Carbon Negative Cement: A Solution for Green Builders

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Traditional cement, which is a key ingredient of concrete, is responsible for 5% of carbon dioxide emissions produced by humans. To tackle this issue, companies like Novacem are developing carbon negative cement, which absorbs more carbon dioxide than it emits during its production. Although Novacem receives many inquiries from builders interested in using their product, the company is still conducting research and development. They aim to produce a pilot product by 2014. Novacem is not the only company working on this solution. Other companies like Calera and Carbon Sense Solutions are also fielding similar inquiries. The interest in green cement indicates the potential market for it. Standard Portland cement, which is used to make concrete, is environmentally unfriendly. Its production contributes to 5% of human-generated carbon dioxide emissions, surpassed only by the burning of fossil fuels and the manufacture of iron and steel. The replacement of carbon-spewing cement with a substitute that reduces emissions would have a significant positive impact. In this article, we will explore different approaches to achieving this goal.

The Search for Carbon Negative Cement

Before discussing how environmentally friendly cement is made, let’s first look at the process of producing Portland cement. The method, discovered by an English stone mason in the early 1800s, has remained unchanged. Each year, 3 billion tons of cement, derived from limestone made up of marine animals’ remains, are transformed into 30 billion tons of concrete.

The process of turning limestone, which is made up of sea creature shells, into cement is responsible for significant carbon emissions. This is because the limestone needs to be heated to a very high temperature, which requires a large amount of fossil fuels, and also releases a lot of carbon. Traditional cement production emits nearly 1,800 pounds of carbon dioxide for every ton of cement made. This contributes to climate change and its negative impacts, such as extreme weather, melting glaciers, and rising sea levels.

However, some companies are creating carbon negative cement, which uses different raw materials and less energy. Novacem, for example, uses magnesium silicates instead of limestone, which don’t have carbon embedded in them. They also only need to be heated to about half the temperature of limestone, which requires less fossil fuels and produces fewer emissions. To make the ingredients harden into cement, Novacem adds magnesium carbonates, which are produced by combining carbon dioxide with other ingredients. This process makes the cement carbon negative, as it absorbs carbon dioxide instead of emitting it.

Novacem is not the only company pursuing carbon negative cement. Calera, based in California, mixes carbon dioxide emissions from power plants with water and other ingredients to make carbonates that go into cement. Both companies have received backing from governments and investors, and their efforts could have a significant impact on reducing carbon emissions. However, there are still challenges to overcome for carbon negative cement to become widely used.

Opportunities and Challenges for Carbon Negative Cement

The building industry may take some time to adopt carbon negative cement, despite the ambitious plans of John Prendergast from Novacem. The aim is to create a cement that can replace Portland cement completely, making any construction project that currently uses standard cement more environmentally friendly by removing carbon dioxide from the environment. However, producers of carbon neutral or negative cement must overcome several challenges. The most significant challenge is to manufacture a reliable product that can replace Portland cement. This will only be tested when the companies unveil their cement for commercial applications. Novacem has internal results that indicate it will produce a cement that is as strong as Portland cement. However, other questions loom, such as whether all the raw materials for production are cheap and abundant enough to compete with Portland cement on a cost basis. Novacem attests that access to the raw materials it requires is not a potential barrier at all. Soon after getting up and running, Novacem cement will have a similar price tag to Portland cement. Acceptance by the building industry and regulators could come as the product proves itself in the marketplace. If carbon negative cement can be produced at the same price and with the same quality of Portland cement, it is likely to be embraced eventually.

More Information

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  • Biello, David. “Cement from CO2: A Concrete Cure for Global Warming?” Scientific American. Aug. 7, 2008. (April 20, 2012)
  • Hirschler, Ben. “Carbon-eating “green” cement wins funds for UK firm.” Reuters. Aug. 6, 2009. (April 24, 2012)
  • Prendergast, John. Strategy and planning manager for Novacem Limited. Personal interview. April 26, 2012.
  • Romm, Joe. “Does carbon-eating cement deserve the hype?” Think Progress. Apr. 2, 2009. (April 25, 2012)
  • Rosenwald, Michael. “Building a Better World With Green Cement.” Smithsonian Magazine. Dec., 2011. (April 21, 2012)
  • Schenker, Jennifer. “Novacem: Cement that Eats Carbon.” BusinessWeek Magazine. Sept. 2, 2010. (April 24, 2012)


1. What is carbon negative cement?

Carbon negative cement is a type of cement that removes more carbon dioxide from the atmosphere than it emits during production. This is achieved by using alternative materials and methods that reduce the amount of emissions produced during the manufacturing process.

2. How is carbon negative cement made?

Carbon negative cement is made by using alternative materials such as fly ash, slag, and other industrial byproducts instead of traditional Portland cement. These materials have a lower carbon footprint and can be used in combination with carbon capture technologies to reduce emissions.

3. What are the benefits of using carbon negative cement?

The benefits of using carbon negative cement include a reduction in greenhouse gas emissions, a decrease in the use of non-renewable resources, and the potential for cost savings. It also has the potential to contribute to the fight against climate change.

4. How does carbon negative cement help fight climate change?

Carbon negative cement helps fight climate change by reducing the amount of carbon dioxide in the atmosphere. By using alternative materials and methods, it emits less carbon dioxide during production than traditional cement. This, in turn, helps reduce the overall carbon footprint and contributes to the fight against climate change.

5. Is carbon negative cement more expensive than traditional cement?

Carbon negative cement can be more expensive than traditional cement due to the use of alternative materials, as well as the cost of carbon capture technologies. However, as the technology and methods improve, the cost is expected to decrease and become more competitive with traditional cement.

6. Who is developing carbon negative cement?

Several companies and organizations are developing carbon negative cement, including Solidia Technologies, CarbonCure Technologies, and the Swiss Federal Institute of Technology in Zurich.

7. What are the challenges in developing carbon negative cement?

Some of the challenges in developing carbon negative cement include the cost of alternative materials, the energy required for carbon capture technologies, and the need for large-scale implementation to make a significant impact on reducing emissions.

8. How does carbon negative cement compare to other carbon reduction methods?

Carbon negative cement is one of several methods for reducing carbon dioxide emissions. It is unique in that it removes more carbon dioxide from the atmosphere than it emits during production. However, it is not a standalone solution and should be used in combination with other carbon reduction methods.

9. What is the potential impact of carbon negative cement on the environment?

If widely adopted, carbon negative cement has the potential to significantly reduce greenhouse gas emissions and contribute to the fight against climate change. It also has the potential to reduce the use of non-renewable resources and promote sustainable development.

10. What is the future of carbon negative cement?

The future of carbon negative cement looks promising as more companies and organizations invest in the development and implementation of this technology. As the cost decreases and the methods improve, it is expected to become a competitive and sustainable alternative to traditional cement.

11. How can individuals support the development of carbon negative cement?

Individuals can support the development of carbon negative cement by advocating for its use in construction projects, supporting companies and organizations that are developing this technology, and promoting sustainable development practices.

12. Is carbon negative cement a viable solution for reducing carbon dioxide emissions?

While carbon negative cement is not a standalone solution for reducing carbon dioxide emissions, it is a viable alternative to traditional cement that has the potential to significantly reduce the overall carbon footprint. Its success will depend on the continued development and implementation of this technology in construction projects around the world.

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