WASHINGTON — Even when U.S. natural gas is super-chilled into a liquid form, shipped by tanker around the globe, and burned to generate electricity, it producers fewer greenhouse gas emissions than the coal it often displaces, according to an industry analysis released Monday.
According to the calculations, developed by the Siemens’ energy management firm Pace Global for the Center for Liquefied Natural Gas, even a newly built coal-fired power plant emits about 92 percent to 106 percent more greenhouse gases than a facility generating electricity from U.S. LNG.
The study assumed that natural gas extracted in Texas would be transported from a Gulf Coast facility to one of five markets around the world, including China, India, Germany, Japan and South Korea.
“Even under the most extreme scenario, power produced from coal in these markets gives off almost twice the emissions as U.S.produced LNG,” said Casey O’Shea, a spokesman for the Center for Liquefied Natural Gas.
Dozens of natural gas export facilities are planned around the United States, with most concentrated on the Gulf Coast, though at least two are proposed in the Pacific Northwest, and another approved by the federal government in Lusby, Md.
The projects have been challenged by environmentalists who warn that the greenhouse gas benefits of natural gas over coal may be illusory, once the emissions from transporting the fuel around the globe and any leaks in the processing system are accounted for. The critics also say using natural gas to create electricity delays a broader transition to renewable fuels.
Fossil fuels produce different amounts of carbon dioxide and other greenhouse gases that contribute to climate change. Natural gas is among the cleanest burning, producing about 117 pounds of carbon dioxide per million British thermal units of energy, according to the U.S. Energy Information Administration. By contrast, anthracite coal generates about 228.6 pounds of carbon dioxide per million Btus.
The new analysis relied on data from the Environmental Protection Agency and includes some of those leaks, or fugitive emissions, though they are still a very small part of the overall greenhouse gas emissions associated with transporting and using U.S. LNG abroad.
Natural gas advocates are hoping to hit back against the environmental criticism as they continue pressing for a speedier federal review process. Right now, most proposed LNG export facilities are subject to two reviews — one by the Federal Energy Regulatory Commission that focuses on the physical plant and one by the Energy Department, which awards LNG export licenses.
The Energy Department’s review of proposed LNG exports to countries that don’t have free trade agreements with the United States typically follows FERC approval, often coming several months later.
Legislation pending in the House would impose a 30-day deadline on those Energy Department decisions.
A separate Senate bill has a more generous timetable and would give the Energy Department 45 days to decide on LNG export permits.
The new CLNG-commissioned analysis breaks down greenhouse gas emissions for every major phase in the lifecycle of liquefied natural gas, from its initial extraction and transmission to its liquefaction at an export terminal and later combustion overseas.
The power generation process itself was responsible for most of those emissions; for LNG sent to Japan, it is about 67.3 percent of total emissions, according to the Pace Global calculations. Processing is estimated to be about 16 percent of the emissions, followed by transportation, which ranged from 10.5 percent to 13.4 percent based on the final destination. Actual raw material acquisition — obtaining the natural gas itself — generally was 3.8 or 3.9 percent no matter the destination, according to the Pace Global analysis.