1. Swiss Researchers are developing thermoelectrics that are integrated into a muffler This would recover 5% of the energy that is wasted by cars now. By integrating it with the muffler it will be more feasible to retrofit existing cars to provide the equivalent of 1 or 2 mpg of extra efficiency. It would be most practical to use the electricity that is generated to power air conditioning and other electronics on the car. Hybrid cars could use the power to more directly improve mileage.