Technical analysis of photovoltaic energy generation for supplying the electricity demand in Brazilian dairy farms

Abstract

In many Brazilian dairy farms, the supply of electrical energy does not fully meet the demands of the production systems and/or presents frequent fluctuations and interruptions, making the expansion of production chain unfeasible. These and other barriers have motivating the adoption of renewable and independent energy sources, installed directly in the farms. The present study was conducted to perform a technical analysis of photovoltaic energy generation required for supplying the electricity demand in dairy farms located at Minas Gerais State, Brazil. Daily global radiations on tilted panels were estimated by mathematical models and long-term meteorological database (greater than 33 years). Electrical energy generated by grid-connected photovoltaic systems was predicted considering minimum, average, and maximum daily global radiation conditions. Electrical energy demands were monitored in small (66 cows), medium (106 cows), and large (158 cows) dairy farms. The direct use of electrical energy in operations performed at Brazilian dairy farms were 4, 28, 15, 39, and 15%, on average, for lighting, milking, water heating/pumping, milk cooling/refrigeration, and miscellaneous, respectively. The estimated energy consumptions were 0.96, 0.87, and 0.81 kWh cow−1 day−1 for farms with 66, 106, and 158 cows, respectively. The photovoltaic panel area varied considerably among small, medium, and large dairy farms in order to meet 80% of renewable fraction for the electricity demand.