The Volt, which GM is showing, and saying they will bring out for sale in 2010, is an ingenious thing. It has a rechargeable battery, which it can run on for about 40-45 miles at a charge on the battery alone. (78% of cars drive in that range, or less, per day.) But it also has an APU, or Auxiliary Power Unit, that is a gas engine that makes electricity and uses that electricity to recharge the battery. The gas usage comes out to about 150 miles per gallon, and the range on the Volt is about 650 miles til fill-up.
Now, some people suspect that GM will end up finding an excuse not to bring it out after all, because of fear of offending their good friends the Oil People. We'll see about that in 2010.
In the meantime, most of the technology is out there and ready to go. The APU has been in common use since the 1950s, so it's pretty efficient. The electric powered car is proven technology. The "problem" is the battery: but the lithium-ion batteries out there now are sufficient to make this work well. There are lots of rumors and reports of better batteries in the pipeline, but unconfirmed at this point in time.
We are having fun speculating about making a conversion kit and starting to convert cars to plug-in electric hybrid of this type. Could be a new industry? What do you think?
"Capitalism is the extraordinary belief that the nastiest of men, for the nastiest of reasons, will somehow work for the benefit of us all."
--John Maynard Keynes