The Wonder of Superconductors

William Halperin investigates the super powers of superconductors — metals that carry electrical charge with zero energy loss.

“Electrical current passing without any frictional loss, without any dissipation whatsoever is a remarkable quantum mechanical effect,” says Halperin, John Evans Professor of Physics at Northwestern. That’s a big deal when you consider that about 7 percent of the energy generated by hydroelectric power at Niagara Falls is lost on its way to New York City.

That phenomenon of zero loss makes superconductors an appealing option in the transmission of power from a major power utility to industry. (The Long Island Power Authority and American Superconductor partnered on such a project in 2008.) Superconductors also use wires with smaller thickness for the same current, which could be beneficial as demand for energy increases in growing population centers. So, the application of superconductors might allow for more efficient use of space as well as reduce the loss of power in transmission.

As with most applications of superconductors, however, there’s also a downside. Superconductors must be kept cold in order to work.  “The goal would be to have such materials that exhibit this phenomenon [of resistance-free transmission] where you don’t need a refrigerator,” Halperin says.

Superconductors are also created from materials that are either fragile, expensive to fabricate or hard to manipulate.

With funding from the Initiative for Sustainability and Energy at Northwestern and grants from the Department of Energy, Halperin is conducting basic scientific investigations into the applications of superconductors, including the possibility that a coil of superconductive wire could create a magnetic field that might store electrical energy for use at a later time.

Other applications for superconductors include the use of magnetic fields for chemical analysis of new drugs. MRI technology also uses magnetic fields created by superconductors. In telecommunications, superconductors can be used as filters to allow for more efficient use of available frequency bands.