A Comprehensive and Systematic Modelling Tool for Natural Gas Value Chain Greenhouse Gas Emissions Quantification

This paper presents a comprehensive and systematic life cycle assessment tool developed at Imperial College, the ICLCA model, that can be used to accurately account for greenhouse gas emissions from any natural gas value chain and quantify their global warming potential. The ICLCA tool covers conventional gas production (onshore, offshore), unconventional gas production (shale gas, tight gas, and coalbed methane), gas processing, pipeline transmission, liquefaction, LNG loading, LNG shipping, LNG unloading, regasification and pipeline transport to city gate. The tool is built at unit processes level. Moreover, engineering design features, operational parameters and GHG emission mitigation options are considered in detail and are fully integrated in the tool. The detailed accounting methodology used allows to reconcile top-down and bottom-up emissions estimation approaches, which is an important step change as compared to currently employed methods. The results demonstrate that the tool successfully identifies and quantifies GHG emissions (CO2, CH4, N2O) at unit process level or equipment level and over time, covering combustion emissions, vent, fugitives, and flares. The dynamics of life cycle CO2 emissions, methane emissions and carbon intensity can be captured accurately and reliably