I thing that is impossible if bitcoin use around 80% of the energy, because I seen bitcoin isn't famous in some country, for example in my country, here just around 20% peoples know about bitcoin and not most people mining bitcoin, maybe they just trading or just hold it and that no need to much energy because we can do that only by smartphone, if bitcoin use more than 80% or the energy, that is possible? I think no, and also not all country can use bitcoin.
If all the world already accept bitcoin and all people mining bitcoin, maybe you can say if bitcoin using more than 80% of the energy in the world.