$19.9 million to turn CO2 into cement

Calera is one of six projects that got money from the DOE for turning waste carbon dioxide into something useful.

This is the second round of government funding for Calera, which has a pilot project to capture flue gas from the smokestacks of a natural gas-driven power plant at Moss Landing, on the Northern California coast.

Calera bubbles gas from the plant through seawater, where magnesium hydroxide (Mg(OH)2) from the ocean combines with the CO2 in the gas to create carbonates, similar to coral reefs -- a chalk-like substance that can be made into cement, sand and various other construction materials.

The company claims it already captures 30,000 tons of CO2 per year at Moss Landing -- the equivalent of a 10-megawatt electrical natural gas power plant -- and the DOE grant (funded with money from the Recovery Act) should help expand production. Calera also has an alliance with Bechtel to develop several other carbon-capturing plants.

Calera has been criticized for green washing -- there was a flap last year after a scientist at the Carnegie Institution, Ken Caldeira, claimed that Calera's process would increase, rather than decrease, CO2 in the atmosphere -- but the controversy apparently didn't hurt Calera's chances with the DOE, which chose six of the 12 projects it funded earlier to go ahead.

For the DOE, these matching grants are another, possibly cheaper way to capture and store carbon dioxide -- they provide an alternative to burying the stuff underground, which is technically difficult and where we could, one day, run out of space.

Calera has several competitors working on other approaches to green cement -- the New York Times last year cited Novacem, which is working on concrete that can absorb carbon dioxide, and Carbon Sense Solutions, which is trying to bubble carbon dioxide through wet cement to sequester the gas.

But Vinod Khosla, the venture capitalist whose firm backed Calera despite figuring it had only a 10 percent chance of success, sounds excited about Calera now.

At a clean tech conference I covered last fall, Khosla called Calera the “only viable solution to carbon sequestration, worth more than GE’s power plant business. It’s one of half a dozen clean tech companies that have the potential to get to tens of billions in revenue…It can apply to existing dirty power plants in India and China…It could replace asphalt in roads and sequester billions of tons of carbon. And they’d be easier to maintain.”

Below is a video from Greentech Media of Calera's founder, Brent Constantz, explaining what Calera does. And here are the rest of the DOE grant winners -- some are looking at converting carbon dioxide into biofuels, or green fertilizer.

This post was originally published on Smartplanet.com


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