The aim of this work was to evaluate the economic feasibility of two biodigestion systems using animal excrements in a rural settlement, in Itaberá - SP, Brazil, in the year of 2005. One of them was constructed to supply biogas for five residences. The other one was constructed to supply biogas for production activities. The generated benefits related to the supply of electric and thermal energy were evaluated, using biogas for five residences and for production activities, in comparison to the annual costs of the biodigestion system construction and operation. The results showed economic feasibility of the biogas production in both cases. It was generated economic benefits of US$ 1,766.84 and US$ 4,338.54 per year for the residential biodigestion system and production activities biodigestion system, respectively, as well as US$ 706.20 per year for biofertilizer production. The costs were estimated in US$ 582.18 per year in each biodigestion system. The pay-back was evaluated in 2.5 years for the residential case and 11 months for the production case, respectively. These results can be used to formulate public policies directed to biomass exploitation to produce low cost energy focused on familiar agriculture.
biodigestion systems; energy economics; rural settlements
