> If that's the case, who's the arbiter of what's "too much" power for a use case? The difference is that Facebook’s energy use potential is limited and gets

> If that's the case, who's the arbiter of what's "too much" power for a use case? The difference is that Facebook’s energy use potential is limited and gets better with improved computer tech. There is a limit to how much analysis you can do. As you get more efficient hardware, the energy use would go down. Facebook also invests a lot of effort in optimizing their code to run more efficiently. With proof of work crypto, the only limit is the price of crypto. Despite any efficiency gains, you can always expect the energy use to scale with the price of crypto. For example, a 10x more efficient miner, won’t cause 10x less energy use, it may actually increase energy use as more people mine with higher rate electricity. There is a chance that we develop a situation that the most monetarily efficient thing you could do with electricity is to mine proof of work crypto. If that becomes the case, then even a carbon tax won’t help because proof-of-work crypto can easily pay the tax compared to all the other uses of electricity.