Superconducting cables were used to supply electricity to consumers for the first time in the world beginning May 28. Some 150,000 residents in the Amager district of Copenhagen, Denmark, are predicted to have their electricity supplied by this new technology.

Discovered as far back as 1911, the phenomenon of superconductivity occurs at extremely cold temperatures and causes almost all electrical resistance — and thus energy loss — to disappear. Within the last 15 years, materials have been discovered that require cooling with only liquid nitrogen (-196°C or -321°F). The Danish technology group NKT has been involved in the research race since the 1980s.

Copenhagen's new super cable is 30 m (98 ft) long, but is ample for practical full-scale testing in the public supply grid. The cable is installed at Amager Substation, a central hub in the Danish capital's energy-supply system.

The super cable is capable of supplying electricity to the whole Amager district and will be tested under all operating conditions. The use of extremely cold liquid nitrogen to cool the cable is a new element in electricity supply. The cable consists of three separate superconducting cables each 30 m (98 ft) long spliced into the grid where the voltage is 30 kV. The super cable has a 2000-amp current rating.

The high-tech superconducting cable was fabricated by NKT's cable company NKT Cables and now will undergo full-scale testing by Copenhagen Energy.
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