Feasibility of using different renewable energy sources in Brazilian swine farmings

Swine farming is one of the main agricultural activities. However, it generates a large amount of waste that, when improperly disposed of, is cause of environmental impacts. One of treatment options is anaerobic digestion that generate biogas, which is used as a renewable energy source. In addition, the roofs of the establishments are suitable for harnessing solar energy. However, the equipment costs for power generation are high. The present study evaluated the feasibility of these two renewable energy technologies for Brazilian swine farmings of different sizes. For this purpose, the numbers of 201, 2001 and 10,001 animals were considered for small, medium and large sizes, according to Brazilian classification. The investment cost, return time, such as Simple Payback (SPB) and Discounted Payback (DPB), and profit from the use of biogas and solar energy were presented. Finally, it was proposed that the surplus energy could be injected into the distribution network, generating credits to the producer in accordance to Brazilian law. The generation of electricity through biogas has economic viability for farmings with size from 2001 (SPB = 6.02 yr and DPB = 7.90 yr) to 10,001 (SPB = 3.20 yr and DPB = 3.71 yr) animals. Meanwhile, the generation of electric energy by the photovoltaic system showed to be viable for the 3 sizes of projects evaluated (small: SPB = 6.52 yr and DPB = 8.75 yr; medium: SPB = 4.90 yr and DPB = 6.08 yr; large: SPB = 4.74 yr and DPB = 5.86 yr). For both sources, the impact of the initial investment in the acquisition of machines, projects and accessories must be considered. It was found that the great energy potential coming from swine farming and, consequently, from other agribusiness chains, contributes to the generation of distributed energy, through renewable sources.