Life-Cycle Assessment of Oilseeds for Biojet Production Using Localized Cold-Press Extraction

Abstract

As nonfood oilseed varieties are being rapidly developed, new varieties may affect agricultural production efficiency and life-cycle assessment results. Current, detailed feedstock production information is necessary to accurately assess impacts of the biofuel life-cycle. The life-cycle impacts of four nonfood oilseeds (carinata [ L. Braun], camelina [ L. Crantz], canola or rapeseed [ L.], and sunflower [ L.]) were modeled using Argonne National Laboratory's GREET model to compare feedstocks for renewable biojet production using cold-press oil extraction. Only feedstock-related inputs were varied, allowing isolation of feedstock influence. Carinata and camelina performed slightly better than other oilseed crops at most product stages and impact categories as a result of current, low-input agricultural information and new feedstock varieties. Between 40 to 50% of SO and NO emissions, ∼25% of greenhouse gas (GHG) emissions, and ∼40% of total energy consumption for the biojet production impact occurred during feedstock production. Within the first standard deviation, total well-to-tank emissions varied between ∼13% (GHG) and ∼35% (SO) for all feedstocks emphasizing the importance of accurate agricultural production information. Nonfood oilseed feedstock properties (e.g., oil content, density) and agricultural management (e.g., fertilization, yield) affect life-cycle assessment results. Using biofuels in feedstock production and focusing on low-impact management would assist producers in improving overall product sustainability.

Comparative Farm-Gate Life Cycle Assessment of Oilseed Feedstocks in the Northern Great Plains

“…The two dedicated oilseed feedstocks (camelina and carinata) evaluated in this study are proposed as alternatives to the wheat-fallow rotation, therefore it is assumed that the oilseed crops do not displace any other alternative crop rotation system (Keshavarz-Afshar and Chen 2015). In contrast, canola and soybeans have established production areas, inputs, and uses (Kim et al 2009;Dale 2003, 2005;Sieverding et al 2016a). …”

“…Seeding rates for soybeans and canola were estimated from existing literature Dale 2003, 2005;Mousavi-Avval et al 2011;Sieverding et al 2015) and regionally adjusted to each CMZ based on regional trial recommendations (Grady and Nleya 2010;MAES 2017;NDSU 2017). The seeding rates for carinata and camelina were obtained from the regional field trial data (Grady and Nleya 2010;MAES 2017;NDSU 2017;Sieverding et al 2016a) and industry best management practice literature (AAFC 2014;Agrisoma 2015). The resulting average NGP seeding rates for canola, soybeans, carinata, and camelina were 8, 65, 14, and 6 kg/ha, respectively.…”

“…Canola and soybean yields were estimated based on historical values from the USDA National Agricultural Statistics Service (NASS 2017) and supplemented with regional trial data (Grady and Nleya 2010;MAES 2017;NDSU 2017). Camelina and carinata yields were determined based upon CMZ aggregated field trial data and assigned a 15% yield penalty based on the assumed decline associated with trial production versus commercial production result (AAFC 2014;Agrisoma 2015;Sieverding et al 2016a). The fertilizer base application rates for soybeans were derived from the historical state-level NASS survey data sets for South Dakota and North Dakota (NASS 2017) for N-P-K levels.…”

“…However, intrastate application rates across CMZs were geographically adjusted based on field test management recommendations across the region (Grady and Nleya 2010;MAES 2017;NDSU 2017). The regional application rates of fertilizer for canola, carinata, and camelina were estimated from field trial data and existing literature (Fore et al 2011;Grady and Nleya 2010;KeshavarzAfshar and Chen 2015;Keshavarz-Afshar et al 2015b;MAES 2017;NDSU 2017;Shonnard et al 2010;Sieverding et al 2016a). …”

“…Recent biofuel production life cycle assessment (LCA) literature (Li and Mupondwa 2014;Shonnard et al 2010;Sieverding et al 2016b) points to carinata and camelina as promising dryland oilseed feedstocks for biodiesel production, resulting in lower emission values and reduced energy demand over their oilseed peers. The efficiency of feedstock production is critical to the sustainability of biofuel and bioproduct production.…”