High-temperature superconductor (HTS) wires are so efficient that they can carry up to 140 times the power of conventional copper wires of the same size. The potential uses for HTS wires in electric power applications include underground transmission cables, oil-free transformers, superconducting magnetic-energy storage (SMES) units, fault-current limiters, high-efficiency motors, and compact generators. Electricity grid losses have grown to be more than 10% of all electricity generated due to resistance and other losses in conventional equipment, and blackouts highlighted transmission bottlenecks in the United States in 2003.

Efficiency and reliability will be enhanced when new transmission technologies are used that have reduced line losses and the capability to carry more current for a given size of conductor. Superconductors have virtually no electrical resistance; therefore, they can carry current with no electrical energy loss. Superconductors are of two types: low- and high-temperature. Low-temperature superconductors (LTS) work at only very frigid temperatures, near 4 K (−452°F). Equipment made with LTS wires can be expensive to operate because they need to be chilled with liquid helium. Equipment with HTS wires, however, works at relatively warmer temperatures, near 77 K (−320°F), and requires liquid nitrogen to operate.