From CO2 to Cement: Recycling Carbon – the Commoditization of Carbon Emissions

converting CO2 emissions into cement - recycling carbonYesterday we posted on the just-released Clean Edge trends report for 2010 that outlines some of the prominent trends in clean tech and renewable energy. One emerging trend mentioned in the report is the commoditization of carbon, where captured emissions are bought and sold as feedstock for other industrial processes.

The idea isn’t new, companies like Mantra Energy have been hard at work for years refining a process known as Electroreduction of Carbon Dioxide or ERC, and CO2 emissions are used for well-head injection to help keep aging oil wells in production. But the concept of using CO2 emissions as a marketable product instead of simply a waste gas is growing as innovators find new methods for utilizing carbon emissions. As we learned last year when I had the opportunity to visit Schwarze Pumpe, the pilot carbon capture and sequestration project in Germany, capturing CO2 is one thing, what to do with the carbon after it is captured is another – and perhaps the greatest challenge in the equation.

From coal plant emission to cement

Peabody Energy, the world’s largest coal company, has announced it will invest $15 million for an equity interest in Calera Corporation. Calera has developed a process called Mineralization vis Aqueous Precipitation (or, thankfully, MAP, for short), that takes in carbon emissions and other waste gasses, and outputs “building materials and water that meet or exceed industry performance standards.”

Calera’s emerging technology represents an innovative solution to advance our energy, environmental and economic goals by recycling carbon dioxide into beneficial building products,” said Peabody Senior Vice President Fred Palmer in a statement.

The process lends itself to the idea of biomimicry, looking at processes in nature and finding ways to mimic that process for industrial and design purposes. MAP began when Calera founder Dr. Brent Constantz studied Aquatic Biology and Geologic Science in the ’70’s and ’80’s, leading to post-doctoral work in “biomineralization” at the U.S. Geologic Survey and Weizmann Institute of Science. The initial focus for his work was in medical applications. In 2007, Constantz contacted an old colleague Vinod Khosla, who was an advocate of clean technologies, with an idea for a new “green cement” to replace portland cement, a material responsible for one-third of all anthropogenic CO2. Khosla liked the idea and immediately funded Calera after only a couple of meetings and without even so much as a powerpoint presentation or business plan.

By percolating fume gasses through seawater, the process seeks to mimic the way in which marine corals create calcium carbonate, thus converting greenhouse gasses into synthetic limestone. According to Calera, the MAP process conserves energy and reduces emissions normally required to manufacture cement. It also sequesters carbon from waste fumes and can purify water by removing minerals and other impurities, Calera claims.

We believe that the CO2 used in our process for producing materials could exceed the current generation rate of CO2 from all global industrial and utility sources,” said Constantz. “The potential is enormous.”

Calera is not without its skeptics and detractors, principal among them is noted climate scientist Ken Caldeira, who says the process just won’t work because the process itself generates carbon. Others complain that Calera isn’t as forthcoming as it should be with specific details on exactly how the MAP process works. Alex Kinnier, a venture partner with Khosla Ventures, purportedly once quipped that the secret ingredient to MAP was “pixie dust.” Nonetheless Khosla Ventures has invested about $50 million in Calera, so there’s been some hard cash to back up that pixie dust.

Calera has recently completed a demonstration project at Moss Landing, California, with one other pilot project in Australia. The company has also been actively involved in the Department of Energy’s FutureGen project as well as GreenGen in China.

Additional source:
Energy & Environment News (subscription required)

Thomas Schueneman
Thomas Schueneman
Tom is the founder and managing editor of and the PlanetWatch Group. His work appears in Triple Pundit, Slate, Cleantechnia, Planetsave, Earth911, and several other sustainability-focused publications. Tom is a member of the Society of Environmental Journalists.

Get in Touch


Please enter your comment!
Please enter your name here

This site uses Akismet to reduce spam. Learn how your comment data is processed.

Related Articles

Stay in touch

To be updated with all the latest news, offers and special announcements.


Latest Posts