It doesn't matter what kind of energy Bitcoin uses, it matters if that energy was going to be wasted or not

Some huge percentage of energy produced is wasted. This article from 2018 says 68% of energy in the US is rejected.

https://www.weforum.org/agenda/2018/05/visualizing-u-s-energy-consumption-in-one-chart#:~:text=Energy%20wasted,gets%20wasted%20through%20various%20inefficiencies.

Bitcoin could use 68% of US energy and it would be theoretically fine if it was only the stranded and wasted energy. But it's ~.1% of world energy. How much of that would be wastedm

A huge amount of Bitcoin has been mined in a coal region of China. But was the energy used for the miners going to be wasted anyways? That's an important question.

In theory it would be good to use whatever waste energy we have to secure our monetary network. That could be a huge number, but again, that would be totally okay if the energy was going to waste anyways.