Greenhouse gas assessment of palm oil mill biorefinery in Thailand from a life cycle perspective

The purpose of this study is to provide a comprehensive assessment of oil palm biomass waste utilization, with the goal of providing palm oil mill owners the best options for biomass applications in order to limit carbon emissions and optimize economic potential. As the third largest producer of palm oil in the world, Thailand is very entrenched in the industry and thus is an ideal country to implement waste utilization strategies. The biomass byproducts result from the processing of fresh fruit bunches (FFB) from the oil palm plant in order to extract the main commodity, crude palm oil (CPO). This paper assesses six major biomass byproducts that result from the processing of the oil palm plants: empty fruit bunches (EFB), palm kernel shells (PKS), mesocarp fiber, oil palm fronds, oil palm trunks, and palm oil mill effluent (POME). The associated net greenhouse gas emissions were calculated for each biomass' potential utilization pathway. The results of the study found that 4 of the 6 biomass waste products have alternative utilization options that resulted in net negative carbon emissions. Regarding the utilization options that are recommended, EFB shows net emissions of -0.14 t CO2 equivalent, -5.33 for shells, -17.68 for fiber, and -0.594 for trunks. In addition, the assessment of the added value for each product guides decision making to ensure economic viability. This analysis is unique in that it encompasses various utilization pathways for each of the major oil palm waste products in one comprehensive study. By comparing the results of these pathways, an optimal use for every waste product is recommended to decrease the overall climate change impact of the mill.