Reading through the article, its just a speculation of what will happen but the issue here is the possibility of that happening because it then means that if bitcoin takes the whole of the world electricity, then banks will not work, government functionaries will also not work which then means that the whole of our lives will be put on hold since I have not seen a generator that can sustain the whole of the country.
How then are we going to use the bitcoin mined if we cannot even charge our phones and gadgets. Its simply something I see not happening in 2020 or forever rather I see more alternative ways to mine bitcoin which the government would have stepped in to stop it being mined on pubic electricity which is what the Chinese government are considering if not implemented already.
I think it is impossible. Bitcoin cannot consume all the world electricity, i think it now becoming easy to provide electricity for mining because states are now find other cheap ways of source of electricity, for example solar energy is the cheapest source of energy, where we have one time investment and can get cost-less electricity after that. We have HYDRO ELECTRIC POWER STATIONS, from where we can get a cheap source of electricity.