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There’s a deeper problem hiding beneath global warming - waste heat (aeon.co)

submitted 2 years ago by niartenyaw@midwest.social to c/solarpunk

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TL;DR

using/generating energy always emits heat as waste and there is an upper limit of efficiency that we are not that far from. if that energy was generated via something that is not a natural heat gradient for the earth's surface there is a net increase of heat in the earth system simply by generating and using energy.

a lot of energy sources fall into this: fossil fuel, nuclear, geothermal, etc. two that don't are (certain types of) solar and wind, since their energy would eventually be dissipated onto earth's surface whether we intercept or not.

that waste heat is currently estimated to be ~2% of the heating power caused by global warming, so already significant. we essentially have an upper limit on sustainable energy usage on earth (and therefore an avg per person usage) or we will have Global Warming 2: Waste Heat Boogaloo.

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[–] thedarkfly@feddit.nl 5 points 2 years ago (2 children)

Very interesting read, thanks for sharing. I particularly liked the part about the origin of the energy we use and wheter that energy would have heated the planet anyway. Carbon trapped in fossil fuel comes from the sun and would have heated the planet during the Carboniferous. By burning it, we "import" heat from this era. Nuclear fission is "importing" heat from the supernovae that seeded the solar system. However, is geothermal "importing" remnant heat of the solar system's creation, as material collapsed in the Earth's gravity well? The heat from the center of the planet would have traveled to the surface eventually, but it would have taken much longer. Maybe we are "importing" heat from the future instead of the past in this case.

There are two things he didn't mention that seem relevant to me. Firstly, that entropy can go down locally. Of course it always rises in a closed system, but the Earth surface is not a closed system. Life, an incredibly organized machine risen from just photosynthesis or chemosynthesis, is an exceptional example of entropy locally decreasing because of external influx of energy from the Sun and the center of the Earth.

Secondly, he justly warned about gathering energy from outer space and importing in on Earth, something that I had never considered. But what if we used this energy in outer space as well? This seems like a good motivation for space colonization. That's a (probably foolish) dream that could be compatible with exponential growth beyond what is available on Earth.

[–] stefanlaser 3 points 2 years ago

That’s a (probably foolish) dream that could be compatible with exponential growth beyond what is available on Earth.

Sounds like a Solarpunk novel to be written. Let's put all incineration activities away. Yet, space colonization is here and serves capital accumulation, first and foremost. There's also the tiny part where rockets have to be shot to outer space with a little bit of energy and waste heat.

[–] niartenyaw@midwest.social 1 points 2 years ago

but the Earth surface is not a closed system. Life, an incredibly organized machine risen from just photosynthesis or chemosynthesis, is an exceptional example of entropy locally decreasing because of external influx of energy from the Sun and the center of the Earth.

yeah, my understanding of this is the earth's surface is generally at an energy equilibrium (combining sunlight, geothermal heat, dissipation to space, etc) which results in the current climate. adding energy to that system via heat changes that equilibrium.

Secondly, he justly warned about gathering energy from outer space and importing in on Earth, something that I had never considered. But what if we used this energy in outer space as well? This seems like a good motivation for space colonization. That’s a (probably foolish) dream that could be compatible with exponential growth beyond what is available on Earth.

wow this is an incredible idea! we could easily use all the energy we want in space or on another body that is less sensitive to heat (moon, mars, etc)