Bitcoin mining consumes 0.5% of all electricity used globally and 7 times Google's total usage

Bitcoin mining consumes around 91 terawatt-hours of electricity annually.
With increased competition, bitcoin mining has become an industry of its own, requiring specialized machines, servers, and huge data centers with enough cooling capacity to keep the computers from overheating.
As noted, the internal mining process itself has become more complex; according to the New York Times, a single desktop computer could easily mine bitcoin back in 2011, when the cryptocurrency had little following.