If governments forced miners to use solar energy only, would Bitcoin become more sustainable and valuable, or would it reduce mining capacity drastically?
Guess what? renewable energy is affecting the government partially so they will not try to push bitcoin mining to use renewable energies only but they will want to complain just to cut percentage or tax the miners that's just about it.
But however, it will only be an opportunity for others to try out there experiments on what will be able to power bitcoin mining farms strongly and had no side effect on the environment as those who are not able to find something to complain about bitcoin did.