Use of Swine Waste in the Production of Electric Energy from the Efficient use of Biodigestors: the Brazilian Case

Abstract

Objective: to calculate the minimum number of animals that a rural pig farm needs to raise so that the implementation of biodigesters to generate clean energy in the context of Brazil is financially viable.
 
 Theoretical framework: a more efficient productive farm tends to include environmentally sustainable actions, since pig farming is considered a relevant activity of environmental concerns due to the amount of manure produced, especially in an intensive system. It is in this context that several current studies have been debating the environmentally correct reuse of pig manure.
 
 Method: using interviews and exploratory searches, data were collected that projected the project's cash flow. From this, the number of animals needed for the net present value of the project to be zeroed was calculated. Also, the probabilistic scenario was designed using the Monte Carlo Simulation.
 
 Results and conclusion: for the deterministic scenario, it was calculated that 736 animals are needed for zero/null NPV and for a probabilistic scenario context with p(NPV<0) = p(IRR<TMA) = 0.2, it is necessary that the rural property has at least 840 animals.
 
 Research implications: the academic and social contribution of this work is that it can help small swine producers in their decision-making for the implementation of biodigesters.
 
 Originality/value: considering rural activities as strong polluters and the large increase in electricity tariffs seen in recent years, mainly due to severe droughts and the COVID-19 pandemic, the reuse of waste becomes increasingly important and relevant for clean and distributed energy generation.