University of Calgary , Calgary, Alberta T2N 1N4, Canada.
Massachusetts Institute of Technology , Cambridge, Massachusetts 02139, United States.
Environ Sci Technol. 2018 Feb 20;52(4):1735-1746. doi: 10.1021/acs.est.7b05298. Epub 2018 Feb 6.
In the determination of the net impact of liquefied natural gas (LNG) on greenhouse gas emissions, life cycle assessments (LCA) of electricity generation have yet to combine the effects of transport distances between exporting and importing countries, country-level infrastructure in importing countries, and the fuel sources displaced in importing countries. To address this, we conduct a LCA of electricity generated from LNG export from British Columbia, Canada with a three-step approach: (1) a review of viable electricity generation markets for LNG, (2) the development of results for greenhouse gas emissions that account for transport to importing nations as well as the infrastructure required for power generation and delivery, and (3) emissions displacement scenarios to test assumptions about what electricity is being displaced in the importing nation. Results show that while the ultimate magnitude of the greenhouse gas emissions associated with natural gas production systems is still unknown, life cycle greenhouse gas emissions depend on country-level infrastructure (specifically, the efficiency of the generation fleet, transmission and distribution losses and LNG ocean transport distances) as well as the assumptions on what is displaced in the domestic electricity generation mix. Exogenous events such as the Fukushima nuclear disaster have unanticipated effects on the emissions displacement results. We highlight national regulations, environmental policies, and multilateral agreements that could play a role in mitigating emissions.
在确定液化天然气（LNG）对温室气体排放的净影响时，发电的生命周期评估（LCA）尚未结合出口国和进口国之间的运输距离、进口国的国家基础设施以及进口国替代的燃料源的影响。为了解决这个问题，我们采用三步法对加拿大不列颠哥伦比亚省的 LNG 出口发电进行了 LCA：（1）审查 LNG 可行的发电市场，（2）制定考虑到向进口国运输以及用于发电和输送的基础设施的温室气体排放结果，以及（3）排放置换情景，以测试有关在进口国被置换的电力的假设。结果表明，虽然与天然气生产系统相关的温室气体排放的最终规模仍不清楚，但生命周期温室气体排放取决于国家基础设施（具体而言，发电机组的效率、输电和配电损失以及 LNG 海洋运输距离）以及对国内发电组合中被置换的电力的假设。福岛核灾难等外生事件对排放置换结果产生了意想不到的影响。我们强调了国家法规、环境政策和多边协议在缓解排放方面可能发挥的作用。
