Biogas for Electricity Production in Agricultural Facilities: A Case Study

Abstract

Biogas has become an attractive alternative source of energy as the renewable fuel serves several policy priorities, ranging from increased domestic energy production to the reduction of greenhouse gases and more efficient waste treatment. It can be produced from many kinds of organic materials but it is closely linked to agricultural activities, integrated into farming processing structures. The primary source is manure from animal production, mainly from cattle and pig farms. Anaerobic digestion is a natural process that converts animal waste to biogas. The anaerobic facility must be designed to meet the individual characteristics of each dairy farm operation. Biogas is produced when bacteria convert organic matter to methane gas. A digestor/generator produces two important outputs: it is capable of generating electricity and heat. Electricity can be used for self-comsumption and the surplus can be delivered in the distribuition grid. The generated heat should be used closed to the generator and attains economic value dependent upon how it is used: to heat water or to refeed anaerobic digestion process. Before a biogas plant is built, a techno-economic assessment should be made. In this study it is done a financial analysis which judges the profitability of a biogas unit from the point of view of the user. The costs and revenues were studied for this particular project considering the known parameters of the technical system.