Analysis on system sizing and secondary benefits of centralized PV street lighting system

The combination of solar and LED lighting has enabled interest in the municipalities and governing authorities to lighten streets/remote areas without setting up electrical infrastructure in a mere traditional way. For which, stand-alone solar street lighting solutions are very popular and often built with customized PV panels and over designed. Recently, AC-centralized street lighting system is adopted by many of the street lighting installers as such system is easy for installation, maintenance and future grid interconnectivity. Generally, solar off-grid solutions are designed for autonomy of 3-5 days to meet lighting requirements under worst environmental conditions. Hence, in situations like continuous sunny days (especially in countries like India), the surplus solar energy gets unutilized, which can be avoided in case of centralized system. This paper presents analytical work on system sizing for two geographical locations in India based on monthly averaged solar irradiance and dusk-dawn length data. Comparison among three solutions (decentralized, AC-centralized, DC-centralized) in terms of system size, amount of surplus energy etc. is presented in this paper. The effect of dust on PV performance is also considered during analysis. An approach to use judiciously available surplus energy in centralized system for other local energy needs is discussed.