Posted on May 05, 2022
In October 2021, the Portland Cement Association released its Roadmap to Carbon Neutrality. The 38-page report outlines a comprehensive plan to make the industry's value chain carbon neutral by 2050. In January 2022, PCA further promoted the plan at the 2022 World of Concrete in Las Vegas.
The value chain begins at the cement plant and extends through the full life cycle of the built environment. What is at stake? As the report declares, “perhaps the most ambitious journey to carbon neutrality ever attempted.” Review the Roadmap’s Executive Summary here.
A Changing Atmosphere
In 1750, atmospheric CO2 concentrations were approximately 277 parts per million (ppm). By 2019, CO2 concentrations were 410 ppm, an increase of 48%. Early on, deforestation was the primary reason. Since the mid-20th century, fossil fuels have become the primary cause. In a single year (2019) human activities released more than 36 billion tons of CO2 into the atmosphere.
Nitrogen and oxygen account for 99% of a dry atmosphere. In high-humidity environments, water vapor may reduce this concentration to as low as 95%. The impact of other atmospheric gasses is impressive, given their relatively small concentrations.
Although nitrogen and oxygen do not interfere with infrared radiation reflecting out into space, carbon dioxide does. Even though atmospheric CO2 is less than 0.5% of the atmosphere, it acts like a blanket or a cap, preventing heat from radiating out into space. Even though methane, nitrous oxide, and CFCs are an even smaller part of the atmosphere, they warm it as well.
Cement, Concrete and Carbon Neutrality
The Roadmap discusses the “5 C’s of the value chain.” They are clinker, cement, concrete, construction, and carbonation.
Clinker is cement’s key reactive ingredient. It is produced in energy-consuming, high-temperature kilns. Cement is the binder in concrete. Concrete is a resilient building material critical to a growing world. The construction phase includes all use-phase impacts.
Finally, thanks to carbonation, the built environment is a quantifiable CO2 sink. As a result, the U.N’s Intergovernmental Panel on Climate Change (IPCC) now accounts for concrete carbonation in its climate reports. Over time, the amount of exposed concrete in the world increases. This increases the carbonation that absorbs CO2 from the air.
Importantly, the Roadmap takes into account the entire value chain, ”beginning at the cement plant and ending with the buildings and roads that are the foundation of our lives.”
Roadmap to Carbon Neutrality: Key Details
In publishing its Roadmap, the Portland Cement Association has done more than set a goal for three decades from now. The PCA also commits to providing annual updates and setting interim goals. It also commits to building the policy support crucial to long-term success.
Interim goals and updates
The roadmap also establishes interim goals for 2030 and 2040. It notes that, over time, market conditions will inevitably change. Also, technological innovation will occur and governments will alter policies. The Roadmap is subject to revision in response. Every year, PCA will publish an annual report on its implementation.
Almost every aspect of the Roadmap requires policy support for success. There’s also the reality of U.S. producers competing against less-regulated counterparts.
Since global warming is an inescapable fact; increased resilience is an inevitable need. As PCA's CEO Mike Ireland says, "Cement and concrete play a critical role in future-proofing our communities against natural and man-made disasters” He further asserts, "We are in a moment where we have both the opportunity and the duty to do so sustainably.” Success requires collaboration across the entire value chain.
The role of carbon pricing
While carbon pricing is not integral to the Roadmap, it is still important to consider its potential impact. PCA supports a cap-and-trade mechanism for establishing a market-based carbon price. It seeks a system that is at once fair, transparent and innovative. See p. 58 of the Roadmap.
Green Cement Prospects
Researchers continue to come up with new cement formulations that, collectively, can reduce the industry’s carbon footprint. Increasingly, the public and private sectors require the use of building products that achieve certain sustainability goals. A 147-page report, “2022 Green Cement and Concrete Market” projects a CAGR of 7.5% for the period 2021-2026.
Compared to traditional alternatives, green cement mixes often reduce water consumption as well. Some green cement achieves reductions of 20% or more.
A post in MIT Technology Review explores progress in green cement adoption. Researchers have come up with numerous low-carbon cements and cement alternatives. Here are a few examples.
Calcium sulfoaluminate (CSA) cement
Non-Portland hydraulic cement
Magnesium oxychloride cement
Reactive hydrothermal liquid-phase densification cement
Commercial viability is a common challenge with alternative formulations. Some are only cost-competitive in specialty applications. Some face supply chain challenges at scale.
A major exception is Portland limestone cement (PLC). It decreases cement’s carbon footprint by about 10%. Numerous cement plants are already switching to PLC.
The cement/concrete industry increasingly focuses on establishing and following green procurement standards. Going forward, it is important to view procurement through a sustainability lens. Consideration of complete lifecycles is vital as well. The Infrastructure Investment and Jobs Act (IIJA) will likely increase green procurement requirements.
A recent publication, “Green Public Procurement for Natural Gas, Cement and Steel,” explores the topic. Its author is Alan Krupnick, a senior fellow at Resources for the Future (RFF), a nonprofit based in Washington D.C.
Overall, the Roadmap to Carbon Neutrality reflects a proactive philosophy. It is vital to lead rather than follow in the quest for carbon-neutral concrete. At the same time, industry efforts in the United States occur against a backdrop of global efforts. A concerted and sustained effort by global industries and nations is crucial. We all share but one atmosphere.
The Pennsylvania Aggregates and Concrete Association (PACA) reports on innovations and sustainability initiatives. Our team welcomes questions you may have about your upcoming concrete project. Please contact us at your convenience.