7 ms·

That is not renewable, it's just a very large source of non-renewable fuel.

by dgemm 7y ago

DennisP 7y ago
Actually, since uranium in the ocean is at equilibrium, if we take some out then the concentration will go back up as more uranium is dissolved from rocks. Of course it will run out eventually but so will the sun, in a similar amount of time.
manfredo 7y ago
There's an estimated 2 billion years worth of dissolved uranium. Not truly renewable I suppose, but by that metric solar power isn't renewable either. Eventually all the hydrogen in th sun will be fused.
- pfdietz 7y ago
  You have mangled your data there. That claim is incorrect.
  - manfredo 7y ago
    This estimate says a billion years: https://www.forbes.com/sites/jamesconca/2016/07/01/uranium-seawater-extraction-makes-nuclear-power-completely-renewable/ https://www.forbes.com/sites/jamesconca/2016/07/01/uranium-s...
    - pfdietz 7y ago
      Um, no it doesn't. It claims that dissolved U would be replenished faster than we'd u se it (but that claim is wrong, I think); it doesn't say the U that us currently dissolved would last a billion years.
      - wahern 7y ago
        FWIW, this might be the primary source everybody is unintentionally quoting, or at least much closer to the primary source: > Although the concentration of uranium is quite low, about 3.3 ppb (parts per billion) in seawater of average oceanic salinity, the amount present in the total volume of the oceans is very great, some 4.5 billion tonnes. Of this, perhaps only that uranium contained in the upper 100 meters or so of the surface well-mixed layer should be considered accessible for recovery, some 160 million tonnes. Practically speaking, the amount contained in the ocean surface layers is unlimited with respect to large scale extraction in the forseeable future. This results from the replenishment by continental weathering and river runoff being much larger than forseeable extraction rates. ... > 1) The surface waters of the oceans comprise a virtually inexhaustible uranium resource of some 160 million tonnes, extractible indefinitely at a rate of a few thousand tonnes per year. Exxon Nuclear Company, "EXTRACTION OF URANIUM FROM SEAWATER: EVALUATION OF URANIUM RESOURCES AND PLANT SITING, VOLUME I", pp 6-7, 9, February 1979, https://www.osti.gov/servlets/purl/6191296 https://www.osti.gov/servlets/purl/6191296 The above quotes are from the executive summary. Page 35 has the money quote: > This represents an influx of about 9000 tonnes annually. Which supports your contention that sea water CANNOT provide an endless supply considering that current annual consumption is ~90,000 tonnes, 10x the replacement rate. EDIT: s/CANNOT NOT/CANNOT/
        pfdietz 7y ago
        The problem with pointing to the influx from rivers is that you also have to look at the outflow of uranium (and there must be such an outflow, probably reduction of uranium to insoluble U(IV) in sediments, since it's in steady state.) Any human extraction is on top of this existing outflow, it doesn't replace it.
        manfredo 7y ago
        The outflow is from the earth's crust at the bottom of the ocean. Sure, it doesn't get replaced. But there's enough uranium to last on the order of billions of years. By this logic, solar power isn't renewable either because the hydrogen in the sun doesn't get replaced.
      - manfredo 7y ago
        > 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.
dredmorbius 7y ago
As someone strongly critical of orthodox economic treatment of pricing for nonrenewable resources, especially fuels, I'm still inclined to say that there is a point at which the distinction is irrelevant. Whether or not nuclear fission meets this bar isn't clear (though I suspect it doesn't). When the US was first making the switch from wood to coal as a principle fuel, in the 1880s, the argument in contemporaneous accounts was that a small fraction of the probable reserves of coal would serve all energy needs for millions of years, given that perennial caveat, at present rates of consumption. What happened, of course, was that rates of consumption increased somewhat. Coal went from fueling a small number of structural heating, locomotion, and smelting uses to vastly expanded railroad, steelmaking, and most especially, electrical generation uses. Trainloads of coal arrive daily at power plants, still. Others are located at mineheads themselves as electrons transport more readily than lumps of fossilised tree. The Jevons paradox is a mighty bastard. By present estimates, again, at present values of consumption, coal reserves are estimated at 100-300 years. At present rates of electrical energy generation, existing terrestrial (non-oceanic) uranium would suffice for fewer than two decades worth of energy use. When you factor in even probable growth due to: - Extending Western standards of living to another five billions of the world's population. - Expansion of total population from 7.5 billions to 11-12 billions. - Continued "normal" economic growth at 2-3% per annum, that is, doubling every 25-30 years, roughly. ... the total energy requirements increase tremendously. (Note that renewables also strain to keep up with such growth -- my sense is that the fact that incident solar power on Earth of some 7,000x present human energy consumption actually represents a dangerously narrow margin of safety.) I'd worked out at one point the remaining reserves given some rate of projected annual growth, a fairly simple application of exponential math. The numbers are exceedingly sobering. TL;DR: If there is some putatively nonrenewable fuel source whose reserves would extend to some point in time beyond the viability of some specified landmark (h. sapiens as a viable species, C3 photosynthesis on Earth, etc., variously a few million to about 800 million years), then the resource is not meaningfully constrained, and we can make reasonable use of it. But given any notion of continued exponential growth, which is to say, a constant percentage increase in economic activity, given all available history, if not some putative but very-much-unproved virtualisation-of-activity hypotheses, that's a high bar to meet.
- 7y ago

That is not renewable, it's just a very large source of non-renewable fuel.

by dgemm 7y ago

That is not renewable, it's just a very large source of non-renewable fuel.

