Life-Cycle Analysis

The abbreviation LCA if used for both life-cycle analysis and for life-cycle assessment. However, they are two different concepts: life-cycle analysis is the scientific and technical analysis of impacts associated with a product or a system, while life-cycle assessment is the political evaluation based upon the analysis.

The need for incorporating study of environmental impacts in all assessment work performed in our societies, from consumer product evaluation to long-term planning decisions, is increasingly being accepted. Energy systems were among the first to be subjected to LCA, trying to identify environmental impacts and social impacts related e.g. to health, or in other words to include in the analysis impacts that have not traditionally been reflected in prices paid in the marketplace. This focuses on the sometimes huge difference between direct cost and the full cost, including what are termed externalities: those social costs that are not incorporated in market prices. It is seen as the role of societies (read governments) to make sure that the indirect costs are not neglected in consumer choices or decision-making processes related to planning in a society. The way externalities are included will depend on the political preferences. Possible avenues range from taxation to legislative regulation.

Life-cycle analysis is a tool suited for assisting planners and decisionmakers in performing the necessary assessments related to external costs. The LCA method aims at assessing all direct and indirect impacts of a technology, whether a product, an industrial plant, a system or an entire sector of society. LCA incorporates impacts over time, including impacts deriving from materials or facilities used to manufacture tools and equipment for the process under study, and it includes final disposal of equipment and materials, whether involving reuse, recycling or waste disposal. The two important characteristics of LCA are:

• Inclusion of “cradle to grave” impacts
• Inclusion of indirect impacts imbedded in materials and equipment

The ideas behind LCA were developed during the 1970s, and went under different names such as “total assessment”, “including externalities”, or “least cost planning”. Some of the first applications of LCA were in the energy field, including both individual energy technologies and entire energy supply systems. It was soon realised that the procurement of all required data was a difficult problem. As a result, the emphasis went towards LCA applied to individual products, where the data handling seemed more manageable. However, it is still a very open-ended process, because manufacture of say a milk container requires both materials and energy, and to assess the impacts associated with the energy input anyway calls for an LCA of the energy supply system. Only as the gathering of relevant data has been ongoing for a considerable time, has it become possible to perform credible LCA’s.

Product LCA has in recent years been promoted by organisations such as SETAC (Consoli et al., 1993) and several applications have appeared over recent years (e.g. Mekel and Huppes, 1990; Pommer et al., 1991; Johnson et al., 1994; DATV, 1995). Site− and technology− specific LCA of energy systems have been addressed by the European Commission (1995f) and by other recent projects (Petersen, 1991; Inaba et al., 1992; Kato et al, 1993; Meyer et al., 1994; Sørensen and Watt, 1993, Sørensen, 1994b; Yasukawa et al. 1996; Sørensen, 1995a, 1996c; Kuemmel et al., 1997). Methodological issues have been addressed by Baumgartner (1993); Sørensen (1993, 1995b, 1996b, 1997b); Engelenburg and Nieuwlaar (1993) and energy system-wide considerations by Knöepfel (1993); Kuemmel et al. (1997) and Sørensen (1997c), the latter with emphasis on greenhouse gas emission impacts.