3 ms·

LOL, sorry but this is bull. The Sun is hitting the Earth continuously with about 173,000 TW of power [1]. Even with the most optimistic sci-fi scenario with

LOL, sorry but this is bull. The Sun is hitting the Earth continuously with about 173,000 TW of power [1]. Even with the most optimistic sci-fi scenario with 24/7 nuclear power for everybody on Earth, it would be barely noticeable. 1: https://news.mit.edu/2011/energy-scale-part3-1026 https://news.mit.edu/2011/energy-scale-part3-1026

rapjr9 4y ago
Sure, but how much heat would it take to tip an ecosystem into collapse? Someone could build a fusion plant that just creates CO2 for a decade out of seaweed or something. What I'm saying is that the scale of power available to us would be changed, and there will be consequences to that. Some good, but not many people seem to be thinking about the potential bad consequences. Maybe we could melt glaciers to get drinking water, would that be a good thing?
- moralestapia 4y ago
  We are far, far away, from being even a rounding error on that massive amount of energy. Also, all energy generation eventually ends up being heat, it's not like fusion does it but not the others.
Schroedingersat 4y ago
Yes, insolation is 173 PW. Trying to intimidate with big numbers doesn't make you any less wrong. Current primary energy is 18TW. Current GHG radiative forcing is 200-600TW Everyone living like americans on fusion energy (180TW) is sufficient to be as bad as GHG climate change would be with 90s level emissions. Everyone taking your attitude would see us back exactly where we are now in a few decades. PV on asphalt or building has little to no net albedo change. 1W of PV on water or grassland produces ~0.5-1W of heat now and 1W of work-becomes-heat that the dark surface would create anyway. With the advent of tandem cells this will go down to being relatively insignificant. Wind is energy that would thermalise anyway. PV on desert or snow is a concern. Steam engines from stored fossil fuels or nuclear produce 2-4W of heat (depending on fuel enrichment or extraction/mining inefficiency) and 1W of new work. Magical fusion technogies are at best like PV on water.
- moralestapia 4y ago
  >Everyone living like americans on fusion energy [...] That argument is true for any source of energy, not just fusion. Fusion, at the very least, doesn't produce a GHG byproduct.
  - Schroedingersat 4y ago
    You can't just ignore the rest of the comment. A solar panel placed above existing asphalt creates no heat (merely delays the transformation of a watt of light into heat via some useful task) whereas a watt of work from a thermal fusion plant creates at least three watts of heat (but likely more). It is also a reason why solar and wind is enough. We do not get to use more energy than they can provide while covering <3% of land without needing to geoengineer the entire planet anyway. Finally the vast amount of steel and exotic materials in the fusion reactor which will only last a few years before needing to be buried for a century requires strictly more GHG than the renewables that would do the same job. It solves no real problem other than to handwave at 'abundance' which cannot be achieved on earth anyway and has massive downsides. Everyone could live like americans (at least energy-wise) on renewables. We couldn't go much further than that, but 0.5W/m^2 of wind and 1% of the land area with solar panels would not cause too much impact on the world. We cannot do this with any other energy source (excepting maybe tidal)
    - moralestapia 4y ago
      You're right and I agree with you that PV is the best bet.
      - Schroedingersat 4y ago
        I'm not sure I'm following what the implied subject of what it's a best bet for (unless you've changed your mind vs. your first comment and now agree we're within a factor of 10-30 of thermal forcing being important?)

rapjr9 4y ago

Sure, but how much heat would it take to tip an ecosystem into collapse? Someone could build a fusion plant that just creates CO2 for a decade out of seaweed or something. What I'm saying is that the scale of power available to us would be changed, and there will be consequences to that. Some good, but not many people seem to be thinking about the potential bad consequences. Maybe we could melt glaciers to get drinking water, would that be a good thing?

moralestapia 4y ago
We are far, far away, from being even a rounding error on that massive amount of energy. Also, all energy generation eventually ends up being heat, it's not like fusion does it but not the others.

Schroedingersat 4y ago

Yes, insolation is 173 PW. Trying to intimidate with big numbers doesn't make you any less wrong. Current primary energy is 18TW. Current GHG radiative forcing is 200-600TW Everyone living like americans on fusion energy (180TW) is sufficient to be as bad as GHG climate change would be with 90s level emissions. Everyone taking your attitude would see us back exactly where we are now in a few decades. PV on asphalt or building has little to no net albedo change. 1W of PV on water or grassland produces ~0.5-1W of heat now and 1W of work-becomes-heat that the dark surface would create anyway. With the advent of tandem cells this will go down to being relatively insignificant. Wind is energy that would thermalise anyway. PV on desert or snow is a concern. Steam engines from stored fossil fuels or nuclear produce 2-4W of heat (depending on fuel enrichment or extraction/mining inefficiency) and 1W of new work. Magical fusion technogies are at best like PV on water.

moralestapia 4y ago
>Everyone living like americans on fusion energy [...] That argument is true for any source of energy, not just fusion. Fusion, at the very least, doesn't produce a GHG byproduct.
- Schroedingersat 4y ago
  You can't just ignore the rest of the comment. A solar panel placed above existing asphalt creates no heat (merely delays the transformation of a watt of light into heat via some useful task) whereas a watt of work from a thermal fusion plant creates at least three watts of heat (but likely more). It is also a reason why solar and wind is enough. We do not get to use more energy than they can provide while covering <3% of land without needing to geoengineer the entire planet anyway. Finally the vast amount of steel and exotic materials in the fusion reactor which will only last a few years before needing to be buried for a century requires strictly more GHG than the renewables that would do the same job. It solves no real problem other than to handwave at 'abundance' which cannot be achieved on earth anyway and has massive downsides. Everyone could live like americans (at least energy-wise) on renewables. We couldn't go much further than that, but 0.5W/m^2 of wind and 1% of the land area with solar panels would not cause too much impact on the world. We cannot do this with any other energy source (excepting maybe tidal)
  - moralestapia 4y ago
    You're right and I agree with you that PV is the best bet.
    - Schroedingersat 4y ago
      I'm not sure I'm following what the implied subject of what it's a best bet for (unless you've changed your mind vs. your first comment and now agree we're within a factor of 10-30 of thermal forcing being important?)