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?
With this analysis, there is need to exercise fear concerning the amount of energy that bitcoin production is consuming which if it continues this way will end up consuming the entire power of a community of about a year.
However, this is something that has been envisaged before the entire bitcoin will be fully mined by 2140 you will agree with me that if we are above 16 million bitcoins according to some sources already mined, then going by that trend we should even finish mining before the next five years but because of the difficulty that has been factored into the design, this will then enable bitcoin to sustain to that point which is over 100 years from now. It will then get to the point where 1 bitcoin will not be mined in a whole year and effort will be channeled on those that have already been mined.