Portland cement is not a brand name but the generic term for the type of cement used in virtually all concrete. Concrete forms when portland cement is mixed with water and aggregate (sand and rock), and allowed to harden. Cement holds the concrete together and has a role similar to flour in a cake mix. Concrete is the most-utilized material after water in the world; the U.S. uses about 260 million cubic yards of concrete each year. It is used to build highways, bridges, runways, water & sewage pipes, high-rise buildings, dams, homes, floors, sidewalks, and driveways.
By way of brief background, understanding the cement production process is essential for understanding the extensive environmental regulations that the industry complies with and its role in the economy. Cement is manufactured through a tightly controlled chemical combination of calcium, silica, aluminum, iron, and other minor ingredients. These chemicals are commonly derived from limestone, chalk, or marl, combined with shale, clay, slate, blast furnace slag, silica sand, and iron ore. These materials are heated to high temperatures, 2700℉ or more until they liquefy and become clinker. Once cooled, gypsum is added to the clinker, and the product is ground into the fine powder that becomes portland cement.
Cement manufacturing is an energy-intensive process that depends on carefully balanced chemistry and physics. Cement plants run continuously, typically 24 hours a day, seven days a week, and generating and maintaining kilns at the high temperatures required to create clinker involves the combustion of significant quantities of fossil or alternative fuels. The chemical process to convert limestone and other ingredients into clinker is also emissions-intensive, typically generating 50 to 60 percent of the CO2 from manufacturing.
Cement plants are large, complex systems stretching hundreds of feet, with carefully calibrated environmental controls. One change to one system, particularly for environmental compliance, affects the entire production process. Cement plants can cost several hundred million dollars to build, with the largest plants exceeding $1 billion, including millions of dollars of investment in emissions monitoring and control equipment and associated operational expenses. Plants are typically collocated with large limestone quarries, selected to supply 50 to 100 years of limestone supply. These extensive capital investments, the complexity of the manufacturing systems, environmental controls and permitting, and geographic constraints associated with siting can complicate rapid changes to the manufacturing process and materials design. When combined with the significant trade exposure domestic manufacturers face from low-cost subsidized or underregulated imports, the industry faces significant challenges.
Yet, while public attention on the cement sector frequently focuses on the environmental impact of the manufacturing (cradle-to-gate) portion of cement’s lifecycle, such limited analyses cannot be considered in isolation for material selection and procurement. Cement is only one of several components in concrete - the end building material – and when considered as part of that end product, the carbon intensity of concrete can be similar if not favorable relative to other building materials with equivalent performance characteristics. During the use phase, cement and concrete products make buildings more energy-efficient, roads more fuel-efficient, and our nation’s infrastructure more resilient, durable, and long-lasting, mitigating the impacts of extreme weather events and reducing the emissions resulting from frequent repair and replacement. It is also fully recyclable, eliminating emissions associated with end-of-life disposal. In short, considered across their full life cycle from cradle to cradle, cement and concrete building materials are critical and sustainable components of any economy-wide decarbonization strategy.
Combating Climate Change Via One Federal System
PCA and its members support market‐based policies and initiatives that will enable the industry’s continued reduction of its carbon footprint responsibly and sustainably. The cement sector is proud to work towards its goal of being carbon net-neutral by 2050. Foremost, we want to see any legislation addressing global warming while preserving America’s manufacturers' global competitiveness. A market-based approach allows manufacturers the flexibility to select the technologies, efficiency upgrades, and other improvements to their capital and operations to reduce their emissions while minimizing economic competitiveness and job creation. Further, as part of any free-market greenhouse gas (GHG) regime is an explicit provision to make GHGs regulations under the federal government by preempting existing systems. PCA is concerned that the benefits of a federal system may be inhibited if manufacturers must comply with a separate level of requirements at the state level. The result may be companies having to follow multiple sets of requirements as it would allow one state to impose rigid command and control performance standards on industrial sources, another state to establish an intrastate cap-and-trade regime, and another state to impose a carbon tax on top of the federal system. To ensure consistency and predictability, while still preserving the United States’ goal with having net-zero emissions by 2050 we encourage the Committee to include a provision that protects manufacturers from being subject to both federal and state-based carbon emissions programs.
