Calera, pulls carbon dioxide out of atmosphere to produce cement

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A secretive Silicon Valley company called Calera says it can stop global warming and ocean acidification by pulling greenhouse gas out of the atmosphere.

It is building a way to grab carbon dioxide from its surroundings during the manufacturing of cement. Cement is a huge culprit of greenhouse gas emissions: It uses about 2.5 billion tons of cement a year, and produces that many tons in carbon dioxide.

Calera, based in Los Gatos, Calif., has raised a round of venture capital to pursue tests of its technology.

Its claims may sound outlandish, but it has credible backers. Khosla Ventures, run by Vinod Khosla, one of the most successful venture capitalists during the first Internet boom, made the investment. The firm has sprayed money into all kinds of clean-technology companies, but most of them have solid credentials.

Calera is active in the area of carbon “sequestering.” Not only are gases not released into the atmosphere, but they are actually pulled out of the atmosphere for the process, according to its founder.

Calera was founded a few months ago by Stanford University professor Brent Constantz (pictured above), a specialist in earth sciences. Constantz has previous started three medical companies involving synthetic materials and medical devices (see his bio here), including cements that helped repair bones. That’s when he learned that a ton of carbon dioxide is created for every ton of cement produced –one of the reasons he says he started Calera. The company is building a test manufacturing facility.

Vinod Khosla tells VentureBeat the company staying quiet on further details. Of the 2.5 billion tons of carbon dioxide cement creates each year, he said: “If this carbon was eliminated, we would be one third of the way to the target of 7 billion tons per year,” citing the target that some climate experts have defined as necessary.

News of the funding was first reported by VentureWire (subscription required).