The use of combustion engines is on the rise due to the visible worldwide cycle of increased movement. I.C. engines are power-intensive devices with low efficiency since approximately 75% of the energy generated during combustion is lost as heat in the engine's coolant and exhaust. There is a pressing need to develop a strategy to stop the massive energy loss.In this work, a thermoelectric generator (TEG) intended for a four-stroke internal combustion engine is used to develop and build a waste heat recovery system. Using a TEG, the device transforms the exhaust manifold's waste heat into electrical energy. Generating electricity in present there is a shortage of fossil fuel, oil, gas, etc. burning of these fuels causes environmental problem like radio activity pollution, global warming etc. So that these (coal, oil, gas) are the limiting resources hence resulting new technology is needed for electricity generation, by using thermoelectric generators to generate power as a most promising technology and environmental free and several advantages in production. Thermoelectric generator can convert directly thermal (heat) energy into electrical energy. In this TEG there are no moving parts and it can not be produce any waste during power production hence it is consider as a green technology. Thermoelectric power generator convert direct waste heat in to generate electricity By this it eliminated emission so we can believe this green technology. Thermoelectric power generation offer a potential application in the direct exchange of waste-heat energy into electrical power where it is unnecessary to believe the cost of the thermal energy input. This method will have an maximum outcome. The application of this option green technology in converting waste-heat energy directly into electrical power can too improve the overall efficiencies of energy conversion systems. Heat source which is need for this conversion is less when contrast to conventional methods. By using this energy is used to charge the mobile electronics.