4 ms·

Something I wondered about fusion is, where does all that 'excess energy' go? I mean don't understand me wrong, it is obvious that is a much better form of ene

by sva_ 4y ago

Something I wondered about fusion is, where does all that 'excess energy' go? I mean don't understand me wrong, it is obvious that is a much better form of energy release than all the other forms of energy production we have; but let us consider we manage to gain energy from fusion, the electricity released still releases heat, so how does it dissipate, if we have near-infitite energy, and anyone can spend as much as they want?

deleted 4y ago
[deleted]
orzig 4y ago
It is a valid question, but to put it in perspective, the sun bathes us in dramatically more kWh than we need to annually power the world every few minutes. So fusion would be a drop in the bucket at a global scale.
- adrian_b 4y ago
  In the beginning, of course. Nevertheless, the heating of the Earth puts a limit on the total usable nuclear power on Earth, both fission and fusion, it cannot be "infinite", but it must remain forever a small fraction of the power of the incoming Solar radiation, otherwise it would cause an excessive heating of the Earth by itself.
  - willis936 4y ago
    Ever getting close to this point is what is considered a "good problem". We are always teetering on the edge of oblivion. Being so wildly successful that our industrial heat rivals that of the incident energy of the sun would be incredible. No problems humans have ever faced would be in living memory (including mortality). This is a science fiction future that does not need planning from the minds of today. It would also have many solutions related to adjusting albedo.
hobscoop 4y ago
It'll ultimately be dissipated by infrared radiation into space. Earth receives something like 173,000 terawatts of radiation from the sun; this is equal to the amount radiated out as infrared, except for the "radiative forcing" which is the amount by which the world is heating. Radiative forcing is currently something like 1000 TW. All of human civilization is powered by something like 20 TW. If we want to stop global heating we need to use a fraction of those 20 TW to "turn the ship" of size 1000 TW.
MaxDPS 4y ago
I'd imagine the excess energy goes out into space. They key difference between nuclear and fossil fuels is the emissions each generates. Fossil fuels burn into greenhouse gasses which trap in heat. If we switch to nuclear, those greenhouse gasses won't accumulate as much.
- freeflight 4y ago
  The near-perfect vacuum of space actually makes it quite bad at absorbing heat, that's why anything we put up there, like space stations and satellites need huge radiators to keep everything cool enough to actually operate. While thermal pollution in Earths atmosphere is a very real and relevant issue with energy generation and all kinds of other human activities; A whole bunch of French fission nuclear reactors are regularly shut/throttled down during summer heat waves due to lack of appropriate cooling. The combination of these factors sometimes makes me wonder if the game Oxygen Not Included is a crude simulation of what we are doing to this planet. There the biggest end-game problem is the asteroid colony overheating due to creating a whole bunch of extra heat inside of it from using up fossil fuels, yet lacking any good way to actually vent all these massive amounts of extra heat from the little biosphere.
  - Matumio 4y ago
    Oxygen Not Included is a good game, but it probably doesn't have a single mechanic that makes physical sense. For example, it allows you to destroy carbon dioxide (preservation of mass?) by turning water into polluted water. And polluted water emits oxygen. Back on earth, thermal radiation is sending massive amounts of heat into space. Additional heat we put into the atmosphere will not stay for long enough to matter, compared to certain gases that block thermal radiation.
    - freeflight 4y ago
      > Additional heat we put into the atmosphere will not stay for long enough to matter I'm just not too sure about that; Fossil fuels took millions of years, and massive natural forces, to accumulate in their modern day form, very similar to uranium and other energy resources. That's a lot of energy that went into "making" them over a lot of time. But humanity is "unloading" all that energy, with all its effects including thermal radiation, into the atmosphere at extremely faster rates than it took to accumulate. And we've been doing it at a literally global and industrialized scales. We even recognize the problem of thermal pollution on a "micro" level when we throttle and shut down generators, reactors and industrial processes that threaten to overheat the natural water bodies they use for cooling. I see no reason why these issues can't accumulate and scale up to global levels. Disregarding that possibility, as if humans couldn't screw up the planet on such scales, are exactly what made us run head first into global warming trough CO2 emissions and littering most of the planet with led and plastics.
googlryas 4y ago
We could build a bunch of space radiators. But really this isn't something we need to think about for a while...global energy consumption is less than 1/10,000th of the energy deposited in soil and water by the sun.
joak 4y ago
The total amount of waste heat is low. Thermal pollution is a local problem (rivers getting hot) but not a global issue.

