Although wood is cheap and plentiful (otherwise it wouldn't be used to just burn it), one can obviously also place a PV-system on an existing house or garage roof (the parking roof was just there to explain, that it is not feasible to grow enough corn ethanol at home to power a gasoline powered car):
In Germany complete small 5 kW PV-system with brandname PV-modules are built for €1.4/W (including import taxes) which is approx. $1.9/W (incl. installation).
32xxx | 5kWp || 1382
(German electricians/roofers don't have lower wages than their American counterparts).
At 1500 sunhours (North America) per year, 1 W of PV produces 30 kWh in 20 years (since PV-modules have no moving parts, there's no reason why they shouldn't even last twice as long:
).
So, 1 kWh of roof power = 6.3 cents/kWh
At an 80% EV efficiency that's 7.9 cents/kWh one pays for the roof-energy at the wheels.
1 gallon of gasoline contains approx. 33 kWh. At an overall efficiency of 25% from tank to wheel (incl. engine heat/drivetrain losses and idling/partial load losses), 8 kWh /gallon are left.
At $3.50 per gallon of gasoline during the next 20 years (no inflation - which is doubtful) the average gasoline costs are 43 cents/kWh: Approximately 5 times more than what one would pay for homegrown as opposed to mostly imported energy (not including the costs to protect interests abroad, prevent potential oil embargos from re-occurring and costs of pollution, CO2, oil-sands, missing import-taxes and what not).
