Feed gas deliveries to U.S. liquefied natural gas (LNG) export terminals that are running at or near peak capacity have grabbed headlines since colder weather settled in across the Northern Hemisphere in recent weeks. But what does it mean for an LNG plant to run at peak capacity?

Never before have so many liquefaction trains been in operation in the United States. The first LNG export cargo left the Lower 48 in 2016. Now, there are 24 trains in service at six terminals in Georgia, Louisiana, Maryland and Texas, while another is being commissioned. 

Asian natural gas prices have hit levels not seen in years, and European prices are also strong. U.S. liquefaction trains are working overtime as American cargoes are moving toward big premiums overseas and helping to recover some of...