Last update:  June 13, 2004 at 6:45 PM

Antidote for blackouts?

Xcel Energy Inc. might have found a local solution to summertime blackouts.

The Minneapolis energy company is considering a plan to buy a new, heat-resistant cable developed by 3M Co. that is designed to prevent bottlenecks on hot days when people crank up their air conditioners.

Known as the 3M composite conductor, the cable can transmit two to three times more electricity than conventional power lines, which should help to prevent the overloads that triggered blackouts last summer in parts of the Midwest and Northeast.

Another benefit: The line doesn't sag. Most power lines tend to elongate as more electricity passes through them, making them droop on hot days when use increases. 3M's cable is composed of a ceramic fiber-reinforced aluminum core that barely expands. That should reduce the stress on transmission towers and limit disruptions caused by power lines falling on objects.

3M said the product has performed well in field tests in Minnesota, North Dakota and Arizona. It has also been the subject of tests at Oak Ridge National Laboratories in Tennessee with the support of the U.S. Department of Energy.

"The outstanding results obtained by independent test laboratories have now been confirmed in the field," said Tracy Anderson, manager of 3M's composite conductor program.

Mary Sandok, an Xcel spokeswoman, said the company had installed a span of the cable in Minneapolis, but hasn't decided yet whether to use it with other projects.

No other utility nationwide is using the material commercially.

Chris Serres is at cserres@startribune.com.

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