Given the increasing importance of liquefied natural gas in the global energy system, an understanding of natural gas value chain Greenhouse gas emissions is increasingly important. Here, we develop models of the key unit processes in the liquefied natural gas value chain: liquefaction, shipping, and regasification. We utilize detailed process-level data for liquefaction terminals and ships to generate granular estimates. Average gate-to-gate emissions of 0.220 and 0.269 tonnes of CO₂e/tonne gas liquefied were estimated for US liquefied gas exported from Sabine Pass and Cove Point liquefaction terminals, respectively. Furthermore, 331 voyages are modeled from four US ports reaching 30 countries, and the average gate-to-gate emissions for the countries to Asia are the highest at 0.200 tonnes CO₂e/tonnes of gas delivered. The estimated average gate-to-gate emissions for regasification terminals is 0.021 tonnes CO₂e/tonne of gas regasified. The developed models can be expanded to other regions, offering a global analysis provision.

Biodiesel is an emerging alternative fuel that is generally made from edible and non-edible oilseed crops. Jatropha curcus has a high potential for producing biodiesel, which yields 25–35% oil along with 75–65% solid byproduct, generally called a de-oiled cake. The present manuscript deals with the co-digestion of Jatropha de-oiled cake along with cattle dung (1:1 ratio) for biogas production in a floating-type biogas digester. The experimental study was carried out in a modified KVIC biogas plant of 6 cubic meter capacity for 60 days’ retention time under psychrophilic and mesophilic temperature conditions. During all the experiments, the total solid content of the slurry was maintained fixed at 10–12% by mixing 10 kg Jatropha de-oiled cake and 10 kg cattle dung with 80 kg water. The experimental results showed that the average specific biogas production of Jatropha de-oiled cake and cattle dung slurry was observed to be 0.216 m³/kg TS, 0.252 m³/kg VS and 0.287 m³/kg TS, 0.335 m³/kg VS, respectively, under the aforementioned conditions. Moreover, the biogas methane concentration was observed to be 62.33% to 69.16% under mesophilic temperature conditions compared to the psychrophilic temperature conditions, 65.21% to 69.15%, respectively. Furthermore, the average total volatile solids mass removal efficiency of feeding material in the abovementioned process was 7% higher under mesophilic temperature conditions than psychrophilic temperature conditions. Additionally, the results indicated that a total 588.8 kg of input volatile solids produced a total of 7306.56 MJ/m³ and 5177.88 MJ/m³ energy in 60 days under psychrophilic and mesophilic temperature conditions. On the basis of the results, it is concluded that Jatropha de-oiled cake may be a superior solution for improving biogas quality and composition as well as a value-added product, i.e., organic manure.