The high efficiency thermoelectric devices developed in the SBIR will also fill many terrestrial needs for renewable energy and energy harvesting. Presently, about 90% of the world's energy comes from burning fossil fuels. This chemical energy is converted to mechanical energy in heat engines, operating at about 30% to 40% efficiency. The result is about 15 terawatts of energy lost as waste heat. Capturing even a small fraction of this energy with thermoelectric energy harvesting devices would have a huge impact, in terms of dollars saved, reduced consumption of fossil fuels, and reduced emission of greenhouse gases. In additional to the primary energy savings, waste heat recovery systems reduce the auxiliary cooling required to protect people and sensitive components from the waste heat. Future NASA missions for deep space and planetary exploration will require radioisotope power conversion systems, for reliable electrical power both near and far from solar radiation sources. Thermoelectric devices offer a simple and reliable means to convert radioisotope thermal energy into useable electrical power, with no moving parts. The high efficiency thermoelectric devices proposed in this SBIR effort will increase the amount of available power for NASA mission requirements, and reduce overall size and weight of the power system.