It is getting close to time to replace my 1998 Honda Civic. One of the cars on my short list is the Toyota Prius. There has been a lot of talk about plug-in hybrids which, unlike the current Prius, are not powered by gasoline alone, but are plugged into an electric socket to recharge the batteries and then run on electric power alone for as much as possible.
The current Prius keeps the charge of the batteries somewhere in the middle and never seems to charge them completely nor let them drain down completely. I think that is the most efficient way to keep a charge on the batteries and also avoids complete charging cycles which shorten battery life.
So the problem with a plug-in is that you will need to top off the batteries and probably run them down much further in order to run the car solely on electrical power. This will shorten battery life. Also there is some inefficiency in using coal to produce electricity and then use the electricity to charge a battery and then use the battery to run the car. You lose a little power with each step. Additionally, by using electricity you are just transferring the pollution from the tailpipe to a powerplant somewhere (which would at least help Atlanta’s air).
So it occurred to me that instead of a plug-in hybrid, it would be better to put solar cells on top of the car and charge the battery that way. One reason this occurred to me is because my car is parked in the sun all the time, whether that is at home or in the MARTA parking lot.