Bitcoin energy wasting is growing exponentially that is the problem , it is growing faster than the infrastructure ability to keep up.
The Banking industry energy footprint took almost a century to reach where it is now , and its growth is not growing exponentially.
The Facts are Proof of Stake is energy efficient, there are even other Proof of Work Algorithms that are way more energy efficient than the one bitcoin uses.
But the miners in their greed, don't want to even switch to a more energy efficient PoW Algorithm such as Groestl or x13 .
https://blog.xtrabytes.global/technology/proof-of-work/Even if 50% of the energy consumption were to come from renewable energy, it would still not be deemed ecological by any means.
The carbon footprint for a single Bitcoin transaction is still very large, having an equivalence of almost 100 kg of CO2 being produced.
Obviously, this is something that needs to change if we want to save our environment.
The Tipping point is no later than ~ Feb 2020, at that point Bitcoin alone will require the same amount of electricity as the Entire world is producing in 2017.
Before then, either they have to fix the problem, which they have shown no interest in , or the cost of making a bitcoin transaction exceeds the price people are willing to pay, and the bitcoin network is frozen in place.
Electric Utilities have only 2 options:
The Smart ones will ban all bitcoin mining in their areas.
The Dumb/Greedy ones will try and feed a industry that can not be sustained, and spend billions on infrastructures
and then go immediately bankrupt if the Bitcoin industry grinds to a halt.
The reason Bill Gates & Warren Buffet talk about bitcoin as a failure is simple, they already had their top people examine it ,
and concluded it can't survive longer than 2 more years.
The Electricity Waste problem is like an Aneurysm in Bitcoin's Brain and we have less than 2 years before it POPS!