In 1997, 5.456 GJ (5.171 million British thermal units (MMBtu)) of energy was required to produce 1 t of cement, according to the Portland Cement Association (PCA). By 2008 that mark had improved to 4.897 GJ (4.641 MMBtu) per t of cement.
Several factors were in play in the cement industry in that 11-year period of energy efficiency improvement. Through its ENERGY STAR® industrial partnership with cement producers, the EPA saw marked improvement in energy performance distributed across US plants.
In 1996, the EPA approached cement producers about developing energy efficiency and GHG reduction goals. The EPA helped by providing a simple tool for estimating energy savings and GHG reductions based on best energy management practices for basic industrial plant systems. The EPA also produced a GHG emissions calculator specifically for cement plant accounting. The tool was adopted by industry, revised over time, and became the foundation for the GHG protocol developed by both the World Business Council for Sustainable Development and the World Resources Institute.
Additionally, the EPA recognised the need for even greater emphasis on energy efficiency and energy management, as well as highlighting the role of benchmarking plant energy performance to give companies the ability to determine how efficient their plants are relative to the industry.
Benchmarking plant performance
The EPA provided a second energy management tool to the cement industry, a plant-level energy benchmark called the Energy Performance Indicator (EPI), also through ENERGY STAR®. The EPA worked with the cement industry in developing the EPI to encourage greater energy performance among US cement plants.
To address differences between plants, the ENERGY STAR® approach to benchmarking draws on statistical methods to develop a model that serves as the foundation of the EPI. The approach requires that the most important drivers of energy use within an industry be identified and normalised to provide a meaningful comparison. While specifics vary across industries, the approach for cement production considers these major factors:
• Product mix.
• External market forces, such as utilisation rates.
• Physical plant size or productive capacity.
Differences in energy use that are not accounted for by these factors are considered 'controllable' by plant managers and operators, and thus represent part of the plant’s actions that contribute to energy-efficient performance.
The EPI is a statistical analysis of confidential plant-level data on energy use, production, and capacity, to assess the range of performance within the cement industry. The statistical model provides a distribution of energy efficiency across the industry and permits corporate and plant managers to answer the question: How would the energy performance of my plant rank relative to others in my industry if all other plants were similar to mine in terms of production and other characteristics?
The full version of this article from the US EPA, including a case study from Salt River Materials Group, can be found in the December issue of World Cement, now available for subscribers to download.
Read the article online at: https://www.worldcement.com/the-americas/03122009/engaging_the_us_cement_industry_to_improve_energy_performance/