Actually, since uranium in the ocean is at equilibrium, if we take some out then the concentration will go back up as more uranium is dissolved from rocks. Of course it will run out eventually but so will the sun, in a similar amount of time.

manfredo 7y ago

There's an estimated 2 billion years worth of dissolved uranium. Not truly renewable I suppose, but by that metric solar power isn't renewable either. Eventually all the hydrogen in th sun will be fused.

pfdietz 7y ago
You have mangled your data there. That claim is incorrect.
- manfredo 7y ago
  This estimate says a billion years: https://www.forbes.com/sites/jamesconca/2016/07/01/uranium-seawater-extraction-makes-nuclear-power-completely-renewable/ https://www.forbes.com/sites/jamesconca/2016/07/01/uranium-s...
  - pfdietz 7y ago
    Um, no it doesn't. It claims that dissolved U would be replenished faster than we'd u se it (but that claim is wrong, I think); it doesn't say the U that us currently dissolved would last a billion years.
    - wahern 7y ago
      FWIW, this might be the primary source everybody is unintentionally quoting, or at least much closer to the primary source: > Although the concentration of uranium is quite low, about 3.3 ppb (parts per billion) in seawater of average oceanic salinity, the amount present in the total volume of the oceans is very great, some 4.5 billion tonnes. Of this, perhaps only that uranium contained in the upper 100 meters or so of the surface well-mixed layer should be considered accessible for recovery, some 160 million tonnes. Practically speaking, the amount contained in the ocean surface layers is unlimited with respect to large scale extraction in the forseeable future. This results from the replenishment by continental weathering and river runoff being much larger than forseeable extraction rates. ... > 1) The surface waters of the oceans comprise a virtually inexhaustible uranium resource of some 160 million tonnes, extractible indefinitely at a rate of a few thousand tonnes per year. Exxon Nuclear Company, "EXTRACTION OF URANIUM FROM SEAWATER: EVALUATION OF URANIUM RESOURCES AND PLANT SITING, VOLUME I", pp 6-7, 9, February 1979, https://www.osti.gov/servlets/purl/6191296 https://www.osti.gov/servlets/purl/6191296 The above quotes are from the executive summary. Page 35 has the money quote: > This represents an influx of about 9000 tonnes annually. Which supports your contention that sea water CANNOT provide an endless supply considering that current annual consumption is ~90,000 tonnes, 10x the replacement rate. EDIT: s/CANNOT NOT/CANNOT/
      - pfdietz 7y ago
        The problem with pointing to the influx from rivers is that you also have to look at the outflow of uranium (and there must be such an outflow, probably reduction of uranium to insoluble U(IV) in sediments, since it's in steady state.) Any human extraction is on top of this existing outflow, it doesn't replace it.
        manfredo 7y ago
        The outflow is from the earth's crust at the bottom of the ocean. Sure, it doesn't get replaced. But there's enough uranium to last on the order of billions of years. By this logic, solar power isn't renewable either because the hydrogen in the sun doesn't get replaced.
    - manfredo 7y ago
      > 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.

dredmorbius 7y ago

As someone strongly critical of orthodox economic treatment of pricing for nonrenewable resources, especially fuels, I'm still inclined to say that there is a point at which the distinction is irrelevant. Whether or not nuclear fission meets this bar isn't clear (though I suspect it doesn't). When the US was first making the switch from wood to coal as a principle fuel, in the 1880s, the argument in contemporaneous accounts was that a small fraction of the probable reserves of coal would serve all energy needs for millions of years, given that perennial caveat, at present rates of consumption. What happened, of course, was that rates of consumption increased somewhat. Coal went from fueling a small number of structural heating, locomotion, and smelting uses to vastly expanded railroad, steelmaking, and most especially, electrical generation uses. Trainloads of coal arrive daily at power plants, still. Others are located at mineheads themselves as electrons transport more readily than lumps of fossilised tree. The Jevons paradox is a mighty bastard. By present estimates, again, at present values of consumption, coal reserves are estimated at 100-300 years. At present rates of electrical energy generation, existing terrestrial (non-oceanic) uranium would suffice for fewer than two decades worth of energy use. When you factor in even probable growth due to: - Extending Western standards of living to another five billions of the world's population. - Expansion of total population from 7.5 billions to 11-12 billions. - Continued "normal" economic growth at 2-3% per annum, that is, doubling every 25-30 years, roughly. ... the total energy requirements increase tremendously. (Note that renewables also strain to keep up with such growth -- my sense is that the fact that incident solar power on Earth of some 7,000x present human energy consumption actually represents a dangerously narrow margin of safety.) I'd worked out at one point the remaining reserves given some rate of projected annual growth, a fairly simple application of exponential math. The numbers are exceedingly sobering. TL;DR: If there is some putatively nonrenewable fuel source whose reserves would extend to some point in time beyond the viability of some specified landmark (h. sapiens as a viable species, C3 photosynthesis on Earth, etc., variously a few million to about 800 million years), then the resource is not meaningfully constrained, and we can make reasonable use of it. But given any notion of continued exponential growth, which is to say, a constant percentage increase in economic activity, given all available history, if not some putative but very-much-unproved virtualisation-of-activity hypotheses, that's a high bar to meet.

7y ago