Since it's a common mistake when discussing cryptocurrency energy use, I should point out that it's really only Bitcoin specifically that uses significant amounts of electricity these days. Most other cryptocurrencies have switched to proof of stake systems, which uses negligible energy.

Just to expand on this, While eth is 99.99% less energy use than Bitcoin, it still added 2.8 kilotonnes of co2 which is equal to about 2000 average houses for a year.

It’s a negligible amount in the scheme of things, but a lot for a virtual currency especially when you add up all the various cryptocurrencies out there.

It wouldn’t hurt to make all the POS ones use green energy, but probably wouldn’t impact anything by itself.

Changing Bitcoin to green energy alone probably would however.

Why is it "a lot for a virtual currency?" What's the typical energy usage of a virtual currency?

In 2019 Visa used 740,000 gigajoules of energy, which is equivalent to 6727 households (google dug up a figure of 110 Gj/year for that). So this really doesn't seem like a lot for this kind of thing.

By your estimate, visa used 3.4x the power of eth. I would guess visa handles much much more than 3.4x the volume of currency transactions and is way more efficient on energy.