Power harvesting is the process of extracting useful electrical energy from ambient low grade energy sources such as solar energy, mechanical energy, and thermal energy using smart materials as transducers. These materials have the ability to convert one form of energy into another. This paper aims at thermal-electrical energy converters based on a pyroelectric effect for energy harvesting, and examines its possible use in ultralow power devices and sensor modules. The present work investigates theoretically the energy harvesting capacity of pyroelectric samples fabricated in our laboratory and commercially available pyroelectric elements/transducers by capturing thermal energy of pavements. The single- and polycrystalline elements: triglycine selenate; lithium tantalate; modified lead zirconate titanate; modified lead titanate; modified lead metaniobate; and pyroelectric polymer nanocomposites such as Portland cement; nanocarbon fibers; polymer-lithium tantalate embedded with silver nanoparticles; and others were characterized for applicable performance parameters. The modeling and numerical simulation of energy harvesting capacity of these samples with the available pavement's temperature-profile data over an extended period of time were investigated. The results indicate that the electrical energy harvesting via pyroelectricity is a feasible technique for powering autonomous low-duty electric devices. Based on our analysis of a single electric-energy harvesting unit, the triglycine selenate elements shall perform better than others with regard to the amount of voltage and energy densities extracted with respect to time. Possible future work and concepts of developing promising multidomain energy harvesters or hybrid harvesters are also briefly discussed.