>>532299316
>wind
>solar
>hydroelectric
>geothermal
>vanometric(magic)
Most rimworld colonies are pretty green, which just leaves
>chemfuel(fossil fuels, kind of)
>wood-fired
>toxifier(magic, with magic pollution)
>electroharvester(magic)
>bioferrite(essentially magic coal)
As the real potential polluters, which many colonies don't use at all. Even things like trash and industrial waste usually get recycled in rimworld, unless you want toxic byproducts and air pollution from the smelter and furnace or something. I guess there's modded power sources like nuclear?