And the profits grow

[kandrathe]

... Solar is good, but not ready for prime time.

The issue is that direct solar power produces about 2-4hp for the surface area of a vehicle using solar cells that are 30% efficient. If we made huge breakthroughs in solar cells and increased efficiency to 60%, we would still only get between 5hp and 10hp in perfect sunny conditions. Solar power is too dilute for vehicle power. Vehicles will need to accelerate reasonably quickly and go up steep hills so 5 hp or so will not usually be sufficient. That leads back to battery storage and the additional weight. The future of vehicle propulsion must be focused on energy storage density. Part of the process will need to be a shift of thinking from 500hp vehicles down to ones sufficient for transport. As you know, bio-fuels are really just another way of storing solar power, and photo synthesis is not a very efficient process. So, the trade off would be between using huge amounts of land for solar cell farms to capture electricity, or huge amounts of land being used to grow crops to be processed into bio-fuels. Which bio-fuel is better then, Bio-diesel or Ethanol? My feeling is that Bio-diesel seems to be currently the better more efficient way to make fuel. I think eventually to replace petro-fuels we will need to rely on a combination of technologies, including hydro, solar, nuclear, and some bio-fuels.