Design and operation of a stand-alone solar pathway for public park lighting

Abstract

The development of solar roads to convert insolation on vast stretches of land to electrical energy, otherwise dedicated solely for transportation, is in its nascent stage. A great potential is seen for PV application with the maturing of solar road technology. Apart from increasing the versatility by smart utilization of land resources, widening the cover of renewable energy generation will lead to a sustainable, secure energy future. A stand-alone solar pathway for public park lighting or area lighting system, completely independent of the power grid, was designed and operated. Public lighting for 65 m stretch of walkway located next to the Electrical, Electronic and Computer Engineering Department building, was chosen as a case study in this study. The case study presented simplified method for sizing, performance evaluation and simulation of a stand-alone solar pathway to power public lighting on the Bellville Campus of the Cape Peninsula University of Technology. Depending on the requirements of the electrical, the quantity and quality of lighting, as well as the required duration of the lighting were calculated. Battery storage capacity, based on the desired autonomy period, and maximum and average daily depth of discharge, were sized. PV array size, based on the type and specifications of PV module, the time of year with the highest average daily lighting load and minimum solar radiation, were selected and measured. Control strategies for battery protection and lighting control conditions were determined, and the control set points were specified. The operating efficiency of solar pathway was evaluated and showed excellent performance compared to the expected with annual average value of the monthly performance ratio and system efficiency. A stand-alone solar pathway system was programmed using MATLAB, in order to size a PV system to the supply public lighting for the walkway. The computer program used, can be applied to any site with different weather conditions.