Japan takes superconducting power transmission leap
TOKYO -- Superconducting power transmission technology, which promises to deliver electricity while leaking almost none along the way, has entered the practical stage in Japan, offering a potentially less costly way to operate trains and a possible countermeasure to global warming.
A Japan Railway-affiliated research institute has laid a 1.5-km superconducting transmission line -- the world's longest practical-use cable -- at a facility in Miyazaki Prefecture, where it is holding demonstration tests.
The production of the line was outsourced to Mitsui Mining & Smelting, and several railroad companies are showing interest in adopting the technology, the institute said.
Transmission loss is mainly caused when electricity turns into heat due to the electrical resistance of electric wires. When a transmission line is cooled to minus 269 C with liquid helium and put into a superconducting state, however, the electrical resistance becomes zero, and power loss can be all but eliminated.
The technology's cost had been a major hurdle to its spread. But thanks to the development of materials that can be superconducting at minus 196 C, liquid nitrogen can be used as a coolant, which is 10% cheaper than the standard liquid helium.
https://asia.nikkei.com/Business/Technology/Japan-takes-superconducting-power-transmission-leap