Dennis the Elder in the other recent Hybrid thread asked about electrical energy conversion efficiencies. I've seen them discussed in an Electric Vehicle group. If I recall correctly you may retain some 85% of your input energy after transferring it to the battery and taking it out again to drive the motor. Line loss (power plant to house electrical meter) averages about 10%, I've heard. Has anyone seen a comparable figure for plant-to-gas-tank fuel shrinkage, and waste or leakage for other forms of energy storage?

If photovoltaic solar panel supply is beginning to catch up to demand, prices should fall rapidly soon. But what I'm looking forward to is solar film rugged or renewable enough to drive on, so exposed road surfaces generate power. That would probably be a plastic solar film, with only 1-5% efficiency, but there are a lot of square meters of paved road in sun every day.

No matter how renewable the power supply, it cannot meet endlessly growing demand.