Detailed Energy-Related Carbon
Energy-Related Carbon Emissions in Manufacturing
Manufacturing, which accounts for about 80 percent of industrial energy consumption, also accounts for about 80 percent of industrial energy-related carbon emissions. (Agriculture, mining, forestry, and fisheries account for the remaining 20 percent.) In 1994, three industries, petroleum, chemicals, and primary metals, emitted almost 60 percent of the energy-related carbon in manufacturing. The next three largest emitters (paper, food, and the stone, glass, and clay products industry) produced an additional 22 percent of the energy-related manufacturing emissions (Figure 1).
The carbon intensity of energy use is the amount of carbon emitted per unit of energy used. Both the mix of energy sources used and the uses of energy affect carbon intensity. For electricity that manufacturers purchase, the carbon emissions occur where the electricity is generated, rather than at the manufacturing establishment. These emissions are assigned here to the ultimate user. Overall, manufacturing industries had a carbon intensity of 17.16 million metric tons per quadrillion Btu in 1994. However, industries' carbon intensities differed markedly (Figure 2), for different reasons.
The metals industry has a relatively high carbon intensity, due to the extensive use of coal (primarily in the iron and steel industry) and electricity (in the aluminum and iron and steel industries). In contrast, the paper industry has a relatively low carbon intensity, due to its use of renewable energy sources. The two industries with the highest carbon emissions, the petroleum refining and chemicals industries, have relatively low carbon intensities. These industries use large amounts of energy, but do not use all of that energy as fuel. Instead, these industries convert energy sources, such as liquefied petroleum gases or natural gas, into other products. A portion of the carbon contained in the original energy source is sequestered in the product rather than emitted to the atmosphere.
File Last Modified: May 31, 2000