Although few people think about it, cement kilns represent 5% of global warming emissions -- that's more than aviation! Now, a Stanford professor thinks he can make a big dent in that output.
As the San Francisco Chronicle points out, Brent Constantz says he has invented a green cement that could not only eliminate the huge amounts of carbon dioxide released by conventional kilns, but could also bind up excess CO2 from power plants.
Constantz's idea has won praise form the Sierra Club and funding from venture capitalist Vinod Khosla. The professor's company, Calera Corp., has a pilot factory in Moss Landing Monterey County.
An inventor primarily of medical cements, Constantz developed a patent-pending process that is not dissimilar to how coral reefs build up their skeletons, though details are still a bit sketchy. The Chronicle reports that Calera takes exhaust gas from power plants and bubbles it through seawater, causing chemical reactions that result in usable cement. The process can bind CO2, instead of releasing it, as you get when you make conventional Portland cement from limestone.
The process involves magnesium and calcium, and Constantz told reporters he expects his cement to go for about $100 a ton, $10 cheaper than typical Portland cement!
Even if the scheme works on a broad scale, which is yet to be proven, there may be hurdles to acceptance in the building industry. So time will tell if Constantz's new cement really will turn out to be a game changer. At any rate, it's encouraging to see such innovation directed at the problem of global warming, particularly as much of the developing world ramps up construction.
Enter your city or zip code to get your local temperature and air quality and find local green food and recycling resources near you.