Effects of total system head and solar radiation on the techno-economics of PV groundwater pumping irrigation system for sustainable agricultural production

Abstract

Several agricultural farms in Nigeria are found in off-grid locations where there is the lack of water supply despite the abundant groundwater resources possessed by the country. Since water is one of the key resources for agricultural production, majority of the farms only resort to the use of fossil fuel-powered generators to pump water for their operations in Nigeria. However, concerns about the frequent increase in fuel cost, the maintenance, and the environmental issues associated with running fossil-fuel generators have driven the need for a clean and sustainable energy source. The photovoltaic (PV)-pumping system is becoming more popular as an alternative energy source of water pumping for irrigation farming. This study presents the effects of total system head and solar radiation on the techno-economic design of PV-pumping system for groundwater irrigation of crop production in Nigeria. It also calculates the quantity of emissions avoided by the PV. The technical design is based on standard methodology to determine the PV capacity that can operate the pump to satisfy the daily water requirements for the crops, while the economic aspect involves the assessment of the life cycle cost and the cost of water per m3. The result reveals that the pump power ranges from 0.158 kW to 0.293 kW and the PV power ranges from 1.90 kW to 3.52 kW for a system head of 10 m and solar irradiation of 5.25 kWh/m2/day, respectively, while the unit cost of water ranges from $ 0.05/m3 to $ 0.054/m3, and the life cycle cost ranges from $ 7004 to $ 12331. This provides insights into the effects of varying the system head and the solar radiation, demonstrating that the PV-pumping system underperforms at higher system heads, but performs effectively at higher solar radiation. This is due to the decrease in the discharge rate and an increase in power output, respectively. The study will be useful for planning PV-based water pumping system for agricultural purposes.