World first in electricity transmission: Air Liquide partner of the longest superconductor cable

The world’s longest and most powerful superconductor power transmission cable has been connected to the commercial power grid in Holbrook, New York, United States, by the Long Island Power Authority (LIPA) and American Superconductor. The 600-meter long cable is cryogenically cooled thanks to the advanced technologies of Air Liquide, the world leader in cryogenics.

This project demonstrates the operation of a high voltage superconductor cable in an urban commercial power grid. Capable of transporting up to 2,400 amps (574 MVA in a 138 kV system), the superconductor cable is the first such high voltage electric cable in the world to be operating in a real transmission system. This cable transports more energy than all of the previously demonstrated high temperature superconductor (HTS) cables together and is capable of powering 300,000 homes.

Air Liquide is providing its innovative cryogenic technologies and the competencies of its teams in operating and maintaining cryogenic systems. The Long Island project involved public and private partners, including the U.S. Department of Energy and Nexans, the worldwide leader in the cable industry.

Superconductor cables can transport three to five times more energy than traditional cables. Capable of transporting electricity without resistance at a certain low temperature (in this case at -200°C), the HTS cables avoid energy loss along the cable. In order to use the exceptional properties of superconductor materials, it is necessary to keep the cables below their critical temperature through an appropriate refrigeration system using liquid nitrogen. Cryogenics is the key to superconductivity and Air Liquide’s fluid refrigeration and distribution system is the technological innovation that enables this performance.

François Darchis, Air Liquide Senior Vice-President in charge of R&D, Advanced Technologies and Engineering & Construction, said: “As the worldwide demand for energy continues to rise, and as the electricity grids become saturated in certain countries, Air Liquide is proud to contribute to the development of this particularly innovative technology which will not only produce significant energy savings in the transport of electricity, but will also lead to the construction of a new generation of energy distribution networks.”

Air Liquide is already involved in this project’s next steps to build a cable with second generation superconductor materials that are even more powerful. In this second phase, Air Liquide will develop special very low temperature refrigeration technology.