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Comment by sidewndr46 | Hacker News Reader

95% conversion into electricity (or steam if you prefer) by a solar plant wouldn't have a cooling effect at all. It's just high grade energy that eventually becomes low grade energy (thermal energy) heating the atmosphere of the earth.

if you actually want to prevent light from becoming thermal energy on earth it'd be far easier to build a dyson swarm to obstruct the sun.

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Isn't that what your parent comment said?

> exporting that heat into the rest of earth (where it is used and expelled as heat)

If you covered the Earth in solar panels and used it solely to charge a battery, the Earth wouldn’t freeze. Energy is not the same as useful energy.

Not even at 95% efficiency? I think it was a hypothetical, not a current consideration.

But it would tho? Imagine if your battery was the earth's core. So basically you're pumping majority of the incoming energy inside the earth. Less heat is reflected to to warm the athmosphere, hence a cooling effect.

Once you release the stored energy it's a different story.

You just need an umbrella at the Lagrange point.

Maybe there already is, but it’s just not observable…

Not necessarily if you get rid of the energy in another way, right? You could perform hydrolysis to turn water into hydrogen + oxygen, and if you release hydrogen into the atmosphere it will just escape our atmosphere into space.

Theoretically, but most hydrogen generated would be burnt to generate back heat. Doesn't make much sense to use hydrolysis to capture Oxygen.

The only practical way to do such a thing would be with a giant mirror. There is no reason why earth cannot radiate energy back into space. A mirror is a good way to do that for the optical wavelengths. Most of the energy received by earth each day is in the optical spectrum and secondarily from the gravitational interaction of the earth-moon system. The moon we can't really do much about. But sunlight absolutely can be reflected.

A mirror would also be much more effective if part of some ring like structure orbiting the earth, as most of the energy would never enter encounter earth's atmosphere in the first place.

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