Iceland has some large aluminum smelters and aluminum is 40% of their export income[1]. They do heat their homes with geothermal. It's basically free and when I was there the lowest setting for the heat in my apartment was 22.4C (72F).
Interesting link. 800,000 mtpy is a lot of aluminium. While the ‘zero environmental imapct’ claim is controversial, the environment impact is definitely lower than many other producers.
[1]https://en.wikipedia.org/wiki/Economy_of_Iceland