Outside the National Renewable Energy Laboratory’s (NREL) Research Support Facility, there are two intriguing brick pavers that stand out from the rest.
One of these bricks is inscribed with the term “BUILD’EM”—an acronym for Biomass Upcycled in Lignin for Decarbonizing Energy-Intensive Materials.
These pavers symbolize the ambitious endeavor of lead researcher Paul Meyer and his team, which includes Julia Sullivan, Kyle Foster, Bob Allen, Jingying Hu, and Heather Goetsch, to develop a carbon-negative alternative to traditional concrete.
A Critical Need for Cement and Concrete Decarbonization
The U.S. Department of Energy’s (DOE) Industrial Decarbonization Roadmap highlights the cement industry as a key area for reducing industrial emissions through innovative manufacturing.
The roadmap advocates for strategies such as minimizing waste in concrete construction, advancing technologies, capturing carbon, and utilizing low-carbon materials to meet net-zero targets.
Cement production is infamous for its significant energy consumption and carbon emissions. The manufacturing process involves heating vast quantities of raw materials to 1450°C, usually with coal or natural gas.
This high-temperature process not only results in considerable emissions but also produces carbon dioxide (CO2) as a byproduct of the chemical reaction where calcium carbonate is converted into calcium-oxide-like compounds. Together, these processes contribute to around 7% of global greenhouse gas emissions.
Developing Carbon-Negative Alternatives
BUILD’EM aims to sequester CO₂ in the form of lignin and incorporate it into building materials to replace traditional concrete.
Meyer’s interest in innovative systems led him to explore polymer-based resins as an alternative to cement. These epoxy-like resins, which do not produce CO2 during synthesis and require much lower temperatures (around 60°C to 200°C), showed promise.
Additionally, these resins offer greater strength compared to concrete, making them suitable for high-strength applications. However, conventional epoxy resins are typically more carbon-intensive and costly than cement.
Around this time, Meyer discovered the extensive waste production of lignin from the pulp and paper industries, which is also expected from future biorefineries.
Lignin, a crucial component of terrestrial plant life and the second-most abundant biomaterial on Earth, is produced annually as a waste byproduct and often burned as low-value fuel.
Meyer saw potential in repurposing lignin as a polymer for building materials rather than burning it. By crosslinking lignin similar to epoxy resins, Meyer aimed to sequester CO2 captured from the atmosphere in a biomass form that would otherwise be incinerated.
With internal seed funding from NREL’s Laboratory Directed Research and Development program, the team identified a chemical combination that not only matched but exceeded the strength of conventional concrete.
They conducted a life-cycle assessment and techno-economic analysis, finding that BUILD’EM could reduce emissions by 50% to 80% and approach cost parity with traditional cement-based concrete.
“It’s basically concrete but carbon negative. If we’re optimistic, it could impact up to 7% of global emissions while being competitively priced,” Meyer stated.
Meyer emphasized the scalability of their approach, with potential production reaching at least 100 million tons per year from plant-derived materials, and a realistic pathway towards market replacement.
The Future of BUILD’EM
The BUILD’EM paver, located outside NREL’s Research Support Facility, withstood the winter of 2023–2024. BUILD’EM aligns with the DOE’s commitment to industrial decarbonization and broader goals of job creation, economic growth, and a cleaner, more equitable future.
“Equity is a significant aspect,” Meyer noted. “Lignin is abundant and can be sourced locally. The low-temperature curing process makes it feasible even in areas without grid access. It’s a straightforward and adaptable solution.”
Despite BUILD’EM’s promising advancements, the team acknowledges the considerable head start that traditional concrete has enjoyed for over two centuries.
“We aim to deepen our understanding of these materials,” Meyer added. “People have walked on it, and one person even kissed it. It’s water-resistant.”
As NREL’s team continues their innovative efforts and secures further funding, they plan to expand their research into lignin-based, carbon-negative construction materials.
The next steps involve exploring the fundamental chemistry, weather resistance, and optimizing the formula to balance performance, cost, and emissions.
They also aim to scale production to multi-ton levels and replace roadway sections to demonstrate the material’s resilience and industrial relevance.
The ultimate goal is a product that can withstand 8,000 pounds per square inch of compressive force, be carbon neutral, and match the cost and durability of traditional cement-based concrete.