[aakilfernandes]

Analyses like this just take the energy cost of each block of transactions and divide it by the amount of transactions in the block. If the number of transactions in a block doubles, the average energy cost per transaction is halved.

Another way of stating it is "the marginal energy usage of a bitcoin transaction is essentially 0".

[MereInterest]

Except that there is a maximum number of transactions per block. Across the entire network, by design, there can never be more than 5 transactions per second. This is stupidly small. If people received their biweekly paychecks in bitcoin, only 6 million people could be paid without going over that transaction limit, assuming that absolutely nothing else is done using bitcoin.

The marginal energy usage being zero is another way of saying that Bitcoin wastes the tremendous amount of energy that it does even if nobody is using it at the time.

[rcxdude]

Yes, but the number of transactions in 'bitcoin' as it's currently defined is severely limited (blocks are already full at a $15 per transaction cost). Conceptually, making something which increases the transaction count involves forking bitcoin, and a fork which aimed to do exactly that was denounced heavily by the community and rejected by the markets. The marginal cost may be small but the cost per transaction is high, by design, and by design which has extremely heavy resistance to even small and simple changes.

[UncleMeat]

But the number of transactions in a block is fixed.

We went through this with BTC/BCH. The BTC folks did not want to increase block size.