Yes, the expenditure of energy is a defining feature of Proof of Work security, however there is going to be a plateau. The immutable base layer Bitcoin provid

Yes, the expenditure of energy is a defining feature of Proof of Work security, however there is going to be a plateau. The immutable base layer Bitcoin provides is also on a trajectory of feature completion and second layer technology will increase the amount of transactions per kWh tremendously. Who knows what benefits micropayments or smart contracts are poised to bring to further increase the efficiency of the global economy?