From a quick research online, it seems that most mining pools are located in China [1]
Roughly 2/3rd of electricity in China is produced from burning coal or gas, which, upon combustion, emit their own weight in CO2, basically. [2]
From this two facts, one can conclude that Bitcoin has a pretty huge carbon footprint overall. This is not the impression that I got from reading that article.
You make the common mistake of assuming that if a pool is Chinese then its users are Chinese. In reality mining pools are used by people from all around the world. For example many like to mine at AntPool, because as the largest pool: their payouts are statistically frequent, they have a reputable and expansive infrastructure, eg. multiple stratum (API) endpoints in various countries which reduces latency for end-users.
As to miners actually physically located in China, many are located in China’s province of Sichuan specifically due to cheap hydropower, not coal.
> coal or gas, which, upon combustion, emit their own weight in CO2, basically
Fossil fuels emit much more than their weight in CO2 when burned. A CO2 molecule produced by burning typically includes two oxygen atoms from the atmosphere.
Yeah, the article makes some false claims about how electricity markets work. By driving up power demand, you're incentivizing fossil fuel usage as it is the marginal molecule. The cheap power on the grid is already likely being max utilized, so any incremental kwh from bitcoin will come from the next cheapest source. Globally, that's probably coal or natgas.
If I remember correctly, mining farms (and data centers in general) are usually colocated to an energy source, i.e. a plant.
Some of those plants are not fully stretched, because there's almost no civilization nearby, so delivering to the next city comes with a huge loss in the energy network.
So miners can get cheap energy from those plants - energy that would otherwise be unused or lost anyway.
Not sure how much this saves in the end, but this shows that you can't simply convert energy to CO2 emission without considering which types of plants are used and where these are located.
It misses the fact that China didn't build power plants out where it's too far away from civilisation to be useful.
Transmission losses are also nowhere near the suggested values. 1.5% per 200 miles is today's standard. Meaning you could cross all of China with a loss of:
east-west axis: 2200 miles
0.985^(2200 miles / 200miles) = 0.846 = 15.4% loss
(and that's from the farthest desert to the east coast. Go south instead, or note that there actually are a billion people living in inland China, and actual losses are <5%)
Unused or lost power is instead never produced in the first place. Unless it’s hydro or wind (and even these are not producing at full power all the time). This argument is effectively bogus, unfortunately.
As to miners actually physically located in China, many are located in China’s province of Sichuan specifically due to cheap hydropower, not coal.