SWINOUJSCIE, Poland — Gargantuan tankers pull into this port on the Baltic Sea twice a month, ferrying liquid natural gas from producers in Qatar, Norway and, increasingly, the United States. The fuel will help light and heat millions of Polish homes, while gradually cutting the country’s dependence on coal.

This fuel is also an important geopolitical strategy.

Poland is determined to end its reliance on Russian energy within the next few years, part of a broader effort in Europe to diversify the region’s energy supply. Relations with Russia have been unsettled, sometimes perilously, over political differences as well as the role of Poland, a former Soviet satellite, in NATO.

The country has found a ready replacement in the United States, which has an abundance of natural gas from the shale boom and a political incentive to ease Russia’s chokehold on Europe. Once it is chilled into a liquid, natural gas can be shipped around the world. American companies now have contracts that span decades and promise to supply Poland with the equivalent of about half of its current gas imports.