In their correspondence, Satoshi addressed what would become one of Bitcoin’s most enduring criticisms: its energy consumption.
Satoshi argued that even if Bitcoin grew to consume significant energy, the cost would be “an order of magnitude less than the billions in banking fees” that characterize the traditional financial system. He framed Bitcoin mining’s energy use as a trade-off that should be compared to the full cost of maintaining the existing banking infrastructure.
He acknowledged the philosophical tension this created:
Satoshi NakamotoIronic if we end up having to choose between economic liberty and conservation.
Satoshi also explained the economics of mining, noting that the value of bitcoins would be relative to the electricity consumed to produce them, and that the extra wattage consumed would go directly to the miner’s power bill, with the value of produced bitcoins being “something less than that.”
He maintained that proof-of-work was “unfortunately” the only method that could ensure Bitcoin would work without trusted intermediaries, calling it “fundamental” to preventing double-spending.