Taking a leading role NETL, in collaboration with Oregon State University (OSU) and Pacific Northwest National Laboratory (PNNL), is exploring how high-temperature carbon dioxide (CO₂) degrades power plant building materials — research that could lead to the development of supercritical CO₂ power plants that could help decarbonize the nation’s power sector.

CO₂ generated from electricity production represents 25% of the total greenhouse gas emissions in the United States. Revolutionary technologies will be required to decarbonize electricity production while simultaneously making electricity more affordable and accessible for all Americans. One promising approach is to use extremely hot carbon dioxide in place of steam to drive a turbine and produce electricity in future power plants.

These “supercritical CO₂” power plants rely on much simpler machinery, provide a smaller physical footprint compared to traditional plants, and can be powered by a variety of energy sources. This makes them ideal to support remote distributed power, increasing the availability of affordable electricity to rural areas and promoting electrification of American society. 

While conceptually simple, commercialization of these supercritical CO₂ systems is severely limited by the availability of materials, specifically structural alloys, that can survive contact with hot corrosive CO₂-rich gases.

NETL researchers, with support from OSU and PNNL, conducted a study titled "Molecular-scale investigation of the oxidation behavior of chromia-forming alloys in high-temperature CO₂." The study examined how the alloys inside these power plants deteriorate as result of increased CO₂ contact and expressed the need for new materials to build the plants of the future and retrofit the existing fleet.

“In this project, our collaborative team used a combination of specialized analytical techniques to reveal precisely how an alloy degrades by reaction with oxygen and carbon in hot CO₂,” explained NETL Research Scientist Richard Oleksak, one of the study’s authors. “This information equips designers with the knowledge required to select cost-effective and durable materials to enable the commercialization of these future power plants, which will aid in decarbonizing the energy sector—a goal shared by NETL and the Biden-Harris Administration.”

In addition to his work on the study, Oleksak was selected to receive the Young Leaders Professional Development Award within the Structural Materials Division of The Minerals, Metals & Materials Society in 2020. Oleksak’s research involves the use of the Lab’s autoclave reactor. The autoclave reactor, located in the Supercritical Materials Research Facility at NETL, generates harsh environments that consist of flowing CO₂-rich supercritical fluids at exceptionally high temperatures and pressures. This allows researchers to test the performance of candidate alloys at conditions which closely simulate those expected in future power plants.

"Molecular-scale investigation of the oxidation behavior of chromia-forming alloys in high-temperature CO₂" was published in Nature Partner Journals Materials Degradation, an open access journal from Nature Research dedicated to publishing high-quality papers that report significant advances on the degradation of all material types. These journals are published in collaboration with internationally renowned partners, driving high-impact open science. The study can be read here.

NETL is a U.S. Department of Energy national laboratory that drives innovation and delivers technological solutions for an environmentally sustainable and prosperous energy future. By leveraging its world-class talent and research facilities, NETL is ensuring affordable, abundant and reliable energy that drives a robust economy and national security, while developing technologies to manage carbon across the full life cycle, enabling environmental sustainability for all Americans.