The usual problems with this approach are 1) the roof is not big enough for solar panels to power multiple chargers and 2) the power is generated when people are not at home (and probably using their car to go to work).
Then the obvious solution is to put solar panels over parking spots at work. Doesn't need to be that much power, 1-2kW is enough if the car sits there all day (for typical distances people commute with cars)
