California startup's technology captures, permanently stores GHGs in concrete

 

BY ROSE RAGSDALE FOR GREENING OF OIL

It’s not the typical Silicon Valley startup, nor even a contender in the competitive high technology industry. But tiny Calera of Los Gatos, Calif. could end up offering the world something more valuable that the best of the computer-age wonders developed by its neighbors—a cleaner planet.

Calera, which is Spanish, meaning “lime-kiln,” is the brainchild of founder Brent Constantz, a biotech wizard who holds some 65 patents for making various types of cement for medical applications. Now Constantz is turning his genius toward the problem of greenhouse gases and climate change.

Calera has developed a process for making cement—a major component of concrete—that absorbs massive quantities of carbon dioxide and other greenhouse gases and converts them into carbonate, or CO3. The process can effectively store the carbon dioxide and other pollutants such as carbon monoxide, nitrogen oxides, sulfur dioxide, mercury and particulates in building materials.

Constantz hopes his environment-friendly cement will one day replace conventional cement, which happens to be the world’s third-largest industrial emitter of CO2, behind coal-fired and gas-fired electricity plants. The burning in high-temperature kilns required to make traditional cement pastes is the culprit.

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An intuitive chemical process

Calera produces cement without high heat. Its scientists mix CO2 with water from a variety of sources, including the ocean, causing the minerals to bond and release as synthetic limestone in the form of cement powder or aggregate pebbles (synthetic rock), the basic ingredients of concrete.

For every unit of CO2 that conventional cement adds to the atmosphere, Calera’s green cement removes three units.

“With this technology, coal can be cleaner than solar and wind, because they can only be carbon-neutral,” Vinod Khosla, the Silicon Valley billionaire, was quoted in a New York Times article in late March. His venture capital firm, Khosla Ventures, has invested about $50 million in Calera, the article said.

Construction industry officials are understandably skeptical, but Calera has won over influential members of the environmental community and is attracting growing interest from Washington, D.C., to Wall Street.

“The potential is huge: It’s like planting forests of trees through pouring of concrete or bricks. In everything I’ve seen, I have never seen anything with the potential that Calera has,” said David Gottfried CEO, Regenerative Ventures; Co-Founder, U.S. Green Building Council.

And Carl Pope, president of the Sierra Club said, “You really ought to be able to replace most of the world’s need for cement with the by-product of sequestering most of the world’s power plant emissions of CO2—that would be game changing.”

Process mimics nature

Calera’s patented process mimics the way that nature grows the hard, durable materials in teeth, bone and sea shells. Minerals in seawater attach to CO2 molecules in the air to create a limestone-like material. The chemical composition of Calera cement is essentially the same thing as limestone, a favorite material for cement, concrete and pavement, or asphalt, Constantz told Greening of Oil in an April interview.

“It’s the same white rock found in geologic formation like the white cliffs of Dover,” he explained.

Because Calera’s process removes minerals and other constituents from water, it also acts as a freshening system to produce fresh water, which also gives it added value for projects in areas of the world that need clean water.

Once the CO2 is converted into Calera cement, only temperatures hotter than 700 degrees Celsius or sustained exposure to concentrated acid can release it again into the atmosphere, said Constantz.

The answer to CO2 storage?

Conventional carbon capture technologies, such as chemical scrubbing, can capture as much as 90 percent of the CO2 from smokestack pollutants. However, they also use a lot of the energy generated by the plant, almost doubling the cost of the power for consumers.

Once the carbon is captured, it still must be stored or sequestered, preferably permanently. The ways and means of storing CO2 is currently a subject of urgent debate. The Obama administration is aggressively funding research into new carbon capture and storage technologies aimed at removing the threat of CO2 emissions, but so far, proposed solutions have proven to be prohibitively costly or unreliable.

Constantz said his company’s relatively low-cost cement-making process can surpass all other carbon capture and storage techniques, cutting a plant’s energy drain to less than 15 percent and the reducing the cost of CCS technology to zero.

“That’s because CO2 is our raw material,” he said. “We need as much of it as we can get.”

Calera’s process is also versatile. It can be economically employed to capture and convert CO2 waste from every coal-fired and natural gas-fired power plant in the world, regardless of size, age or location, into cement and aggregate products that could meet the demand of the construction industry while eliminating most of the threat to the planet that the greenhouse emissions pose.

Calera boasts on its Web site that the process is the only CCS technology that is also economical in India and China.

“Let’s face it,” Constantz said. “Coal is not going anywhere. The Chinese and Indians are going to be burning it for the next 100 years. Things like mitigation and cap and trade ain’t going to happen in those countries.”

