Case Story Brazil

DISTRIBUTED GENERATION USING BIOGAS IN A MICROGRID

In the Western Region of Parana, Brazil

February 2019

MISSION AND VISION

Projections from the Food and Agriculture Organization of the United Nations suggest that Brazil will consolidate its position as the world’s largest producer of animal protein, soy, corn and biofuels. The Western region of Paraná is one of the largest and most important producers of animal protein in Brazil. Animal husbandry uses the feedlot model. This leads to significant numbers of pigs, poultry and dairy cattle, which generate a large amount of organic wastes (such as animal manures and bedding material) in a concentrated space. This can be a limiting factor in expanding the scale of production if there is no suitable safe disposal or treatment route in place to address the organic waste produced. The feedlot model also requires electrical energy on site. Biogas systems offer a solution in that the organic wastes produced represent a significant resource of energy potential in the form of biogas, which can be used to produce electricity and digestate for biofertilizer, whilst reducing the environmental impact of the wastes and the associated feedlot model.

CONCEPT

One of the challenges faced when using organic wastes arising from animal husbandry for biogas production is the scattererd rural nature of the resource. Animal husbandry practices are usually spread throughout the territory and are remote from the national electricity distribution grid. The possibility of distributed generation (DG) in combination with the electricity grid does not increase existing demand on the national grid and can reduce losses in transmission and distribution lines. DG can improve the reliability of the electrical system and improve the quality of energy in congested areas and at the edges of the distribution grid.

If the electrical energy produced from biogas is not of the specified quality, particularly in regions with vulnerabilities in the electricity grid, the electrical utility may not allow connection. To overcome this, distributed generation must be supported by microgrids. A microgrid can be defined as a portion of the electrical grid, in which one or more generating units provide the electric power needed to supply the internal demand of the microgrid in case of contingency, such as in the event of a fault in the energy supply from the electrical utility (Figure 1). Under normal conditions of operation, i.e. when the electrical utility supplies electrical power, the energy is sent to the grid (DG), reducing the energy cost to the owner of the generating unit (Figure 2).

Rural microgrids have several benefits both for the rural producer/farmer and for the electrical utility. The rural producer will be able to invest in infrastructure to treat organic wastes associated with production of animal protein, whilst improving the environmental sustainability of meat production, and will have reliable electrical energy with overall reduced energy bills. The electrical utility will benefit from overall gains in stability of the grid, higher efficiency electricity with a decrease in transmission losses, and local controllability.