About 1,200 kWh per transaction, currently[0]. I wrote about this back in 2022, when it was about 2,200 kWh per transaction[1].

Edit: made a chart with this data, but adding in a bitcoin transaction[2]

[0]: https://digiconomist.net/bitcoin-energy-consumption

[1]: https://rollen.io/blog/crypto-climate/

[2]: https://imgur.com/a/ggAGylW