As the above examples illustrate, not all LNG facilities are created equal. In British Columbia, industry proponents have a range of technologies and strategies at their disposal—both “upstream” at the source of gas extraction and “downstream” at the LNG plant, and at all points between—that could bring down the life cycle carbon footprint of British Columbia LNG to a world-leading standard.
Broadly speaking, three factors influence the carbon footprint of LNG, from wellhead to waterline.
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Natural Gas Sourcing and Processing: Due to characteristics of different natural gas fields and how they are extracted, some deposits innately have much lower greenhouse gas emissions than others. For example, raw natural gas sourced from the Horn River basin, near Fort Nelson in the province’s far northeast corner, contains 12 percent carbon dioxide. Meanwhile, the Montney field, in the vicinity of Fort St. John and Dawson Creek, contains just one percent carbon dioxide. Gas sourced from the Montney field will have a smaller carbon footprint than Horn River gas, unless the latter’s significant carbon dioxide content is captured and stored at the wellhead—a process not currently required in British Columbia. Carbon dioxide in natural gas must be separated in a processing plant, and without carbon capture and storage, it is vented to the atmosphere, where it exacerbates climate disruption. Further, at least in British Columbia, the industry presently burns a great deal of natural gas to process natural gas, releasing more carbon pollution. Electrification of processing plants with clean electricity would offset some of these emissions, however this is not currently required.
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Compression: Liquid Natural Gas plants are essentially enormous refrigerators that work in much the same fashion as a home chiller, but at an industrial scale. The plants run massive power-hungry compressors to cool incoming natural gas to -162 degrees Celsius (Woodside, 2011). Typically, LNG facilities burn natural gas to run these compressors directly—a configuration known in the industry as “direct drive.” However, they can also be run by electricity, in a configuration referred to as electric drive, or E-Drive. Electric drives can be more efficient, and can use lower carbon energy sources such as wind, hydro, and also natural gas, burned in an efficient “combined-cycle” power plant.
- Power Generation: LNG facilities require electricity to accomplish ancillary tasks other than the compression phase of production. How this electricity is sourced influences the carbon footprint of the plant, and the LNG produced there. Renewable energy sources such as wind and hydro produce almost no carbon pollution. Combined cycle natural gas electricity generation does produce carbon pollution, but is currently the most efficient form of gas-fired generation available.
