Saturday, May 23, 2009

Wire Power

Here's a short article on the effort (and advantages) of using superconducting wires for power transmission.

"They" are scientists and engineers at a handful of companies in Europe, the U.S. and Japan who have figured out how to turn brittle, fragile superconductors into flexible wires. "We basically found a way to bend the unbendable," says Greg Yurek, who left the MIT faculty in the late 1980s to found American Superconductor in Massachusetts. Superconductors have found their way recently into ships, wind turbines and electric cars. But the big push now is for power transmission. A major element of the "smart grid" is a new set of long-distance power lines to carry electricity from renewables like wind and solar. Conventional power lines are expensive, unsightly and wasteful-they can lose 14 percent of their energy from the resistance of the copper cables.

Superconducting cables have no such problem. A set of cables carrying five gigawatts of power-the output, of, say, five big nuclear power plants-can fit into a pipe just three feet across, and you could even bury it underground. Part of the pipe will be taken up with a cooling system: these superconductors work only when kept at the temperature of liquid nitrogen, about minus-170 degrees Celsius. Nitrogen is relatively cheap to manufacture and keep cold compared with the liquid helium (minus-269 degrees) needed for old-fashioned superconductors. The cooling equipment draws some energy from the cable, but still far less than the losses in copper cable. Even so, the power industry isn't likely to trash its old but serviceable transmission lines and install superconductors, even if they are more efficient. If the world is going to start using climate-friendly renewables, it'll require new transmission lines anyway. In the U.S., for example, the most abundant and reliable wind power comes from a belt stretching from Texas north to the Dakotas. The best spots for solar are in Arizona and New Mexico. The biggest consumers of electricity-the cities-are mostly along the coasts and near the Great Lakes.

The article is obviously referring to the high-Tc cuprate superconductors that have a critical temperature above liquid nitrogen. There's a lot yet to be done, but the commercial application using these superconductors are growing every year.


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