The latest Environmental Protection Agency Inventory of U.S. Greenhouse Gas Emissions and Sinks cites 2022 GHG loads of 5.489 billion metric tons of carbon dioxide equivalent, a 1.3 percent increase from the prior year. The GHG Inventory factors emissions of CO2, methane, nitrous oxide, hydrofluorocarbons, perfluorocarbons, sulfur hexafluoride and nitrogen trifluoride—all pegged for their global warming potential when released to the atmosphere.
Actual CO2 emissions in 2022 climbed just over 5 billion metric tons, of which 41.9 million mt or 0.008 percent, involved U.S. cement plants’ 80.5 million mt of clinker production. Combustion and chemical reactions in cement calcining and kiln phases account for nearly a quarter of the 168.9 million mt of emissions in the GHG Inventory Industrial Products and Product Use (IPPU) chapter. Additional CO2 emissions attributable to the generation of electricity consumed in processing and finishing clinker and cement are pooled in the GHG Inventory Energy chapter. Under Energy, IPPU accounts for just over 800 million mt of CO2 emissions, tallied from iron & steel, petrochemical plus specialty chemical or metallic compound production, along with cement.
“Through a rigorous development and review process, EPA annually refines and strengthens inventory, producing a comprehensive tally of U.S. greenhouse gas emissions and sinks,” says Assistant Administrator for the Office of Air and Radiation Joseph Goffman. “Reflecting input from hundreds of experts across the government, academia, industry, and consulting, the GHG Inventory report is a model for high-quality and transparent national GHG accounting.” The agency has published the GHG Inventory as an impartial, policy neutral report since 1993, he adds, submitting it to the United Nations Framework Convention on Climate Change.
The Inventory is under the EPA Office of Atmospheric Protection Greenhouse Gas Reporting Program (GHGRP). Authors of the latest edition note that the agency “continues to review methods and data used to estimate CO2 emissions from cement production in order to account for organic material in the raw material and to discuss the carbonation that occurs across the duration of the cement product. Work includes identifying data and studies on the average carbon content for organic materials in kiln feed in the United States and on CO2 reabsorption rates via carbonation for various cement products—information [presently] not reported by facilities subject to GHGRP reporting.”