A European Union-funded collaborative research project designed to convert exhaust waste heat into onboard electricity via is moving into the prototype stage, according to Ricardo. The company, a partner in the project (called PowerDriver), reported that recently completed simulation work on a potential automotive application of the thermo-electric generator technology (TGEN) indicates a possible output of 300 W and equivalent fuel savings over the NEDC drive cycle of 2.5%. Next on the project agenda is the production of prototype TGEN designs for a gasoline-powered Jaguar passenger car and for two marine diesel engine applications that are of interest to Rolls-Royce. To extract the energy from the exhaust gas flow, the TGEN has to be mounted between two heat exchangers—a hot side heat exchanger and a cold side heat exchanger, according to Ricardo. This is necessary because the thermo-electric materials produce energy when exposed to a large difference in temperature. In both cases the hot side heat exchanger forms part of the exhaust line and the cold side heat exchanger forms part of the engine cooling system. The thermoelectric materials under consideration for the automotive application—both n-type and p-type, to form a couple—are silicide-based materials. These have a potentially low cost base but need further development to achieve the performance and thermal stability required for the application. This is not least due to the fact that the TGEN is located within the exhaust line and is subject to significant thermal cycling. In addition, the lead telluride based thermo-electric materials being investigated for the marine application have a proven track record in similar applications but present financial and thermal stability issues that need to be overcome. Among additional challenges, the TGENs require electronic controls that also need to be developed to maximize output efficiency.