Novacem: Cement That Eats Carbon

The construction materials industry emits gobs of carbon dioxide, but a British startup has devised a new cement that absorbs and stores CO2 when it's produced

In 1824, English stone mason Joseph Aspdin invented Portland cement in his kitchen and patented what has remained the primary material used in concrete ever since. Trouble is, global demand for cement—a $130 billion annual business—is skyrocketing but the process used to make it already produces an estimated 5 percent of the world's manmade carbon dioxide emissions. It took 184 years, but now another English company, Novacem, has come up with a different formula—one that actually absorbs more carbon than it releases.

The two-year-old company, which was spun out of London's Imperial College, has built the first cement works in central London since the Romans, with an eye toward becoming the first great cement company of the 21st century. "Cement is a vital strategic material and the glue that holds the world together," says Stuart Evans, Novacem's chief executive officer. "There is a lot more science and technology in cement and concrete than you would imagine."

Novacem is among 31 enterprises named Sept. 1 by the Geneva-based World Economic Forum as Tech Pioneers offering new technologies or business models that could have a positive impact on people's lives. It is one of six in this year's class that are either reengineering basic building blocks used in the $3.8 trillion construction industry or developing other ways to make buildings "greener" and more energy-efficient.

Buildings' Big Footprint

The rising interest in green buildings is being spurred by economics, scarcity, and the environment, according to a report by New York-based strategic advisory firm Lux Research. Construction, operation, and maintenance of the buildings where we eat, sleep, work, and visit represent the single largest source of energy and material consumption of any human activity, the report says.

Buildings consume 40 percent of the U.S.'s annual energy (and a comparable amount throughout the rich world), including 72 percent of electricity and 34 percent of natural gas just for heating and cooling. Some 40 percent of all raw materials produced each year—including concrete, steel, glass, wood, and ceramics—are used in buildings.

The carbon dioxide (CO2) released in producing building materials is also substantial and has been targeted as a leading contributor to global climate change. Each ton of cement emits about 800kg (1,763 lb.) of CO2 during manufacture. This is because cement is made from limestone, which releases a huge amount of carbon when it's dug up and then releases even more when it's heated to 1,400 degrees Celsius (2,552 degrees Fahrenheit). When you consider that every year, some 3 billion tons of cement turn into nearly 30 billion tons of concrete, it is no wonder that the industry produces more CO2 emissions than the entire airline business, says Novacem CEO Evans.

Novacem's cement, by contrast, is based on magnesium silicates that contain no stored carbon. Evans says there are world reserves of more than 10,000 billion tons of such silicates, which are the basis for materials such as asbestos and talc. Making cement from these silicates also consumes less energy, because it's only heated to 600 degrees Celsius (1,112 degrees Fahrenheit), and in the process, carbon is absorbed and fixed into the material. The net result: For every ton of Portland cement replaced by Novacem, the atmosphere would be spared up to 850kg (1,873 lb.) of CO2.

Innovative Fund-Raising

Evans argues Novacem's cement will be attractive to the construction industry, which is under pressure to get greener. In July, the company announced the closing of an innovative fund-raising vehicle, in which it sold $1.5 million worth of "Green Cement Bonds" to investors including building materials giant Lafarge (LFRGY). The proceeds will be used to accelerate development and commercialization of Novacem's cement, which also has the backing of the Royal Society, Britain's national academy of science.

Subscribers to the bond are expected to participate in the company's planned Series A financing round, which will be used in part to support the construction of a planned semicommercial plant that could produce up to 25,000 tons of carbon-negative cement per year. Novacem says it will work closely with bond subscribers in the development of this plant and the commercial-scale plants it expects to build later.

Novacem doesn't have the field entirely to itself. A number of other companies—including Los Gatos (Calif.)-based Calera and Sriya Green Materials in Marietta, Ga.—are also making greener forms of cement, says Michael LoCascio, a New York-based senior analyst that heads up Lux Research's green building and water unit. LoCascio says there is a huge opportunity for companies that can make building materials and buildings more energy-efficient.

Evans, the Novacem CEO who's a two-time winner of the WEF Tech Pioneer award, is betting on that. "The world is your oyster if you are a low-carbon technology pioneer," he says.

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