This article is sensationalist nonsense. I would argue it is a positive point that a globally tradeable cryptocurrency with billions in market cap only requires the energy of a "small city."
It only sounds good because we haven't really considered the scale here, so let's scale that up a bit.
What if even 1% of non cash financial transactions in the US were handled with BTC? For 2015, that would have worked out to about $1.8T.
How big would BTC need to be to handle that? Well, it looks like last year it's estimated to have done a little over $100B, so it'd have to scale somewhere around 15-20x to even cover 1% of one country's transactions...
[1] https://www.federalreserve.gov/newsevents/press/other/2016-p...
[2]https://blockchain.info/charts/estimated-transaction-volume?...
I really don't think things are as clear cut as the article implies, but I dont have numbers for the amount of energy consumed by modern electronic value transaction and storage.
Edit: also, "city's worth" as a measure of electricity, as in the article, is a terrible choice because it immediately biases the reader and does not convey much useful information. My GPU maxes at 300W; the article provides no way of conversion. Never mind that a small city may be a suburb using one hundredth of the power used by a small city center full of servers and a handful of skyscrapers.
No, I didn't but the article did, and it's cited elsewhere on HN - Visa for example uses 1/7000th of the energy per transaction...