Internal Combustion Engine Fueled with Biogas: Energetic, Economic and Environmental Analyses
Abstract
The use of internal combustion engines operating with biogas for electric power generation is an alternative to meet electrical demands mainly in rural regions where the availability of this BioSource is greater. Two configurations with that engine are studied in this paper, the first one considers only electricity generation while the second one consists of a cogeneration system. Considering the Brazilian regulation dealing with distributed generation, and the extension of the electric grid to rural regions, both configurations studied in this paper are applicable to rural consumers with biogas production feasibility. A generator group that operates with biogas as fuel is analyzed in terms of energy, economics and the environment. In the technical analysis, the first law of thermodynamics is used to assess the power plant. On the other hand, the economic analysis, made with the calculation of electricity production cost, shows that the selected set is attractive and presents a low payback period of investment, less than three years. Results also show that, when the generator group is used in cogeneration mode, the payback is even lower. Finally, from the environmental analysis it is observed that the system has a low pollution indicator of 0.11 kgCO2e / MJ, which considers the equivalent emissions of carbon dioxide, resulting in an ecological efficiency in relation to electricity generation of 82%; in the case of cogeneration mode, this efficiency increases to 94%.
