I have seen several articles relating Toyota's plan to equip a Prius model with solar cells to run the air conditioning. The articles claimed that the panels, to be obtained from Kyocera, would put out 2 to 5 KWatts. A quick check of the Prius dimensions shows a planform area of approximately 8 square meters. Since the maximum solar input to be expected is only 1 KWatt per square meter on a clear summer day when the area is normal to the suns rays, I can state that, even in the Tropics, when the sun is at the zenith, only 8 KWatts of sunlight will rain down on the car. Even the minimum 2 KWatt power collection reflects cutting edge solar cell technology. 5 KWatts is absolutely unthinkable now, and probably for the next decade or two (if ever). Irresponsible statements such as must have appeared in the press release from Toyota, do little to advance the cause of solar power. My guess would be that a collector the size of the car, with no provision for windows(!) which produced 2 KWatts would cost much more than the car itself.

What do you think of Tesla Motors and their all-electric vehicle? Very expensive at the moment, but I was reading some editorial recently which claimed that their car could go into mass production in the relatively near future (and would presumably become much cheaper).

I believe it's just waiting for reliable batteries to be complete.