Abstract
Nutrient film technology-based hydroponic systems are hydrophilic. Hence, a constant water supply is essential for the optimal yield and viability of the investment. Though the national grid could power water pumps for a hydroponic system in urban areas, incessant load shedding in South Africa has significantly affected the yield. Hence, the need for an alternative power supply for these systems. This study conducted a techno-economic analysis on a proposed solar photovoltaic (PV) for a hydroponic food garden located in Johannesburg. The case study constitutes one of the Urban Agricultural Initiatives (UAI) in the city. The optimal solar-PV sizing for the hydroponic system was developed. Two scenarios for powering the hydroponic system were investigated vis-à-vis the standalone solar-PV and national grid with solar-PV and battery backup. Among other cost functions, the levelized cost of electricity (LCOE) was used to evaluate the systems. The simulations were performed using HOMER Pro tool for Microgrid Analysis to determine the profitability of the two alternative energy sources on the system. Among the two alternatives, the hybrid system offered a lower net present value (NPV) of 79, 156.74 (ZAR) and an LCOE of 0.47 (ZAR) compared with the standalone system with an NPV of 290,930.73 (ZAR) and an LCOE of 2.57 (ZAR). However, the indirect value chain of the hybrid solution is associated with environmental emissions. The results obtained from the two scenarios could be used as a model for powering other urban hydroponic systems in other geospatial locations. While system effectiveness is highly prioritized, an economical scenario that mitigates the load shedding effects and enhances the productivity of the hydroponic food garden is very vital.
