There was an interesting article in the Daily Texan today discussing a new type of plug-in hybrid. The vehicles use ultracapacitors, along with (lithium ion) batteries, to provide acceleration without overheating. The batteries can be charged overnight through a 110-volt household outlet. In terms of costs, this is equivalent to roughly 75 cents per "gallon" (in terms of miles traveled).
Basically, the batteries power the first 40 miles of a trip, then the vehicle switches to a traditional combustion engine (The U.S. Department of Transportation estimates that 80 percent of Americans daily driving demands are approximately 40 miles).
The article goes on to quote Edward Furia, CEO of AFS Trinity Power Company (the company showcasing the vehicles):
"Austin has more potential for plug-in hybrids than any city in the country...You've got enough electricity in the middle of the night coming from West Texas wind farms Austin Energy operates that you could charge all the cars in Austin with wind."Sounds like a cool idea for Austin, or other places with spare nighttime electricity generation. Given that these cars would have the ability to run solely on gasoline, their flexibility sounds promising.