Carbon footprint of Argentine peanuts

Purpose: The general objective of this study is to perform a Carbon Footprint of peanut production, transportation and processing in Córdoba, Argentina, in order to have a better understanding of all the life-cycle stages of peanut production; study the environmental sustainability performance of peanut production; and to find hotspots in the existing farming, hauling and processing systems, that may be improved for environmental purposes. The intent of the study is to generate results that can be publicly communicated to different audiences. Methods: Surveys were conducted for the 2012-2013 crop season, in the province of Córdoba, with farmers and companies that processed 46% of the total national production (1.022.516 t), i.e., 470,000 t of raw peanuts or 223,000 t of shelled peanuts. The functional unit is 'one metric ton of raw peanuts in Argentina, at the farm gate'. A Carbon footprint analysis -based on the ISO 14067 standard (ISO, 2013)- from cradle-to-gate was conducted, up to the 'port of export' located in Zárate (Argentina), including crop production, processing and transportation. Co-product allocation was based upon economic value. Results from Carbon Footprint are: Crop production and mill processing contribute with 87 kg CO2 eq (37%) and 91 kg CO2 eq (38%), respectively, while transportation contributes with 59 kg CO2 eq (25%). This analysis also considers the use of co-products, such as hull and skin. Even though its industrial use also generates some emissions, substantial environmental benefits were derived from the combustion of peanut hulls for electricity cogeneration and heat, which reduced CO2 eq emissions by 196 kg CO2 eq (-83%), reaching a final value of 41 kg CO2 eq. Without considering the use of co-products, results from Carbon footprint are 237 kg CO2 eq. GWP was also estimated for a set of peanut-based final products, and expressed in terms of kg of CO2 eq per kg of product. CO2 values ranged from 0.4 for fried peanut, toasted peanut, and refined oil; 0.7 for peanut flour, coated peanut, caramelized peanut, and chopped peanut; 0.8 for peanut butter; and 1.0 for essential oil. In some cases, packaging environmental burdens overtake that of the products. The main hotspot in the farm stage was harvesting, explained by fuel consumption. Reduced tillage and soil nutrient reposition increased CO2 eq. emissions. In the milling stage, due to the use of liquefied petroleum gas (LPG) curing was the hotspot. Replacing road transportation by railway transportation decreases carbon footprint values. Conclusions: A Carbon Footprint analysis was successfully performed on the Argentine peanut value chain. This research is the first assessment of the contribution of peanuts to the global warming potential. Results are useful for the analysis of other food products that use peanut as ingredient.