Submitted on April 3rd, 2009 by gwashtracker (not verified)
A couple of comments.
1) Neither Brent Constantz nor Calera have any expertise in metabolic/pathway engineering - I know this first-hand.
2) The use of an engineered microbe does not enable the production of a cement from carbon dioxide and seawater - all you can do is produce carbonate, or more correctly, carbonate/carbonate-directing protein composites (carbonate biominerals, skeletons, etc) - these are thermodynamically stable composite materials which have no cementing activity. In other words, you cannot produce a cement from carbonate biominerals (they will not “set” into a cement, since they are preformed cements) - you would have to convert them into a reactive/metastable state, and Calera has no know-how or technology for doing this.
3) We have examined the Calera patents - it is a dirty, CO2-producing chemistry of the worst type - and is anything but “Green”. They take limestone, calcine it (releasing CO2), and react it with CO2 (flue gas) and seawater to reform limestone. This is not Clean Technology - it is Snake Oil. The patent vividly demonstrates how abysmal Calera’s technology is.
4) Finally, the nature of Calera is clearly demonstrated by their publicly documented statements and press releases. Brent Constantz and Vinod Khosla first claimed they had a 100% replacement for Portland cement, and that their cement would sequester 1 ton of CO2 for every ton of cement produced (impossible, unless their cement is pure CO2). They then said that their cement would be used at 50% replacement level for Portland cement and that it would sequester 0.5 tons of CO2 for every ton. Then late last year they changed their story again - no cement - instead they are producing aggregate. Now Brent is saying that he never claimed a cement product.
What we have seen from Brent and Vinod is a steady stream of pseudo-scientific hot air and untruths without any scientific basis. They clearly do not have a cement, their process is a Greenwash and their mode of operation is repugnant.
We commend Ken Caldeira for his principled stand - he has done the public, the industry and the scientific community a great service by exposing the Calera scam.
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Calera is Greenwash
Submitted on April 3rd, 2009 by gwashtracker (not verified)A couple of comments.
1) Neither Brent Constantz nor Calera have any expertise in metabolic/pathway engineering - I know this first-hand.
2) The use of an engineered microbe does not enable the production of a cement from carbon dioxide and seawater - all you can do is produce carbonate, or more correctly, carbonate/carbonate-directing protein composites (carbonate biominerals, skeletons, etc) - these are thermodynamically stable composite materials which have no cementing activity. In other words, you cannot produce a cement from carbonate biominerals (they will not “set” into a cement, since they are preformed cements) - you would have to convert them into a reactive/metastable state, and Calera has no know-how or technology for doing this.
3) We have examined the Calera patents - it is a dirty, CO2-producing chemistry of the worst type - and is anything but “Green”. They take limestone, calcine it (releasing CO2), and react it with CO2 (flue gas) and seawater to reform limestone. This is not Clean Technology - it is Snake Oil. The patent vividly demonstrates how abysmal Calera’s technology is.
4) Finally, the nature of Calera is clearly demonstrated by their publicly documented statements and press releases. Brent Constantz and Vinod Khosla first claimed they had a 100% replacement for Portland cement, and that their cement would sequester 1 ton of CO2 for every ton of cement produced (impossible, unless their cement is pure CO2). They then said that their cement would be used at 50% replacement level for Portland cement and that it would sequester 0.5 tons of CO2 for every ton. Then late last year they changed their story again - no cement - instead they are producing aggregate. Now Brent is saying that he never claimed a cement product.
What we have seen from Brent and Vinod is a steady stream of pseudo-scientific hot air and untruths without any scientific basis. They clearly do not have a cement, their process is a Greenwash and their mode of operation is repugnant.
We commend Ken Caldeira for his principled stand - he has done the public, the industry and the scientific community a great service by exposing the Calera scam.