Accelerating Carbon Mitigation Technology
U.S. cement manufacturers have invested billions of dollars in technologies in increasing energy efficiency and reducing carbon emissions, but energy efficiency alone will not be enough to meet long-term reduction goals. As mentioned, over 60% of the cement industry’s carbon emissions result from the chemical conversion of limestone and other ingredients into cement - there is no way to prevent the generation of CO2 during this process – it is a “chemical fact of life.” Any long-term carbon reduction strategy for the cement manufacturing industry will require significant advances in carbon capture, use, distribution, and storage (CCUS) technologies – with a particular focus on research, development, and cost-effective deployment (RD&D) for the cement sector. While promising CCUS technologies are under development domestically and overseas, none have reached the commercial stage of deployment. Nearly all research and federal funding have focused on the energy sector, not industrial sector solutions. The CCUS technologies developed to date remain prohibitively expensive for energy-intensive trade exposed industries, including cement, which face a significant risk of leakage. Cement plants and other industrial sources also face different technical, regulatory, and economic challenges in deploying CCUS technologies, particularly in the U.S. Any long-term strategy to reduce carbon emissions from the industrial sector must recognize that there is no one-size-fits-all solution to capturing, transporting, and using or storing carbon emissions, particularly across industries and countries. Congress should continue to expand and focus funding to assess research and technology gaps, as well as regulatory and economic barriers to CCUS deployment, in the cement sector. Lastly, Congress should reward early investment and adoption of new technologies by manufacturers to pursue comprehensive climate change legislation.
The cement industry has a long history of safe and efficient use of alternative fuels, ranging from used tires and biomass to a wide variety of secondary and waste materials. Cement kilns are uniquely suited to the safe and efficient use of a wide range of alternative fuels. Cement kilns heat limestone and other raw materials to over 2,700 degrees Fahrenheit during the cement manufacturing process. The high operating temperature and long residence times make cement kilns extremely efficient at combusting any fuel source with high heating value while maintaining emissions at or below the levels from traditional fossil fuels. The final product, cement, is the main component in concrete, a critical component of roads, buildings, water projects, and other forms of resilient infrastructure that are desperately needed at this time. For the cement industry, secondary materials that would otherwise have little market value are valuable commodities, offering a cost-effective and environmentally sustainable alternative to traditional fossil fuels.
Legal barriers constrain the cement industry through the Resource Conservation and Recovery Act, the Clean Air Act, as interpreted by the courts, and Environmental Protection Agency regulations restricting the use of non-hazardous secondary materials and wastes as fuels. Today, alternative fuels make up only about 15 percent of the fuel used by domestic manufacturers, compared to more than 36 percent in the European Union, including as high as 60 percent in Germany.
The cement industry can beneficially reuse the millions of tons of plastics and other landfilled materials for energy recovery. The cement industry’s use of scrap tires provides an illustrative example for beneficially reusing materials traditionally landfilled as fuels. EPA lowered regulatory barriers to using scrap tires as fuel, helping the industry to increase its use of tire derived fuel (TDF) from 40 million tires in 2011 to 60 million tires in 2017. TDF serves as excellent fuel for cement kilns as they have high heating value and have demonstrated lower GHG, nitrogen oxide (NOx), sulfur dioxide (SO2), and particulate matter (PM) emissions than
traditional fossil fuels. There is a similar opportunity to reuse the millions of tons of plastics discarded into landfills, including the marine debris plastics that could further reduce GHG and other air emissions, promote energy security, and ensure cleaner waters. Considering Congress’ interest in addressing climate change, we encourage further exploration into ways the EPA can lower barriers for manufacturers to increase their use of alternative fuels.
Regulatory barriers are preventing cement manufacturers from investing in technology and process improvements to reduce GHG emissions. Manufacturers seeking to improve efficiency and reduce carbon intensity of operations face extended and costly permitting processes and potential unrealistic emissions and monitoring requirements from the New Source Review (NSR) program under the Clean Air Act (CAA). The current NSR program, as interpreted by the courts and EPA, penalizes companies and poses an obstacle to facilities seeking to improve operational efficiency. This forces many companies to reject upgrades and investments in their facilities to avoid undertaking the NSR permitting process. Further, the cement industry is using more natural gas to reduce GHG and other air emissions. Pipeline and related infrastructure are not in place in many areas preventing many cement plants from using natural gas as fuel. Natural gas use at cement plants could be further increased if pipelines and related infrastructure were in place to supply those plants. Barriers under the National Environmental Policy Act (NEPA) regulations, Clean Water Act (CWA), and state standards prevent needed energy infrastructure being put in place.
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