# Comprehensive LCA of Biobased Sustainable Aviation Fuels and JET A-1 Multiblend
## 2 Materials and Methods
### Environmental Assessment  
The life cycle assessment (LCA) methodology was used for environmental assessment. Requirements for conducting an LCA are defined in the international standards ISO 14040 and ISO 14044, which are recognized worldwide for the quantification of the environmental impact of products and services [25; 26]. According to these standards, the analysis covers the complete product life cycle from the production of the raw material to the final disposal of the product after the use phase, including all the preproducts and energy carriers used. To that end, the life cycle of the product under investigation was analyzed, starting from raw material acquisition through to manufacturing, use of the product, and up to its disposal in order to fully apprehend all potential environmental impacts associated with this product. All auxiliary and operating materials used during the product's life cycle were taken into consideration as well. Emissions and expenditure associated with the production and use of the auxiliary and operating materials as well as other products and services were also taken into account. To properly carry out life cycle assessment in accordance with DIN ISO 14040/14044, the following conditions and parameters were defined. To conduct the life cycle assessment, we used the Umberto software [27] as LCA tool and the internationally recognized ecoinvent database as the life cycle inventory database (ecoinvent version v3.3 was used) [28]. The impact assessment, which helps to understand and evaluate the environmental significance for a product system [25], was carried out using the ReCiPe (H) method v.1.13 [29]. This method allows the determined emissions to be established according to pre-defined factors and enables their expression within the scope of more easily understandable categories (e.g., greenhouse effect). The selected impact categories from ReCipe Midpoint v.1.13 that were used to compare the environmental performance of the considered SAF are as follows:  
* Global warming potential (GWP 100) describes the potential to change global temperatures through greenhouse gas emissions. The main greenhouse gases relevant for GHG calculation are carbon dioxide (CO\({}_{2}\)), methane (CH\({}_{4}\)), and nitrova oxide (N\({}_{2}\)O). The global warming potential of greenhouse gases is expressed in kg of carbon dioxide equivalents (CO\({}_{2}\)-eq.). To convert a specific methane mass to kg CO\({}_{2}\)-eq., the methane weight is multiplied by 25 and the nitrova oxide mass is multiplied by 298 (based on a period of 100 years according to IPCC 2007) [30]. * ALOP (agricultural land occupation potential) refers to the continuous use of the agricultural land. * Fossil depletion potential (FDP) describes the consumption of fossil resources and indicates the decrease in availability of fossil resources. FDP is measured in kg oil-eq. * Freshwater eutrophication potential (FEP) includes ammonia, nitrate, nitrogen oxide, and phosphorus emissions, which affect eutrophication. The FEP is expressed in kg P in water and soil. * Marine ecotoxicity potential (METPinf) describes the effects of toxic substances, such as heavy metals, on the marine ecosystem. * Terrestrial acidification potential (TAP) describes the acidification potential of water and soil through SO\({}_{2}\) and NOx emissions. * Water depletion potential (WDP) states the water consumption. The consideration of by-products is an important aspect in LCA [25,31]. In addition to the main product, the production process of ATJ also provides the by-products maize oil, feed, and isooctane. In this study, the by-products were taken into consideration by means of allocation based on the lower heating value. This allocation method allows the environmental impacts of different manufactured products to be divided into a product-based assessment of multiproduct systems.