Life cycle assessment Product category rules Standardization Greenhouse gas

Life StemRegenin 1 assessment; Product category rules; Standardization; Greenhouse gas emissions; Oil sands
1. Introduction
Comparisons between products derived from crude oil depend increasingly on the use of life cycle assessment (LCA) to calculate the intensity of greenhouse gas (GHG) emissions. This is done on a well-to-wheel basis (from extraction of crude oil to the use of final products such as transportation fuels) by including direct emissions (e.g., onsite generation of steam), and indirect emissions, such as from producers external to the crude oil production chain (e.g., electricity produced offsite) (WRI and WBCSD, 2012). Canada's oil sands are bituminous petroleum reserves that require energy-intensive extraction of extra heavy or ultra-heavy crude oil, and often additional upgrading when compared with their conventional equivalents (National Energy Board, 2006, p. 38). These requirements generally result in products derived from oil sands crudes that have higher life cycle GHG emissions (Bergerson et al., 2012).