https://www.theregister.co.uk/2018/11/07/cryptocurrency_mining_energy/

Cryptocurrencies require as much, if not more, energy to mine as precious metals like copper, gold or platinum, according to some latest calculations.

The figures were jotted down by Max Krause, a researcher at the Oak Ridge Institute for Science and Education, and Thabet Toloymat, an environmental engineer working in Cincinnati, Ohio, in the US.