Approaches to correct for double counting in tiered hybrid life cycle inventories

This paper presents an approach for inventory compilation and adjustment of double counting in tiered hybrid life cycle inventories (LCIs). The combination of input-output and physical inventory data on coefficient level is a convenient way of constructing a hybrid LCI that has both good detail and completeness. The proposed approach formalizes how to deal with partially overlapping data in inventory compilation. This particular approach requires that the issue of double counting is resolved in a consistent manner. Algorithms for identifying and adjusting for double counting are developed. Identification is performed based on a structural path analysis (SPA). Two algorithms for adjustment are presented. The first method is relatively simple to implement but has limitations to its applicability when performing a detailed assessment. The second method is more complex to implement but provides results that allow for more comprehensive structural inventory analysis. Numerical examples are provided in Appendix. (C) 2008 Elsevier Ltd. All rights reserved.