Greenhouse gas emissions from the global transportation of crude oil: Current status and mitigation potential

Global crude‐oil transportation contributes a significant portion of greenhouse gas (GHG) emissions in the marine transportation sector. In this work, we first compile a detailed country‐level global crude‐oil transportation network in 2018 and estimate that the direct and well‐to‐hull GHG emissions related to crude transportation were 97 and 109 million metric tons, respectively. Combining with the country‐specific crude recovery GHG intensities, the consumption‐based well‐to‐country‐gate crude‐oil GHG intensities are derived for individual countries, ranging from 2.99 to 27.32 g CO2eq/MJ, with a global crude‐volume‐weighted average of 8.67 g CO2eq/MJ. We then project the global crude transportation emissions at the regional level in 2050 under a static (no change) scenario (based on current ship energy efficiency) and a sustainable‐development (SD) scenario (based on the International Energy Agency's projections of ship energy efficiency and penetration of alternative marine fuels). Results show that the global well‐to‐hull GHG emissions related to crude transportation would be 82 and 59 million metric tons in 2050 in the static and SD scenarios, respectively. To further evaluate the impact of potential fuel‐switching on decarbonizing the crude oil transportation sector, we estimate the GHG emissions for 20 fuel/production options in 2050. We find that, in comparison to the static scenario, ∼50% reduction in global well‐to‐hull GHG emissions from crude transportation could be achieved under the SD scenario if green ammonia further replaces conventional ammonia. The methodology developed here can be applied to other commodities to estimate the emissions associated with their global marine transportation and to evaluate the potential emission mitigation options.