I´m tired of hearing the argument "but Bitcoin wastes more energy than
a whole country..." all over the mainstream media.
Here are a few reasons why the energy that is consumed by Bitcoin mining is not wasted:
1. The energy that is consumed by Bitcoin mining is the foundation of the security of the network
2. Proof-of-work is superior to other consensus algorithms like Proof-of-Stake and offers less attack vectors
3. Fiat currencies are supposedly backed by the power of the state... meanwhile the US military consumes more energy than Bitcoin mining per year
(this is a comparison of the military of a single country compared to a truly global currency)
4. No one is talking about the enormous costs of transporting fiat money, securing it and printing it in the first place
5. The mining of other commodities is extremely energy-intensive as well
If you take all these factors into account, Bitcoin may actually be less energy-intensive than traditional
fiat currencies. Besides, many mining companies have set up their operations in countries with an abundance
of renewable energies like Canada or Iceland. The days where Bitcoin was solely mined in rural Mongolia and China
may finally be behind us.
The BTC network does around 3-4 transactions/s with the costs of electricity of an entire country. Meanwhile Visa can process 2000/second with the costs of running a normal datacenter. What do you thing will happen when BTC will actually get used like Visa or Mastercard is? I pay everything right now with a credit card, even 2$ transactions.
Also the BTC vs cash money comparison is flawed. It should be BTC vs wire transfers vs credit cards.
The market can regulate that, in a way that only large solar fields in very sunny and sparsely populated areas (with low land property costs) are profitable. I've already mentioned some regions - an ideal region for that would be the Altiplano/Atacama Desert in South-Western South America (Argentina/Chile/Bolivia) with extremely sunny conditions and not too much heat. There are 1-3 persons per square kilometer there, or even less.
And as I've said - the required total space for a "mega solar field" that would generate the whole energy for a $2 million Bitcoin (see my calculation some posts ago based on the Andasol plants) would be probably not much larger than a small US state of ~10000 square km.
I think in densely populated regions you may be right, there could be restrictions, like a mining tax, or local governments refusing authorizing large solar fields only for mining. But in many regions of Europe anyway a wind/solar combination may be better. And I don't think countries like Morocco, Bolivia, Argelia, Argentina or Chile would restrict solar mining in their desert regions. It would be too lucrative to simply tax these miners ... maybe even the State would mine in these regions.
solar energy has the huge downside of being dependant on weather and time of day, while mining requires constant 24/7 energy. At night the powergrid would overload. The only way to sustain the mining requirements are coal and nuclear plants.