Handling of multi-functionality in life cycle assessments for steel mill gas based chemical production

Life cycle assessment is needed for quantifying potential greenhouse gas savings through material utilization of steel mill gases. However, methodological guidance for this purpose is lacking. Therefore, the article presents different approaches to handle multi-functionality. The investigation of steel mill gas based-methanol shows varying impacts on climate change due to handling multi-functionality differently. System expansion is recommended for assessing cross-sectoral cooperation and substitution as well as economic allocation for product-specific analyses.