Your numbers are way off.

Energy consumption is massively impacted by the size of the semiconductor die, e.g. 110 nm vs. 50 nm vs. 20 nm. Currently, most ASIC rigs are using 110+ nm chips, but the currently available semiconductor techology available to OEMs is in the 2x-nm class. The 1x-nm class isn't far behind now.

Have a read around here:

http://www.samsung.com/global/business/semiconductor/minisite/Greenmemory/

That will give you an idea about how die size affect energy consumption.

With ever smaller classes of chips, energy consumption will decrease. So, any prediction of future energy consumption must take into account the energy efficiency of semiconductor technologies available in the future.

For example, would you calculate it in cords of wood or tonnes of coal for a steam engine to produce your electricity? Of course not, because that technology is pretty much obsolete now (outside of a few specialty cases).