Curing Concrete Of Its Environmental Affliction
Concrete, although often obscured from our vision by metals, woods, and other materials, is the most-used substance in the world after water. It accounts for 8% of global emissions due to its lengthy cementing process. In the past 60 years, the entire plastic industry emitted over 8 billion metric tons of carbon. In just 2020, the cement industry emitted approximately 2.8 billion metric tons, according to The Guardian. Additionally, concrete creation uses nearly 10% of industrial water.
To create typical cement, which is the primary ingredient of concrete, limestone, clay, and other materials such as slate and slag are fired in a kiln at extremely high temperatures of over 1400 degrees Celsius to create “clinkers,” that are then combined with gypsum broken down into a powder. This finished cement is then mixed with water, rocks, and sand to become concrete.
Creating clinkers is by far the most damaging part of the concrete-making process, as the amount of heat used requires a large amount of energy and gaseous effluents are released in the process. In this calcination process, the kiln’s components are split into calcium oxide and carbon dioxide. Of concrete’s total emissions, carbon released from calcination accounts for about half, and thermal emissions from the clinker-making process account for 40%, according to BBC.
Fortunately, companies including Holcim (formerly LafargeHolcim), Cemex, Heidelberg Cement, and Vulcan Materials have been implementing ways to reduce carbon emissions in their concrete and cement and researching ways to make these composites truly “green.” Typically, these methods include carbon capture and storage, clinker substitution, alternative fuels in the production process, and creating innovative cements. Holcim, a current holding in KBC’s Biodiversity Impact Strategy and the largest company in the industry, produces a range of concrete that has 30-100% less emissions than standard CEM I concrete under its ECOPact brand. ECOPact+ incorporates used construction and demolition materials. Mid last year, Holcim launched ECOPact in the U.S. On July 27 of this year, Holcim launched in Europe a green cement line, EcoPLANET. It promises a 30% lower carbon footprint and is made of 20% recycled construction and demolition materials.
A variety of start-ups – many of which are private – and researchers are in the field as well. For example, three groups are eliminating limestone in their cement. Novacem is using magnesium oxide in place of limestone, Calera mixes carbon dioxide from power plant emissions with salt water to create cement carbonates that also can replace limestone, and researchers at Louisiana Tech University replace limestone with a paste made of fly ash from coal power plants, sodium hydroxide, and potassium hydroxide. Alternatively, Calix is using superheated steam that separates carbon dioxide and makes it easier to capture. Even more potentially disruptive start-ups include BioMason, which injects bacteria into sand to create bio-concrete bricks. Despite so many companies striving to create green concrete, few products have ever reached the market due to high production costs and low strength.
Other organizations and entities have recognized green concrete and cement’s role in a sustainable future as well. The Global Cement and Concrete Association, founded in 2018, created a sustainability charter with guidelines that members are required to follow, focusing on CO2 and other emissions, safety, water usage, raw materials, and quarry rehabilitation and biodiversity management. In New York, the state legislature passed a bill that encourages companies to purchase low-carbon concrete and cement, and New Jersey’s legislature has drafted a similar bill that applies price discounts to low-carbon cements to provide additional incentive.
Momentum is clearly picking up in the shift toward green and low-carbon cements and concrete. As manufacturers continue to innovate and more options come onto the market, construction companies will have a breadth of options to ensure that their buildings cause minimal environmental harm.
DISCLOSURE: As of the date of this blog, Karner Blue Capital (“KBC”) held positions in Holcim Ltd. ADR and Vulcan Materials, Inc. on behalf of its clients. These securities do not represent all of the securities purchased, sold or recommended by KBC for its advisory clients, and readers should not assume that investments in these securities were or will be profitable. KBC and some of its partners may hold positions in certain securities issued by the companies identified in this blog in corporate and/or personal accounts. As fiduciaries, KBC prioritizes its clients' interests above these corporate and personal accounts to avoid any conflict of interest in trading these commonly held securities.