Hey Cryptoversity, thanks for your detailed response (and I have tried to provide some references as links!). Do you think that any of those PoW alternatives could provide the same level of trust as PoW? That seems to be the special strength of PoW — i.e. you can maintain trust in the currency by just dialing up the mining cost. Is there an equivalent for that mechanism in the alternatives?

Your link about the cost of printing and circulating conventional currency is a comment piece, so it’s not strictly impartial! And I think these comparisons are often unhelpful because, of course, you’re comparing the costs of the conventional currencies with the cost of running a cryptocurrency now, while only a fraction of the final total are in issue. If Bitcoin is 1xAustria now what will it be in ten years? And will the cost of printing bills etc. be the same then? Also, PoW burns CPU/power by design. It simply can’t get more efficient. Other currencies can — even if the incentives aren’t always there.

I agree with you about the drawbacks of e.g. electric cars etc. but I’m not sure how that relates to Bitcoin/PoW. One other problem with PoW, though, that I didn’t mention in the post, is what will happen if the cost of renewables does keep dropping. Presumably this will drive down mining costs, making it more viable to mine and driving up the total quantum of mining done! Cheaper, more accessible renewables could actually make the PoW power sink worse! Or am I misreading this?