United States

United States

Freeing the bottlenecks

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Wind power in the three states with the greatest wind potential in the northern United States is stymied because there is not enough transmission available to move the electricity to market. At least two US companies -- 3M and American Superconductor -- are experimenting with new line conductor technology that could increase transmission capacity along existing paths without going through the pain of building entirely new transmission lines.

One of those new power line conductors, being developed by 3M and the US Department of Energy (DOE) and undergoing field testing by the Western Area Power Administration (WAPA), may hold the key to getting wind energy out of Montana and North and South Dakota.

Made from a mix of zirconium and aluminium and woven into cable like a typical transmission line, 3M's aluminium conductor compost reinforced wire conducts two to three times more electricity, is temperature resistant, lighter and has less line sag than conventional aluminium transmission wire, says 3M's John Cornwell. The company is running the prototype wire through lab tests at the DOE's Oak Ridge National Laboratories and two limited field trials. So far it has tested a small wire in Hawaii and last month it installed a larger diameter wire on a one mile section of a WAPA 230 kV transmission line near Fargo, North Dakota, to test its ability to stand up to the extreme winter conditions of the region.

WAPA's LaVerne Kyriss says the federal agency has already identified a number of areas where the more efficient composite wire could be helpful. It would be especially promising when changing out conductors on existing transmission towers, she says. In most cases, the new conductor could be installed with no modifications to existing towers, so a line's capacity could be doubled or tripled without having any new towers or needing to buy new rights of way.

Although the new technology will reduce the public and regulatory battles typical of building new transmission lines, it does not necessarily result in a lower cost project. In fact, 3M's new product will cost more, but that could be offset by using existing infrastructure, as well as by the additional transmission fees a grid organisation can expect when using the new technology. 3M has yet to confirm those savings, so WAPA will complete a cost benefit analysis during the two year trial to determine if the new wire makes economic sense.

At this point, 3M is unable to manufacture the product on a large scale. "It's beyond the experimental lab phase," Cornwell says. "But it's not yet at the large scale production stage. That is several years away."

Europe testing

American Superconductor's Jack Jackson says the company has one generation of superconductor in commercial testing in Europe -- in Denmark and France -- and a few locations in the US and is working on the next generation of wire, a nitrogen-cooled coated conductor composite high temperature superconductor. It could be ready for commercial testing by 2005 or 2006. Greg Yurek, CEO of American Superconductor predicts the product will eventually prove to have a "price-performance ratio below that of copper."

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