No more power lines?

The supercooled cables from American Superconductor, the nation’s largest maker of superconducting cable, are already being used in small projects by the Long Island Power Authority, American Electric Power, and National Grid. Perhaps two dozen locations worldwide rely on superconducting cable, but often it is to connect key stations less than a mile from each other.

Tres Amigas would be a “game changer,” company officials say.

“What we’re starting to see is a new phase in commercialization of superconducting cable – not just in this country but globally,” says Daniel McGahn, president and chief operating officer of American Superconductor in Devens, Mass.

A tour of American Superconductor’s factory found the company creating flat metal tape out of “high-temperature superconducting” (HTS) oxide materials and costly silver, then slicing it into thin flat strips. The strips wrap around a pipe carrying liquid nitrogen, which cools the cable to minus 346 degrees Fahrenheit.

At that temperature, electrons that ordinarily move randomly, losing energy in bumper-car-like collisions that generate heat, shift to highway mode. Electrons then move in pairs in one direction, generating no heat and losing no energy.

Eliminating the inefficiencies of traditional copper wires would save around $16 billion a year, estimates the US Department of Energy – and pave the way for long-distance transmission of wind and solar power. Another advantage: Being underground, the cable would be resistant to terrorist strikes.

Cost, however, has long been a major issue. However, the price gap is closing, American Superconductor says. A 1,000-mile length of superconducting cable capable of carrying 5,000 megawatts would cost about $8 million to $13 million per mile, a recent company white paper says. That’s about on par with the 
$7 million to $10 million cost per mile for an equivalent conventional 765 kilovolt line.

Tres Amigas trading hub – which Harris says would be the world’s largest use of superconducting cable – is like an automobile traffic circle. It could bring into the loop up to 5,000 megawatts of power at any one moment from any or all of the three grids. The power would then be sent out to whichever grid needs the electricity.

“We need the ability to send energy produced in New Mexico to surrounding states,” Gov. Bill Richardson said in a statement in October. “Tres Amigas will break that barrier, creating a larger market for our energy.”

But there are larger implications here, too. Building 130-foot-high transmission lines to deliver renewable energy from distant locations to big cities is a costly challenge. One major expense comes from potential neighbors who file lawsuits to avoid alternative-energy projects or connecting wires from obscuring historical areas or natural vistas. This not-in-my-backyard mentality could drastically slow the nation’s renewable-power development.

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