Government Lab Tests 'super' Power Cables For NYC

Less than a year ago, Oak Ridge scientists were still testing the new cables in an open bath of foggy liquid nitrogen. They are now testing the final prototype, which has layers of superconductive wire ribbon wrapped around a liquid nitrogen core.

"When you get it cold below superconducting transition temperature, it can carry an enormous amount of current," explained Chris Rey, who is overseeing the Oak Ridge tests.

In normal operation, the superconductor wire has little or no loss of electrical current known as resistance. But when a power spike occurs that could lead to a blackout, the cable comes out of its superconductor state and acts "exactly like a surge protector," he said. The extra electricity dissipates as heat.

American Superconductor CEO Greg Yurek said there have been 15-20 superconductor cable projects of various kinds built around the world since 1997. Project Hydra will be the first with "fault limiter" capability to suppress surges — a kind of firewall for the grid.

"Our sense is we are kind of at the tipping point now, once we are in Manhattan," Yurek said. "The eyes of the utility world are actually viewing this with great interest."