LIFE CYCLE ASSESSMENT OF A STRAW-BASED ENERGY SUPPLY SYSTEM FOR ORGANIC ARABLE FARMS

摘要

Today’s agricultural industry produces large amounts of greenhouse gases (GHG) from the combustionof fossil fuels during the production activities, for example tractor use and grain drying. Moreover, arable soils emitan important part of the global antropogenic GHG emissions in the form of nitrous oxide (N_2O) and carbon dioxide(CO_2). The aim of this study is to assess the impact on GHG emissions from an organic, arable farm that changesfrom a fossil fuel-based energy system to a renewable energy system based on straw. Straw is produced on-site as aby-product from cash crop production and can be used in technical systems for production of heat, electricity and fuelthat covers the farm use, including the process energy for production of the energy carriers. The system is comparedto a reference system, in which the straw is incorporated into the soil and the energy demand is covered with fossilfuels. The results show that the emissions related to energy consumption are eliminated, but that the net soilemissions increase as a consequence of the new production system that includes straw removal, cancelling out mostof the gains from the reduction of fossil fuel consumption.