A Review of Harvesting Green Energy from Road

Abstract

This paper presents a review of harvesting green energy from road. There are three forms of green energy exist in road: light, thermal and mechanical energy. Photovoltaic technology, thermoelectric technology, directly heat transferring and piezoelectric technology are discussed in this paper, as well as the cases studied in Europe, USA, Japan, Israel and China. Solar panels installed along road are current available to harvest light energy from the roadside land. Alternatively, the solar panels can be installed on the road instead of pavement structures, such as the Solar RoadwayTM. This technology is rather conceptual at this moment, and the main challenge is to design and build durable materials and structures that can withstand traffic at a reasonable maintenance and replacement cost. Thermoelectric generators can potentially be embedded in pavements, and generate electric power from the temperature gradient existing in pavements. However, instrument capable of efficiently generate electricity from the relatively small temperature gradient in pavement is still under development. Directly heat transfer solution is to have fluid flow through pavement, and the fluid is heated (in summer) by the pavement. An extra benefit in addition to energy collection is that this method can reduce pavement temperature as well as the associated negative effects on pavement performance and the environment. However how the heated fluid can be utilized was not clear. Electricity can be generated by piezoelectric ceramic generators embedded in pavement, as a result of the compressive stress and deformation induced by moving vehicles. Trials have been reported in Israel and China, and it was estimated that one lane-mile of highway can potentially general electricity of 200 kW.