Is it fanciful to hope this could - in and of itself - allow several polluting power stations to be decommissioned, and/or appreciably reduce energy prices for the rest of us?
A quick look at https://whattomine.com/ shows that several altcoins are within 70% profitability of mining Ethereum.
That math is going to change as the Ethereum miners reconfigure for altcoins and the difficulties change, but the bottom line is that mining will continue as long as some coin is still profitable to mine.
I've read that a lot of former ETH miners have sold or are planning to sell their rigs (I think this is related to the submission yesterday about the GPU shortage being over[1], as Ethereum is usually mined on GPUs)
We'll see if it plays out, but cryptocurrency prices falling have certainly reduced the energy consumption as well (it becomes less profitable to mine at a given difficulty when your mining reward is worth less).
If Ethereum does eventually manage to overtake Bitcoin, that'll bode well for crypto's energy footprint in the long term (fingers crossed for this happening, or at least for there to not be another Bitcoin/PoW bubble)
But Ethereum mining rewards are orders of magnitude greater than the mining rewards for all of the altcoins (combined). The attack cost on this page [0] is a good reference for the relative mining incentive.
Given this, a LOT of mining capacity is going to go offline when this occurs.
Something here it not computing. They said Ethereum energy consumption is similar to the Netherlands. This would mean a single coal planet can power the Netherlands 35 times over. Some numbers are definitely wrong here.
A terawatt is a trillion watts (or a billion kilowatts), so no, you're out by 3 orders of magnitude and Ethereum ceasing to use PoW would be the equivalent of losing the need for 30-40 typical coal power plants (or a handful of the world's largest coal power plants)
Those numbers don't look right. A plant running at 90% uptime is ~8000 h/yr, and a typical large power plant produces 100s of MW. So you should be looking at a yearly output in ~1000s GWh/yr range.
