Concrete Dreams

How CarbonCure promises to lock CO2 into our roads and buildings

To wrap up our first series on green commodities, we’ll be looking at CarbonCure, a company that is developing technology to inject carbon dioxide into concrete during the mixing process, reducing the carbon footprint of cement manufacturing. CarbonCure aims to make concrete a climate solution rather than a problem by providing long-term carbon sequestration. 

The cement industry is one of the largest sectors, providing essential materials for infrastructure, urban development, and housing. Last year, the global cement production was 4.1 billion metric tons, and is expected to continue growing at a rate of 2-3% per year. However, cement is also one of the largest contributors to greenhouse gas emissions, accounting for 7% of global carbon dioxide emissions. That creates a dilemma because cement is fundamental for shaping how we live, but producing it is causing negative environmental effects. 

Problem

Cement manufacturing produces one ton of carbon dioxide emissions for every ton of cement. The cement manufacturing process involves four main stages: (1) raw material extraction, (2) clinker production, (3) cement grinding, and (4) cement distribution. Raw materials, such as limestone, iron ore, and sand, are mined. These materials are crushed into smaller pieces and heated in a rotary kiln to form clinker, which is an intermediary product in cement manufacturing that contains calcium silicates and other minerals. The clinker is then ground and mixed with other additives to produce cement. Finally, the cement is packaged and transported to end customers. Along every stage of this process, greenhouse gasses are emitted; fossil fuels are needed for everything from transportation and materials extraction to heating and cooling intermediary products.       

Solution

There are many flavors of green cement as the term has been (we believe incorrectly) applied to any form of cement manufacturing that minimizes carbon footprint. The highest impact method is to use carbon capture and storage techniques to capture the carbon dioxide emitted during the calcination of limestone in the second stage. You then need to figure out what to do with the captured emissions. One solution is to use it later in the process in concrete.  

Companies, including CarbonCure, are adding carbon dioxide to concrete by mineralizing the carbon dioxide into a solid material that can be incorporated during the mixing process. This permanently embedded the carbon dioxide into concrete, which reduces the carbon footprint as well as the amount of cement needed in concrete production as this mineralized carbon dioxide can act as an aggregate. While CarbonCure currently uses other carbon dioxide sources, eventually we’d like to see them use the emissions collected from cement manufacturing. 

Products & Commercialization

CarbonCure’s business model is providing its technology as a service to concrete producers. They install their equipment at the concrete plants and charge a monthly fee based on the amount of carbon dioxide injected into the concrete. They’ve already seen adoption as their technology has been used in construction projects from parking structures to high-rise buildings, largely driven by the green building sector as well as access to carbon credits. To support this they’ve developed a few tools including a service called CarbonCure Express Environmental Product Declarations (EPD), that uses real-time data to automate product-specific EPD generation for concrete plants. This helps concrete producers measure and report their carbon impact, which in turn helps them win new business in the growing green building sector.

The success of their business model is driven by alignment with both concrete producers and end customers. For the concrete producers their technology improves profitability by reducing their cement consumption, improving product performance and quality, and differentiates them from competitors. For the end customers this technology can help them comply with environmental regulations and meet their company sustainability goals. 

Impact

The amount of carbon dioxide captured varies depending on a number of factors including mix design and application method. However, CarbonCure has reported that their technology typically captures between 25-100 kilograms of carbon per cubic meter of concrete. While this doesn’t negate carbon emissions for the cement industry, they estimate that this technology can reduce the carbon footprint by up to 15%. 

Challenges

Disrupting a centuries old industry is not without its challenges. To increase market penetration CarbonCure needs to address the following:

• Customer Education: CarbonCure requires both concrete producers and end customers to change their building practices. They need to educate and market to both stakeholder groups to explain the benefits, both performance and environmental, of adopting this new concrete mixture that replaces some cement with mineralized carbon dioxide. 

• Carbon Dioxide Availability and Cost: Today CarbonCure relies on local sources for captured carbon dioxide to inject into their concrete. Not all regions have easy access to this carbon dioxide. CarbonCure needs to work with partners to improve the carbon dioxide supply chain, as well as to reduce the environmental impact and costs from transporting the carbon dioxide from the distributor to the plant. 

• Regulations / Certifications: CarbonCure needs to continue to work with government and industry agencies to certify their product and promote adoption. 

• Uncertainty of Carbon Credit Industry: One of the key differentiators is their ability to track the amount of carbon dioxide sequestered, which can be used to certify carbon credits. The carbon credit market is still evolving and lacks clear standards for measuring, verifying, and reporting carbon removal. CarbonCure needs to work with these stakeholders to establish frameworks for measuring carbon removal to ensure their current process continues to align. 

• Competitors: CarbonCure is not the only company developing technologies to use carbon dioxide in concrete (or other products). Today what differentiates CarbonCure from these companies is their technology requires minimal modifications to the existing concrete production equipment and processes, lowering the barrier to adoption. 

If you enjoyed this, check out our piece on methods to improve capture efficiency in carbon capture and storage solutions for manufacturing.