[plopilop]

> because you'd be looking at blocks the size of several terabytes in order to fit in global scale transactions.

My comparison would rely on running several bitcoin networks in parallel. Of course it does not make sense economically speaking, but it allows for a back of the envelope estimate.

> Electricity for mining is also not directly related to transaction throughput

This is true, but when you look at the C02 consumption (which was the topic of discussion when I first posted, before my OP decided to completely change subject), the mining cost is what you look for.

[scottiebarnes]

> My comparison would rely on running several bitcoin networks in parallel. Of course it does not make sense economically speaking, but it allows for a back of the envelope estimate.

Mmmm, I understand you're looking for a convenient way to mathematically equate the two on a per transaction basis for comparison's sake, but its just really difficult. For example, your several bitcoin networks in parallel doesn't really exist, because separate networks running in parallel are not interoperable (Bitcoin vs Litecoin). You lose the utility of network effects, etc.

Its like comparing energy costs of bicycles and ocean freighters, but no amount of bicycles could ever tow freight across an ocean.

[plopilop]

> You lose the utility of network effects, etc

Oh yes, you lose a lot of functionalities, but it's not the focus of the computation, simply to estimate, with the current technology, how much it compares to Visa in terms of electricity consumption. To be honest it would maybe make more sense to actually scale Visa down to bitcoin transaction rate, as we can assume more linearity there. The end result is the same though.

> Its like comparing energy costs of bicycles and ocean freighters, but no amount of bicycles could ever tow freight across an ocean.

Quite. However it seems to me its seems unavoidable to do so, since energy efficiency is a big topic these days. Also, while nobody pretends to be able to carry a load across oceans with a bike, it is usually advised to commute by bike rather than a freighter.