Environmental Comparison of Thermochemical and Biochemical Ways for Producing Energy from Agricultural Solid Residues: Coffee Cut-stems Case

Coffee Cut-Stems (CCS) are an abundant wood waste in Colombia obtained generally from crops renovation. However these residues are used directly in combustion processes for heating and cooking in coffee farms where their energy efficiency is very low. In the present work, an energy and environmental assessments for two energy production processes (ethanol fermentation and gasification) using CCS as raw material were performed and compared. The potential environmental impact (PEI) was evaluated by the Waste Reduction Algorithm (WAR algorithm) which allows determining the process with the best performance from the point of view of the Potential Environmental Impact (PEI). Besides, the performance of the two processes were compared based on the productivity and the energy efficiency. Biomass gasification seems to be the most promising technology for the use of Coffee Cut-Stems with high energy yields and low environmental issues.