By the first week of January the plant had already captured 100,000 tons of carbon, and barring any major glitches, plant operators expect to hit a million tons by early summer.

Houston-based NRG began construction on the project in 2014, and the company says it finished in December, on time and within its $1 billion budget. But whether or not the new plant will be profitable depends on the price of crude oil, which is nearly half what it was when NRG began construction years ago.  The carbon dioxide is pumped into oil wells to increase production and prices need to be relatively high to make it worthwhile for oil companies to use the process, known as increased oil recovery, which can add costs of $20 to $30 a barrel, according to the Energy Department.

The plant captures carbon released by the WA Parish coal-fired power plant, located in Thompsons, and runs it through a complex chemical process that separates the carbon, liquefies it and sends it 80 miles through a pipeline. The cost of running Petra Nova would be borne by the sales of oil, rather than by electric customers, said David Greeson, NRG’s vice president of development.