Enviro-Friendly Cement , Less CO2 Is Company’s Claim

Cement is a huge source of greenhouse gas emissions, with approximately one ton of CO2 equivalent emitted into the atmosphere for every one ton of cement produced. Cement is responsible for five percent of the Earth’s CO2 emissions, and it’s the third largest source of greenhouse gas pollution in the U.S., according to the EPA.

A new technology may have the potential to greatly lessen the dispersion of carbon dioxide into the atmosphere.

A new company called Calera Corp., based in Los Gatos, Calif., has raised a round of venture capital to pursue tests of its technology that claims to grab carbon dioxide from its surroundings during the manufacturing of cement. The system is said to sequester a half-ton of CO2 for every ton of cement made.

Calera was founded by Stanford University professor Brent Constantz, whose expertise is in earth sciences. Calera is building a test manufacturing facility.

Constantz’s inspiration for sequestering CO2 comes from biomimicry, lookinging to nature for design inspiration. Sea coral creates a kind of marine cement as one component of the reef building, he explains. A combination of calcium, magnesium and seawater helps coral adhere. Constantz asserts he has figured out a way to mimic the same process using the spent CO2 as source material. “We are turning CO2 into carbonic acid and then making carbonate,” Constantz explains. “All we need is seawater and pollution.”

The seawater will supple all the necessary calcium and magnesium. The pollution will be from the 2,775 power plants in the U.S. alone that pumped out 2.5 billion metric tons of CO2 in 2006. Constantz’s process will strip the seawater of calcium and magnesium—ideal for desalinization purposes—but also safe to be pumped back into the ocean.

The Calera process will prevent CO2 from entering the atmosphere in two ways: It eliminates the need to heat limestone (the key ingredient in traditional cement), which is one of the main sources of emissions in traditional cement. It will also sequester the CO2 released during cement manufacturing. In addition to using otherwise unusable materials and sequestering all that CO2, Constantz estimates that his cement will be cheaper to produce.