Greenhouse Gas Emissions Of Biodiesel Research Articles

Effects of soybean varieties on life‐cycle greenhouse gas emissions of biodiesel and renewable diesel

AbstractThis study presents a life‐cycle analysis (LCA) of the greenhouse gas (GHG) emissions of biodiesel (BD) and renewable diesel (RD) produced from soybean varieties with altered oil profiles and meal composition. The varieties evaluated include those with high oleic oil content (78% of oil being oleic oil vs. the current content of 25%), high lipid content (25% vs. the current content of 19%) or high protein content (45% vs. the current content of 35%). The results suggest that high‐oleic soybean oil could reduce GHG emissions of RD by 1 g CO2e/MJ by reducing hydrogen consumption in the hydro‐treating stage of RD production. With the default allocation method (mass‐based allocation between oil and meal), changes in lipid and protein contents have negligible impacts on GHG emissions of BD/RD pathways. Since high‐protein soybean meal has a higher nutrient value, we employed the market‐based allocation for sensitivity analysis. Assuming a market price of $1.17/dry kg and an average of two substitute feeds with similar protein contents (corn gluten and fish meal), the allocation factor for soybean meal increases from 63 to 81%. Compared with the results for the case with commodity soybean using mass allocation, GHG emissions could be 1.9 and 1.8 g CO2e/MJ lower for BD and RD, respectively. In addition to product‐level LCA, we employed a land‐based LCA to evaluate the effect of soybean properties on product slates with the same land area and the associated displacement of conventional products. The results suggest that high‐lipid soybeans may offer more GHG savings than other varieties as the higher BD/RD yield replaces more fossil diesel. © 2023 UChicago Argonne, LLC, Operator of Argonne National Laboratory and Northrup, Ag. Biofuels, Bioproducts and Biorefining published by Society of Industrial Chemistry and John Wiley & Sons Ltd.

Life Cycle Greenhouse Gas Emissions of Biodiesel and Renewable Diesel Production in the United States.

This study presents a life-cycle analysis of greenhouse gas (GHG) emissions of biodiesel (fatty acid methyl ester) and renewable diesel (RD, or hydroprocessed easters and fatty acids) production from oilseed crops, distillers corn oil, used cooking oil, and tallow. Updated data for biofuel production and waste fat rendering were collected through industry surveys. Life-cycle GHG emissions reductions for producing biodiesel and RD from soybean, canola, and carinata oils range from 40% to 69% after considering land-use change estimations, compared with petroleum diesel. Converting tallow, used cooking oil, and distillers corn oil to biodiesel and RD could achieve higher GHG reductions of 79% to 86% lower than petroleum diesel. The biodiesel route has lower GHG emissions for oilseed-based pathways than the RD route because transesterification is less energy-intensive than hydro-processing. In contrast, processing feedstocks with high free fatty acid such as tallow via the biodiesel route results in slightly higher GHG emissions than the RD route, mainly due to higher energy use for pretreatment. Besides land-use change and allocation methods, key factors driving biodiesel and RD life-cycle GHG emissions include fertilizer use and nitrous oxide emissions for crop farming, energy use for grease rendering, and energy and chemicals input for biofuel conversion.

Examination of an attempt to improve rapeseed cultivation in France in order to reduce the greenhouse gas emissions of biodiesel

“Démarche de progrès DIESTER®” was an attempt by French farmers, industrialists, technicians, agricultural cooperatives and private grain trading companies to continuously improve the environmental performance of rapeseed biodiesel. The objective was to implement certain rapeseed cultivation operations that had shown their efficiency in previous studies to reduce greenhouse gas (GHG) emissions: (i) the use of decision support systems (DSS) to calculate nitrogen fertilisation rates, (ii) the cultivation of legumes as intercrops with rapeseed or (iii) as previous crops. This paper first presents an estimate of the potential GHG effects of these cultivation operations, using results from previous studies obtained under experimental conditions or using crop modelling. It then presents the level of adoption by farmers of these cultivation operations in the context of the “Démarche de progrès DIESTER®” initiative to continuously improve the environmental performance of rapeseed biodiesel. Depending on the year, 39 to 74 agricultural cooperatives and grain trading companies were involved in the study, and 90 170 to 283 480 hectares of rapeseed have been monitored. This is the first time in France that an attempt to improve cultivation operations for environmental reasons has been made on such a scale. The average GHG reduction values, compared to fossil fuels, varied from 49.5 to 55.8% depending on the year, which was most often above the 50% minimum reduction value for sustainable biodiesel, but well below the 70% minimum for very low GHG emission biodiesel. Using the results of previous studies, this article shows that the widespread use of decision support systems to calculate mineral N fertilizer rates, and the cultivation of legumes as a preceding crop or intercrop, would make it possible to significantly reduce GHGs and make it possible to produce very low GHG-emitting biodiesel in certain locations and/or years. However, the actual changes in cultural operations were too small to be effective. The reasons for this lack of impact and how to achieve results in the future are discussed in this article.

Transition towards a more environmentally sustainable biodiesel in South America: The case of Chile

This study uses a site-specific life cycle assessment (LCA) to evaluate the environmental profile and energy and water demand of potential production options for rapeseed biodiesel in Chile. The first step is the analysis of the biodiesel supply chain in a standard scenario, associated with the most likely production conditions. The second step is the evaluation of the following alternative scenarios related to a production strategy involving low-impact or renewable resources: (1) Addition of livestock manure as organic fertilizer, (2) Use of degraded grassland, (3) Biodiesel transport by rail, and (4) Use of forest residues for industrial steam. The results show that the biodiesel in the standard scenario has less environmental impacts than fossil diesel in 4 of the 13 indicators evaluated. The rapeseed production is the stage with the highest contribution to impacts. The scenario 1 presents the best environmental profile. The scenario 2 reduces the greenhouse gas emissions of biodiesel. The scenarios 3 and 4 moderately improve the profile of the biofuel. The four situations could be implemented in the short term, but should be backed up by economic and social studies.