The reality here is it is a huge step change.. but over a 20 year period..
Look at power/ economy gains in ICE tech since the 80'S
Not to mention PCs and MOBILE communication tech.
If the currently poor plug ins double their
EFFICIENCY.
and double their storage capacity
( should be less than 10 years away..but still cheaply mass produced)
The generating requirement will be reasonably achieveable
My calculations generously made no allowance for charging inefficiency. I can't really see tractive efficiency doubling unless they go to superconductors and there is not much sign of that at present. Mind you we were saying the same thing about LED lighting 20 years ago. Doubling the storage capacity only brings the possibility of needing double the generating capacity if the additional range is used on a regular basis.