It's just a very obfuscating way to describe what's happening. Not only is it not a useful abstraction, but it actively leads you to wrong conclusions to talk about it in terms of energy use per transaction.
The amount of energy spent on a Bitcoin transaction is partially a function of the expected payout for mining that transaction.
The network doesn't only pay the energy cost one time per block, Bitcoin by design duplicates effort mining that block because miners compete with each other -- that's the whole point of POW, duplicated effort. The amount of attention/price of Bitcoin influences that, which is partially dictated by usage.
If Bitcoin crashed to $10 a coin tomorrow, the amount of energy being expended on each block would go down because there would be fewer people mining it. The number of miners (and the amount of duplicated work) will increase with Bitcoin's usage.
Energy usage in Bitcoin is not a global constant, the coin is designed so that people will suck up as much available electricity as possible until the cost of that electricity is higher than the profitability of mining. It is designed to always take up the maximum amount of electricity/hardware possible and to immediately consume any extra bandwidth or lower prices on the electrical grid (sidenote, this is why the "Bitcoin pushes renewables" argument is so silly).
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> There is no "energy cost for transaction" in Bitcoin, it's an energy cost per block.
This feels like word games to me. The blocks are getting mined in order to process the pooled transactions, that's why mining was invented in the first place.
If we say that the transactions aren't contributing to the energy usage, then we might as well take it a step further and say that the energy is all wasted because it would be spent anyway, regardless of how many transactions are happening. But I think the more reasonable way to approach what's going on is to say that the energy is expended in order to keep a functional network that supports transactions, and that it supports transactions at a fixed maximum rate.
It's like arguing that the environmental/human cost of gold shouldn't be factored into its usage because literally handing someone a block of gold doesn't at that moment incur that cost. That doesn't mean the gold mine stops existing and it doesn't mean that the usage of gold as an asset isn't the main reason why the mine was built in the first place.
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And in a lot of ways, this take (the block would be mined anyway so transactions are environmentally free) is kind of the opposite of the conclusion that would be more logical to reach. The fact that Bitcoin's energy usage can rise independently of functional usage is a flaw, not a strength. One of the sources for the article goes into more detail (https://digiconomist.net/bitcoin-energy-consumption#scalabil...). It argues:
> Unlike the network’s transaction limit, the energy consumption of the network isn’t capped. The price of Bitcoin is the main driver of the network’s environmental impact, and there’s no limit to how high this can go.
It isn't actually a positive that Bitcoin's energy usage can spike to match the entire country of Hungary while still only processing at max 7 transactions per second; far from meaning that individual transactions don't matter for energy usage, this means that individual transactions can spike to even higher energy usage than they would otherwise require regardless of how congested the network is. It's bad that the spike in energy usage does not come with any benefits to scalability.
If you leave the amount of transactions constant, and the price rises, the security of those transactions goes up (this might be too idealistic of a model, maybe wrong, but it's widely accepted basic microeconomics, not macro). If you leave out the speculation aspects of the price of bitcoin (say, in a couple of decades), a price increase means the market wanted to pay for more security (which is why the price rises). If the price goes down to say, $10, it's just the market signaling that bitcoin is not useful anymore.
I don't know about you, but I would like to have some backup next time Trudeau wants to freeze my accounts for protesting his measures. I'm not sure about 30k, or $10, probably right now something in the middle. But if that isn't a concern that bothers me, I would leave for a warmer authoritarian country, if there are any left.