Do the dam project−evaluating floating solar photovoltaic and energy storage at Inanda dam within eThekwini Municipality, South Africa

Abstract

South Africa's electricity generation plant portfolio includes several aged units, resulting in frequent breakdowns, electricity shortages and load shedding. This study evaluates the feasibility of generating electricity at the Inanda Dam located within eThekwini Municipality of South Africa by installing a floating photovoltaic (FPV) system. The Inanda Dam provides water for many local communities, and load shedding affects pumping operations and disrupts the continuity of water supply. Therefore, the study further evaluates the plausibility of coupling energy storage/alternate generation with the FPV system to provide enough electricity for pumping operations during an outage. In addition, this study evaluates the financial benefits to the municipality resulting from the project implementation. The Hybrid Optimization Model for Multiple Energy Resources (HOMER) software tool was utilised to conduct techno-economic analysis and optimise the size of system components to meet the load requirements while minimising the overall net present costs (NPC). Without limiting the dam usage space for FPV, the optimal FPV system size was 10 MWp to maintain the least NPC. However, with the generation system size larger than the water pumping demand, the excess solar energy generated can be exported back into the grid resulting in the municipality gaining $1 015 473 in the first year of operation. Incorporating battery energy storage or a diesel generator can mitigate load shedding at the pumping site. However, battery energy storage requires significantly more capital upfront and produces a nil financial investment return compared to the diesel generator option, making it the least preferred option to implement.