[thayne]

> An air conditioner powered by solar energy (or anything solar powered) ends up releasing the exact same amount of "excess" heat as the sunlight would have if it hadn't been absorbed by the panels.

Sure. But solar panels are intentionally designed to absorb a lot of energy. So if you are putting the panels over a dark surface, like asphalt, you'll probably have a net zero effect on heat. If you put them over something light colored, you are now converting more visible light that would have been reflected into space into heat. To be clear, that is still a lot better than burning fossil fuels, but it isn't completely free either.

[yrjrjjrjjtjjr]

You gotta take entropy into account too. Sunshine is high grade energy, infrared is low grade. Reflecting high grade energy is a huge waste. You could even (in theory) run a solar powered space-ir-dumper and end up with net cooling of earth.

[thayne]

Solar panels work by taking "high grade" energy from sunshine, doing some useful work with it, and increasing entropy by producing heat. That heat does radiate energy away at infrared wavelengths, but then greenhouse gases come into play. Greenhouse gases are very effective at reflecting infrared radiation back down to earth, so the heat is trapped.