GHG Reduction

• Ways to Reduce Cement GHG at Cement Plants
  • Blending SCM at Cement Plants
  • Environmentally Friendly Fuel for Cement Kilns
  • Use of Interground Limestone
  • Production Efficiency Improvements
• Ways to Reduce Concrete GHG at Batch Plants
  • Blending SCM at Concrete Batch Plants
  • Optimize Cement Content
  • Reduce Concrete Waste
  • Universal GHG Emission Standards

Related Links

Significant GHG emission reduction for California is not expected of this particular strategy. One of the reasons being that the cement industry in California is already among the most energy efficient in the world. It has been reported that one of the most recent cement plants built in California has a GHG intensity of only 0.02 below that of the 2005 California average GHG intensity factor of 0.86 ton of CO₂ per ton of cementitious material.

Modern California Equipment Factors

All cement plants in California except one have precalcinators. These pre-heaters significantly improve energy efficiency by heating limestone prior to its placement in the cement kiln. Another process-related piece of equipment that significantly improves energy efficiency is the dry kiln compared to wet kiln usage: All cement plants in California have dry kilns. Using one kiln instead of multiple is also recommended to further improve energy efficiency. Only one cement plant in California uses multiple kilns. According to the California Cement Industry (2008), the energy efficiency of California cement plants is 15 percent better than the average U.S. value since 1995.

Limited Impact Factors

Another reason for a small GHG emission reduction is the fact that production efficiency improvement only affects 40 percent of the GHG emission from cement production. The other 60 percent of GHG emissions comes from calcination, which is a natural chemical process inherited from the cement production process in which limestone (CaCO₃) is converted to calcium oxide (CaO) by releasing carbon dioxide (CO₂) in the presence of heat, as follows: CaCO₃ + heat -> CaO +CO₂.

Since fuel combustion is responsible for only 40 percent of the GHG emissions, a reduction in energy consumption of 4.5 percent accomplished by California Portland, only reduced GHG emissions by 1.8 percent. California Portland was named the 2007 Energy Star Partner of the Year for such energy reduction. This saved the company about $850,000 in operating costs.

 

 

 

 

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