by sva_ 4y ago

deleted 4y ago

[deleted]

orzig 4y ago

It is a valid question, but to put it in perspective, the sun bathes us in dramatically more kWh than we need to annually power the world every few minutes. So fusion would be a drop in the bucket at a global scale.

adrian_b 4y ago
In the beginning, of course. Nevertheless, the heating of the Earth puts a limit on the total usable nuclear power on Earth, both fission and fusion, it cannot be "infinite", but it must remain forever a small fraction of the power of the incoming Solar radiation, otherwise it would cause an excessive heating of the Earth by itself.
- willis936 4y ago
  Ever getting close to this point is what is considered a "good problem". We are always teetering on the edge of oblivion. Being so wildly successful that our industrial heat rivals that of the incident energy of the sun would be incredible. No problems humans have ever faced would be in living memory (including mortality). This is a science fiction future that does not need planning from the minds of today. It would also have many solutions related to adjusting albedo.

hobscoop 4y ago

It'll ultimately be dissipated by infrared radiation into space. Earth receives something like 173,000 terawatts of radiation from the sun; this is equal to the amount radiated out as infrared, except for the "radiative forcing" which is the amount by which the world is heating. Radiative forcing is currently something like 1000 TW. All of human civilization is powered by something like 20 TW. If we want to stop global heating we need to use a fraction of those 20 TW to "turn the ship" of size 1000 TW.

MaxDPS 4y ago

I'd imagine the excess energy goes out into space. They key difference between nuclear and fossil fuels is the emissions each generates. Fossil fuels burn into greenhouse gasses which trap in heat. If we switch to nuclear, those greenhouse gasses won't accumulate as much.

freeflight 4y ago
The near-perfect vacuum of space actually makes it quite bad at absorbing heat, that's why anything we put up there, like space stations and satellites need huge radiators to keep everything cool enough to actually operate. While thermal pollution in Earths atmosphere is a very real and relevant issue with energy generation and all kinds of other human activities; A whole bunch of French fission nuclear reactors are regularly shut/throttled down during summer heat waves due to lack of appropriate cooling. The combination of these factors sometimes makes me wonder if the game Oxygen Not Included is a crude simulation of what we are doing to this planet. There the biggest end-game problem is the asteroid colony overheating due to creating a whole bunch of extra heat inside of it from using up fossil fuels, yet lacking any good way to actually vent all these massive amounts of extra heat from the little biosphere.
- Matumio 4y ago
  Oxygen Not Included is a good game, but it probably doesn't have a single mechanic that makes physical sense. For example, it allows you to destroy carbon dioxide (preservation of mass?) by turning water into polluted water. And polluted water emits oxygen. Back on earth, thermal radiation is sending massive amounts of heat into space. Additional heat we put into the atmosphere will not stay for long enough to matter, compared to certain gases that block thermal radiation.
  - freeflight 4y ago
    > Additional heat we put into the atmosphere will not stay for long enough to matter I'm just not too sure about that; Fossil fuels took millions of years, and massive natural forces, to accumulate in their modern day form, very similar to uranium and other energy resources. That's a lot of energy that went into "making" them over a lot of time. But humanity is "unloading" all that energy, with all its effects including thermal radiation, into the atmosphere at extremely faster rates than it took to accumulate. And we've been doing it at a literally global and industrialized scales. We even recognize the problem of thermal pollution on a "micro" level when we throttle and shut down generators, reactors and industrial processes that threaten to overheat the natural water bodies they use for cooling. I see no reason why these issues can't accumulate and scale up to global levels. Disregarding that possibility, as if humans couldn't screw up the planet on such scales, are exactly what made us run head first into global warming trough CO2 emissions and littering most of the planet with led and plastics.

googlryas 4y ago

We could build a bunch of space radiators. But really this isn't something we need to think about for a while...global energy consumption is less than 1/10,000th of the energy deposited in soil and water by the sun.

joak 4y ago

The total amount of waste heat is low. Thermal pollution is a local problem (rivers getting hot) but not a global issue.