydrogen and then ammonia very soon. And the market has already seen that inevitable future, lots of right-wing Australian mining billionaires have jumped into the market hard for example. The main saving is avoided carbon, which isn't priced in everywhere. But the sheer scale of ammonia production means it's easy to gradually introduce this as long as you spread the initial upfron cost across all the users (which is basically everyone). It's a very mutually beneficial arrangement for renewables so the two things reinforce each other strongly and I think it'll be one of those things that moves faster than they expect.
- deleted 5y ago
  [deleted]
- Retric 5y ago
  The equipment is cheap relative to the cost of electricity to run it. This analysis is 5 years old and it was already the case back then: https://www.sciencedirect.com/topics/engineering/hydrogen-production-cost https://www.sciencedirect.com/topics/engineering/hydrogen-pr...
  - ZeroGravitas 5y ago
    I'm not sure exactly what you're referencing, as that seems a general topic you've linked to, but one of the articles I see at that link says that basically electrolizers are expensive enough that you need to be utilizing them at a high rate in order for it to make sense, and I think that's still true. > In case of PtG applications, electrolyzer utilization becomes a key parameter. To illustrate the resulting utilization of electrolyzers when run on “surplus” electricity alone it is helpful to plot the residual load duration curves for different penetration levels of intermittent renewables.21Figure 11.4 depicts two typical residual load duration curves for a 30% and 80% share of generation from intermittent renewables of total electricity demand.
    - Retric 5y ago
      As I said, it’s an outdated analysis the point was theses things are a long way from 24/7 operations and have been for a long time. “High electrolyzer utilization reduces the specific share of electrolyzer capital costs in hydrogen production costs; on the other hand, a higher utilization increases electricity costs, as hours of expensive electricity will increasingly be included. Hence, in order to minimize hydrogen costs, electrolyzer utilization has to be balanced with the electricity price.” Of course the specific utilization percentage varies based on how expensive the equipment, it’s overall efficiency, and grid spot prices. We don’t actually know how expensive it is at scale so picking exact percentages is impossible.
      - ZeroGravitas 5y ago
        Okay, there's a gap between requiring 24/7 usage, and "only exist for the purposes of using excess power that would otherwise go to waste" and I think we agree that electrolysis is somewhere in the middle of those two extremes.
        Retric 5y ago
        If we are talking today then absolutely. However, the grid is expected to have a lot of unused capacity. California is already at the point where 5% of all solar power produced is wasted and people are still constantly adding solar because the current economic break even is ~50% of all solar produced being wasted. That would average around 4-5 hours a day of basically “free” electricity which isn’t quite enough, but at scale at scale electrolysis equipment is almost that cheap and will probably hit that point. This becomes more likely when you consider efficiency as a useful tradeoff. 40% efficiency at 2c/kWh or 20% efficiency at 1c/kWh potentially spend the same amount on electricity per kg of hydrogen but the second is likely much cheaper to build. You could potentially have several designs that get turned on or off depending on the current spot price.
hannob 5y ago
Unfortunately that's not the case. Electrolyseurs are expensive (though hopes are they're gonna get cheaper quickly, as there's a lot of investment in this sector right now). The economic balance of running an electrolyseur only part of the time is something to be worked out. Still the balance is almost certainly not "we need baseload".
- Retric 5y ago
  The cost of electricity is already vastly more import than the cost of an electrolyzer at scale. https://www.semanticscholar.org/paper/Economics-of-converting-renewable-power-to-hydrogen-Glenk-Reichelstein/d0580340e9bd6d6d89e9542ded212855a8294247 https://www.semanticscholar.org/paper/Economics-of-convertin... It’s to the point where even running 1/3 the time at the cost of 3x the equipment is likely a cost savings at scale assuming the local grid has a lot of wind/solar.

ZeroGravitas 5y ago

I don't think electrolysis equipment is particularly cheap, there's some excitement about cheaper alternatives coming to market and mass production that use cheaper materials. But overall it's going to be the cheapest way to make hydrogen and then ammonia very soon. And the market has already seen that inevitable future, lots of right-wing Australian mining billionaires have jumped into the market hard for example. The main saving is avoided carbon, which isn't priced in everywhere. But the sheer scale of ammonia production means it's easy to gradually introduce this as long as you spread the initial upfron cost across all the users (which is basically everyone). It's a very mutually beneficial arrangement for renewables so the two things reinforce each other strongly and I think it'll be one of those things that moves faster than they expect.

deleted 5y ago
[deleted]
Retric 5y ago
The equipment is cheap relative to the cost of electricity to run it. This analysis is 5 years old and it was already the case back then: https://www.sciencedirect.com/topics/engineering/hydrogen-production-cost https://www.sciencedirect.com/topics/engineering/hydrogen-pr...
- ZeroGravitas 5y ago
  I'm not sure exactly what you're referencing, as that seems a general topic you've linked to, but one of the articles I see at that link says that basically electrolizers are expensive enough that you need to be utilizing them at a high rate in order for it to make sense, and I think that's still true. > In case of PtG applications, electrolyzer utilization becomes a key parameter. To illustrate the resulting utilization of electrolyzers when run on “surplus” electricity alone it is helpful to plot the residual load duration curves for different penetration levels of intermittent renewables.21Figure 11.4 depicts two typical residual load duration curves for a 30% and 80% share of generation from intermittent renewables of total electricity demand.
  - Retric 5y ago
    As I said, it’s an outdated analysis the point was theses things are a long way from 24/7 operations and have been for a long time. “High electrolyzer utilization reduces the specific share of electrolyzer capital costs in hydrogen production costs; on the other hand, a higher utilization increases electricity costs, as hours of expensive electricity will increasingly be included. Hence, in order to minimize hydrogen costs, electrolyzer utilization has to be balanced with the electricity price.” Of course the specific utilization percentage varies based on how expensive the equipment, it’s overall efficiency, and grid spot prices. We don’t actually know how expensive it is at scale so picking exact percentages is impossible.
    - ZeroGravitas 5y ago
      Okay, there's a gap between requiring 24/7 usage, and "only exist for the purposes of using excess power that would otherwise go to waste" and I think we agree that electrolysis is somewhere in the middle of those two extremes.
      - Retric 5y ago
        If we are talking today then absolutely. However, the grid is expected to have a lot of unused capacity. California is already at the point where 5% of all solar power produced is wasted and people are still constantly adding solar because the current economic break even is ~50% of all solar produced being wasted. That would average around 4-5 hours a day of basically “free” electricity which isn’t quite enough, but at scale at scale electrolysis equipment is almost that cheap and will probably hit that point. This becomes more likely when you consider efficiency as a useful tradeoff. 40% efficiency at 2c/kWh or 20% efficiency at 1c/kWh potentially spend the same amount on electricity per kg of hydrogen but the second is likely much cheaper to build. You could potentially have several designs that get turned on or off depending on the current spot price.

hannob 5y ago

Unfortunately that's not the case. Electrolyseurs are expensive (though hopes are they're gonna get cheaper quickly, as there's a lot of investment in this sector right now). The economic balance of running an electrolyseur only part of the time is something to be worked out. Still the balance is almost certainly not "we need baseload".

Retric 5y ago
The cost of electricity is already vastly more import than the cost of an electrolyzer at scale. https://www.semanticscholar.org/paper/Economics-of-converting-renewable-power-to-hydrogen-Glenk-Reichelstein/d0580340e9bd6d6d89e9542ded212855a8294247 https://www.semanticscholar.org/paper/Economics-of-convertin... It’s to the point where even running 1/3 the time at the cost of 3x the equipment is likely a cost savings at scale assuming the local grid has a lot of wind/solar.