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This study investigates the life cycle GHG emissions of jet fuel produced via the hydroprocessed esters and fatty acids (HEFA) pathway from canola grown in western Canada, with a focus on characterizing regional influences on emissions. We examine the effects of geographic variations in soil type, agricultural inputs, farming practices, and direct land use changes on life cycle GHG emissions. We utilize GREET 2016 but replace default feedstock production inputs with geographically representative data for canola production across eight western Canadian regions (representing 99% of Canada's canola production) and replace the default conversion process with data from a novel process model previously developed in ASPEN in our research group wherein oil extraction is integrated with the HEFA‐based fuel production process. Although canola production inputs and yields vary across the regions, resulting life cycle GHG emissions are similar if effects of land use and land management changes (LMC) are not included; 44–48 g CO2e/MJ for the eight regions (45%–50% reduction compared to petroleum jet fuel). Results are considerably more variable, 16–58 g CO2e/MJ, when including effects of land use and LMC directly related to conversion of lands from other uses to canola production (34%–82% reduction compared to petroleum jet fuel). We establish the main sources of emissions in the life cycle of canola jet fuel (N‐fertilizer and related emissions, fuel production), identify that substantially higher emissions may occur when using feedstock sourced from regions where conversion of forested land to cropland had occurred, and identify benefits of less intense tillage practices and increased use of summerfallow land. The methods and findings are relevant in jurisdictions internationally that are incorporating GHG emissions reductions from aviation fuels in a low carbon fuel market or legislating carbon intensity reduction requirements. [ABSTRACT FROM AUTHOR]

The cost of cellulases remains a key issue in the production of cellulosic ethanol, and the impact of enzymes on greenhouse gas ( GHG) emissions of cellulosic ethanol has received little attention. This study evaluates life cycle emissions and cellulase production costs for bioethanol production, considering on-site and off-site production options. A complete enzyme production process was simulated using AspenPlus, generating mass and energy balance information required to calculate GHG emissions and financial metrics. GHG emissions for cellulase production range from 10.2 to 16.0 g CO2 eq g-1 enzyme protein, depending on on-site or off-site production and the method of transportation. Enzyme GHG emissions are predicted to be 258 g CO2 eq. L-1 of ethanol for on-site production, versus 403 g CO2 eq. L-1 for off-site production, based on a 150 MMLY ethanol plant using 11.5 mg enzyme g-1 substrate and a cellulase fermentation yield of 90%. Cellulase production costs were estimated for a range of conditions, including ethanol plant size, enzyme dose and protein yield for on-site production, and enzyme plant size, protein yield and return on investment for off-site production. On-site production costs range between $3.80 and $6.75 kg-1 protein, versus $4.00 to $8.80 kg-1 for off-site production. In both scenarios, the lowest cost corresponds to a 90% protein yield, and a high enzyme demand and production capacity. An enzyme production cost of $4.70 USD kg-1 corresponds to an enzyme cost of 0.46 USD gal-1 ($0.12 L-1) of ethanol in a 150 MMLY plant using 11.5 mg enzyme g-1 substrate. © 2013 Society of Chemical Industry and John Wiley & Sons, Ltd [ABSTRACT FROM AUTHOR]