Environmental Implications of United States Coal Exports: A Comparative Life Cycle Assessment of Future Power System Scenarios

Abstract

Stricter emissions requirements on coal-fired power plants together with low natural gas prices have contributed to a recent decline in the use of coal for electricity generation in the United States. Faced with a shrinking domestic market, many coal companies are taking advantage of a growing coal export market. As a result, U.S. coal exports hit an all-time high in 2012, fueled largely by demand in Asia. This paper presents a comparative life cycle assessment of two scenarios: a baseline scenario in which coal continues to be burned domestically for power generation, and an export scenario in which coal is exported to Asia. For the coal export scenario we focus on the Morrow Pacific export project being planned in Oregon by Ambre Energy that would ship 8.8 million tons of Powder River Basin (PRB) coal annually to Asian markets via rail, river barge, and ocean vessel. Air emissions (SOx, NOx, PM10 and CO2e) results assuming that the exported coal is burned for electricity generation in South Korea are compared to those of a business as usual case in which Oregon and Washington's coal plants, Boardman and Centralia, are retrofitted to comply with EPA emissions standards and continue their coal consumption. Findings show that although the environmental impacts of shipping PRB coal to Asia are significant, the combination of superior energy efficiency among newer South Korean coal-fired power plants and lower emissions from U.S. replacement of coal with natural gas could lead to a greenhouse gas reduction of 21% in the case that imported PRB coal replaces other coal sources in this Asian country. If instead PRB coal were to replace natural gas or nuclear generation in South Korea, greenhouse gas emissions per unit of electricity generated would increase. Results are similar for other air emissions such as SOx, NOx and PM. This study provides a framework for comparing energy export scenarios and highlights the importance of complete life cycle assessment in determining net emissions effects resulting from energy export projects and related policy decisions.

The greenhouse gas effects of increased US oil and gas production

“…For exports of natural gas, global emissions could decrease if the primary fuel displaced is coal, while emissions could increase if more renewables or other lower-emissions sources are displaced [17]. For coal exports, important considerations include the elasticity of supply for seaborne coal, along with the thermal efficiency of the combustion units where the coal is ultimately burned [54].…”

Natural gas and climate finance

“…Internationally, emissions may simply be displaced. For example, the abundance of natural gas in the US has led to exports towards East Asia, where coal is currently used (Bohnengel, Patino-Echeverri et al 2014).In conclusion, there are little grounds to use climate finance to support gas-fuelled electricity generation.…”

Understanding the Contribution of Mining and Transportation to the Total Life Cycle Impacts of Coal Exported from the United States

“…Publically available data and studies on the coal supply chain and cradle-to-busbar LCAs on coal power production are limited. NETL has conducted LCA research on coal power production and Bohnengal et al produced a study on coal exports [9,13,14]. The scope of this study is broader than previous studies.…”

“…The Bohnengal et al [9] study was focused on the impact of a coal exports from a specific coal terminal facility in Oregon, while this study seeks to compare multiple exporters. Previous NETL studies do not include the exportation of coal within their study boundaries, while and Bohnengal et al produced a study on coal exports [9,13,14]. The scope of this study is broader than previous studies.…”

“…The scope of this study is broader than previous studies. The Bohnengal et al [9] study was focused on the impact of a coal exports from a specific coal terminal facility in Oregon, while this study seeks to compare multiple exporters. Previous NETL studies do not include the exportation of coal within their study boundaries, while this study does.…”