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The big issue I'm not seeing any discussion of in the comments here is cost per watt. We can divide this into two big buckets: the cost of heat, and the cost o

by kragen 2y ago

The big issue I'm not seeing any discussion of in the comments here is cost per watt. We can divide this into two big buckets: the cost of heat, and the cost of turning heat into electricity. This article is all about how geothermal can reduce the cost of heat (especially EGS), how immense that resource is, and how it's basically carbon-free. But I think the bigger issue is the second bucket: the cost of turning heat into electricity seems to still be too high to compete with solar and wind, even if the heat were free. The article doesn't mention this at all, but I think it's the crucial issue. I don't understand why heat engines are still so expensive 250 years after James Watt, but they do seem to be. In January I came across https://www.eia.gov/analysis/studies/powerplants/capitalcost/pdf/capital_cost_AEO2020.pdf https://www.eia.gov/analysis/studies/powerplants/capitalcost... which is an EIA-commissioned study of the capital cost of building different kinds of power plants, and I am hoping that studying it will give me the answer. The article mentions the intermittency of wind and solar a few times as if it were a showstopper—as if no amount of solar and wind power generation capacity could be an adequate substitute for any amount of geothermal power, because you don't have solar power at night, for example. But actually that's just a question of how much it costs to store the energy until it's needed or transmit it from where it's still being produced. We have upper bounds on those storage costs from existing utility-scale storage facilities, and they already look pretty okay. We can expect that they will get cheaper over time.

micro2588 2y ago
You are right there is no getting around that relatively low grade heat in geothermal is a big barrier for scaling in terms of energy production. Binary /organic rankine cycle geothermal plants used for these low / medium temperature resources operate at ~10% efficiency. Dry / flash steam resources are higher but produce waste in terms of emitted GHG and / or crap in the geothermal brine.
- kragen 2y ago
  Deep geothermal promises to provide what is usually considered high-grade heat (800+°), but what I'm trying to understand is how cheaply you can convert that high-grade heat into electricity, because the answer seems to be "far too expensively to be competitive with wind and solar".
  - micro2588 2y ago
    Supercritical geothermal is similar to talking about the economics of fusion. There is a DOE enhanced geothermal test site near the Newberry Volcano in central Oregon which has temperatures close to this range at reachable depths. That is more of a demonstration site for drilling technology.
    - kragen 2y ago
      Yes, but if (as I am claiming) there's no way to economically turn heat into electricity, it's irrelevant whether supercritical geothermal steam costs trillions of dollars per borehole or is free; either way it's uneconomic as a source of electricity.
filleokus 2y ago
> as if no amount of solar and wind power generation capacity could be an adequate substitute for any amount of geothermal power, because you don't have solar power at night, for example. But actually that's just a question of how much it costs to store the energy until it's needed or transmit it from where it's still being produced. I guess this depends on the region, at least to some extent. In Northern Europe we've had these periods during fall/winter in recent years where it's cold, essentially dark, and (worst) no wind. It's not really feasible to store ≈multiple days of consumption for tens of millions of people. In three of the four Swedish price regions I think we are essentially in a situation now where wind power is "worthless" and can't be built out any more, at least not without major changes to consumption patterns. When the wind is blowing there is such high production that prices go almost to 0, and the operators earn ish nothing, and when prices go up there is no wind so no-one can produce.
- kragen 2y ago
  Storing multiple days of consumption is feasible but definitely harder than the usual case of storing hours. The pricing problem sounds like an artifact of how you've structured the market, not a fundamental obstacle to the profitability of intermittent power sources. An alternative structure that would solve the problem would be for generation operators to buy put options for energy they expect to be able to produce, eliminating the risk of a price collapse. Consumers who want access to such intermittent energy would have to write those put options, which would be limited to particular times on particular days when they could use the energy. Having written the option, they would have to accept the generation operator's decision whether or not to exercise it. Utility-scale storage providers could write puts for low-demand times and buy puts for high-demand times, or they could write puts for low-demand times, write futures contracts for high-demand times, and make up the shortfall on the spot market. This might produce major changes in consumption patterns, but, more likely, would enable continued investment to minimize those changes.
  - Paradigma11 2y ago
    I think this would show the true cost and unviability of the system. Which would be good.
simplysublime 2y ago
Cost is an artificial construct (see: oil subsidies, corn subsidies, EV subsidies, and so on). "It's too expensive!" is such an uncreative response to technology we desperately need to stop overheating the planet.
- JumpCrisscross 2y ago
  Cost describes tradeoffs. Environmentalists ignoring costs and generating a backlash that completely undoes their work shouldn’t be a lesson needing relearning twice a generation.
  - kragen 2y ago
    Thank you for saying this. I didn't have the patience, and it's a rather subtle issue with a lot of nuance. Tradeoffs are indeed inherent in any human effort, but actual market prices are an imperfect reflection reflection of those inherent tradeoffs, and can indeed be distorted by subsidies, externalities, etc. And often tradeoffs cannot really be reduced to a single scalar the way costs do—not everything can be traded off against everything else. Yet that observation does not mean there aren't any real tradeoffs, or real tradeoffs that can be reduced to a single number. Also, while this god's-eye viewpoint of the options available for collective action by humanity as a whole is important, for most of us it isn't useful tactical or even strategic information about the possible courses of action we could undertake to affect the world, much less our own lives. It's most useful if you're a billionaire, a Central Committee member, or a Civ player. For the rest of us, even Bilderbergers and the like, those subsidy-distorted costs and the failures of collective action that produce them are merely facts about the world; we cannot make them evaporate in a puff of logic by pointing out their irrationality.

