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The "near limitless energy" claim of articles like these is very deceptive. The true destination is perpetual heat generation, which is low grade energy and a p

The "near limitless energy" claim of articles like these is very deceptive. The true destination is perpetual heat generation, which is low grade energy and a potential pollutant on this planet. The only thing we can do with such amounts of heat to produce the kind of energy we need and consume is build thermo-electric power plants to generate electricity. Here is the crunch: > Thermoelectric power use has a significant impact on water resources and the power sector is highly dependent on these water resources; the United States Geological Survey (USGS) estimated on a national level that 41% of all freshwater withdrawals in the United States in 2005 were for thermoelectric power operations, primarily for cooling needs.[1] [1] Operational water consumption and withdrawal factors for electricity generating technologies - https://iopscience.iop.org/article/10.1088/1748-9326/7/4/045802/meta https://iopscience.iop.org/article/10.1088/1748-9326/7/4/045...

king_magic 7y ago
With this (absurd) line of thinking, we should probably just not generate any power at all.
- wffurr 7y ago
  The point is that even if unlimited cheap heat becomes possible, turning that heat into useful forms (e.g. electricity) has limits that we are already close to. I don't see how that observation is in any way absurd. It's actually quite helpful to counter the "fusion as a panacea" narrative with a dose of reality of how power plants actually work.
  - jimhefferon 7y ago
    We put the plant near a river. It intakes river water, which is heated to steam to make the electricity, and is then cooled and reused or released. I don't see how that is terrifically destructive; I must be missing something. Explain it to me, please? (Serious question.)
    - epistasis 7y ago
      Imagine that we decide to increase energy usage by 5x-10x, and increase size of the plant, and the change in river eater temperature goes up by that much. Eventually the plant starts to change the river water temperature to the degree that it changes the ecosystem. This is already regulated, see for example this discussion of monitoring systems for proving compliance: https://www.power-eng.com/articles/2007/01/external-temperature-monitoring-for-power-plants.html https://www.power-eng.com/articles/2007/01/external-temperat...
    - SECProto 7y ago
      How do you cool it down? The only way to cool one thing is to heat another. Evaporative cooling is usually the method if you must cool your water, but it has diminishing returns and isn't practical to cool all the way to inlet temperature (because source water is colder than the air wet-bulb temperature). This results in water above ambient being discharged to the environment, which affects fish and plant life in the water body.
    - jhayward 7y ago
      We already do that, and those nuclear power plants (and other thermal plants) already have to shut down under certain climate conditions to avoid damaging the local ecosystem by overheating it. [1] [1] https://www.chicagotribune.com/news/ct-xpm-2012-08-20-ct-met-nuclear-water-20120820-story.html https://www.chicagotribune.com/news/ct-xpm-2012-08-20-ct-met...
- strainer 7y ago
  Wind and solar do not require cooling or have problematic thermal emissions. It is possible for solar to have a slightly lower (or higher) albedo than ground it is situated, and possible for wind to cause some local heating from air mixing (with corresponding distance cooling) but these effects are much less intense than thermoelectric plants essential need to release Gigawatts of heat in order to produce gigawatts of electricity (in addition to the heat which the produced electricity ultimately results as).
  - pfdietz 7y ago
    Even if solar albedo is equal to the ground it was on, that will cause a net cooling at the solar collection site, since ~20% of the absorbed solar energy is converted to electrical power, not heat. The power then eventually gets converted to heat by the consumers, but that's true of power from any source.
acjohnson55 7y ago
But isn't water a renewable resource?
- epistasis 7y ago
  Thermoelectric plants often change their local ecosystem by raising the temperature of natural water bodies used for cooling. However, it doesn't have to. And in particular, as water becomes more constrained by growing population and climate change, using water the same way that it has in the past is becoming untenable. Recent regulations are starting to end "once through" use of water this way, which is leading to the shut down of older plants that are close to the end of their lifespan anyway. And then there are plants like this nuclear plant in Arizona which cools using treated sewage, which has almost zero impact: https://en.m.wikipedia.org/wiki/Palo_Verde_Nuclear_Generating_Station https://en.m.wikipedia.org/wiki/Palo_Verde_Nuclear_Generatin...
  - strainer 7y ago
    Afaik the arizona plant doesnt use sewage but grey water, from drains and canals and such. Large amounts of it, and it gets straight up evaporated. Grey water should ideally be remediated and used for irrigation, not just evaporated - not in desert regions at least. We will need to use water resources better! There are options for doing that, but no way to make thermoelectric power plant use insignificant.
- baq 7y ago
  Sometimes and not everywhere. The problem with water is that there’s usually too much or to little in the spot you want it. For cooling purposes the water should be of particular quality (eg fresh), so building on the beach comes with its own problems.
dmos62 7y ago
Apart from warming up the water, I take it there's nothing inherently pollutant about using it for cooling. Edit: On second read, your point is that heat is a pollutant itself. My next sci-fi daydream will be about cooling down the planet by converting atmospheric heat.
- deleted 7y ago
  [deleted]
thunderbird120 7y ago
