Bitcoin's Proof of Work has been seriously criticized in the past years for its high energy consumption. While the
CBECI index from the University of Cambridge is most likely overestimating the electricity consumption, it cannot be negated that the problem would be substantial if this electricity was generated majorly from fossil fuels, primarily from coal (although numbers are disputed*, see below).
Some jurisdictions, primarily the EU, have considered severe restrictions for Proof of Work cryptocurrencies like Bitcoin. The EU proposal, which was rejected in early April, aimed at banning trading and other services for PoW currencies for EU companies, which would have forced all EU exchanges to delist Bitcoin (and other PoW currencies like Litecoin and Monero).
Often in the justifications for the regulation Proof of Stake is mentioned as a "better" and "more environmental friendly" consensus method. However, PoS has a number of severe disadvantages, and relies on what's called "
weak subjectivity", what means that the consensus is never completely objective and could be theoretically "faked" with sophisticated methods. It also favours centralization in much more direct ways than PoW.
So a "PoW ban" or even a "PoW restriction" would threaten one of Bitcoin's main innovations.
But instead of banning or restricting PoW currencies like Bitcoin, there is actually a much more promising alternative:
Large-scale miners should have to demonstrate real carbon neutrality.
This could mean miners could have two alternatives:
1) Mine disconnected from the grid with exclusively own renewable electricity. (For example they could use a solar park or wind turbines, and store the energy accordingly).
2) Mine connected to the grid with a "100% renewable energy tariff", but ensuring they don't rely on fossil electricity in cases of scarcity of renewable electricity. This could be achieved a) powering off the mining equipment in these situations, or b) investing directly in new renewable generation. Miners would have to be equipped with smart meters, so the authorities could ensure they obey these rules.
The word
real is emphasized because it wouldn't be enough to simply buy CO2 certificates (like some experts have proposed); they'd have to
directly contribute to carbon-neutrality.
This kind of regulation would have at least
three effects which would help combat climate change:
1) it
solves the problem of miners competing with households for renewable electricity, as this wouldn't be allowed anymore (they can only mine connected to the grid as long as there is no renewables' scarcity, i.e. they can use "surplus" electricity),
2) provide a
strong incentive for economies of scale in the renewable generation and storage industry,
3) provide a
strong incentive to move to places where renewable energy is abundant (Sahara desert, some regions in South America like Patagonia, Brazil and the Altiplano, North American desert regions, Scandinavia/Iceland)
Feedback is much appreciated! The idea is to create an article about this topic in several languages (above all, EU languages as there the discussion about a de facto PoW ban hasn't stopped) to contribute to the discussion in a constructive way and preventing catastrophic decisions by politicians, without negating the problem.
*Estimations diverge, a recent one from the Bitcoin Mining Council
claims 58% is coming from renewables, but this would be still 42% from fossil fuels and (probably on a much smaller scale) nuclear energy.