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Aluminum’s Essential Efficiencies

Aluminum cans, car parts, gutters, siding—the demand for aluminum products continues to grow worldwide.

Kentucky, with the highest concentration and diversity of aluminum facilities in the world, is a key player in meeting this increasing demand. A recent study found that Kentucky’s aluminum industry shipped products worth $2.5 billion. With 112 aluminum industry facilities in the state, employing about 15,000 workers at an average salary of $45,000, aluminum has a huge economic effect on Kentucky.

Aluminum also has a huge impact on Kentucky’s electric generating and distribution system. Kenergy electric cooperative, headquartered in Henderson, is the nation’s largest electric co-op in terms of the amount of electricity supplied to customers, due to the tremendous amounts of power required at two aluminum smelters in its service area.

Century Aluminum in Hawesville, in Hancock County, requires roughly 488 megawatts every hour, and the Alcan Primary Metals Products smelter in Sebree, in Henderson County, requires at least 360 megawatts every hour of every day. That 848 megawatts is enough electricity to provide power for half a million homes.

But unlike homes, where lights and appliances cycle on and off throughout the day and night, varying from season to season, aluminum smelters run continuously every minute of the year.

Kenergy’s Director of Member Services David Hamilton says, “The aluminum smelters’ demand is a steady load on the area’s transmission system that must be met, no matter what is happening with demand elsewhere.”
Smelting aluminum is just one part of a long process that begins with bauxite ore. It includes an intermediate component called alumina.

Smelting is energy-intensive. During smelting, electrolytic reduction causes changes in the raw materials. Rather like melting cheese in a pan on the stove, the huge crucibles in an aluminum smelting plant contain ingredients that are “cooked” at extremely high temperatures. Part of this process involves passing large amounts of electric current through the alumina; it achieves a molten state, then succeeding steps remove impurities and add other elements, to eventually produce aluminum with the desired characteristics for various users in their respective manufacturing industries.

Secat Inc., at the University of Kentucky’s Coldstream Research Campus in Lexington, is dedicated to researching and developing innovative technologies and products for the aluminum and automotive industries.

Business manager Todd Boggess says, “Traditionally, melting aluminum involves using a flame fueled by natural gas. Secat recently began a research project to test if the use of immersion heater tubes, which could be powered by either natural gas or electricity, would improve energy efficiency. When using the traditional open flame method, a lot of heat is lost upward through the stack. It also allows oxygen to form a film, called dross, on the metal. Excess dross must be removed, and doing so results in energy waste. While the new technology is promising, the costs of new equipment or processes must be carefully balanced against payback times.”

Boggess notes that another Secat project involved energy audits of aluminum plants. Teams spent two to three days in an aluminum industry plant and looked at their entire processing cycle, then gave suggestions about where and how electricity could be saved in various motors, pumps, and compressors.

At the Alcan Primary Products Corporation’s Sebree Works, Acting Controller Pam Schneider takes a very practical approach.

“In general, the amount of power consumed per ton of aluminum produced has steadily declined over the years,” Schneider says. “Most of that is due to technological innovations in new plant design. A new smelting facility in Quebec, which Alcan brought into production in 2003, produces almost twice the amount of aluminum as our Kentucky facility, yet uses far less electricity per ton than we do.

“At our plant, built in 1972, we produce about 196,000 metric tons of aluminum annually,” Schneider continues. “Power accounts for about 40 percent of our overall cost here. In conjunction with Kenergy, we have just launched a project to help reduce electricity consumption in the nonsmelting operations of this plant. That includes everything, even the lights in my office.”

Schneider notes that her team went to every building on the site to look at every piece of equipment and exactly how people use it to do their jobs.

“We’ve put together an action plan,” she says, “with a goal of reducing our electricity cost by at least $100,000 annually. We want to be good community stewards, using only the amount of electricity we must and be as efficient about it as possible. However, we have to work within the technology we have at this older plant, so our goal is to be the benchmark, the most efficient in our class of facility.”

To find out more about the aluminum industry, visit these Web sites: www.world-aluminium.org or www.rocksandminerals.com.




ALUMINUM, THE RECYCLABLE

  • After its initial manufacture, aluminum is 100% recyclable.
  • Recycling used aluminum takes only 5 percent of the energy needed to make fresh aluminum from bauxite ore.
  • Recycling one can saves enough energy to power a 100-watt light bulb for four hours.
  • The Novelis Corporation’s Berea facility is the world’s largest plant fully dedicated to aluminum can recycling.

Next month: Balancing home electricity uses

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