Life Cycle Assessment (LCA) of Worsted and Woollen processing in wool production: ReviWool® noils and other wool co-products

The textile and fashion industry is becoming increasingly active in measuring its environmental performance. As far as wool is concerned, there is quite abundant literature on environmental impacts available. However, previous studies very rarely distinguish between the different co-products of the wool transformation, and often attribute the same impact to fibers produced from worsted processing (longer and more expensive fibers) and woollen processing (shorter and cheaper fibers). This study firstly provides a detailed mapping of processes and products involved in the wool production chain, from sheep grazing to yarn production, with particular attention to the shorter fibers, which have been mostly neglected in previous literature. Secondly, this study uses the Life Cycle Assessment (LCA) methodology to analyze the environmental impacts of the different intermediate co-products. In particular, when multi-output processes occur, impacts are distributed proportionally to their relative economic value, using therefore an economic allocation. This approach enabled the calculation of environmental impacts of fibers used both in the worsted and woollen processing. It results that shorter fibers generally have lower impacts than longer fibers used for the production of fine yarns. Specifically, most short fibers have an impact on climate change ranging from 25 to 30 kg CO2 eq/kg, while, longer fibers have an impact of 78–97 kg CO2 eq/kg. The physiological variation in the ratio between worsted and woolen co-products of multi-output processes appears to have little effect on the final impact results. Finally, since the grazing phase is highly variable, impacts on climate change of the analyzed intermediate products have been re-calculated using, for the greasy wool, the lowest and highest values of impact found in literature. Impacts of the analyzed products vary sensibly according to the value considered for the greasy wool, but the relationship between them is rather stable. This paper contributes with detailed information and easily replicable data which could be used as a basis for the environmental assessment of wool garments and for improving the sustainability in the wool sector.