Currently, bitcoin network consumes 26 TWh a year or 250 kWh per single transaction and is growing at a rate of over 1% daily (according to this website
https://digiconomist.net/bitcoin-energy-consumption.)
250 kwh (single transaction!) is now roughly the same to to what an average home/household uses in a month.
Is this really sustainable?
If bitcoin should grow even more, how much power will be used just to run it?
The most surprising stat here isn't really the twh or whatever but rather the 1% growth that is alarming. Right now it's still not an issue because of the fact that bitcoin is still in its early adoption phases, but it's definitely not going to be sustainable if bitcoin goes mainstream.
This has been discussed before but with no avail. The first PoS coin PPC has much decreased adoption, though, which probably means that right now, people don't sense the urgency.
Hopefully, we'll figure this out soon as a community.