Exporting Coal to Asia Curbs Carbon Emissions

Under the right circumstances, exporting US coal to power plants in South Korea could curb carbon emissions, compared to burning the fossil fuel at plants in the United States, according to a new study. The move could lead to a 21 percent drop in greenhouse gas emissions.

"Despite the large amount of emissions produced by shipping the coal such a long distance, our analysis shows that the total emissions would drop because of the superior energy efficiency of South Korea's newer coal-fired power plants," Dalia Patiño-Echeverri, from Duke University, said in a statement.

Although, there is a fine line between reducing and increasing greenhouse gases, in which both US plants would need to replace the exported coal with natural gas and South Korea would need to replace other coal with the imported coal. If imported US coal were to replace natural gas or nuclear generation in Korea, the emissions produced per unit of electricity generated would increase, rather than decrease.

"This significant difference in results highlights the importance of analyzing domestic energy policies in the context of the global systems they affect," Patiño-Echeverri said.

This revelation is important to keep in mind considering that US coal exports to Asian countries have tripled since 2009.

Researchers decided to perform lifecycle air-emissions and economic assessments of two scenarios: one in which the United States continues to burn coal domestically in its own power plants, and one in which coal is shipped to South Korea.

In the export scenario, emissions of "equivalent carbon dioxide" - a scientific measure of the coal emissions' total global warming potential over a 100-year period - dropped 21 percent.

Other harmful emissions, including sulfur dioxide, nitrogen oxide and particulate matter, were also reduced.

According to the study, published in the journal Environmental Science & Technology, the move would also generate more than $25 billion for the US economy.

Though the results seem promising, "it's too early to give the export scenario an unequivocal green light," Patiño-Echeverri added.

This study follows Beijing's recent announcement that it plans to ban all industrial use of coal by the end of 2020 in a continued effort to severely cap its country's greenhouse gas emissions.