Harvesting Thermoelectric Energy from Asphalt Pavements

The goal of this study was to develop a prototype for harvesting thermoelectric energy from asphalt pavement roadways. This emerging research field encompasses technologies that capture the existing thermal energy in pavements to generate electricity without depleting natural resources. In lower latitudes, such as south Texas, the asphalt pavement surface temperature in the summer can reach 55 degrees C because of solar radiation. Soil temperatures below the pavement, however, are roughly constant (i.e., 27 degrees C to 33 degrees C) at relatively shallow depths (150 mm). This thermal gradient between the surface temperature and the pavement substrata can be used to generate electrical power through thermoelectric generators (TEGs). The proposed prototype collects heat energy from the pavement surface and transfers the energy to a TEG embedded in the sub-grade at the edge of the pavement shoulder. Evaluation of this prototype was carried out through finite element analysis, laboratory testing, and field experiments. The results suggest that the 64- x 64-mm TEG prototype can generate an average of 10 mW of electric power continuously over a period of 8 h in the weather conditions in south Texas. Scaling up this prototype by using multiple TEG units could generate sufficient electricity to sustainably power low-watt LED lights and roadway and traffic sensors in off-grid, remote areas.