No abstract

In this study, the energy requirements associated with producing synthetic crude oil (SCO) and bitumen from oil sands are modeled and quantified, on the basis of current commercially used production schemes. The production schemes were (a) mined bitumen, upgraded to SCO; (b) thermal bitumen, upgraded to SCO; and (c) thermal bitumen, diluted. Additionally, three distinct bitumen-upgrading methods were modeled and incorporated into schemes a and b. In addition to energy demands, the model computes the greenhouse gas (GHG) emissions associated with supplying the energy required to produce bitumen and SCO. This study comprises two distinct situations. The first is the base case in which all the energy is produced using current technology, in the year 2003. The second situation is a future production scenario, where energy demands are computed for SCO and bitumen production levels corresponding to the years 2012 and 2030. The results from the base case include the energy demands for producing thermal bitumen and mined bitumen, upgraded to SCO. These demands are expressed in terms of amounts of hot water, steam, power, hydrogen, diesel fuel, and process fuel for upgrading processes. The model output indicates that the majority of the GHG emissions (70−80%) result during bitumen upgrading. Additionally, it was found that steam, hydrogen, and power are the most GHG-intensive energy inputs to the process, accounting for 80% of the GHG emissions in the base case. CO2 accounts for 95% of the total GHG, while methane and nitrous oxide are responsible for the remaining GHG emissions of all the producers in the base case. The energy demands for production estimates in the years 2012 and 2030 are also presented. Of all energy commodities, steam demands for thermal bitumen extraction, as well as hydrogen demands for upgrading are poised to multiply roughly 6-fold by 2030, with respect to 2003 levels. The model results reveal that electricity and steam demands for upgrading and mining operations will roughly double by 2012 and increase by a factor of 2.4 between 2012 and 2030.

In this paper, a model for optimizing energy production for oil sands operations is presented. The objective of the model is to minimize the total annual cost of supplying energy to the oil sands industry, subject to CO2 emissions constraints. The energy is supplied in the form of power, hydrogen, steam, hot water, diesel, and process fuel. The model, which is named the energy optimization model (EOM), is conceived as an analytical and planning tool for the energy industry and government sectors. The EOM determines optimal combinations of power and hydrogen plants that satisfy given energy demands of oil sands operations, at minimal cost and with reduced CO2 emissions. The EOM thus generates optimal energy infrastructures and quantifies the costs and emissions associated with energy production for bitumen and upgraded bitumen production. A case study is used to showcase the capabilities of the model and illustrate its applicability as a tool to develop and evaluate optimal CO2 mitigation strategies in the oil sands industry. The case study consists of optimizing the historical energy demands of oil sands operations in the year 2003, with added CO2 emissions constraints. The EOM results for the case study include the energy costs and emissions associated with SCO (synthetic crude oil) and bitumen production at increasing CO2 reduction levels. Optimal energy infrastructures for each CO2 reduction level are determined by the EOM. The model quantifies the cost increases because of CO2-constrained energy production on a per-barrel-of-oil basis as well as the maximum attainable CO2 emissions reductions for the featured case study. A discussion of the usefulness of the model as a technology screening tool for specific energy production scenarios is provided.