Assuming "cleaner" means more sustainable for the environment (not only carbon footprint, but considering biodiversity), then I think it's pretty much a fact: we are living a mass extinction right now, and that's really correlated to our energy consumption.

If it's purely about carbon footprint ("let's finish killing the biodiversity and make living on Earth as close as possible to what it would be to live on Mars"), then it's still debatable whether or not we could keep increasing consumption with the end of fossil fuels (and that's coming).