In theory yes, in practice, which electric car charger has a built in 3kw inverter for backfeeding? Have you seen how large a 3kw inverter is? They are also not cheap. Secondly, most homes aren't metered in both directions. What is the ROI of one car plugged into the grid in this system? How much does it depend on how long the vehicle is actually plugged in and whether it is plugged in at useful times.
Taking the number above for installed capacity of pumped hydro. You are looking at nearly half a million cars and homes to match the capacity (assuming 50kwh per vehicle), before considering the plugged in factor.
At say a nice round £1000 to upgrade each home you are already looking at a cool half a billion. Already around the cost of the Dinorwig pumped hydro station before you figure out how to compensate electric car owners for the extra wear on their batteries or the fact that when they leave for work their car is flat because it has been powering your neighbors electric showers.
Taking the number above for installed capacity of pumped hydro. You are looking at nearly half a million cars and homes to match the capacity (assuming 50kwh per vehicle), before considering the plugged in factor.
At say a nice round £1000 to upgrade each home you are already looking at a cool half a billion. Already around the cost of the Dinorwig pumped hydro station before you figure out how to compensate electric car owners for the extra wear on their batteries or the fact that when they leave for work their car is flat because it has been powering your neighbors electric showers.