A Concrete Cure for Global Warming?

Posted by: Adam Aston on August 19, 2008

To halt climate change, we need to start capturing the millions of tons of CO2 pouring out of the world’s electricity plants. So far, most of the focus has been on pumping the CO2 back underground, to bind with rocks. But why not just stash it in the cement used to make sidewalks, buildings and roads, mankind’s version of rocks? Calera, a California-based startup says it can capture and stash more than 90% of the CO2 pouring out of a power plant and lock it in cement. The feat address two challenges at once: power plant emissions and cement production. The first problem is well known; CO2 pouring out of cement kilns is less recognized even though it is a huge source of green house gases — the third largest producer in the U.S., says the EPA. Calera mixes the hot CO2-rich flue gas from the power plant with sea water to make calcium carbonate, a key component in cement that is conventionally made at very high temperatures by using oodles (technical term!) of energy. Caldera says cach ton of its cement can sequester an equal mass of CO2. The potential, especially in developing countries which consume the lions share of concrete, are enormous. Check out the full story at Scientific American.

Reader Comments

Jonathan chelseagreen.com

August 19, 2008 3:27 PM

Wow, pretty darn cool. The SciAm article says,

Seawater containing billions of tons of calcium and magnesium covers 70 percent of the planet and the 2,775 power plants in the U.S. alone pumped out 2.5 billion metric tons of CO2 in 2006. The process results in seawater that is stripped of calcium and magnesium--ideal for desalinization technologies--but safe to be dumped back into the ocean.


It's probably true that no harm is done, directly, by stripping the calcium and magnesium out of the seawater and then pouring the demineralized water back into the ocean. But I can imagine the possibility of some indirect problems. For example, in highly populated coastal areas where lots of power plants are utilizing this technology, might you end up with zones of water that is measurably demineralized? Will demineralized seawater support microscopic life and crustaceans that need the minerals to form their shells? If there's enough distance between the return pipe pouring the water back into the ocean and reefs or other places with dense sea life, then probably there's no issue. But if they are near to one another, I imagine it would be possible to starve sea life of the calcium they need in local demineralized "hot spots."

sumit

May 28, 2009 12:23 AM

it is good dude but one and simple way to cure global warming is plants more and more trees.

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BusinessWeek correspondents John Carey and Mark Scott, cover the green scene, keeping on top of the business aspects of energy, the environment and climate change, as well as the technologies, policies, markets and people that are shaping how the earth's resources will be used in the century ahead.

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