Treats to concrete: Penn State Bakery to use grad student’s carbon capture tech

UNIVERSITY PARK, Pa. — The Penn State Bakery has long supported the University community through baked goods and desserts. Now, with a system developed by Matthew Hollingham, a third-year doctoral student in architectural engineering, the Bakery will also help pave the way for carbon capture and utilization.

Hollingham’s system collects carbon dioxide (CO2) from flue gas — a byproduct of boilers that contains water vapor, CO2 and nitrogen — and converts it into materials that can be used to make concrete. The system is expected to start operating this fall at the Penn State Bakery, where the boilers used for cooking emit flue gas in accordance with state and federal regulations.

“We’re hoping to take this carbon byproduct and recycle it into something useful through the carbon mineralization process,” Hollingham said. “Imagine if we could see a bakery making a sidewalk.”

Concrete is typically made by binding fine and coarse aggregates with water and cement. The most common types of cement are produced when a mixture of limestone and silica-containing material is fired in a kiln at temperatures above 2,600 degrees Fahrenheit. The product, known as clinker, is ground into a fine powder and mixed with additives to create cement.

The chemical reaction that forms clinker also emits CO2 as a byproduct, accounting for about half of all CO2 emissions associated with cement production. The rate of CO2 emission per ton of cement has remained unchanged since 2019, when it was estimated to generate up to 8% of all global CO2 emissions. Hollingham said he aims to reduce this carbon footprint with carbon capture technology.

Hollingham began working on his carbon capture system in 2024, when his doctoral studies were more focused on experimentation and development of low-carbon cement substitutes. His current dissertation research focuses on policies surrounding carbon mineralization, a method for storing gaseous CO2 by converting it into stable, solid carbonates.

“My thesis is on carbon capture policy now, but I still really believe in this technology,” Hollingham said. “It’s a practical application of the methods and mechanisms I study.”

After running controlled experiments with CO2 canisters, Hollingham said he was eager to test the system in a real-world setting. While looking for a suitable location, Hollingham’s team found that the boilers in the Penn State Bakery were both well-sized and accessible. Seeing Hollingham’s dedication to advancing sustainable concrete, Haley Sankey, Auxiliary and Business Services’ director of sustainability, supported the collaboration, enthusiastic about this innovative project and its potential environmental and economic benefits.

“We are proud to support graduate research that emphasizes sustainable practices,” Sankey said. “Capturing CO2 emissions from the Penn State Bakery is an exciting step toward advancing innovative solutions for a more sustainable future."

Hollingham’s system draws flue gas from a point source and passes it through a condenser to separate the acidic water and the gas. The acidic water is drained into a vessel while the gas is injected into a mill containing basalt, an igneous rock rich in calcium. During a high-energy crushing process, the basalt is ground into reactive fines, which absorb CO2 from the injected gas and release calcium ions.

The activated basalt fines are combined with the separated acidic water in the vessels, where the absorbed CO2 forms carbonic acid and reacts with the calcium ions to form stable calcium carbonate. The overall procedure yields both calcium carbonate and activated basaltic fines, which can be mixed into concrete as a replacement for some of the traditional cement.

“With the carbon capture system, we avoid using some of the limestone, so we save CO2 there,” Hollingham said. “And it also collects waste CO2 in the process. So, it’s kind of a two-pronged approach.”

Hollingham has filed a patent application for his carbon capture system through Penn State’s Office of Technology Transfer (OTT). He also co-founded Distributed Materials, a startup dedicated to reducing CO2 emitted from concrete production at a larger scale, and is working with OTT to explore commercialization pathways.

“It was already great to work in the lab and say this could theoretically reduce emissions,” Hollingham said. “I'm looking forward to seeing the system in action and knowing that we really are stopping CO2 from entering the atmosphere.”

Hollingham earned his integrated master’s degree in mechanical design engineering at the University of Glasgow in Scotland. At Penn State, he conducts research with his adviser, Anne Menefee, assistant professor in the John and Willie Leone Department of Energy and Mineral Engineering.

This project is supported by the College of Earth and Mineral Sciences, the Climate Consortium, the Gordon D. Kissinger Graduate Fellowship in Architectural Engineering and the Partnership for Achieving Construction Excellence (PACE) at Penn State. Hollingham expressed gratitude to the Decarbonizing Cement and Concrete Technologies (D/Carb) lab group at Penn State, as well as the following individuals:

• Anne Menefee, assistant professor in the John and Willie Leone Department of Energy and Mineral Engineering
• Juan Pablo Gevaudan, leader of the D/Carb group and assistant professor of architectural engineering who is also affiliated with the Department of Materials Science and Engineering and the Larson Transportation Institute
• Anand Swaminathan, research and development engineer in the Department of Architectural Engineering at Penn State
• Jayden Confer, laboratory manager with the D/Carb group
• Jonathan Smith, who earned a master’s degree in architectural engineering from Penn State in 2026
• Abigail Erich, a fourth-year undergraduate student in architectural engineering