It is a major contributor to climate change – the way buildings and roads are made of concrete. It is also a problem that is growing as more of the world develops. So the race is on to find solutions for a material responsible for roughly 8% of global CO2 emissions.
Now a California startup has developed a technology that reduces carbon dioxide in cement production and could have the potential to operate on a large scale. Fortera captures carbon dioxide emissions from the kilns where cement is made and directs them back inside to make additional cement. In an initial commercial-scale effort, the technology will be added to a CalPortland plant in Redding, California, one of the largest cement plants in the western US. It opens on Friday.
“Our goal is to be a ubiquitous solution that can truly work in any factory,” said Ryan Gilliam, CEO of Fortera.
Initially, Fortera will produce enough to blend with about one-fifth of CalPortland’s product in a blend that reduces carbon emissions by about 10%. Gilliam said there is strong demand for higher blends that reduce carbon emissions by 40-50%, and for a pure product the company makes, which contains 70% less carbon.
The first large bags are expected to leave the factory in Redding in the first week of May.
Fortera emerged in part from an earlier company called Calera, which as of 2007 was one of the first to convert carbon dioxide into cement. It poured about 100 tons of its low-carbon cement into office buildings and sidewalks in California, but closed in 2014 due to financial problems. challenges. Building on that knowledge, Gilliam founded Fortera in 2019 with a number of former Calera employees.
There is “a cement factory almost every 250 miles in the world,” he said, and most are located near a limestone quarry. Because it works with these existing factories and uses the same material the industry already uses, Fortera says its technology is an economically competitive option to quickly stop CO2 emissions from warming the planet.
One difference from some other low-carbon cement and concrete projects is that it at least offers the possibility of being widely installed in cement plants rather than changing the way the industry currently functions.
Fortera’s is one of many efforts to reduce the climate impact of concrete. The American Institute of Architects informs many of the world’s largest architectural firms about the carbon emissions of building materials.
Some jurisdictions, including Vancouver, British Columbia, have building standards that encourage low-carbon concrete. California passed a law in 2021 requiring the state’s Air Resources Board to develop a strategy for the state’s cement industry to reduce greenhouse gas emissions by 40% by 2035 and reach net zero by 2045.
The First Movers Coalition, an organization of more than 90 companies, has announced an initiative in 2021 to create greater demand for low-carbon cement through their massive purchasing power.
The same year, 40 of the largest cement and concrete manufacturers announced through the Global Cement and Concrete Association that they were committing to making concrete that does not contribute to climate change by 2050. They agreed to reduce cement emissions and fossil fuel use in production processes and develop new ways to capture carbon.
Concrete is, after water, the most used product on earth. Cement makes up 10-15% of concrete by volume, but is responsible for 88% of concrete’s significant emissions. Other ingredients in concrete are sand, gravel, crushed stone and water.
The production of one ton of cement releases almost one ton of carbon dioxide. There has been no simple replacement.
“The social benefits of concrete are absolutely enormous… it is the backbone of modern society,” said Thomas Guillot, CEO of the Global Cement and Concrete Association. Other materials sometimes can’t compete because they aren’t as durable, can’t hold as much weight or don’t withstand heat as well, he said.
HOW FORTERA’S TECHNOLOGY WORKS
Cement manufacturers heat kilns to about 2,500 °F (1,400 °C) to break down limestone and separate it into carbon dioxide and calcium oxide.
Fortera’s process sucks out the carbon dioxide and feeds it to a machine where it is converted into a solid. The technology operates at approximately 1,800°F (1,000°C), requiring less energy and emitting less carbon.
When the captured carbon dioxide is mixed with calcium oxide, it turns into a type of limestone that, when wet, becomes cement-like. This product, which Fortera calls ReAct, is mixed with other ingredients to make concrete.
Fortera uses a 15% ReAct mixture in concrete because that is all that is allowed under existing industry standards that regulate material strength and durability.
The company is trying to get a product that is 100% ReAct approved as a replacement for cement and says tests show it can meet international requirements, but the regulatory process will take more than five years.
Some of the fastest growing consumers of cement are in Southeast Asia and Africa, so global solutions are critical.
“The United States must do what it can and be a leader to help other countries,” said Mike Ireland, president and CEO of the Portland Cement Association, the national trade association for U.S. cement makers. “But we need to push the rest of the world, especially the South, as they industrialize, to adopt some of the technologies we had.”
Carbon emissions from cement production are “an existential threat to the world and to our industry,” he said.
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