Smart Design of Stand-Alone Solar PV System for Off Grid Electrification Projects

Abstract

Solar PV has seen a remarkable growth across the globe with the total PV installation now exceeding several gigawatts (GW). The technology has the versatility and flexibility for designing systems in different regions, especially in remote rural areas. While conventionally straightforward designs were used to set up off-grid PV-based systems in many areas for a wide range of applications, it is now possible to adopt a smart design approach for the off-grid stand-alone solar PV system. A range of off-grid system configurations are possible, from the more straightforward design to the relatively complex, depending upon power and energy requirements, electrical properties of the load, as well as on site specificity, and available energy resources. The overall goal of the off-gird system design should be such that it can give maximum efficiency, reliability and flexibility of the system at an affordable price. In this chapter, the three basic PV systems, i.e. stand-alone, grid connected- and hybrid-systems are briefly described. Assessment of energy requirement including load profiling, load distribution and load categorisation is provided in a lucid way. That is then matched with a section on solar resource availability. Furthermore, a systematic approach has then been presented regarding sizing and designing of the above systems. Guidelines for selection of PV components and system optimisation are provided. Owing to the natural variance of the solar resource there is a critical need for storage batteries to satisfy energy demand during nocturnal and overcast periods. Furthermore, under a highly variable cloud regime there is a frequent demand for charging and discharging of battery in a PV system. So, the type of battery used in a PV system is not the same as in an automobile application. Detailed guidelines for selection of battery are therefore also provided.