A few months ago, we posted a short piece on the MDI AirCar, a small commuter vehicle that runs on compressed air. AP has an updated report on the AirCar, which apparently has gotten past its earlier limitation of only operating for about 7 kilometers. Current models are able to go about 50 miles on a single tank of compressed air, more if you drive below the maximum speed of about 70 miles per hour. Recharging the tank (by plugging it in) takes about four hours; MDI claims that the electricity required to recharge the tank costs about $2.50 in France (presumably, AP took care of the currency and km/miles translation correctly). Let's see... 50 miles for $2.50... that's a bit better than a hybrid gets at California gas prices, but not outrageously so. Of course, the AirCar is cleaner than a hybrid as a greenhouse/pollution emission source, and much cleaner if you can charge it with your rooftop solar panels.
Sadly, there's still no sign of the AirCar being made available in the United States any time soon.
I wonder if you could use this to do electrical load-leveling. Compress air at night when power is cheap and plentiful; use it to run a generator when you need a lot of juice. Or, use your solar panels to compress air during the day and use it to create electricity at night.
Its already been done;/ By the power company of all people. They stuffed air into a cave then released it when they needed power. Worked rather well too.
What about covering the body of the car with the solar film from this article here: http://www.worldchanging.com/archives/000883.html, then you have a self-sustaining mode of transportation (more or less). With no use of power created by coal etc.
According to their website: theaircar.com, average range of the aircar will be about 150 miles per charge. They also say they are negotiating with investors for USA franchises.