Any use of energy eventually results in heat; that’s just the Second Law of Thermodynamics in operation.

But this effect is orders of magnitude smaller than the greenhouse effect.

I am aware of the 2nd law. I am looking for data on the magnitudes involved. Every time there is a promise of very cheap energy, I wonder how we will deal with the waste heat.

I cannot vouch for the quality of this model, but I remembered I had bookmarked this tweet, having wondered the same:

https://twitter.com/anderssandberg/status/145528744318439424...

The waste heat will be radiated away to space. The premise of global warming is that CO2 (and other "greenhouse" gasses such as methane) cause more of the heat to be retained in the atmosphere.

Yes, I am aware of the 2nd law and the greenhouse effect. I was asking about the magnitudes. It is okay if nobody has any idea about them.

The magnitude is the same as current power sources that they would be replacing i.e. 100's of MWs to 1-10s of GWs. The amount of heat being brought up would have to be about the same as you would otherwise be getting from coal, gas etc and so the same amount of heat would be vent to the environment.

The claims about geothermal and fusion are that they will make energy ridiculously cheap. Won't we use much more if it is cheap?

Maybe, but what it will do first is replace our usage of other more expensive forms of energy (fossil fuels, presumably)

Fusion will never be cheap, or used.

Geothermal will not be as cheap as solar, so if we use a lot more power, it will mostly be solar. (Geothermal would be used mainly for baseline, at night.)

Solar intercepts energy already arriving, to use before it is then re-radiated to space. It arrives regardless.

So, no problem. What we have now is a catastrophically big unfolding climate crisis. Even if there were a problem, any small problem is a wonderful substitute for a catastrophically big problem.

Seems that solar panels can work at night too:

https://www.saurenergy.com/solar-energy-news/arriving-soon-s...

Energy will only ever be as cheap as the government allows, because it gets to tax it.

This assumes a more powerful or wise government than I have encountered.

However bringing heat from in the earth to the surface (while not creating new heat) does increase atmospheric heat.

Global energy production in 2019 across all sectors was ~18TW. Excess radiative forcing from anthropogenic greenhouse gas emissions was ~560TW.

So we have room to ~20x our energy consumption before we start having to worry about climate change from direct heating, so long as we draw down the excess CO2 we've emitted.

Wind doesn't contribute to that total, as it's harvesting energy already in the system. Solar mostly doesn't contribute to that total, but it does increase surface albedo.