Members Highlights: authored by Lei Shen
- Article: Factory-level measurements on CO2 emission factorsof cement production in China
- Source Information
- Original Title: Factory-level measurements on CO2 emission factors of cement production in China
- Authors: Lei Shen, Tianming Gao, Jianan Zhao, Limao Wang, Lan Wang , Litao Liu a, Fengnan Chen, Jingjing Xue
- Affiliations: Institute of Geographic Sciences and Natural Resources Research, University of Chinese Academy of Sciences, China Building Materials Academy
- Keywords: Emission factors; CO2 emission; Cement production; China
- Source Link: https://www.sciencedirect.com/science/article/pii/S1364032114001865
- Editor’s Comments
The paper presents a groundbreaking study on the precise measurement of CO₂ emission factors in China’s cement production, offering valuable insights into a critical aspect of global climate change. By highlighting significant discrepancies in previous global and domestic estimates, the research underscores the importance of accurate and up-to-date data for effective climate policy development.
One of the most innovative aspects of this paper is its methodological approach. The authors employed a bottom-up factory-level sampling method (BFSM) across 289 production lines in 18 major cement-producing provinces, allowing for a detailed and nuanced examination of the various emission sources within the cement production process. This comprehensive dataset is a significant contribution to the field, as it provides a more accurate picture of CO₂ emissions from cement production in China.
The paper’s key findings are equally noteworthy. It reveals that traditional IPCC defaults and CSI standards likely overestimate China’s cement-related CO₂ emissions due to a range of factors, including technological shifts, lower-than-assumed limestone content in clinker, dynamic clinker-to-cement ratios, and the widespread use of industrial waste substitutes. These findings challenge previous assumptions and provide a more nuanced understanding of the complex dynamics of CO₂ emissions in the cement industry.
Furthermore, the paper’s case studies demonstrate that different kiln types and cement formulations exhibit varying emission factors, adding another layer of complexity to the issue. These findings underscore the importance of refined regional emission factor databases and grid-specific electricity emission factors in enhancing the accuracy of China’s carbon accounting.
In conclusion, this paper makes a substantial contribution to the field of climate science and policy by providing a detailed and nuanced examination of CO₂ emission factors in China’s cement production. Its innovative methodological approach, comprehensive dataset, and key findings offer valuable insights that will inform global emission inventories and climate policy development for years to come.
- Original text summary
This article presents a detailed study on the precise measurement of CO₂ emission factors in China’s cement production, highlighting significant discrepancies in previous global and domestic estimates. Through field sampling of 289 production lines across 18 major cement-producing provinces, combined with a bottom-up factory-level sampling method (BFSM), the research distinguishes contributions from process-related, combustion-related, and electricity-related emission sources. Key findings reveal that traditional IPCC defaults and CSI standards likely overestimate China’s cement-related CO₂ emissions due to technological shifts (e.g., transitioning from wet to dry processes), lower-than-assumed limestone content in clinker, dynamic clinker-to-cement ratios, and widespread use of industrial waste substitutes. Case studies show that NSP kilns emit 1–3% less CO₂ per ton of cement compared to traditional shaft kilns, while higher-grade cement formulations exhibit elevated emission factors due to increased clinker content. The study advocates for refined regional emission factor databases and grid-specific electricity emission factors to enhance the accuracy of China’s carbon accounting, providing critical data for global emission inventories and climate policy development.
Fig. 1. Relationship between cement consumption and per capita GDP.
Fig. 2. Total cement production of China: 1978–2010.
Fig. 3. Types of emissions from cement production.
Fig. 4. Energy consumption and productions of clinker and cement of China.
Fig. 5. Standard coal equivalent consumption of different types of kilns.
Fig. 6. Differences of CaO content at provincial level of China.
Source: self tested by authors in 2012.
Fig. 7. Differences of provincial cement and clinker production of China.
Fig. 8. Three tiers of integrated estimating method.
Fig. 9. Main types of cement production process in China.
Fig. 10. Spatial distribution of samples collected for cement production lines.
Fig. 11. Shares of CO2 emission factors of clinker production for cases A, B, C (kg CO2/t, %).
Fig. 12. Shares of CO2 emission factors of cement production for cases A, B, C (kg CO2/t, %).
Fig. 13. Differences of our tests on clinker and cement emission factors with IPCC and CSI default values.
- Original text information
ABSTRACT
Cement is a primary component of concrete and is consumed extensively for construction and transportation infrastructures worldwide. Cement is largely produced and consumed locally but has global impact in terms of both energy consumption and greenhouse gas emissions. China is both the largest producer of cement and the biggest emitter of CO2 emissions in the world. It has been widely recognized that uncertainties of China׳s CO2 emissions were poorly quantified and clear discrepancies can be identified among different sources. These discrepancies arise from many uncertainties, including system boundary and statistical standards, availability of production data (especially for the clinker and cement outputs), and emission factors. We argue that the emission factors (EFs, either default values or adjusted ones) are the most important here and highlight the importance of clearly defining the CO2 accounting and reporting boundaries for determining the emission factors. We therefore developed a factory-level measurement for different types of clinker and cement production, primarily using onsite surveys and sampling, with the objective of distinguishing process-, combustion- and electricity-related emission factors on a factory level. It is a bottom-up CO2 emission inventory for China using the uniform formula and calculators and the first time factory-level sampling method (BFSM) based on three tiers of production lines, provincial and national integrations. Our results indicate that China׳s carbon emissions from cement production might be overestimated in the previous estimates because they overlooked the technology transition from the wet process to the dry process, differences in lime content and clinker-to-cement ratios, raw materials and fuels substitutions, and usages of blend additives.
- This issue’s editor
Ms Xinyi WU, Doctoral candidate at Institute of Geographic Science and Natural Resources Research (IGSNRR), the Chinese Academy of Sciences (CAS), focuses on the research of natural resources economics.