Once a bitcoin has been mined, if I want to use it to pay for something, what is the average amount of electrical power required to process that payment or bitcoin transfer? Does this vary with the value of the transaction, and if so in what manner?
Please note that I am not asking about the electricity cost, as that would clearly depend on the location as well as what deal you've been able to strike with the power company. Hopefully the number of kWh, J, or whichever other unit happens to be convenient, will be easier to answer reasonably objectively.
Answers for any point in time during which Bitcoin has existed are acceptable, but more recent data is better. It is acceptable to exclude costs that are not actually related to the data being transferred being about bitcoins per se (for example, I see no real need to calculate how large a percentage of Internet core router traffic is for bitcoin transfers and account for that).
(I did find e.g. Energy to confirm one block? and Can it really be true that the Bitcoin system consumes almost $1.000.000 in electricity per day? as well as (on Skeptics) Does one transaction on Bitcoin require 215kWh? but all of these appear to conflate the total power usage of the Bitcoin network with the power required for a transaction using already mined Bitcoin by lumping the two together.)