Interesting piece about how VW is experimenting with putting heat recovery systems in the exhaust pipes of a car which is able to produce 30% of the electricity needed by the car when running. It uses the Seebeck or Peltier Effect to generate current from a heat differential.

Purportedly the thermoelectric generator is able to gain about 600W from a car running on a highway, meeting about 30% of the car’s electrical consumption requirements. For the moment, the thermoelectric generators haven’t been embedded in a hybrid car, although VW says with the current setup it can save about 5% of your fuel consumption (not 5L/100km, but 5% of 5L).

BMW and DLR (German Aerospace) also competed with Volkswagen by showing a system with a 200W output. They say it has been used for more than 12,000 km. They are both integrating TEGs with future gasoline powertrains. BMW even has them in their plan for the 2010 - 2014 Series 5 cars.