I use "mining premium" to refer to the premium people are willing to pay to mine, i.e. as a hobby, research, or to evade taxes or capital controls. I think when considering efficiency, we can disregard these costs - i.e. energy spent evading taxes is really an inefficiency of taxes, not bitcoin.
The mining block reward will become 0 in the long run.
So really:
Energy used = transaction costs * (1 - mining profit margin) / unit cost of energy
So basically energy usage is being driven by the transaction costs the market is willing to pay, which will adjust accordingly as people are willing to move transactions off-chain.
This formula which I haven't gone through in detail enough to see if I completely agree, directly support the point of waste.
As society lowers the cost of energy, we would expect even more energy to be wasted with all other variables remaining equal.
Halve the cost of energy and now you've doubled the amount of energy spent.
If the cost all energy worldwide improved dropped by a factor of 100, society should explode with new technology. Instead this formula says we'll just spend 100x as much of it mining.
At least with mining gold as technology improves, you gain efficiency in gold extracted per joule. Crypto mining works exactly reverse. The better technology gets, the more wasteful it has to become to compensate.
Where mining reward = (mining block reward + transaction costs + mining premium)
I use "mining premium" to refer to the premium people are willing to pay to mine, i.e. as a hobby, research, or to evade taxes or capital controls. I think when considering efficiency, we can disregard these costs - i.e. energy spent evading taxes is really an inefficiency of taxes, not bitcoin.
The mining block reward will become 0 in the long run.
So really:
Energy used = transaction costs * (1 - mining profit margin) / unit cost of energy
So basically energy usage is being driven by the transaction costs the market is willing to pay, which will adjust accordingly as people are willing to move transactions off-chain.
Looks pretty efficient to me.