Modelling of rooftop photovoltaic systems for electrification of public schools in developing countries

Abstract

The present work investigates the techno-economic-spatial-environmental feasibility of a Rooftop Photovoltaic System (RTPVS) for electrification of a grid outage-ridden, space-restricted public school in Sikkim, India and the techno-economic impact of electric cooking (e-cooking) against gas cooking to tackle rising Liquified Petroleum Gas (LPG) prices used in Pradhan Mantri Poshan Shakti Nirman (PM POSHAN) scheme, for enhancing student enrolment in public schools. Remote-Areas Multi-energy-systems-load Profiles (RAMP) for load modelling; PVsyst for estimating maximum Photovoltaic panel capacity and optimum Performance Ratio (PR); and HOMER PRO for techno-economic investigation is used. 5 Dispatch Strategies (DSs) are implemented for three RTPVS configurations including two customized HOMER PRO-MATLAB DSs for the grid-connected configurations to understand the impact of employment of advanced and traditional grid-tied and hybrid converters during grid outages. Further, the impacts of transition to energy-efficient appliances, grid unreliability and various sensitivity parameters on the modelled system outcomes are also investigated to generate broader comprehension of the system performance. For unreliable grid, PV-grid-battery configuration with grid sales yields the best feasible result with a lower global warming potential (GWP) and a reduced Levelized Cost of Energy (LCOE) at 0.0548 $/kWh than both the presently implemented grid-diesel generator (DG)-LPG configuration at 0.306 $/kWh and prevalent grid-battery configuration at $0.212 $/kWh, while the standalone PV-battery configuration is also economically competitive at 0.269 $/kWh with the least GWP. The PV-grid-battery configuration also shows economic viability across entire India for various component costs, grid tariffs and climatic conditions. The optimum converter capacity is conflictingly impacted by grid sales and converter costs. The advanced hybrid converter despite their high costs will be economically more viable over traditional hybrid converters in PV-grid-battery configuration for locations with high frequency and duration of grid outages. The charging of batteries via grid is not recommended as it increases LCOE and system GWP. In locations with high grid tariffs and high percentage sellback rates, the PV-grid-battery configurations can be oversized to increase grid sales and system reliability without impacting the economic viability of the configuration. The degradation of Lead Acid Battery (LABs) increases LCOE and GWP. Policy implementation like carbon credits and subsidies on RTPVS and e-cooking appliances equivalent to LPG may further promote the RTPVS and e-cooking adoption in public schools.