, spivonious wrote

Until we can capture and convert more of the sun's energy (like powering a modern sedan with just solar panels on the roof and hood), we will need to use less Earth-friendly sources of power.

That's not likely to happen, I'm afraid. With an average daily insolation of 6 kWh/m2 ; even a sedan designed in the '70s would be way too small.

Not to mention that the sun is, by definition, a variable source: you must have a way to store large amounts of energy somehow. 

Cheap, light, non-polluting, large capacity batteries is the nut we need to crack; once we get there, the energy source becomes less relevant.