Gaming on a mid-tier modern GPU probably uses around 50-100w, the Steam stats probably have a number of users to multiply with. I'm sure it's a massive amount of power.

I don't like video games and they are not-necessary so I propose that we ban them globally, or only allow gaming if using renewable energy. If you don't live in a place where this is an option, too bad!

Maybe instead of this we require all games to be limited in graphical effect (imagine early source games or something). We could save a lot of power globally if we enforced this.

This is why I strongly dislike this line of thinking. I don't think power plants work that way anyways, they probably make a constant-ish amount of power rather than taking exactly 50w worth of fuel every time someone opens up Call Of Duty.

There are also much lower hanging fruit to get upset about if you care about the planet, like cars with large motors or people with heated drive ways (yes thats a thing).