title: Life-cycle greenhouse gas assessment of Nigerian liquefied natural gas addressing uncertainty.
abstract: Natural gas (NG) has been regarded as a bridge fuel toward renewable sources and is expected to play a greater role in future global energy mix; however, a high degree of uncertainty exists concerning upstream (well-to-tank, WtT) greenhouse gas (GHG) emissions of NG. In this study, a life-cycle (LC) model is built to assess uncertainty in WtT GHG emissions of liquefied NG (LNG) supplied to Europe by Nigeria. The 90% prediction interval of GHG intensity of Nigerian LNG was found to range between 14.9 and 19.3 g CO2 eq/MJ, with a mean value of 16.8 g CO2 eq/MJ. This intensity was estimated considering no venting practice in Nigerian fields. The mean estimation can shift up to 25 g CO2 eq when considering a scenario with a higher rate of venting emissions. A sensitivity analysis of the time horizon to calculate GHG intensity was also performed showing that higher GHG intensity and uncertainty are obtained for shorter time horizons, due to the higher impact factor of methane. The uncertainty calculated for Nigerian LNG, specifically regarding the gap of data for methane emissions, recommends initiatives to measure and report emissions and further LC studies to identify hotspots to reduce the GHG intensity of LNG chains.
authors.affiliation: †Research and Development Unit, INESC-Coimbra, R. Antero Quental, 199, 3000-033 Coimbra, Portugal.|‡ADAI-LAETA, Department of Mechanical Engineering, University of Coimbra, Pólo II Campus, Rua Luis Reis Santos, 3030-788 Coimbra, Portugal.
authors.forename: Amir
authors.initials: A
authors.lastname: Safaei
authors.affiliation: ‡ADAI-LAETA, Department of Mechanical Engineering, University of Coimbra, Pólo II Campus, Rua Luis Reis Santos, 3030-788 Coimbra, Portugal.
authors.forename: Fausto
authors.initials: F
authors.lastname: Freire
authors.affiliation: †Research and Development Unit, INESC-Coimbra, R. Antero Quental, 199, 3000-033 Coimbra, Portugal.|§Department of Electrical Engineering and Computers, Faculty of Sciences and Technology, Polo II, University of Coimbra, 3030-290 Coimbra, Portugal.
authors.forename: Carlos
authors.initials: C
authors.lastname: Henggeler Antunes
mesh_terms: D000393:Air Pollutants / Q000737:chemistry*; D002245:Carbon Dioxide / Q000032:analysis; D017752:Greenhouse Effect; D008697:Methane / Q000032:analysis*; D008962:Models, Theoretical; D059206:Natural Gas / Q000032:analysis*; D035501:Uncertainty
chemical_list: D000393:Air Pollutants; D059206:Natural Gas; D002245:Carbon Dioxide; D008697:Methane