The pipeline company said it placed its Cameron Access project into service in Louisiana. The project involved overhauls and extensions to an existing network that would feed an export facility slated to start operations by the end of next year.

"The completion of Cameron Access creates significant value for our customers by providing additional connectivity for their domestically produced natural gas to the high-value U.S. Gulf Coast LNG export market," Stanley Chapman III, TransCanada's president of U.S. natural gas pipelines, said in a statement.

The $10 billion Cameron liquefaction project is led by a consortium of Japanese and French companies. The first train, a unit that converts gas to its liquid form, will be operational next year for exports. At least three trains are envisioned.

U.S. leaders see LNG as a way to add diversification to a global energy sector that depends on a handful of major producers, like Russia. With shale natural gas production outpacing demand in some U.S. regions, and new infrastructure planned for exporting liquefied natural gas, outgoing U.S. Secretary of State Rex Tillerson said late January that Poland, which is almost entirely dependent on Russia, represents "fertile ground" for expanded business relations between the two countries.

"U.S. companies have the right products and services to contribute to Poland's energy security," he said.

Polish Oil and Gas Co., known commonly as PGNiG, signed a five-year contract to secure LNG from the Sabine Pass terminal in Louisiana, the first mid-term contract of its kind, in November.

The consortium behind Cameron LNG has authorization from the U.S. Department of Energy to export U.S.-produced LNG to countries that have a free trade agreement with the United States and non-FTA countries alike, adding overseas leverage to U.S. shale.