by kragen 2y ago

micro2588 2y ago

You are right there is no getting around that relatively low grade heat in geothermal is a big barrier for scaling in terms of energy production. Binary /organic rankine cycle geothermal plants used for these low / medium temperature resources operate at ~10% efficiency. Dry / flash steam resources are higher but produce waste in terms of emitted GHG and / or crap in the geothermal brine.

kragen 2y ago
Deep geothermal promises to provide what is usually considered high-grade heat (800+°), but what I'm trying to understand is how cheaply you can convert that high-grade heat into electricity, because the answer seems to be "far too expensively to be competitive with wind and solar".
- micro2588 2y ago
  Supercritical geothermal is similar to talking about the economics of fusion. There is a DOE enhanced geothermal test site near the Newberry Volcano in central Oregon which has temperatures close to this range at reachable depths. That is more of a demonstration site for drilling technology.
  - kragen 2y ago
    Yes, but if (as I am claiming) there's no way to economically turn heat into electricity, it's irrelevant whether supercritical geothermal steam costs trillions of dollars per borehole or is free; either way it's uneconomic as a source of electricity.

filleokus 2y ago

> as if no amount of solar and wind power generation capacity could be an adequate substitute for any amount of geothermal power, because you don't have solar power at night, for example. But actually that's just a question of how much it costs to store the energy until it's needed or transmit it from where it's still being produced. I guess this depends on the region, at least to some extent. In Northern Europe we've had these periods during fall/winter in recent years where it's cold, essentially dark, and (worst) no wind. It's not really feasible to store ≈multiple days of consumption for tens of millions of people. In three of the four Swedish price regions I think we are essentially in a situation now where wind power is "worthless" and can't be built out any more, at least not without major changes to consumption patterns. When the wind is blowing there is such high production that prices go almost to 0, and the operators earn ish nothing, and when prices go up there is no wind so no-one can produce.

kragen 2y ago
Storing multiple days of consumption is feasible but definitely harder than the usual case of storing hours. The pricing problem sounds like an artifact of how you've structured the market, not a fundamental obstacle to the profitability of intermittent power sources. An alternative structure that would solve the problem would be for generation operators to buy put options for energy they expect to be able to produce, eliminating the risk of a price collapse. Consumers who want access to such intermittent energy would have to write those put options, which would be limited to particular times on particular days when they could use the energy. Having written the option, they would have to accept the generation operator's decision whether or not to exercise it. Utility-scale storage providers could write puts for low-demand times and buy puts for high-demand times, or they could write puts for low-demand times, write futures contracts for high-demand times, and make up the shortfall on the spot market. This might produce major changes in consumption patterns, but, more likely, would enable continued investment to minimize those changes.
- Paradigma11 2y ago
  I think this would show the true cost and unviability of the system. Which would be good.

simplysublime 2y ago

Cost is an artificial construct (see: oil subsidies, corn subsidies, EV subsidies, and so on). "It's too expensive!" is such an uncreative response to technology we desperately need to stop overheating the planet.

JumpCrisscross 2y ago
Cost describes tradeoffs. Environmentalists ignoring costs and generating a backlash that completely undoes their work shouldn’t be a lesson needing relearning twice a generation.
- kragen 2y ago
  Thank you for saying this. I didn't have the patience, and it's a rather subtle issue with a lot of nuance. Tradeoffs are indeed inherent in any human effort, but actual market prices are an imperfect reflection reflection of those inherent tradeoffs, and can indeed be distorted by subsidies, externalities, etc. And often tradeoffs cannot really be reduced to a single scalar the way costs do—not everything can be traded off against everything else. Yet that observation does not mean there aren't any real tradeoffs, or real tradeoffs that can be reduced to a single number. Also, while this god's-eye viewpoint of the options available for collective action by humanity as a whole is important, for most of us it isn't useful tactical or even strategic information about the possible courses of action we could undertake to affect the world, much less our own lives. It's most useful if you're a billionaire, a Central Committee member, or a Civ player. For the rest of us, even Bilderbergers and the like, those subsidy-distorted costs and the failures of collective action that produce them are merely facts about the world; we cannot make them evaporate in a puff of logic by pointing out their irrationality.