Comparative Life Cycle Assessment of Cannabis Production Systems in Washington State

Legalization for medicinal and recreational consumption of Cannabis L. Sativa has created new and rapidly growing industries across the United States. Methods for producing cannabis products rely upon energy, water, and material inputs. Innovation in these methods have focused on increasing product potency and improving the use experience while neglecting the efficiency of the production process. Comparative life cycle assessments quantify the total embodied carbon emissions in a production process. The existing literature on this topic is limited, though some national estimates exist. We were given access to three cultivation facilities and two processing labs (Open-Field, Mixed-Light, Indoor Plant Farm, and (2) processing labs) where we collected annual data on energy, water, transport, and material inputs as well as annual product output rates. We found a range of emission rates from 12 to 140 kilograms of CO2e per kg of dried product at the point of sale. Results in biomass production across all methods averaged to 62 kg CO2e per kilogram of dried cannabis biomass. Extraction methods across all methods averaged to about 4 kg CO2e per gram of cannabis oil. An analysis of hourly emission rates showed the average emission rate methodology reports higher emissions than applying block emission rates for corresponding hours.