[jonathanaird]

It also depends on the available market for asics. In bear markets, asics are very affordable as miners go out of business but the price can go up quite a lot in bull markets which affects the profitability of buying new machines.

[hntrader]

I wonder what the observed relationship is if we were to plot energy usage vs price over the last 3 years

[jonathanaird]

In case you’re interested the two bitcoin forks BCH and BSV have unlimited block size and so energy/transaction validated can scale very well. Eventually all forks will have to rely on transaction fees as the block reward has a halving schedule. If something like BSV succeeds the hash rate and thus energy consumption will be a complicated combination of transaction volume, and variable transaction fees. It will essentially be a race to the bottom to see who can provide the cheapest transactions while still being profitable. I think one should expect much higher energy efficiency than something like Visa just from pure scale and the intense competition.