could be used to build new cities, dams,
wind turbines and airports and many other useful cement construction as productive carbon sequestering. It would be possible to simply build our way out of any CO2 issues. Carbon taxes or credits for removing CO2 ($25-100/ton in Europe) such as those proposed by Al Gore could make Calera cement virtually free for builders.
UPDATE: A less secretive Canadian company, Carbon Sense Solutions, has the same goal, storing carbon dioxide in cement but ten to fifteen times less than the Calera goal
Converting the world cement industry to cement that removes CO2 instead of adds it would be a reduction 5 billion tons of CO2/year. The entire US production of CO2 is now 6 billion tons. The Al Gore proposal of de-carbonizing all US electricity generations was a plan to remove 2.4 billion tons of CO2 generation per year.
There was 2.35 billion tons of cement used in 2007 and demand is increasing at 130 million tons per year. 1.4 billion tons of cement produced and used in China is 2007.
Cement production makes between 1 to 1.25 tons of CO2 per year
Calera, a Vinod Khosla funded company, is starting up a pilot plant for a new type of cement and process that would remove that 1 ton of CO2 from the air to make the 1 ton of cement. The plan is have 100 plant producing up to 1 billion tons of the new cement by 2015.
CO2 emmissions are 27 billion tons per year worldwide.
Various goals for avoiding climate change suggest reducing those emissions by 7 billion tons/year or more aggressively to have the current level
An accelerated conversion of all cement production to a successful Calera process by 2015 would be 3.4 billion tons of cement in 2015 under normal growth. Increasing cement construction using contour crafting and the new cement and making more buildings and other objects so that usage is 10-40 billion tons/year instead of 4 billion tons per year (under normal growth) in 2020 would be a major form of productive carbon sequestering. Productive in that the buildings made of cement now holding carbon would be useful for economic enterprise.
The World trade center used 955,000 tons of cement and 200,000 tons of steel and had 10 million square feet of space.
The world commercial building business is a trillion dollar industry making billions of square feet each year.
Shanghai had 3000 buildings over 24 meters (12 stories) high by 2000 and a hundred over 100 meters and there has been a lot more construction since then.
New 5-7 MW and larger wind turbines are over 120 meters tall and use hundreds of tons of cement each.
There is also demand for hundreds of airports.
10.8 million tons of cement used for the Three Gorges Dam.
Cement costs between $90-150/ton
Wind turbine material usage
Enercon 6MW model has 36 concrete section
Fast company has coverage on the Calera startup The pilot plant should be open by the end of 2010.
Making cement without also making carbon dioxide seems impossible; the basic chemistry of the process releases the gas. But maybe that's not really true, Stanford University scientist Brent Contstantz began thinking last year.
Calera is only now preparing to open its first cement plant, on a 200-acre site next door to a gas-fired electric-power utility. Carbon-dioxide-laden exhaust from the power plant will be captured and used to make and dry the cement. Calera plans to be in pilot production by the end of the year, in commercial operation by 2010, and running 100 sites in North America five years later.
wikipedia has information on how others are working on cement that absorbs CO2 but this may or may not be similar to the Calera process which is secret.
Eco-Cement sets and hardens by sequestering CO2 from the atmosphere and is recyclable. The rate of absorption of CO2 varies with the degree of porosity and the amount of MgO. Carbonation occurs quickly at first and more slowly towards completion. A typical Eco-Cement concrete block would be expected to fully carbonate within a year.
Calera website. Almost no info
Other carbon sequestration startups and methods and background from earth2tech
Carbon sequestering Startups:
* Calera: There are few details on this Silicon Valley startup, but the company was founded by Stanford earth sciences professor Brent Constantz and has received funding from Khosla Ventures. Calera looks to make cement, a carbon-intensive undertaking, by taking CO2 out of the atmosphere.
* GreatPoint Energy - Their main product is natural gas derived from coal called “bluegas.” Using a chemical catalyst to break down low-grade, and low cost, carbon fuels (tar sands, petroleum coke, etc.) in a process called “catalytic coal methanation” GreatPoint produces pipeline grade methane. The resulting emission stream is nearly all CO2 that GreatPoint recommends can be used in EOR operations. GreatPoint has raised $137 million in three rounds of funding and have announced a pilot plant and R&D program. Investors.
* PowerSpan - Maker of pollutant controls focusing on SOx and NOx, PowerSpan is working on CCS as part of its ECO2 program. ECO2 is an ammonia-based scrubber system that can be added to existing plants ad remove CO2 from flue gases after other pollutants have been scrubbed. PowerSpan has plans for two different pilot programs, one in a partnership with BP Alternative Energy and the other with NRG Energy to prove the commercial scalability. Investors.
* Blue Source: A carbon middleman, Salt Lake City-based Blue Source orchestrates sales of carbon emissions along their gas pipelines between polluters and EOR projects. MIT Technology Review lauded them as financially innovative for coupling CCS with carbon offset sales.
* Skyonic: Skyonic’s “SkyMine process” is a post-combustion system that can be implemented in existing plants. The process reacts flue effluent with sodium hydroxide and pulls CO2 out to form sodium bicarbonate (”better-than-food-grade baking soda”) while also removing heavy metals and acid gases. The process uses energy in the form of waste heat from the plant. Oh, and it’s profitable since emitters can sell off the chemicals byproducts. Skyonic has installed a pilot project on a Luminant (formerly TXU) plant in Texas and are planning on installing a system on a large plant (500 MW) in 2009. Skyonics has raised $4.25 million in two rounds of funding, including investment from TXU.
* GreenFuel Technologies: Looking to sell biomass to biofuel makers, GreenFuel plans to take CO2 from flues and use it to grow algae. The “emissions-to-biofuel” process pulls flue gases through an algal farm to grow the algae and released a performance summary in September. They have raised $18 million in Series B led by Polaris and are raising more funding now.
A related or unrelated though interesting process (patent description) of carbon dioxide absorption from cement sludge by Japanese scientists
University of Wisconsin-Milwaukee are working on another process to sequester CO2 in concrete. They are trying to quantify how well porous concrete absorbs carbon dioxide. They're exposing crushed concrete to carbon dioxide in the atmosphere, triggering a chemical reaction that sequesters the gas and keeps it from leaching out. Through the reaction, which converts calcium hydroxide to limestone, porous concrete gets stronger. But eventually the material becomes saturated with carbon dioxide and stops absorbing it.
Tarun Naik at the University of Wisconsin-Milwaukee is also helping to recycle concrete products