DESIGN OF SOLAR PHOTOVOLTAIC SYSTEM FOR UNDERGROUND IRRIGATION PUMPING WATER FOR THE AGRICULTURAL FARMLAND IN NATIONAL ROOT CROPS RESEARCH INSTITUTE, UMUDIKE (NRCRI), ABIA STATE, NIGERIA.

This study addresses the critical challenge of water scarcity and high energy costs impacting agricultural productivity in regions like Abia State, Nigeria, by proposing a sustainable solar photovoltaic (SPV) irrigation pumping system. The objective was to design and evaluate an SPV system for underground irrigation at the National Root Crops Research Institute (NRCRI), Umudike, and ensure a reliable water supply for its 5-hectare farmland. The methodology involved determining pump energy demand (36.3 kWh/day), applying three distinct SPV component sizing methods for cross-validation, and performing a robust stochastic reliability and temperature-adjusted performance analysis using Monte Carlo simulation. Key results indicate that a system with 36 solar panels, 24 batteries, and a 6.0 kVA inverter can consistently meet the daily energy demand. The stochastic analysis demonstrated that while monthly solar deficits can be high in certain periods (e.g., 99.9% in August), even minimal (e.g., 1 day) battery autonomy drastically reduces the probability of energy shortfall. This research provides a practical and resilient framework for off-grid agricultural irrigation in sun-rich developing regions.