[Levin]

Can it be used at room temperature?

There is no super conductor at room temperature.

Not at room temperature. 

According to the article during testing in July, the cable is under refrigeration. The article stated that it was the longest superconducting cable so far that is operational in an urban core.

https://interestingengineering.com/innov...conducting

https://zmscable.es/en/cable-superconduc...kv-prueba/

South Korea did it first in 2019 but with a 1km cable instead of a 1.2km cable. 

https://transformers-magazine.com/tm-new...ing-cable/