Raising Energy Efficiency in a New Materials Economy, Part I
This is the first of a two-part column on solutions for raising energy efficiency. As I note in
The global steel industry, producing over 1.2 billion tons in 2006, is the second largest consumer of energy in the manufacturing sector, accounting for 19 percent of industrial energy use. Energy efficiency measures, such as adopting the most efficient blast furnace systems in use today and the complete recovery of used steel, could reduce energy use in the steel industry by 23 percent. Reducing materials use means recycling steel, the use of which dwarfs that of all other metals combined.
Steel use is dominated by three industries--automobile, household appliances, and construction. In the United States, virtually all cars are recycled. The U.S. recycling rate for household appliances is estimated at 90 percent. For steel cans it is 60 percent, and for construction steel it is 97 percent for steel beams and girders, but only 65 percent for reinforcement steel. Still, the steel discarded each year is enough to meet the needs of the U.S. automobile industry.
Steel recycling started climbing more than a generation ago with the advent of the electric arc furnace, a technology that produces steel from scrap using only one fourth the energy it would take to produce it from virgin ore. Electric arc furnaces using scrap now account for half or more of steel production in more than 20 countries. A few countries, including Venezuela and Saudi Arabia, use electric arc furnaces for all of their steel production. If three fourths of steel production were to switch to electric arc furnaces using scrap, energy use in the steel industry could be cut by almost 40 percent.
Restructuring the transportation system also has a huge potential for reducing materials use. For example, improving urban transit means that one 12-ton bus can replace 60 cars weighing 1.5 tons each, or a total of 90 tons, reducing material use by 87 percent. Every time someone decides to replace a car with a bike, material use is reduced by 99 percent.
The big challenge in cities everywhere is to recycle, since recycling uses only a fraction of the energy of producing the same items from virgin raw materials. Virtually all paper products can now be recycled. So too can glass, most plastics, aluminum, and other materials from buildings being torn down. Advanced industrial economies with stable populations, such as those in Europe and Japan, can rely primarily on the stock of materials already in the economy rather than using virgin raw materials. Metals such as steel and aluminum can be used and reused indefinitely.
One of the most effective ways to encourage recycling is to adopt a landfill tax. For a recent example, the state of New Hampshire adopted a "pay-as-you-throw" program that encourages municipalities to charge residents for each bag of garbage. In the town of
San José, California, already diverting 62 percent of its municipal waste from landfills for reuse and recycling, is now focusing on the large flow of trash from construction and demolition sites. This material is trucked to one of two dozen specialist recycling firms in the city. For example, at
Before the program began, only about 100,000 tons per year of the city's mixed construction and demolition materials were reused or recycled. Now it is nearly 500,000 tons. The scrap metal that is salvaged goes to recycling plants, the wood can be converted into mulch or wood chips for fueling power plants, and the concrete can be recycled to build road banks. By deconstructing a building instead of simply demolishing it, most of the material in it can be reused or recycled, thus dramatically reducing energy use and carbon emissions. San José is becoming a model for cities everywhere.
* Next week I will look at more ways in which companies, communities, and individuals can reduce materials use and increase energy efficiency.
For more on this subject, see Chapter 11, "Raising Energy Efficiency" in