1) This is an absurd complaint 2) It's not even totally accurate. Aneutronic fusion can create electricity directly from charged particles without going through the heat generation step[1]. It's an active area of research with the highest profile group working on it being TAE[2]. [1]https://en.wikipedia.org/wiki/Aneutronic_fusion https://en.wikipedia.org/wiki/Aneutronic_fusion [2]https://en.wikipedia.org/wiki/Tri_Alpha_Energy,_Inc https://en.wikipedia.org/wiki/Tri_Alpha_Energy,_Inc.
- pfdietz 7y ago
  The people associated with TAE were told 20 years ago that their scheme would straight up not work. https://www.researchgate.net/profile/Wallace_Manheimer/publication/235032059_Comments_on_the_Colliding_Beam_Fusion_Reactor_Proposed_by_Rostoker_Binderbauer_and_Monkhorst_for_Use_with_the_p-11B_Fusion_Reaction/links/00b7d53453384bee2e000000/Comments-on-the-Colliding-Beam-Fusion-Reactor-Proposed-by-Rostoker-Binderbauer-and-Monkhorst-for-Use-with-the-p-11B-Fusion-Reaction.pdf https://www.researchgate.net/profile/Wallace_Manheimer/publi... The story reminds me of Transatomic. Venture capital doesn't necessarily evaluate science well.
  - thunderbird120 7y ago
    That study was using assumptions based on a 1987 study which predicted that the fusion chain would result in 1 high energy and 2 low energy alpha particles. More recent results suggest that this is incorrect[1], with the reaction actually generating 2 high energy and 1 low energy alpha particles. This would push the CBFR method well within the realm of possibility. [1]https://www.sciencedirect.com/science/article/pii/S0370269310013626 https://www.sciencedirect.com/science/article/pii/S037026931...
    - pfdietz 7y ago
      Your argument there does exactly nothing to counter the criticisms in the paper I cited. It's totally irrelevant.
- wffurr 7y ago
snarfy 7y ago
Aneutronic fusion [1] produces only fast moving charged particles. You can call fast moving particles 'heat', but if they are charged you don't need thermo-electric to generate power. It already is useful power. A fusion plant capable of fusing boron + hydrogen basically produces a 2 million volt battery. [1] - https://en.wikipedia.org/wiki/Aneutronic_fusion https://en.wikipedia.org/wiki/Aneutronic_fusion
- strainer 7y ago
  That sounds cool (sorry couldn't resist) but very much a long shot as the wikipedia article itself notes : "None of these efforts has yet tested its device with hydrogen–boron fuel, so the anticipated performance is based on extrapolating from theory, experimental results with other fuels and from simulations." Also, even with good proportion of energy contained in such particles to somehow tap efficiently in practice, the reactor itself is still going to need a great deal of cooling, just to stop it melting. Also the article we are commenting on, does not seem to concern such a reactor.
mrob 7y ago
Heat pollution is a very minor concern. From "Sustainable Energy – without the hot air" by David MacKay, pages 170 to 171: "let’s assume that in 100 years or so, the world population is 10 billion, and everyone is living at a European standard of living, using 125 kWh per day derived from fossil sources, from nuclear power, or from mined geothermal power. The area of the earth per person would be 51 000 m^2. Dividing the power per person by the area per person, we find that the extra power contributed by human energy use would be 0.1 W/m^2. That’s one fortieth of the 4 W/m^2 that we’re currently fretting about, and a little smaller than the 0.25 W/m^2 effect of solar variations. So yes, under these assumptions, human power production would /just/ show up as a contributor to global climate change." http://www.withouthotair.com/c24/page_170.shtml http://www.withouthotair.com/c24/page_170.shtml
- epistasis 7y ago
  That's assuming that we use the same order of magnitude of energy. If the promise of a technology is that we can use several orders of magnitude more energy per person, then that .1W/m2 could become 10W/m2. If we don't increase energy usage, sure, no big deal, but the entire point of pursuing fusion is to enable fantastically more energy usage, at least as I see it. So we also need a second revolutionary technology, direct conversion of energy rather than thermal energy conversion. Fusion will never be a cost winner if it's using thermal energy conversion, anyway. Solar and wind will soon undercut the steam turbine lifetime costs, so even if the fusion part were free, there's no way for heat engines to compete on cost.
  - tomatotomato37 7y ago
    I have the feeling when we do hit the first milestone on the Kardashev scale that we'll have a lot more options available to mitigate terrestrial concerns, so let's just concentrate on getting there without killing the planet first
    - mrec 7y ago
      I've never understood why people get excited about the Kardashev scale. It's a proposal for classifying civilizations which has no place for the one and only civilization we actually know of. Doesn't that make it kind of silly?
pfdietz 7y ago
The problem here is not direct thermal pollution, it's that thermal power plants in general -- nuclear, fossil, solar, geothermal -- are becoming obsolete. https://www.forbes.com/sites/amorylovins/2014/09/07/fusion-power-the-case-of-the-wrong-competitors/ https://www.forbes.com/sites/amorylovins/2014/09/07/fusion-p...
bufferoverflow 7y ago
Heat, unlike CO2, is relatively easy to deal with - install cheap giant mirrors in deserts, reflect a ton of heat back into space. Space blanket type of mirrors are VERY cheap, especially at large scales.
- strainer 7y ago
  I think we may find such schemes happen as we miss our CO2 targets and may need to urgently limit global temperature rise. A controllable sun shade in space would be my preference over consigning regions of earth to heat dumping grounds. But such geohacks will not be able to target the ecological disruption of local heat pollution or make water resources abundant where they are scarce, they will just perhaps be able to ameliorate a global emergency.

