Remember Jevon's Paradox: most of us instinctively look to improving efficiency. But when you do that, people just use more of the thing. Rewriting Python in Rust often won't mean less electricity used, it means your code will get run more.

For example, none of the improvements in combustion engine efficiency over the last 40 years have results in less gasoline being used, it resulted in bigger, more powerful cars and more driving of them.

Really the biggest lever is reducing human population growth and mandating renewables when they are workable, even if moderately less economically viable.