Some may be skeptical of its credentials, but carbon capture has its proponents, and as policy makers have been known to say, everything should be on the table.
In an oil field south of Houston, the process is getting a lot of praise. Texas energy developer NRG announced in January that it has completed construction on the Petra Nova project, which it described as “the world’s largest post-combustion carbon-capture system.”
Located on an existing coal-fueled electrical generating unit at the company’s W.A. Parish power plant in Fort Bend County, Texas, Petra Nova captures carbon dioxide (CO2) and sends it through a pipeline to the West Ranch oil field 80 miles away.
The process takes flue gas from the coal plant to a carbon-capture facility. There, the CO2 is removed from the flue gas by an amine solution in an absorption tower. It is separated from the amine as 99.9 percent pure CO2 in a smaller regenerator tower. Finally, the separated gas is compressed and delivered to the oil field.
At the oil field, the compressed CO2 is used to boost oil extraction. The company projects that, with the aid of the compressed CO2 injection into its wells, oil extraction will increase from 300 to 15,000 barrels per day.
The system, which started in 2014, is a joint effort of NRG and JX Nippon, a Japanese oil and gas exploration company. The U.S. Department of Energy also provided up to $190 million in grants as part of the Clean Coal Power Initiative Program.
NRG said Petra Nova is capable of capturing more than 5,000 tons of CO2 per day, equivalent to taking more than 350,000 cars off of the road.