Refineries are complex systems that require the use of full-refinery models to accurately characterize any single process ( ICCT 2011). Understanding these models, including their assumptions, differences among one another, and limitations is important for LCA practitioners conducting product life cycle studies with activities occurring in the United States. US federal agencies sponsor many of these models. In the US, a number of datasets and models have been created to estimate petroleum-related impacts for related activities from petroleum extraction to combustion. Developers must create models of the life cycle of petroleum consisting of detailed inputs and outputs to and from each stage of production to be a comprehensive model, these life cycle stages should typically reach from cradle to grave. When conducting LCAs, whether it be from the point of view of the producer, the intermediate consumer, or end consumer, petroleum-related environmental impacts need to be accounted for with a high degree of accuracy, as they are likely to influence final results. They are included in the reference life cycle databases of China (CLCD), Europe (ELCD), and the United States (USLCI) as well as commercial databases such as ecoinvent and GaBi. Stakeholders may need to consider carefully the tradeoffs inherent when selecting a model to conduct life cycle assessments for systems that make heavy use of petroleum products.Ī petroleum model is a necessary core component of any life cycle database.
A data quality assessment of the models’ documentation revealed real differences between models in temporal and geographic representativeness, completeness, as well as transparency. Effects of these deviations on well-to-wheels passenger vehicle and truck transportation life cycle models may be minimal for effects such as global warming potential (6% spread), but for respiratory effects of criteria pollutants (41% spread) and other impact categories, they can be significant. Differences in allocation do not appear to explain differences in predictions. Carbon dioxide well-to-pump emissions for gasoline showed a variation of 35%, and other pollutants such as ammonia and particulate matter varied up to 100%.
Our paper studies five of these models, demonstrating the differences in their predictions and attempting to evaluate their data quality. Many organizations have attempted to develop an accurate well-to-pump life cycle model of petroleum products in order to inform decision makers of the consequences of its use.