Energy Costs andGreenhouse Gas Emissions of Giant Reed (Arundodonax L.) Production for Use as a Bioenergy Vector

Abstract

This study estimates the energy costs and greenhouse gas emissions for the production and the processing for thermal use of Giant reed (Arundo donax L.), a second-generation perennial energy crop. The agronomic study took place in Buenos Aires (Argentina) under humid to subhumid climatic conditions. Rhizomes and in vitro micropropagated plantlets were employed and cultivated under both fertilization and rainfed conditions during 2018–2022. The yield demonstrated a substantial increase from 3.8 t/ha to 23.1 t/ha from implantation to crop setting. Throughout this period, the energy input escalated from 23 to 70 GJ/ha, with the planting phase exhibiting the highest energy intensity. This surge can be attributed to the use of herbicides, accounting for 44.1%–61.3% of the energy consumed. Energy outputs were 17 (±0.19) MJ/kg as the low heating value obtained from the biomass elemental composition. The net energy yield for the 10-year lifecycle resulted in 2851.3 (±20.2) GJ/ha, and the output/input ratio varied from 41 (for pellets) to 126 (for chips). Carbon emissions ranged from 343.9 (for plantlets) to 371.9 (for rhizomes) kg CO2e/ha during the implantation stage, resulting in 208.3, 397.6, and 859.6 kg CO2e/ha for chips, bales, and pellets, respectively. This study reinforced the knowledge about the farming of this energy crop and displayed a promising scenario for the sustainable development of the Arundo donax L. based value chain.