Abstract:
Running a farm that solely depends on grid electricity, is not easy-going, considering the current state of electrical energy in our country (South Africa). Therefore, onsite electricity generation is achieved by using off-grid approaches, such as wind, diesel generator, conventional small hydro system and solar. However, due to high cost of diesel fuel, unavailability of continuous energy from the sun and wind, these energy generation methods may require extra energy storage systems in order to be considered as a reliable solution for onsite electricity generation for farming environment. Further combination and incorporation with various affordable energy generating sources, is a necessity in improving the grid’s economical management. This study used solar PV, incorporated with an underground pumped hydro storage (UPHS) system, whilst a borehole is used as a lower reservoir.
An off-grid UPHS is a promising technology that may be used in any farming environment that has sufficient underground water. This technology is currently under development and lacks implementation.
The purpose of this study was to investigate the possibilities of controlling and optimising the daily operation of the proposed grid-connected renewable energy system, by maximising the usage of the renewable resources, whilst minimising the use of grid electricity to supply the load demand of a farm, without any load supply shortage. The design and sizing of the proposed system was performed, using a Hybrid Optimization Model for Electric Renewable (HOMER). The model formulation, effectiveness and economic analysis was performed and simulated, using linear programming with MATLAB software. Therefore, the simulation results reveal that using the developed model to optimally manage power generated by PV and the PHS, the cost of the electricity for farm operation may be reduced. Nonetheless, the study also raises awareness to the use of renewable energy in conjunction with grid electricity under TOU tariff rates. As well as water conservation and food production to boost our current economic status.