king_magic 7y ago

With this (absurd) line of thinking, we should probably just not generate any power at all.

wffurr 7y ago
The point is that even if unlimited cheap heat becomes possible, turning that heat into useful forms (e.g. electricity) has limits that we are already close to. I don't see how that observation is in any way absurd. It's actually quite helpful to counter the "fusion as a panacea" narrative with a dose of reality of how power plants actually work.
- jimhefferon 7y ago
  We put the plant near a river. It intakes river water, which is heated to steam to make the electricity, and is then cooled and reused or released. I don't see how that is terrifically destructive; I must be missing something. Explain it to me, please? (Serious question.)
  - epistasis 7y ago
    Imagine that we decide to increase energy usage by 5x-10x, and increase size of the plant, and the change in river eater temperature goes up by that much. Eventually the plant starts to change the river water temperature to the degree that it changes the ecosystem. This is already regulated, see for example this discussion of monitoring systems for proving compliance: https://www.power-eng.com/articles/2007/01/external-temperature-monitoring-for-power-plants.html https://www.power-eng.com/articles/2007/01/external-temperat...
  - SECProto 7y ago
    How do you cool it down? The only way to cool one thing is to heat another. Evaporative cooling is usually the method if you must cool your water, but it has diminishing returns and isn't practical to cool all the way to inlet temperature (because source water is colder than the air wet-bulb temperature). This results in water above ambient being discharged to the environment, which affects fish and plant life in the water body.
  - jhayward 7y ago
    We already do that, and those nuclear power plants (and other thermal plants) already have to shut down under certain climate conditions to avoid damaging the local ecosystem by overheating it. [1] [1] https://www.chicagotribune.com/news/ct-xpm-2012-08-20-ct-met-nuclear-water-20120820-story.html https://www.chicagotribune.com/news/ct-xpm-2012-08-20-ct-met...
strainer 7y ago
Wind and solar do not require cooling or have problematic thermal emissions. It is possible for solar to have a slightly lower (or higher) albedo than ground it is situated, and possible for wind to cause some local heating from air mixing (with corresponding distance cooling) but these effects are much less intense than thermoelectric plants essential need to release Gigawatts of heat in order to produce gigawatts of electricity (in addition to the heat which the produced electricity ultimately results as).
- pfdietz 7y ago
  Even if solar albedo is equal to the ground it was on, that will cause a net cooling at the solar collection site, since ~20% of the absorbed solar energy is converted to electrical power, not heat. The power then eventually gets converted to heat by the consumers, but that's true of power from any source.

