Modeling a new energy harvesting pavement system with experimental verification

A novel design of an energy harvesting pavement system (EHPS) is introduced in this paper. The basic concept behind this design is to transform asphalt layers into a piezoelectric energy harvester to collect dissipated vehicle kinetic energy in a large-scale system. This EHPS design consists of two conductive asphalt layers and one piezoelectric material layer. To verify the feasibility of the design, this ongoing study theoretically analyzed the EHPS via a three-degree-of-freedom electromechanical model and practically tested a prototype in the laboratory. As a result, voltage outputs measured in the laboratory from the prototype design matched those estimated from the electromechanical model. Through testing the effects of several components in the EHPS on electricity generation, this study confirms that using more flexible conductive asphalt mixtures and arranging more piezoelectric elements with a higher piezoelectric stress constant can increase electrical outputs from the EHPS. Regarding specific external vibration conditions, a high frequency of external vibration can lead to a dramatic effect of each piezoelectric element's capacitance on increasing electrical outputs, but also can reduce the benefit from adding more piezoelectric elements to produce higher electrical outputs. After optimizing this EHPS prototype by adding more piezoelectric elements with higher piezoelectric stress constant and improving the flexibility of conductive asphalt mixtures, the maximum electric power from the proposed EHPS can be increased from approximately 1.2 mW to 300 mW under a high frequency (30 Hz) external vibration. The levelized cost of electricity of this EHPS can be $19.15/kWh on a high-volume roadway within a 15-year service life.