Ethereum transactions are claimed to use about 1-22 Wh per transaction. Not sure where the wide range comes from, but at least it’s quite a lot better then Bitcoin’s ~700-2000kWh per transaction. Ethereum is comparable to how much a credit card transaction is said to spend, although those figures only take into account power needed for their computer systems. Blockchain currencies replace a lot more infrastructure than just the computer systems, so I think it’s reasonable to say that Eth2 is more energy efficient than credit cards.
That’s not enough to make it a replacement for credit cards yet, but it’s a good lowest of the low barriers to be crossed to qualify as a replacement.
In a few years, we’ll probably be spending a huge amount of power for AI also, and there doesn’t seem to be any Proof-of-Stake -like technology to help with that. Good times.