A process systems engineering approach to designing a solar/biomass hybrid energy system for dairy farms in Argentina

Argentina targets a 20% share of renewables in the energy mix by 2025 and a 15% emissions reduction by 2030, while at the same time removing subsidies for grid electricity. This paper aims to provide a feasible solution for small farm owners for sustainable and affordable energy: a grid-connected hybrid system able to fulfill the demand in a cheaper, reliable and sustainable way. The case study of an existing dairy farm in Carmen de Areco, Buenos Aires, is taken. A grid-connected hybrid system with solar photovoltaics, unheated anaerobic digestion (AD) coupled to an internal combustion engine and storage system, was selected. The size of the hybrid system was optimized via a mathematical model that compared different technologies. The interrelation between sources was economically optimized in order to match the demand on an hourly basis. The scenario comparison defined the optimal solution for this case study, which was the installation of an unheated AD plant with 2.4 kW capacity, and 16 solar panels with a capacity of 5.2 kW, added to a shift in the demand profile. The initial investment required is 17,042 USD, with a payback of 3.4 years and a GHG reduction of 275.9 tons of CO2 eq per year.