Life Cycle Assessment of North American Conventional Crudes for Production of Transportation Fuels

• Author / Creator

  Rahman, Md Mustafizur

• Global energy demand is expected to grow substantially and will lead to increased production of crude oil from various sources. The production of crude oil and it’s conversion to transportation fuels result in the release of greenhouse gases (GHGs) into the atmosphere. As one of the highest GHG-emitting sectors, the transportation sector requires GHG emissions reductions plans that push forward different policy regulations that require appropriate quantification of life cycle GHG emissions for transportation fuels derived from various crude types. A life cycle assessment (LCA) is an extremely useful tool to assess the greenhouse gas (GHG) emissions for transportation fuels on a well-to-wheel (WTW) basis. In this study, a WTW life cycle assessment was conducted for five North American conventional crude oils. The well-to-wheel life cycle assessment of crude oil includes both the well-to-tank (WTT) and tank-to-wheel (TTW) stages. The WTT stage includes crude recovery, transportation of crude from the feedstock location to the refinery, refining of crude, and transportation and distribution of refined fuels (gasoline, diesel, and jet fuel) to the refueling stations. The combustion of transportation fuels in vehicle engines is known as the TTW stage. All of the life cycle stages consume energy and produce a significant amount of GHG emissions. The purpose of this study was to provide a comprehensive and transparent quantification of greenhouse gas (GHG) emissions for transportation fuels derived from five North American conventional crudes through the development of a data-intensive bottom-up engineering model called FUNNEL-GHG-CCO (FUNdamental ENgineering PrinciplEs-based ModeL for Estimation of GreenHouse Gases in Conventional Crude Oils). The model estimates GHG emissions from all the life cycle stages from the recovery of crude to the combustion of transportation fuels in vehicle engines. GHG emissions from recovery, refining, and transportation were calculated using the amount of energy required for each stage, process energy shares, and emission factors. GHG emissions from crude recovery depend on crude oil and reservoir properties, depth of reservoir, extraction method applied, and gas-to-oil and water-to-oil ratios. The contribution of recovery emissions in the total WTW GHG emissions ranges from 3.12% for Mars crude to 24.25% for California’s Kern County heavy oil. The transportation of crude oil and finished fuels contributes only 0.44-1.73% of the total WTW life cycle GHG emissions, depending on the transportation methods and total distance transported. Refining energy use and resulting GHG emissions were allocated to gasoline, diesel, and, jet fuel based on a sub-process level allocation method. Refining emissions vary from 13.66-18.70 g-CO2eq/MJ-gasoline, 9.71-15.33 g-CO2eq/MJ-diesel, and 6.38-9.92 g-CO2eq/MJ-jet fuel derived from Alaska North Slope and California’s Kern County heavy oil, respectively. The total WTW life cycle GHG emissions range from 97.55-127.74 g-CO2eq/MJ-gasoline, 95.01-126.02 g-CO2eq/MJ-diesel, and 88.17-118.17 g-CO2eq/MJ-jet fuel derived from Mars and California’s Kern County heavy oil, respectively.

• Subjects / Keywords

  • Life-cycle assessment
  • Conventional crude
  • Greenhouse gas
  • Transportation fuels

• Graduation date

  Spring 2015

• Type of Item

  Thesis

• Degree

  Master of Science

• DOI

  https://doi.org/10.7939/R3HD7P14Z

• License

  This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.