Pulling electricity from tailpipes could save 29M barrels of oil

June 3, 2008   by Jozef Winter

Despite our society’s love affair (hopefully a dwindling one) with the internal combustion engine, it still remains a very inefficient technology as more than two-thirds of the energy used goes into the production of heat that just dissipates into the atmosphere, unused. Think of that next time you are filling up at the pump with $4 per gallon gas… you are only getting $1.33 worth of “moving” energy at best, depressing eh? Well researchers in Germany are hoping to capture some of that energy by harnessing the heat emitted from the tail pipes and feeding it back into the car.

Their thermoelectric generator (TEG) will make use of the differential of temperatures between the 700° Celsius exhaust heat and the engine cooling fluid. This differential will drive charge carriers through special semiconductors, generating an electrical current that can be fed into onboard systems or into batteries for hybrid vehicles. What the team hopes to accomplish in the long run is to eliminate the need for an alternator, having all the juice come from the waste heat. Capturing this lost energy will cut fuel consumption between 5% and 7%, also reducing emissions.

While it might not sound like a lot, based on their calculations, in Germany alone there are 50 million vehicles on the road, and if each of then were being driven for 200 hours annually (a VERY conservative figure if you look at US driving habits), and each were outfitted with a TEG with an output of 1 kilowatt, this would add up to 10 Terawatt hours (trillion watts), the equivalent of 5.9 million barrels of oil, and that’s only for Germany! For the US, with 243 million passenger cars (not even other transport vehicles), that’s 28.7 million barrels of oil, or the the equivalent power of 7 nuclear power plants! Sadly, the researchers will only be putting a prototype together soon, so it will be a while before we see this technology on the road.

via ScienceDaily