Greenhouse Gas Emissions
Greenhouse Gases: the portland cement industry was among the first to tackle the issue of climate change, and it has remained at the forefront of developing policies and improving the manufacturing process to reduce greenhouse gas emission. carbon dioxide, CO2, is the major GHG produced by portland cement manufacturing.
Carbon dioxide emissions from a cement plant are divided into two source categories: combustion and calcination. Each accounts for about one-half the total CO2 emissions from a cement manufacturing facility. The combustion-generated CO2 emissions are related to fuel use. The calcination CO2 emissions are formed when the raw material is heated and CO2 is liberated from the limestone. Calcination is a necessary key to cement production. Therefore, the focus of reductions in CO2 emissions during cement manufacturing is on energy use, and since 1975, the cement industry has reduced GHG emissions from fuel use by 33 percent. Today, the cement industry accounts for less than 1.5 percent of U.S. CO2 emissions, well below other sources such as electric generation plants for heating and cooling (33 percent), transportation (27 percent), and industrial operations (19 percent).
The most recent progress involves newly introduced guidelines that will allow for greater use of limestone as a raw material of cement, which will ultimately reduce CO2 by more than 2.5 million tons per year.
By 2020, the cement industry aims to reduce CO2 emissions by 10 percent below the 1990 baseline levels. To achieve this goal, the cement industry has adopted a three-part strategy:
1. Improve the energy efficiency by upgrading plants with state-of-the-art equipment
2. Improve product formulation to reduce energy of production and minimizes the use of natural resources
3. Conduct research and develop new applications for cement and concrete that improve energy efficiency and durability