Saturday, July 12, 2008

Superconductive transmission goes online

I missed this one last week, but it's highly significant, I think. From IEEE Spectrum Online: Last Wednesday, American Superconductor officially commissioned the world's first high-temperature superconductor power-transmission cable system to be used in a commercial power grid. Superconductors can supply lots of energy quickly, efficiently, and unobtrusively. They conduct 150 times the electricity of similarly sized copper wires. However, because of technological difficulties, the commercial development of superconductor power-cable systems has been slow.

The system commissioned last week, part of the Long Island Power Authority's grid and funded by the Department of Energy, consists of three cables operating at 138 kilovolts. It was energized in April 2008 and has the ability to power 300 000 homes when operating at full capacity.

However, there are still some technological hurdles to overcome before superconductors replace the copper wires in our power grids. The main issue is cost. The first-generation cables, now operating successfully on Long Island, are costly, mainly because the wires are coated with silver. Testing has just begun on a second-generation cable coated with copper, which cuts four-fifths of the cost…..

….Besides economics, another advantage the company is touting is that the cables can prevent fault currents, surges that are caused by grid-scale short circuits. Superconductors have an inherent current-limiting ability in that if the current increases past a certain threshold, they lose their superconducting abilities and become normally resistive, damping the current.

American Superconductor is working with Consolidated Edison Co. to develop a fault-current-limiting superconductor power system in New York City. The Department of Homeland Security provided a grant for that project, which is expected to be operating by 2010....

Will transmission lines become relics? Photo by "Yanachka," who has generously released the image into the public domain via Wikimedia Commons

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