Exporting liquefied U.S. natural gas (LNG) would have global environmental benefits because lifecycle greenhouse gas (GHG) emissions from LNG-fueled power generation are roughly half those of coal-fired power, according to a new study paid for by the Center for Liquefied Natural Gas (CLNG).
Pace Global prepared the "LNG and Coal Life Cycle Assessment of Greenhouse Gas Emissions" report. The firm found GHG emissions from coal-generated power to be 92-194% higher than power generated from U.S.-produced LNG in five international markets (Germany, Japan, South Korea, China and India). The findings are in line with recent analysis from the U.S. Energy Information Administration showing that carbon emissions from the power sector hit a 27-year low last April, Pace said.
According to theresearch, an efficient newbuild coal plant emits about 92% more GHG than the most intensive (high GHG) LNG scenario, with emissions from the average existing coal-fired plant being about 139% to 148% higher. And an efficient newbuild coal plant typically emits 106% more GHG than the least intensive (low GHG) LNG scenario, with emissions from an existing coal facility being about 117% to 194% higher.
"Over the last two decades natural gas has played an increasingly important role in helping the United States to cut our greenhouse gas emissions," said CLNG spokesman Casey O'Shea. "What this new report demonstrates is that U.S. natural gas exports can similarly reduce greenhouse gas emissions globally. Even under the most extreme scenario, power produced from coal in these markets gives off almost twice the emissions as U.S.-produced LNG."
The study included a breakdown of elements in the lifecycle that are most emissions intensive. A substantial majority of emissions from both coal and U.S.-produced LNG were found to originate during the combustion phase (67-74% for LNG and 77-79% for coal), demonstrating that emissions of GHG during the liquefaction process for natural gas are "relatively insignificant," CLNG said.
The study assumed that the natural gas in the LNG scenario originated at the Haynesville Shale, is transported to a U.S. Gulf Coast LNG export terminal for liquefaction and then shipped to one of five markets, where it then undergoes regasification and is transported to a local power plant for gas-fired electric generation.
The lifecycle analysis for coal covers emissions from mining to overland land transport within the country of origin, export via ocean vessel for markets that import most of their consumed coal, and final usage in power generation. Fugitive emissions from mining and post mining activities were also considered, but emissions from the construction and decommissioning of coal extraction infrastructure were not included.
As the majority of coal consumed in Germany, China, and India is produced domestically, mining emissions were estimated assuming local conditions for both mining operations and transport. Coal consumed in Japan and South Korea is almost entirely imported, typically from Australia.