http://www.coindesk.com/microscope-economic-environmental-costs-bitcoin-mining/
I think the author is conservative, and the likely power consumption is way higher.
When you have projects like MegaBigPower wanting to add 50PH/s to the nethash each month, that's a new power station each year just for them.
http://www.coindesk.com/megabigpower-launches-global-franchisee-network-add-50phs-per-month-bitcoin-network/
At some point the exponential growth has to stop, if only by governments cracking down on the large scale energy wastage.
Mining uses an insane amount of energy. I honestly hope governments do crack down on people doing this (at least those who aren't powering it with their own PV setup). This really is the biggest problem with bitcoin in my opinion, it's a huge energy hog. I think most of the things about bitcoin taking over would be great, but this is definitely not one of those aspects of bitcoin that are a positive. (Yeah, I know, the fiat system also uses a tremendous amount of energy, but we really should be striving to do better than them, rather than merely not as bad.)