It's tricky. Bitcoin can process about 400k transactions per day at close to zero in energy consumption. There are two forces to drive energy consumption high

It's tricky. Bitcoin can process about 400k transactions per day at close to zero in energy consumption. There are two forces to drive energy consumption higher: 1: Demand. If there is demand for more then 400k transactions per day, then bidding for inclusion drives the fees up which makes it viable for miners to invest more in Energy. 2: Security. A chain that is run on a single computer with low energy consumption could cheaply be recreated. So you would always think "Yes, I have been paid $X a month ago. But someone could invest $Y to make a longer chain without that transaction. That scares me.". Currently that $Y is about $1B per month. Which everyone assumes to be "Big enough". Not sure if $1M would also be big enough. If so, Bitcoins energy consumption could be reduced by a factor of 1000. It is hard to predict to what type of equilibrium this will lead in the long run. We will only know in a couple of years when more halvings have happened and the mining reward is reducrd to the transaction fees.