Life cycle assessment of corn-based ethanol production in Argentina

Abstract

The promotion of biofuels as energy for transportation in the world is mainly driven by the perspective of oil depletion, the concerns about energy security and global warming. In Argentina, the legislation has imposed the use of biofuels in blend with fossil fuels (5 to 10%) in the transport sector. The aim of this paper is to assess the environmental impact of corn-based ethanol production in the province of Santa Fe in Argentina based on the life cycle assessment methodology. The studied system includes from raw materials production to anhydrous ethanol production using dry milling technology. The system is divided into two subsystems: agricultural system and refinery system. The treatment of stillage is considered aswell as the use of co-products (distiller´s dried grainswith solubles), but the use and/or application of the produced biofuel is not analyzed: a cradle-to-gate analysis is presented. As functional unit, 1 MJ of anhydrous ethanol at biorefinery is chosen. Two life cycle impact assessment methods are selected to perform the study: Eco-indicator 99 and ReCiPe. SimaPro is the life cycle assessment software used. The influence of the perspectives on the model is analyzed by sensitivity analysis for both methods. The two selected methods identify the same relevant processes. The use of fertilizers and resources, seeds production, harvesting process, corn drying, and phosphorus fertilizers and acetamide?anillide-compounds production are the most relevant processes in agricultural system. For refinery system, corn production, supplied heat and burned natural gas result in the higher contributions. The use of distiller´s dried grains with solubles has an important positive environmental impact.