Grab the average electricity price from a chart online, fill the first table in excel, grab the specs of a miner, fill the second row, and wow, you have numbers on how expensive mining a bitcoin is! Majic!!!
Why not, I mean what could possibly go wrong? I mean the worst-case scenario is ending with a "study" that is complete bullshit, not the end of the world, and they still get paid for doing the excel sheet trick.
Honestly, it's will be near impossible to know the cost of mining bitcoin using just the public information you find on Google, nobody knows exactly how much it costs someone else to mine a bitcoin, simply because, you don't know how much they pay for power, bribe, maintenance and all that, even the simplest part of the equation which is the $/kWh is not easy to figure out, nobody has an answer for how much it cost the large U.S miners, some might have 2 cents rate, some maybe 4 cents, some might magically have access to free power, some might be paying 7 cents and pretend to be paying only 3.5 cents to attract more investors to buy their stocks, nobody has the slightest clue.
With that in mind, why waste time trying to figure out the cost of mining bitcoin when all the variables you need to place in the equation are missing, guessing won't take you anywhere, you will look as dumb as the guys who conducted this "study", I mean we can speculate and chit-chat about how do I think 3-4 cents the average for large U.S miners, but then I will give you a bag of salt to take it with, I won't go to as far as making claims and studies regarding the suject.