Researchers at Pennsylvania State University have developed a compact thermoelectric generator capable of converting waste heat from vehicle exhaust into usable electricity. Their prototype successfully produced 40 watts of power—enough to power a light bulb.
Internal combustion engines, which power most conventional vehicles, operate at an efficiency of only about 25%, meaning that nearly three-quarters of the energy from fuel is lost as heat. As global carbon emissions continue to rise and cleaner energy alternatives remain in development, maximizing energy efficiency in existing technologies has become a pressing concern.
Thermoelectric generators (TEGs) work by utilizing temperature differences across materials to generate electricity. While the concept has existed for some time, traditional TEGs rely on semiconductor materials and require external water-based cooling systems to maintain efficiency. These cooling systems add bulk to the design, making the generators less practical for real-world applications.
To overcome these limitations, a research team led by Wenjie Li and Bed Poudel at Penn State University introduced a novel approach.
Instead of depending on water-based cooling, the researchers incorporated heat exchangers commonly used in air conditioning systems to capture and utilize heat from vehicle exhaust. Their generator, built using the semiconductor material bismuth-telluride, also featured an additional heatsink to maximize the temperature difference—crucial for boosting energy output.
The prototype generated 40 watts of power, but tests showed that higher airflow conditions, such as those found in moving vehicles, further enhanced performance. Simulations predicted that the generator could produce 56 watts when installed in a car and an impressive 146 watts when attached to a helicopter exhaust—equivalent to the output of 12 lithium-ion batteries.
Because the new thermoelectric generator can be directly integrated into exhaust systems without requiring extra cooling infrastructure, it can be easily retrofitted onto existing vehicles. The researchers believe this innovation could pave the way for the widespread adoption of thermoelectric devices in everyday transportation, significantly improving energy efficiency and reducing waste.
