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.