Posted on Thu, Aug. 28, 2003
3M says its new power cable could ease power grid strains
Associated Press
MAPLEWOOD, Minn. - 3M Co. is promoting a new kind of power line in hopes of drawing interest from utilities looking to prevent a repeat of this month's massive blackouts out east.
The Maplewood-based manufacturer is field testing an advanced cable that can transmit two to three times more electricity than conventional cables of the same diameter, without adding weight or the need to build more transmission towers.
The company says it might reduce electrical transmission congestion and prevent the bottlenecks and overload problems that are believed to have triggered the blackouts.
3M says the product has performed well in field tests in Minnesota, North Dakota and Hawaii. It also has been the subject of a pilot program at the Oak Ridge National Laboratories in Tennessee with the support of the U.S. Department of Energy.
Known as the 3M composite conductor, the heat-resistant conductor would enable utilities to increase power-line capacity on existing structures instead of incurring the expenses and clearing the political hurdles needed to build new transmission lines.
"Congestion is recognized as a key issue facing America's transmission grid and our unique conductor could well be an important part of the solution to this problem," said Tracy Anderson, who heads 3M's composite conductor program.
3M is holding initial discussions with customers about making the product widely available, but Anderson couldn't say how soon a rollout might take place.
She declined to name the companies that have expressed interest but said some were waiting for studies of the blackout to be completed before proceeding.
Anderson said the technology for the composite conductor grew out of the company's expertise in ceramics and ceramic fibers. The lightweight conductor is composed of a ceramic fiber-reinforced aluminum core wrapped in aluminum-zirconium wires and then in aluminum wire. The industry standard is a steel core wrapped in aluminum.
Xcel Energy has been testing the product in Minneapolis for about two years, said to Steve LaCasse, a principal transmission engineer at the utility.
LaCasse said Xcel has been pleased with the conductor, which 3M will take down next year and examine for durability. He said he will probably consider using the conductor as Xcel upgrades its lines.
Anderson said the field tests have been done in different climates to learn how the conductor withstands a variety of weather. In North Dakota, it is being tested to see how it performs when ice builds up on lines, Anderson said.
In Hawaii, the product is being tested on the north shore of Oahu to see how it withstands possible corrosion from salt water. The lines perform well, but it could still be another year or two before Hawaiian Electric Co. decides whether to buy more, said Sucuma Elliot, a technical services engineer with Hawaiian.
The new conductor also has been found to sag less than conventional power lines, so it might be used to span difficult geographic features, such as wide rivers, canyons or lakes.
At least two other companies are working on high-temperature, low-sag wires made of special composites, but "they're substantially behind 3M," said Luther Dow, director of power delivery and markets for the Electric Power Research Institute in Palo Alto, Calif.
In addition, two companies are working on lines made out of ceramic-based superconductors that are buried underground and can carry five times the power of conventional steel and aluminum cables. Intermagnetics General Corp. of Latham, N.Y., has completed a short demonstration project, and American Superconductor Corp. of Westborough, Mass., plans to have cables ready for commercial use in 2006 or 2007.
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