Engineering a carbon-negative power plant

As renewable power generation increases, conventional energy sources like natural gas, coal, and nuclear power will still be required to balance the nation’s energy portfolio. Traditional power plants will not, however, need to produce as much energy as they do now, leaving them to sit idle some of the time.

Katherine Hornbostel, assistant professor of mechanical engineering and materials science at the University of Pittsburgh’s Swanson School of Engineering, and her team received $800,283 in funding from the U.S. Department of Energy’s Advanced Research Projects Agency-Energy (ARPA-E) Flexible Carbon Capture and Storage (FLECCS) program to design a natural gas/direct air capture hybrid plant that will take advantage of those idle periods. The proposed design will not only eliminate carbon emissions from the power plant when it is producing electricity for the grid but will also capture carbon from the atmosphere during idle periods, ideally making the plant carbon negative.

“We still have a large fleet of natural gas and coal plants in our country. As we add renewables, which provide intermittent energy, we’ll still need those fossil power sources to make sure the grid is consistently powered,” explained Hornbostel. “The FLECCS funding call asks how we can make those fossil sources cleaner and even use them to improve air quality.”

For the project, Hornbostel will partner with Glenn Lipscomb, professor of chemical engineering at the University of Toledo; Debangsu Bhattacharyya, professor of chemical engineering at West Virginia University; and Michael Matuszewski, founder of Aristosys LLC in Venetia, PA.

The team has proposed a system design that integrates natural gas with two carbon capture technologies: a membrane system that captures carbon dioxide (CO2) from the plant’s exhaust, and a sorbent system that will absorb leftover CO2 from the exhaust and CO2 from the air outside. During normal operations, the hybrid plant will capture about 99 percent of the CO2 it generates; during off-peak hours, the plant will use its power to run the carbon capture systems to remove CO2 from the air.

“This is a very exciting and important project, and I’m pleased – but not surprised – to see this innovative research is being undertaken in Pittsburgh,” said Congressman Mike Doyle. “The world must achieve net-zero carbon emissions in a few short decades, or the impact on the environment and our society will be devastating. It’s essential that, as we make the transition to carbon-free energy, we also make efforts like this to reduce carbon emissions from existing power plants that use fossil fuels – and explore technology that could reduce the carbon already in our atmosphere. ARPA-E is playing a critical role in promoting groundbreaking research on all aspects of energy production and consumption, and I strongly support its important work.”

The highly competitive ARPA-E FLECCS Program awarded $11.5 million in Phase 1 funding to 12 projects that develop carbon capture and storage processes. Hornbostel will be the second in the Swanson School to receive an ARPA-E award, following Assistant Chair of Research and Professor of Chemical Engineering Robert Enick.

“ARPA-E grants are very prestigious and are only awarded to the most innovative applications that propose high impact projects,” said David Vorp, associate dean for research and John A. Swanson Professor of Bioengineering. “Dr. Hornbostel and her team will use this FLECCS funding to address several important gaps in the field, and we could not be prouder of her for winning this award.”

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