I hate the "MPGe" that someone came up with. Gasoline and electricity may both contain energy but they are not equivalent. If you make an assumption that you are starting with a fossil fuel then those two containers of energy are a number of conversions apart to get from one to the other. Electricity is a "higher grade" form of energy than a fossil fuel is.
It makes a whole lot more sense to use kWh / 100 km or km / kWh as those are directly related to what you are paying for in order to "fill up".
The upcoming Chevrolet Bolt with its approximately 60 kWh pack, at 10 cents / off-peak kWh, will cost $6 to "fill up" and you will supposedly be able to do something over 300 km on that. A comparable gasoline engine vehicle (Chevrolet Trax) would probably use about 7 L/100 km = 21 litres to go that distance and cost (today) about $19.
There are places where it could cost more to feed an electric than to drive an equivalent gasoline vehicle, especially if you are recharging during peak demand times.
It makes a whole lot more sense to use kWh / 100 km or km / kWh as those are directly related to what you are paying for in order to "fill up".
The upcoming Chevrolet Bolt with its approximately 60 kWh pack, at 10 cents / off-peak kWh, will cost $6 to "fill up" and you will supposedly be able to do something over 300 km on that. A comparable gasoline engine vehicle (Chevrolet Trax) would probably use about 7 L/100 km = 21 litres to go that distance and cost (today) about $19.
There are places where it could cost more to feed an electric than to drive an equivalent gasoline vehicle, especially if you are recharging during peak demand times.