https://www.theguardian.com/technology/2018/nov/05/energy-cost-of-mining-bitcoin-more-than-twice-that-of-copper-or-gold > New research reveals that cryptocurrencies require far more electricity per-dollar than it takes to mine most real metals > The amount of energy required to “mine” one dollar’s worth of bitcoin is more than twice that required to mine the same value of copper, gold or platinum, according to a new paper, suggesting that the virtual work that underpins bitcoin, ethereum and similar projects is more similar to real mining than anyone intended.