Additional Greenhouse Gas Emissions and Offset Potential from Sugarcane Straw Recovery for Bioenergy Production in Southern Brazil
Abstract This study was designed to assess the additional greenhouse (GHG) emissions including measurements of soil CO 2 -C emissions in sugarcane areas plus emissions associated with the recovery and transport operations of straw bales up to the factory gate for electricity production, contrasting with leaving all straw on the soil surface. The total additional GHG emissions considering the main sources evaluated ( i.e ., soil CO 2 -C, diesel use and N 2 O from straw), was estimated at 1,465 kg CO 2 eq ha -1 , resulting an emission factor of 212. 6 kg CO 2 eq ton -1 of straw recovered. Applying the parameters cited in this study for electricity or 2G ethanol production (GHG balance of emission and offset potential), our results showed that straw-based for electricity production would result in additional GHG emissions of (+) 860 kg CO 2 eq ha -1 . In contrast, applying the same study parameters for 2G ethanol production replacing gasoline, an avoided GHG emission of (-) 2,316 kg CO 2 eq ha -1 could be achieved. The route of recovering around 27% of sugarcane straw through bale system for bioelectricity production using technical parameters and industrial efficiency rate of this study could not be a sustainable option because the additional emissions can be higher than its potential to offset generated emissions, based on the emission factor of Brazilian energy matrix. Applying the same experimental parameters, the option of producing ethanol 2G with around 6.89 ton DM ha -1 of sugarcane straw could offset gasoline GHG emissions, contributing with sustainable energy systems.