Terra CO2 Is Building A Low Carbon Concrete Factory In Texas – CleanTechnica

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Concrete is one of the most widely used construction materials on Earth. Traditionally, it relies on Portland cement, whose primary component is calcium derived from limestone. First, the limestone is heated to a high temperature using fossil fuels, which creates lots of carbon dioxide. Second, as the limestone decomposes into calcium, a large quantity of carbon dioxide is released. Because of the carbon double whammy, cement accounts for about 8% of global carbon dioxide emissions.

There are alternatives, and we have discussed some of them here at CleanTechnica, including C-Crete, a company that is making cement-free concrete in the state of Washington, and Sublime Systems, created by MIT’s famed materials scientist Yet-Ming Chiang, which makes cement using electricity.

Terra CO2 Concrete Factory In Texas

Now another innovative company has entered the competition to reduce the carbon emissions associated with making concrete. Terra CO2 announced this week it is building its first full-scale factory in Texas. The work is partially funded by the Breakthrough Energy Ventures, which is also funding several other alternative cement and concrete technologies.

Why Texas? In an email to CleanTechnica, the company says the Dallas Fort Worth area uses about 26.3 million cubic yards of concrete every year, making it the largest concrete market in North America. Much of that concrete currently depends on fly ash derived from coal-powered generating stations. As the number of coal plants declines, less fly ash is available.

Another material often used is slag from steel mills. Once again, new technologies are altering how steel is made, which will limit the amount of slag available. Scarcity, of course, always drives up prices.

OPUS SCM Concrete

Unlike other sustainable cement solutions, many of which are still in the lab phase, Terra’s OPUS supplementary cementitious material (SCM) can scale to meet the market demand, making decarbonized concrete a viable, affordable alternative for the industry. This first plant will be able to produce up to 240,000 tons per year of Terra’s OPUS SCM, which can substitute for up to 40% of the Portland cement used in ordinary concrete mixes, resulting in a reduction of 70% of carbon dioxide and 90% of NOx emissions for every ton used.

Bill Yearsley has 40 years of experience in the construction materials industry and is the CEO of Terra CO2 Technology, which is headquartered in Golden, Colorado. He says his company has found a method to turn some of the world’s most abundant and commonly used minerals — silicate rocks such as granite, basalt, alluvial sand and gravel, glacial flood gravel, and clay/sand mixtures — into a drop-in replacement for the additives used in cement production.

“The reason we focused on silicate rock is twofold,” Yearsley said. ​“One, silica rock for the most part doesn’t have any embodied CO2. The other reason we chose silicate rock is they’re approaching 90 percent of the earth’s crust. We can for most cases work with existing construction aggregate mines — the sand and rock quarries that exist in most urban environments.”

Terra CO2 puts these rocks into a reactor that heats them to their melting point, yielding glassy powders that can replace 25 to 40% of the Portland cement needed for different mixes of concrete. The company estimates that every ton of cement replaced by Terra’s SCM results in 70% lower carbon-dioxide emissions compared to pure Portland cement.

The first thing most CleanTechnica readers will notice is that this seems like just using the same heat ordinarily used to convert limestone. That’s true, except the process avoids the carbon emissions released when limestone is heated. Also, the temperatures don’t need to be as high as those used in a conventional limestone kiln.

Yearsley anticipates that renewable energy — something there is quite a lot of in Texas — will be able to replace the fossil fuels used now to heat the silicate rocks, which would make the process completely zero emissions.

 Cost Competitive

He also says because the materials Terra CO2 uses are widely available locally, ​“for the most part, we are the same price — and in some cases, cheaper — than the traditional SCMs like fly ash, and that’s without green incentives.” Concrete is a low margin business. Keeping costs down will be critical to gaining market acceptance for any new process.

Ian Hayton, who leads materials and chemical research at Cleantech Group in the UK, tells Canary Media the key factors for successful SCMs are being able to meet government and industry standards for strength and durability of the cement they produce, and being widely and cheaply available.

Even while these traditional SCMs remain available, they’re becoming increasingly hard to find in certain regions, which forces cement and concrete users to pay higher costs to transport them to where they’re needed, he noted. ​“These products are all sold by the ton, and every mile you move it makes you less competitive, with less margin,” he said. ​“Today, they’re railing fly ash into Denver from 1,000 miles away.” Terra CO2 facilities, by contrast, can be located close to sources of silicate minerals and to the concrete ready mix providers that serve regional construction markets, he said.

Meets ASTM Standards

The key factors for successful SCMs are, first, being able to meet government and industry standards for strength and durability of the cement they produce, and second, being widely and cheaply available.

On the first front, Terra CO2 has earned approval from ASTM International, a nonprofit standards-setting body, for varieties of SCMs the company produces from various rock feedstocks. Terra CO2 has also tested cement and concrete using varying proportions of its SCMs in sites from roadways in Minnesota to buildings in Texas.

On the second front, the silicate rocks that Terra CO2 uses to make SCMs are already more widely and cheaply available than traditional materials, Yearsley said — and that’s only growing more pronounced.

“Fly ash is already supply-distressed now,” he said. ​“By the end of the decade, it’s going to go away. And blast furnace slag is going away as well. The way we make steel is changing fast. If we can’t find a scalable and viable SCM for the future, understanding the traditional ones are going away rapidly, the only alternative for concrete-making is going back to full Portland cement — which will increase the industry’s carbon footprint substantially.”

Terra CO2 facilities can be located close to sources of silicate minerals and to the concrete ready-mix providers that serve regional construction markets, he said. The company now operates a test reactor in Vancouver, Canada, and a larger-scale reactor in Golden, Colorado.

First Factory Is Pre-Sold

Terra CO2 has entered into a binding agreement with Asher Materials, a subsidiary of Instar Holdings. That agreement is for Asher to buy the first Terra CO2 factory in Texas once it is completed. ​“We’ve got to build and commercialize it — there’s technology risk there — but once we build it, we have a definitive binding agreement with a buyer. That’s enabled us to bring in bank debt on the first project, which normally you can’t do,” said Yearsley.

Jonathan Green, founder of Instar Holdings, said in a statement this week that he sees this first plant laying the groundwork for ​“building a progressive network of these advanced processing facilities across Texas.”

Terra CO2 is just one of many companies trying to make cement and concrete in new ways that produce fewer carbon emissions, but Yearsley said his company has a distinct advantage. “A lot of the other emerging technologies, they’re scientists trying to work out of labs and eventually commercialize.” Readers will readily see the parallel to new battery technologies that work well in the lab, but are a long way from commercial production.

Yearsley says his product is ready right now; no waiting needed. Low cost + low emissions + immediate availability? That sounds like the formula for a commercial success just waiting to happen.