Assessment of guar gum production cost and environmental impact in the US Southwest

Abstract

Current drought conditions in the US Southwest, linked to the inherent water resilience qualities of guar and the increased demand for guar gum, can make guar production an attractive option in that region. This study includes new US guar cultivation experimental field data to analyze the economic costs and environmental impacts of growing guar and transforming it into guar gum using comprehensive techno-economic and life cycle assessments. Additionally, an uncertainty analysis was included to better understand the feasibility and risks associated with growing guar in the US Southwest. Results show that the minimum selling price of guar gum is 2.71 $/kg guar gum, with a 90% confidence interval (CI) around the mean ranging from 1.18 to 3.87 $/kg guar gum. Agricultural expenses represent 85% of the costs. Rent payments and irrigation represent the largest contributors to the guar gum minimum selling price. Net greenhouse gas (GHG) emissions are estimated at 1.87 kg CO2/kg gum, with a 90% CI ranging from 0.89 to 2.81 kg CO2/kg guar gum. Irrigation is the main contributor to GHG emissions. The large spread in the results is explained by guar yield being the most important variable to compute minimum selling price and GHG emissions, and by the high variability in guar yields across different sites.