acjohnson55 7y ago

But isn't water a renewable resource?

epistasis 7y ago
Thermoelectric plants often change their local ecosystem by raising the temperature of natural water bodies used for cooling. However, it doesn't have to. And in particular, as water becomes more constrained by growing population and climate change, using water the same way that it has in the past is becoming untenable. Recent regulations are starting to end "once through" use of water this way, which is leading to the shut down of older plants that are close to the end of their lifespan anyway. And then there are plants like this nuclear plant in Arizona which cools using treated sewage, which has almost zero impact: https://en.m.wikipedia.org/wiki/Palo_Verde_Nuclear_Generating_Station https://en.m.wikipedia.org/wiki/Palo_Verde_Nuclear_Generatin...
- strainer 7y ago
  Afaik the arizona plant doesnt use sewage but grey water, from drains and canals and such. Large amounts of it, and it gets straight up evaporated. Grey water should ideally be remediated and used for irrigation, not just evaporated - not in desert regions at least. We will need to use water resources better! There are options for doing that, but no way to make thermoelectric power plant use insignificant.
baq 7y ago
Sometimes and not everywhere. The problem with water is that there’s usually too much or to little in the spot you want it. For cooling purposes the water should be of particular quality (eg fresh), so building on the beach comes with its own problems.

dmos62 7y ago

Apart from warming up the water, I take it there's nothing inherently pollutant about using it for cooling. Edit: On second read, your point is that heat is a pollutant itself. My next sci-fi daydream will be about cooling down the planet by converting atmospheric heat.

deleted 7y ago
[deleted]

thunderbird120 7y ago

1) This is an absurd complaint 2) It's not even totally accurate. Aneutronic fusion can create electricity directly from charged particles without going through the heat generation step[1]. It's an active area of research with the highest profile group working on it being TAE[2]. [1]https://en.wikipedia.org/wiki/Aneutronic_fusion https://en.wikipedia.org/wiki/Aneutronic_fusion [2]https://en.wikipedia.org/wiki/Tri_Alpha_Energy,_Inc https://en.wikipedia.org/wiki/Tri_Alpha_Energy,_Inc.

pfdietz 7y ago
The people associated with TAE were told 20 years ago that their scheme would straight up not work. https://www.researchgate.net/profile/Wallace_Manheimer/publication/235032059_Comments_on_the_Colliding_Beam_Fusion_Reactor_Proposed_by_Rostoker_Binderbauer_and_Monkhorst_for_Use_with_the_p-11B_Fusion_Reaction/links/00b7d53453384bee2e000000/Comments-on-the-Colliding-Beam-Fusion-Reactor-Proposed-by-Rostoker-Binderbauer-and-Monkhorst-for-Use-with-the-p-11B-Fusion-Reaction.pdf https://www.researchgate.net/profile/Wallace_Manheimer/publi... The story reminds me of Transatomic. Venture capital doesn't necessarily evaluate science well.
- thunderbird120 7y ago
  That study was using assumptions based on a 1987 study which predicted that the fusion chain would result in 1 high energy and 2 low energy alpha particles. More recent results suggest that this is incorrect[1], with the reaction actually generating 2 high energy and 1 low energy alpha particles. This would push the CBFR method well within the realm of possibility. [1]https://www.sciencedirect.com/science/article/pii/S0370269310013626 https://www.sciencedirect.com/science/article/pii/S037026931...
  - pfdietz 7y ago
    Your argument there does exactly nothing to counter the criticisms in the paper I cited. It's totally irrelevant.
wffurr 7y ago

