Design, simulation, and Financial Analysis of a Hybrid Solar PV - Biogas system for Dairy Farms in Uganda case study: Mutanoga Dairy Farm.

Abstract

Lack of reliable electricity, rising energy costs, insufficient waste management and over dependence on firewood for milk pasteurization and cooking has led to environmental issues such as pollution, health issues and deforestation. Therefore, this study aimed to design, simulate and conduct the financial analysis of a hybrid solar PV-biogas energy system for Mutanoga diary farm as an alternative source of energy to meet the demands of the farm. The objectives were to determine the energy profile and energy resources of the dairy farm, to determine the appropriate size of the hybrid solar-biogas energy system components to meet the energy demand of the dairy farm and to conduct the financial analysis of the solar-biogas hybrid system to evaluate its feasibility. The solar GIS software and the solar radiation meter were used to determine the solar resource data. Cow dung used in the biodigester to produce energy is collected by a group of workers and transported from the farm using donkeys. HOMER software was used to perform technical and financial analysis. The energy demand of the farm was 278.404kWh/day with a peak load of 14.55 kW, yearly average global horizontal irradiation of 5.145 kWh/m2 per day. The designed hybrid energy system comprised of 53.374 kW PV modules, a 10 kW biogas generator, battery storage with capacity of 5,043.78 Ah, and a 11.2 kW sized Inverter. The hybrid energy system generated annual electricity of 117,352kWh/year producing excess electricity of 15,735kWh/yr equivalent to 15.5%. The levelized cost of energy (LCOE) of 403 Ushs/kWh and a total net present cost (NPC) of Ushs 488,002,900. The LCOE is about 1.62 and 1.196 times lower than the average electricity end-user tariffs for households and commercial consumers in Uganda. With a lifespan of 25 years, the return on investment (ROI), internal rate of return (IRR), simple and discounted payback period (PBP) of this renewable energy project is estimated at 62.8%, 29.7%, 7.09 years, and 7.09 years, respectively. This research has provided an insight that the hybrid solar PV-biogas system is a valuable investment for dairy farms aiming to reduce their operating costs while ensuring a stable energy supply. Its adoption could play a vital role in advancing sustainable agriculture for dairy farms and fostering renewable energy transitions in rural communities. However, there is a need for further studies to be done on the comprehensive Life Cycle Assessment (LCA) of the hybrid energy system to evaluate its full environmental impact.