Robert L Kleinberg 

Exports of liquefied natural gas (LNG) from the United States are growing rapidly, and the United States government must balance a multiplicity of interests in deciding to what extent the growth of LNG exports should be further encouraged. Its decisions must be consistent with the Natural Gas Act, which mandates that exports of natural gas be in the public interest. In the current administration, reduction of greenhouse gas emissions is an important component of the public interest determination. It has generally been regarded that the replacement of coal with natural gas, reducing the volume of power plant carbon dioxide emissions, satisfies this component of the public interest determination. However, a recent life cycle analysis has cast doubt on this conclusion. Here we compare two life cycle analyses that come to different conclusions as to the wisdom of coal-to-gas conversion of electric power industries. We identify the technical factors underlying the diverse results. Among other problems, both studies use a widely accepted but defective and misleading methodology. Recommendations for improvements are provided.