snarfy 7y ago

Aneutronic fusion [1] produces only fast moving charged particles. You can call fast moving particles 'heat', but if they are charged you don't need thermo-electric to generate power. It already is useful power. A fusion plant capable of fusing boron + hydrogen basically produces a 2 million volt battery. [1] - https://en.wikipedia.org/wiki/Aneutronic_fusion https://en.wikipedia.org/wiki/Aneutronic_fusion

strainer 7y ago
That sounds cool (sorry couldn't resist) but very much a long shot as the wikipedia article itself notes : "None of these efforts has yet tested its device with hydrogen–boron fuel, so the anticipated performance is based on extrapolating from theory, experimental results with other fuels and from simulations." Also, even with good proportion of energy contained in such particles to somehow tap efficiently in practice, the reactor itself is still going to need a great deal of cooling, just to stop it melting. Also the article we are commenting on, does not seem to concern such a reactor.

mrob 7y ago

Heat pollution is a very minor concern. From "Sustainable Energy – without the hot air" by David MacKay, pages 170 to 171: "let’s assume that in 100 years or so, the world population is 10 billion, and everyone is living at a European standard of living, using 125 kWh per day derived from fossil sources, from nuclear power, or from mined geothermal power. The area of the earth per person would be 51 000 m^2. Dividing the power per person by the area per person, we find that the extra power contributed by human energy use would be 0.1 W/m^2. That’s one fortieth of the 4 W/m^2 that we’re currently fretting about, and a little smaller than the 0.25 W/m^2 effect of solar variations. So yes, under these assumptions, human power production would /just/ show up as a contributor to global climate change." http://www.withouthotair.com/c24/page_170.shtml http://www.withouthotair.com/c24/page_170.shtml

epistasis 7y ago
That's assuming that we use the same order of magnitude of energy. If the promise of a technology is that we can use several orders of magnitude more energy per person, then that .1W/m2 could become 10W/m2. If we don't increase energy usage, sure, no big deal, but the entire point of pursuing fusion is to enable fantastically more energy usage, at least as I see it. So we also need a second revolutionary technology, direct conversion of energy rather than thermal energy conversion. Fusion will never be a cost winner if it's using thermal energy conversion, anyway. Solar and wind will soon undercut the steam turbine lifetime costs, so even if the fusion part were free, there's no way for heat engines to compete on cost.
- tomatotomato37 7y ago
  I have the feeling when we do hit the first milestone on the Kardashev scale that we'll have a lot more options available to mitigate terrestrial concerns, so let's just concentrate on getting there without killing the planet first
  - mrec 7y ago
    I've never understood why people get excited about the Kardashev scale. It's a proposal for classifying civilizations which has no place for the one and only civilization we actually know of. Doesn't that make it kind of silly?

pfdietz 7y ago

The problem here is not direct thermal pollution, it's that thermal power plants in general -- nuclear, fossil, solar, geothermal -- are becoming obsolete. https://www.forbes.com/sites/amorylovins/2014/09/07/fusion-power-the-case-of-the-wrong-competitors/ https://www.forbes.com/sites/amorylovins/2014/09/07/fusion-p...

bufferoverflow 7y ago

Heat, unlike CO2, is relatively easy to deal with - install cheap giant mirrors in deserts, reflect a ton of heat back into space. Space blanket type of mirrors are VERY cheap, especially at large scales.

strainer 7y ago
I think we may find such schemes happen as we miss our CO2 targets and may need to urgently limit global temperature rise. A controllable sun shade in space would be my preference over consigning regions of earth to heat dumping grounds. But such geohacks will not be able to target the ecological disruption of local heat pollution or make water resources abundant where they are scarce, they will just perhaps be able to ameliorate a global emergency.