As estimates for the amount of U.S. natural gas resources have grown, so have the prospects of rising U.S. natural gas exports. The United States is expected to go from a net importer of natural gas to a net exporter by 2020. Projects to export liquefied natural gas (LNG) by tanker ship have been proposed-cumulatively accounting for about 12.5% of current U.S. natural gas production-and are at varying stages of regulatory approval. Projects require federal approval under Section 3 of the Natural Gas Act (15 U.S.C. 717b), with the U.S. Department of Energy's Office of Fossil Energy and the...