Roshar also looks like it'll get clean energy, via Investiture no less, pretty soon. Look at fabrial discoveries in RoW and Dawnshard! Look at that Highstorm and imagine how much energy it produces, how much Investiture, it's free power! Scadrial does not have that advantage, Feruchemy is not suited towards that, but maybe Allomancy is. Maybe they could also harness energy from the Mists. Their planet is near-empty, they'll have an easier time with fossil fuels (which Preservation artificially put there?) for longer, so they might not feel the need for looking into clean energy, maybe places like New Seran could promote green energy. But Investiture energy conversion is the way to go and the future of the Cosmere, imo.