Solar cars?
Given that solar cells just cracked the 40% efficiency barrier not too long ago, and electric cars are down to needing around 10kWh per 100km, and given the usual variations in solar flux, and assuming you can cram 3 square metres of solar cells onto the top surfaces of a car, plus another 2 on each side (although only one side would be able to charge at a time), I find the math comes out to a light, modern-style car being able to charge itself with around 17-170 km (winter-summer) of juice a day if it's parked outside. (Feel free to check my math.)
Now, that's not necessarily going to be enough to drive everywhere you want, especially in winter. However, in summer the majority of urban commuters would not need to buy fuel (hybrid) or charge from a socket (pure electric), assuming they didn't park in the shade. In winter, it's still going to knock a chunk off refuelling bills if people can get a free 10-15km per day out of their cars. And that's not counting garages/houses fitted with solar cells/batteries which can build up a commuting charge while the car's at work.
The major issue at this point appears to be the cost of the super-efficient solar cells. When that comes down, and as hybrids become more popular, we may start seeing the advent of the car which hardly ever needs a refuelling nozzle (whether liquid or electric) plugged into it.
What's also interesting is that, five years ago, thin-film solar cells were able to generate/return their production-energy costs in approximately a year. I'm waiting for the point where a cell purchased through whatever means can return its purchase price in paybacks from the local electric company in a fairly short amount of time. You can then use the money to buy another cell and have two of them pumping electricity back into the grid - which will recover your money in half the time and let you buy a third cell, etc. Eventually you'd have a farm of cells which basically cost you nothing and are generating free money all day long.
(This would work better in places where it's sunny and you have access to sufficient amounts of sun-drenched surface or land to place all the cells, of course.)
Now, that's not necessarily going to be enough to drive everywhere you want, especially in winter. However, in summer the majority of urban commuters would not need to buy fuel (hybrid) or charge from a socket (pure electric), assuming they didn't park in the shade. In winter, it's still going to knock a chunk off refuelling bills if people can get a free 10-15km per day out of their cars. And that's not counting garages/houses fitted with solar cells/batteries which can build up a commuting charge while the car's at work.
The major issue at this point appears to be the cost of the super-efficient solar cells. When that comes down, and as hybrids become more popular, we may start seeing the advent of the car which hardly ever needs a refuelling nozzle (whether liquid or electric) plugged into it.
What's also interesting is that, five years ago, thin-film solar cells were able to generate/return their production-energy costs in approximately a year. I'm waiting for the point where a cell purchased through whatever means can return its purchase price in paybacks from the local electric company in a fairly short amount of time. You can then use the money to buy another cell and have two of them pumping electricity back into the grid - which will recover your money in half the time and let you buy a third cell, etc. Eventually you'd have a farm of cells which basically cost you nothing and are generating free money all day long.
(This would work better in places where it's sunny and you have access to sufficient amounts of sun-drenched surface or land to place all the cells, of course.)