Monero is mining-resistant, which means mining farms are going to be unprofitable. The people mining Monero are regular enthusiasts, so that should mean there's less wasted energy from a ton of people competing over the same number of coins. Oh, and Monero has no maximum block-size, which keeps transaction costs low (which means even less competition over mining).

I don't know of a good way to estimate Monero electricity usage, but I'm guessing it's way less than Bitcoin has per transaction, or at least it would be if they had a similar number of transactions. Monero is a lot more complex currency (so one transaction will actually spawn a bunch of "fake" transactions), but that mining-resistance is doing some work.

Here's Monero's webpage, which has some discussion on energy usage, which I think I've summarized well above.