We say it is inefficient but I've not seen a detailed study on the origin and amount of electricity used for Bitcoin mining vs. the origin and amount used to ke

We say it is inefficient but I've not seen a detailed study on the origin and amount of electricity used for Bitcoin mining vs. the origin and amount used to keep a similar portion (by transaction volume) of the VISA network (not just the main clearing house) running. I hear much of the electricity is hydro power in China. Lastly, Bitcoin isn't finished yet. I was dialing up to the internet on a 56kbps modem just 20 years ago. I can't imagine where crypto currencies will be in 20 years.