VIABILIDADE ECONÔMICA/FINANCEIRA NO USO DE ENERGIA FOTOVOLTAICA EM PIVÔS DE IRRIGAÇÃO NO SUDOESTE GOIANO

Abstract

This study analyzed the economic and financial feasibility of using photovoltaic energy to supply electricity for a central pivot irrigation in Southwest Goiás, Brazil. Understanding how this issue impacts people's lives and the environment is of great importance, as it relates to everyday societal concerns. The central pivot irrigation system has significant growth potential in Goiás due to the characteristics of rural properties, such as soil slope, water availability, cultivated crops, and large farming areas. The high solar irradiation potential in Goiás and the limited availability of electricity in rural areas further enhance the use of photovoltaic energy for irrigation. One of the analyzed projects considered an on-grid system connected to the power utility, supplying a central pivot with a demand of 198 kW and an average annual energy consumption of 177.5 MWh.year⁻¹, for soybean, seed corn, and bean crops in the municipality of Rio Verde, GO. Another scenario examined an off-grid system powered by two diesel generators of 500 kVA each, for soybean, corn, and bean crops in the municipality of Quirinópolis, GO. The results of these scenarios were mainly influenced by the removal of 10% discount for rural producers on electricity bills, the increase in utility electricity rates, the reduction in investment costs per kWp for photovoltaic plants, and irrigation seasonality. Considering a 25-year project (photovoltaic system lifespan) and a minimum attractiveness rate of 7.0%, the costs of electricity, whether from the utility or diesel, were used to calculate financial indicators such as Net Present Value (NPV), Average Profit (LMd), Internal Rate of Return (IRR), and Payback Period. The results showed that the enterprise is economically viable regardless of the energy source used, whether conventional electricity or solar photovoltaic energy. For the first scenario with on-grid electricity, the annual savings were 42.44%, with a payback period of 8 years and 7 months. In the off-grid project, with 70% photovoltaic energy implementation, the average monthly savings amounted to R$92,988.74, or 72.41%, with a payback period of 1 year and 1 month. It is concluded that the use of photovoltaic energy, both on-grid and off-grid, for central pivot irrigation represents a promising solution for making agriculture more sustainable and cost-effective.