Life Cycle Assessment of Greenhouse Gas Emissions from Marine Fuels: A Case Study of Saudi Crude Oil versus Natural Gas in Different Global Regions

Abstract

The understanding of the greenhouse gas (GHG) emissions dimension in discussing the future of marine fuels makes it important to advance the current life cycle assessment (LCA) practice in this context. Previous LCA studies of marine fuels rely on general LCA models such as GREET and JEC well-to-wheels study. These models do not fully capture the various methane losses in the fuel supply chain. The primary goal of this LCA study is to compare the GHG emissions of heavy fuel oil and marine gas oil produced from Saudi crude oil to liquefied natural gas (LNG) in different global regions. A sensitivity analysis was performed to show how results may vary with non-Saudi crudes. A secondary goal was to advance LCA of marine fuels by utilizing, for the first time, a set of bottom-up engineering models that enable detailed analysis of specific oil and gas projects worldwide. The results show particular cases where LNG use in marine applications has a significant countereffect in terms of climate change compared to conventional marine fuels produced from a low-carbon-intensity crude oil. When the results are calculated based on a 20- versus 100-year methane global warming potential, LNG appears noncompetitive for climate impact in marine applications.