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The point is that no existing storage system is sufficient and thus solar and wind is really solar, wind, and fossil fuels. And nuclear power is indeed sufficie

The point is that no existing storage system is sufficient and thus solar and wind is really solar, wind, and fossil fuels. And nuclear power is indeed sufficient. They can indeed modulate power output, and we have the capacity to build them at the required scale. Some countries already have, like France. > Why does pumped hydro have to be close to transportation infrastructure, btw? Can one not build roads or rail lines? You can, but the more remote the build site the more expensive it becomes.

pfdietz 4y ago
Current nuclear technology isn't sufficient either. A world powered by nuclear burner reactors runs out of uranium very quickly. Breeder reactors or seawater uranium extraction would be needed, and neither of these are "existing" in the sense you're using for storage.
- Manuel_D 4y ago
  This is incorrect, even existing supplies with no different form of extraction would last over 200 years: https://www.scientificamerican.com/article/how-long-will-global-uranium-deposits-last/ https://www.scientificamerican.com/article/how-long-will-glo... Nuclear seawater extraction is already conducted, at a price of about $200 per pound [1]. Raw fuel extraction is a small portion of nuclear's cost (enrichment is a much bigger portion) so this is not a significant cost increase. 1. https://www.forbes.com/sites/jamesconca/2016/07/01/uranium-seawater-extraction-makes-nuclear-power-completely-renewable/?sh=5ad01bb0159a https://www.forbes.com/sites/jamesconca/2016/07/01/uranium-s...
  - pfdietz 4y ago
    200 years at today's consumption rate. To power the world with nuclear would require many more reactors. Current world average primary energy consumption is 18 TW, which is 6000 3 GWth reactors. That's an order of magnitude more than currently are in operation. Add in demand growth from industrializing countries and the uranium would last maybe a decade. Uranium availability is not an immediate problem if you assume nuclear remains a sideshow on the global energy stage. That's to assume nuclear is neither needed nor particularly useful for addressing global warming. Is that what you're assuming?
    - Manuel_D 4y ago
      Did you read the article? > However, seawater concentrations of uranium are controlled by steady-state, or pseudo-equilibrium, chemical reactions between waters and rocks on the Earth, both in the ocean and on land. And those rocks contain 100 trillion tons of uranium. So whenever uranium is extracted from seawater, more is leached from rocks to replace it, to the same concentration. It is impossible for humans to extract enough uranium over the next billion years to lower the overall seawater concentrations of uranium, even if nuclear provided 100% of our energy and our species lasted a billion years
      - pfdietz 4y ago
        Yes, I did read it. Did you lose track of what I said? I'll help by quoting myself: "Current nuclear technology isn't sufficient either. A world powered by nuclear burner reactors runs out of uranium very quickly. Breeder reactors or seawater uranium extraction would be needed, and neither of these are "existing" in the sense you're using for storage" (emphasis added) So, your comment about seawater there doesn't contradict what I wrote at all.
        Manuel_D 4y ago
        Again, from the same article: > And these advances by PNNL and ORNL have reduced the cost by a factor of four in just five years. But it’s still over $200/lb of U3O8, twice as much as it needs to be to replace mining uranium ore. > Fortunately, the cost of uranium is a small percentage of the cost of nuclear fuel, which is itself a small percentage of the cost of nuclear power. Over the last twenty years, uranium spot prices have varied between $10 and $120/lb of U3O8, mainly from changes in the availability of weapons-grade uranium to blend down to make reactor fuel. > So as the cost of extracting U from seawater falls to below $100/lb, it will become a commercially viable alternative to mining new uranium ore. But even at $200/lb of U3O8, it doesn’t add more than a small fraction of a cent per kWh to the cost of nuclear power. This is technology that actually has a demonstrated cost. Moreover it doesn't need to get cheaper at scale since raw extraction is such a small portion of nuclear power's cost. It's not like synthetic methane or hydrogen storage where it's all white papers promising cheap cost, but not actually delivering any storage systems at that cost.

pfdietz 4y ago

Current nuclear technology isn't sufficient either. A world powered by nuclear burner reactors runs out of uranium very quickly. Breeder reactors or seawater uranium extraction would be needed, and neither of these are "existing" in the sense you're using for storage.

Manuel_D 4y ago
This is incorrect, even existing supplies with no different form of extraction would last over 200 years: https://www.scientificamerican.com/article/how-long-will-global-uranium-deposits-last/ https://www.scientificamerican.com/article/how-long-will-glo... Nuclear seawater extraction is already conducted, at a price of about $200 per pound [1]. Raw fuel extraction is a small portion of nuclear's cost (enrichment is a much bigger portion) so this is not a significant cost increase. 1. https://www.forbes.com/sites/jamesconca/2016/07/01/uranium-seawater-extraction-makes-nuclear-power-completely-renewable/?sh=5ad01bb0159a https://www.forbes.com/sites/jamesconca/2016/07/01/uranium-s...
- pfdietz 4y ago
  200 years at today's consumption rate. To power the world with nuclear would require many more reactors. Current world average primary energy consumption is 18 TW, which is 6000 3 GWth reactors. That's an order of magnitude more than currently are in operation. Add in demand growth from industrializing countries and the uranium would last maybe a decade. Uranium availability is not an immediate problem if you assume nuclear remains a sideshow on the global energy stage. That's to assume nuclear is neither needed nor particularly useful for addressing global warming. Is that what you're assuming?
  - Manuel_D 4y ago
    Did you read the article? > However, seawater concentrations of uranium are controlled by steady-state, or pseudo-equilibrium, chemical reactions between waters and rocks on the Earth, both in the ocean and on land. And those rocks contain 100 trillion tons of uranium. So whenever uranium is extracted from seawater, more is leached from rocks to replace it, to the same concentration. It is impossible for humans to extract enough uranium over the next billion years to lower the overall seawater concentrations of uranium, even if nuclear provided 100% of our energy and our species lasted a billion years
    - pfdietz 4y ago
      Yes, I did read it. Did you lose track of what I said? I'll help by quoting myself: "Current nuclear technology isn't sufficient either. A world powered by nuclear burner reactors runs out of uranium very quickly. Breeder reactors or seawater uranium extraction would be needed, and neither of these are "existing" in the sense you're using for storage" (emphasis added) So, your comment about seawater there doesn't contradict what I wrote at all.
      - Manuel_D 4y ago
        Again, from the same article: > And these advances by PNNL and ORNL have reduced the cost by a factor of four in just five years. But it’s still over $200/lb of U3O8, twice as much as it needs to be to replace mining uranium ore. > Fortunately, the cost of uranium is a small percentage of the cost of nuclear fuel, which is itself a small percentage of the cost of nuclear power. Over the last twenty years, uranium spot prices have varied between $10 and $120/lb of U3O8, mainly from changes in the availability of weapons-grade uranium to blend down to make reactor fuel. > So as the cost of extracting U from seawater falls to below $100/lb, it will become a commercially viable alternative to mining new uranium ore. But even at $200/lb of U3O8, it doesn’t add more than a small fraction of a cent per kWh to the cost of nuclear power. This is technology that actually has a demonstrated cost. Moreover it doesn't need to get cheaper at scale since raw extraction is such a small portion of nuclear power's cost. It's not like synthetic methane or hydrogen storage where it's all white papers promising cheap cost, but not actually delivering any storage systems at that cost.