The same way China, UK and other places track down power thieves: use IR cameras to find buildings that have an abnormally high heat signature and investigate the reason. All we need is ~190 more countries coming to the same logical conclusion and banning crypto. There is no value in crypto-mining if it cannot be exchanged for anything anywhere on Earth anymore.
Once enough countries have banned crypto, it may become a prerequisite for future trade and collaboration agreements to add pressure.
1. Prevent Swedish Banks from working with bitcoin clearing houses. This means if you are mining in Sweden, then you'll have to have an account somewhere outside Sweden. And that will raise a few eyebrows. So this will take care of small mining operations that live in country.
2. Just about every MODERN energy company monitors usage of every individual client. They then compare trends year over year, and with your neighbors and against the weather and sometimes even time of day (Smart Meters which are common in USA and Europe now). This is essential so they know how to upgrade infrastructure. or there are problems. They will notice if you sit outside the standard deviation. "Why is this house/warehouse consuming 20% more power than their neighbors?" That 500W 24/7 adds up. And this is one reason why illegal Chinese mining farms are stealing electricity in a bid to stay hidden.
Sweden is so right in doing this. The planet is turning into a giant desert, and people are generating more heat and CO2 to earn virtual fools gold. Unless there is a solution that doesn't need massive computational resources, it should be outright banned.