When asked about reports that Indian researchers have developed a cement-making process similar to the Calera process, Constantz said he’s not surprised. With technology, there can be some “leakage,” he said, especially since Khosla is one of Calera chief investors. Khosla, he explained, is a prominent venture capitalist who is well known in India.

“If the Chinese, for example, completely ripped off our technology, it would be great for our grandchildren, and we would still have plenty to do in the rest of the world,” he said.

Consider, for example, that 32 billion tons of rock used in making concrete or aggregate for road base is imported into the United States every year, Constantz said. Further, of the 25 billion tons of CO2 released into the atmosphere in this country every year, only 9.5 billion tons comes from fossil fuel-burning power plants and 6 billion tons come from other industrial plants. The remaining CO2 emission come from transportation sources, which cannot be efficiently captured, he said.

For us, CO2 is an essential raw ingredient in our process, so the cost of capturing and storing it in construction materials would be more than offset by profits from the sale of those products, he said.

But if the Calera process immediately replaced 100 percent of conventional cement-making in the United States, the 15.5 billion tons in current CO2 emissions from fossil fuels would not even be enough to address the demand of the aggregate market, Constantz said.

The environmental benefit would be immense, especially when you factor in the impact of a cessation of rock mining.

Constantz this means that for every ton of coal burned to make electricity, 2&1/2 tons of CO2 is released to the air and Calera’s process would capture most of it to produce 5 tons of cement or aggregate and replace the need to mine 7&1/2 tons of limestone.

Industry, investors take note

Industry, meanwhile, has gotten wind of Constantz’s work at Calera.

In March, Peabody Energy, the world’s largest private-sector coal company, led Calera’s latest round of investors by purchasing a $15 million equity interest in the three-year-old venture. With 2009 sales of 244 million tons and $6 billion in revenues, Peabody’s coal products fuel 10 percent of all U.S. electricity generation and 2 percent of worldwide electricity. The company serves 330 customers on six continents.

Constantz said Peabody looked at Calera in every which way they could. “Peabody has got some very smart guys who are also very conservative,” he added.

Fredrick D. Palmer, Peabody senior vice president in charge of Btu conversion activities said, “Calera’s emerging technology represents an innovative solution to advance our energy, environmental and economic goals by recycling carbon dioxide into beneficial building products.”

Calera also recently completed a demonstration project near Moss Landing, Calif. that is capable of capturing 30,000 tons per year of a CO2, equivalent to a 10MWe natural-gas power plant. In January, Calera began drawing 1 percent of the stack gas from a Dynegy power plant across the street through a massive pipe to its cement plant. Calera was hoping to capture 80 percent of the smokestack CO2, and sequester it in its patented cement mixture using the abundant stock of magnesium hydroxide (Mg(OH)2) available on site or from Calera’s novel electrochemistry process.

If it works, Constantz said at the time, the potential profits from Calera’s green cement would substantially offset the financial loss of reduced power plant output.

According to the New York Times article, Calera’s cement plant is capturing 86 percent of the carbon dioxide in the flue gas from the Dynegy plant per a study by R.W. Beck, a consulting firm hired by Calera.

Constantz said Calera’s costs of goods are lower than Portland cement because it doesn’t have to burn coal or build a quarry and quarry limestone, “so our capital costs are quite a bit lower.”

Calera also entered a strategic alliance with Bechtel Power Corp. in December to develop and construct facilities. Calera’s business plan calls for construction of multiple demonstration plants to validate the commercial viability of its technology. The companies are currently working to develop a demonstration projects with a large-scale conventional cement plant, a coal waste remediation facility in the Midwest and a large coal-fired power plant.

In Yallourn, Australia, Calera is also building a $120 million demonstration project to be based in the Latrobe Valley in the state of Victoria, Australia. It will be co-funded with local grants, and construction is starting this year. After the initial demonstration phase, Calera Yallourn will capture more than 300,000 tons of carbon dioxide and produce more than 1 million tons of building materials per year. The facility also will produce 2 million gallons of fresh water per day. Alkalinity for the carbon dioxide capture process may come from sub-surface brines and ongoing fly ash produced by the power plant. After the demonstration period, Calera Yallourn will be capable of expanding to a 200MW scale.

“In another few months, we will also announce plans to build another plant in Southern California, but I can’t give you any details now,” Constantz added.

Links of interest:

http://www.calera.com/
http://www.calera.com/index.php/about_us/faqs/
http://www.calera.com/index.php/technology/the_science/
http://www.calera.com/index.php/lifecycle_carbon_scalability/top_100_emitters/
http://www.khoslaventures.com/
http://www.bechtel.com/
http://www.peabodyenergy.com/default.asp

Contact Rose Ragsdale via publisher@greeningofoil.com