Not sure why you are downvoted, but 77% of light vehicles does not equate to 77% of total consumption. 77% of the light vehicles are likely exactly that 77% that is used rarely, it's just the Pareto principle at work: https://en.wikipedia.org/wiki/Pareto_principle , the bulk of the consumption will be done by a relatively small number of consumers. And so a very large number of those consumers could be converted to electricity without much impact on the grid or generating capacity but that would not be a huge impact on total consumption of fossil fuels.
"77% of the light vehicles are likely exactly that 77% that is used rarely"
I won't use the word 'extraordinary', but that's at least a strong claim, so needs strong evidence to back it. Why wouldn't 77% of vehicles mean 77% of the load?
I don't think that it is that strong a claim at all, not all vehicles are used to the same degree by their owners, every second hand car website can tell you that.
Cars that are 5 years old can have anywhere from 20K to 300K km on them. It all depends on the usage.
Lots of good data here:
http://www.solarjourneyusa.com/EVdistanceAnalysis7.php
People using their cars for 50K to 70K km per year are not exceptional (professional use), private individuals using their cars for < 5K km per year are not exceptional either.
You didn't claim 'not all vehicles are used to the same degree by their owners'. You claimed that if a report says 77+% of cars could be electric using the current grid, it probably means the least-used 77%. That's the strong claim.
It's the claim that makes most sense. You'd take the least used vehicles because their usage patterns will match current production EV sweet spots best (always assuming we are talking 100% electric and not hybrids).
Consider that wind and solar installations are accelerating (and that wind is so cheap in parts of Texas, its free at night!) and I can assure you, there is no electrical grid burden.
EDIT: Citation
http://www.world-nuclear.org/information-library/non-power-n...
"The UK Department of Transport and teh Royal Academy of Engineering (2010) have both estimated that if the UK switched to battery electric vehicles, electricity demand (kWh) would rise about 16%. The US Electric Power Research Institute modeled 60% of US vehicle use being electric and found a 9% increase in electricity demand. As can be seen from the graphs above, this need not increase the system's peak capacity if most charging is off-peak, thereby greatly increasing the proportion of total generating capacity supplied by base-load plant – see below. A study conducted by the Pacific Northwest National Laboratory for the US Department of Energy in 2006 found that the idle off-peak grid capacity in the USA would be sufficient to power 84% of all vehicles in the USA if they all were immediately replaced with electric vehicles. Areva has calculated that if 10% of cars in France were electric it would increase base-load demand by more than 6000 MWe ("four EPRs", or 10% of nuclear capacity). In the above diagrams, assuming significant move to electric cars mostly charged off-peak, the base-load demand is increased by about 35%."