Historical trends in greenhouse gas emissions of the Alberta oil sands (1970–2010)

Abstract

There has been increased scrutiny of the Alberta oil sands due to their high carbon intensity (CI) relative to conventional crude oil. Relying entirely on public and peer-reviewed data sources, we examine historical trends in the CI of oil sands extraction, upgrading, and refining. Monthly data were collected and interpolated from 1970 to 2010 (inclusive) for each oil sands project. Results show a reduction in oil sands CI over time, with industry-average full-fuel cycle (well-to-wheels, WTW) CI declining from 165 gCO _2 e MJ ^−1 higher heating value (HHV) of reformulated gasoline (RFG) to 105 (−12, +9) gCO _2 e MJ ^−1 HHV RFG. 2010 averages by production pathways are 102 gCO _2 e MJ ^−1 for Mining and 111 gCO _2 e MJ ^−1 for in situ . The CI of mining-based projects has declined due to upgrader efficiency improvements and a shift away from coke to natural gas as a process fuel. In situ projects have benefitted from substantial reductions in fugitive emissions from bitumen batteries. Both mining and in situ projects have benefitted from improved refining efficiencies. However, despite these improvements, the CI of oil sands production (on a pathway-average basis) ranges from 12 to 24% higher than CI values from conventional oil production. Due to growing output, total emissions from the oil sands continue to increase despite improved efficiency: total upstream emissions were roughly 65 MtCO _2 e in 2010, or 9% of Canada’s emissions.

Keywords

• 88.05.Hj
• 92.60.Sz
• 92.30.Np
• 89.30.aj
• transportation fuels
• Alberta oil sands