Approaches to Avoid Double Counting in Hybrid Life Cycle Inventories

Abstract

Hybrid life cycle analysis methodology offers a convenient way to combine traditional life cycle inventories and input output tables to construct inventory data that has both good detail and completeness. This combination easily leads to double counting. i.e the accounting of the same production process in both LCA process and input-output requirements matrix. This paper present some aspects of double counting in hybrid inventories. An algorithm for identifying double counting and four methods to adjust for this are developed. The first two have a low complexity of implementation but limitations to their applicability when performing a detailed assessment. The last two have a somewhat higher complexity in implementation but provide correct results for all types of structural inventory analysis. By the application of one of these, the quality of a hybrid life cycle inventory can be increased at a low effort.