Petra Nova: The Cutting-Edge of Carbon Capture

Energy demand across the world continues to rise and shows no sign of slowing. In the United States alone, projections of energy consumption postulate an increase in demand of nearly 25 percent by 2040! While there is a general consensus in the energy science community that a range of power generation options must be created and refined—it is impossible to meet the power needs of the future without continuing to employ traditional power generation options. Fossil fuels are an integral part of the American energy portfolio.

However, it is also clear that in order to continue the use our existing power infrastructure, changes must be made. The average generating unit of a coal-fired power plant in the U.S. is nearly 42 years old. Improvements to this technology must be made to reduce its environmental costs and transform it into a sustainable power source. Specifically, the development of post-combustion carbon capture technology is vital to reduce carbon dioxide emissions. Carbon capture and storage (CCS) technology offers great potential in reducing carbon emissions while retaining a key, domestic energy resource.

The National Energy Technology Laboratory (NETL) is intent on developing technology solutions to the energy challenges we face—including the development and demonstration of cutting-edge carbon capture technology. Six years ago, NETL entered into a cooperative agreement for the development of a post-combustion CCS project to design, construct, and operate a system that will capture and store approximately 1,400,000 metric tons of carbon dioxide per year—the Petra Nova project. Petra Nova is a joint venture between NRG Energy Inc. (NRG) and JX Nippon Oil and Gas Exploration (JX) a Japanese oil and gas exploration and production firm.

The Petra Nova CCS project is located at NRG’s W.A. Parish Generating Station, which is southwest of Houston. The system will treat a portion of a coal-derived flue gas stream from the plant, and will capture approximately 90 percent of the carbon from that stream, capturing and storing (or using) roughly 1.4 million metric tons of this greenhouse gas annually. The project will rely on a carbon capture process that uses a high-performance solvent for carbon absorption and desorption. Additionally, the energy needed to operate the capture and compression system being put in place will be generated by a combustion turbine with a heat recovery boiler, increasing the system flexibility and allowing installation and operation of the carbon capture unit without disrupting operation of the power system.  

Once captured, the carbon will be compressed and transported through an 80 mile pipeline to an operating oil field where it will be utilized for enhanced oil recovery (EOR) and ultimately sequestered. The demand for carbon for EOR purposes at the oil field actually spurred an increase in the scale of the Petra Nova project, as the original scale would not have yielded enough captured carbon to induce significant oil production.

The carbon captured at the power plant will be compressed and delivered to the oil field via pipeline where it will be injected into the ground and used to displace previously unreachable oil. Once the oil has been retrieved and separated from the carbon, the carbon will once again be injected down, this time for permanent storage in an underground geologic formation. Carbon dioxide has been successfully used since the early 1970s to safely bring up more oil from reservoirs previously considered to be uneconomic for further production.

The Petra Nova CCS project is an exciting illustration of the promise of CCS technology. The addition of carbon capture capability to the existing fleet of power plants will enable those plants to continue to produce clean electricity and simultaneously reduce the impact of carbon emissions. Recently, the project was honored with a Peabody Energy Clean Coal Award, citing the important strides it has made towards making clean coal a reality.

Peabody Energy is the world’s largest private-sector coal company. The annual Clean Coal awards were established in 2014 to recognize leadership and improve awareness about the benefits of clean coal technologies. The awards are based on data available from the Environmental Protection Agency that showed that the selected, winning projects improved plant efficiency while attaining lower sulfur dioxide and nitrogen oxides emissions rates and lowering carbon footprints through the use of cutting edge CCS technology.

Judges from Peabody Energy commended the Petra Nova’s innovative capture technology, noting that it “represents the first large-scale retrofit of an existing coal-fired power plant.”