2. Materials and Methods
The goal of this study is to quantify the product carbon footprint of feed-grade soy protein concentrate produced by Porta Hnos. S.A. in Córdoba, Argentina, and to identify the life-cycle hotspots that drive greenhouse gas emissions for improvement purposes. The study is a partial product carbon footprint, cradle-to-gate plus end-of-life for packaging, appropriate for a business-to-business context where product use is outside the direct control of the producer. The agricultural reference year is 2023/2024 and the industrial reference year is 2024.
The assessment follows ISO 14040 and ISO 14044 for life cycle assessment principles, requirements, and guidelines, and ISO 14067 for product carbon footprint quantification. Climate change is reported as Global Warming Potential (GWP, “Climate change – total”), expressed in kg CO2-equivalent and comprising fossil, biogenic, and land use and land use change (LULUC) components, with characterization factors consistent with the Intergovernmental Panel on Climate Change (IPCC) 2006 Guidelines as refined in 2019. For agricultural nitrous oxide emissions from managed soils and carbon dioxide emissions from lime and urea, Tier 2 methods and country-specific parameters from Argentina’s Biennial Update Reports are applied.
Modeling was performed in SimaPro 9.6.0.1, using Ecoinvent 3.10.1 and Agri-footprint 6.0 as background data sources for energy, materials, transport, agricultural inputs, and waste management. Selected background profiles are listed in Annex 1 of the technical report.
Five declared units were analyzed, each with a reference flow of one kilogram of product: (i) soy protein concentrate at the factory gate in bulk, (ii) soy protein concentrate at the factory gate packaged, (iii) soy protein concentrate in bulk delivered to international customer, (iv) soy protein concentrate packaged delivered to international customer, and (v) soy protein concentrate packaged delivered to local customer. Packaging mass is excluded from the one-kilogram reference flow where applicable.
The system includes upstream soybean cultivation in Córdoba province; industrial production of expeller (pressing) and soy protein concentrate (extraction, washing/neutralization, and drying); packaging when relevant; and outbound logistics to local and international markets. End-of-life for packaging is included. The use phase is excluded because the product is incorporated into compound feed by downstream manufacturers under varying formulations and conditions. For LULUC, the study assumes soybean is produced on land under agricultural use for more than 20 years, and consequently excludes LULUC emissions in the base case.
Primary agricultural data were collected from soybean producers in the departments of Río Primero, Santa María, and Colón. Based on purchase records, these departments account for the majority of soy supply to the plant and together provide 63.9% coverage of 2024 soybean purchases used to define representativeness. The average inbound distance from farm to plant is 53 km by 30-t EURO 3 trucks. When primary data were missing for certain inputs or operations, values were estimated from producer information, technical publications, and regional sources as specified in the report.
The agricultural inventory includes seeds, inoculants, plant protection products, occasional nitrogen fertilization, fuels and lubricants for no-till planting, spraying, harvesting, on-farm storage in silo bag when used, plastic for agrochemical containers, and inbound transport of inputs. Emissions from crop residue mineralization and fertilizer-related nitrogen are calculated following IPCC 2019 Refinement; leaching factors of 0 (dry climates) or 0.24 (humid climates with >1000 mm rainfall) were applied by department. Field operations and diesel consumption values combine primary records and literature-based defaults.
Industrial production is modeled in two modules. First, soybean is cleaned, cracked, dehulled via multi-aspirator, extruded for thermal deactivation and oil release, and mechanically pressed to produce expeller, with crude oil, hulls, and foots as co-products. Second, expeller is milled and mixed with process water, sulfuric acid, and hydrogen peroxide to enable protein extraction and isoelectric precipitation, followed by two centrifugation steps and drying via flash and spray units; wash waters are internally reused by the company’s alcohol fermentation line and carry no additional environmental burden in this model. Natural gas consumption is inventoried for cogeneration of electricity and for steam and thermal needs in dryers. For one kilogram of packaged soy protein concentrate at the factory gate, the model includes, inter alia, approximately 0.046 m3 of natural gas for cogeneration and 0.144 m3 of natural gas for steam, together with 0.025 kg of sulfuric acid (98%) and 0.080 kg of hydrogen peroxide (60%), with associated inbound transports of 93.4 km and 375 km, respectively.
When applicable, the product is packaged in one-ton big bags, with ancillary materials such as pallets and corrugated cardboard accounted for along with their inbound transports (e.g., pallets 18.2 km by 28-t semi-trailer; corrugated cardboard 110 km by 24-t truck; big bags 602 km by 4-t truck). End-of-life assumes landfill disposal of big bags with a 50 km truck transport to the disposal site.
Outbound distribution reflects actual 2024 sales routes and modes. International bulk shipments to Chile are modeled as 1,066 km by EURO 5 tipper trucks (28 t). Packaged exports to Mexico follow a multimodal route of 7,716 km by sea plus 1,100 km by road (24-t semi, EURO 5). Local market deliveries of packaged product are modeled with representative truck distances around 314 km. Vehicles are modeled according to EURO classes and payloads noted in the report; empty returns are considered where they occur.
Mass allocation is applied at two points. During pressing, the expeller receives 71.4% of upstream burdens, with 10.2% to crude oil, 14.3% to hulls, and 4.1% to foots. During the concentrate process, soy protein concentrate receives 69.8% of burdens and molasses 30.2%. These allocation factors originate from measured yields at the facility.
Excluded items include the transport and disposal of crop protection containers, construction and capital goods (infrastructure, buildings, vehicles), office utilities and staff commuting, due to their low significance relative to total output. Exceptions are explicitly noted where minor infrastructure is embedded in background datasets for certain operations (e.g., boilers and cogeneration). For labeling materials with negligible mass per kilogram of product, transport modeling was simplified under ISO 14067 principles of relevance and materiality. The product use phase is excluded as justified in Section 2.5.
Results are reported as Climate change – total (GWP) in kg CO2-eq per kilogram of product for each declared unit, with fossil, biogenic, and LULUC contributions available for transparency. The indicator selection and calculation approach follow ISO 14067 and IPCC 2019 characterization.
Geographical coverage reflects Córdoba Province for agriculture and the Córdoba industrial site, with deliveries to domestic customers in the province and international customers in Chile and Mexico; background datasets were selected for temporal proximity (≤ 10 years for most processes) and technological representativeness. Data completeness, consistency, and precision were qualitatively evaluated following ISO 14044; the report documents checks for integrity across upstream, core, and downstream stages.
A forward-looking sales mix scenario for 2025 was developed (75% bulk export and 25% local packaged), used to test the sensitivity of results to logistics profiles given the prominence of road transport emissions. The scenario yields an estimated increase in average carbon footprint relative to the 2024 base case, primarily driven by additional trucking.