enviromentalists are not the issue with that..it'd be security and the oil conglomerates .. to do it right you'd make the power cells transferrable.. you wouldnt put one in every car, you'd sell one to a driver for life and transfer it from car to car, and then resell it once the person dies.. LOL.. or have then leave it in their will etc etc..

anyhow was a random 10 second brain fart and not a real idea.