«So given that for BTC to become a successful reserve currency» Your premise is wrong to start with... BTC could be very successful without necessarily being a

«So given that for BTC to become a successful reserve currency» Your premise is wrong to start with... BTC could be very successful without necessarily being a major worldwide reserve currency! «But that's more electricity than currently exists» Not true. Bitcoin currently uses only about 0.2% of the world's electricity consumption (http://blog.zorinaq.com/bitcoin-electricity-consumption/#updates http://blog.zorinaq.com/bitcoin-electricity-consumption/#upd...). 100× would be 20%. Some miners are currently building their own power plants for their mining farms. Getting to 20% is definitely possible.