Superconducting Cables to Connect Solar Plant, Data Center

2014/02/12 21:18
Kenji Kaneko, Nikkei BP CleanTech Institute

Sakura Internet Inc, Chiyoda Corp, etc established a technology research association for promoting a direct-current (DC) power transmission business using high-temperature superconducting cables.

Sakura Internet is a Japan-based firm that runs data centers. The business is planned to start in Ishikari City, Hokkaido.

In Phase 1, a solar power plant and a data center will be connected by using about 500m-long high-temperature superconducting cables. And electricity generated at the plant will be directly used at the data center. In Phase 2, a transforming substation of Hokkaido Electric Power Co Inc (HEPCO) and a data center will be connected by using about 2km-long superconducting cables by the end of March 2018 so that commercial power can be directly transmitted to the data center from HEPCO.

The technology research association established by Sakura Internet, Chiyoda, etc is Ishikari Superconducting, Direct-current Power Transmission System Technology Research Association. After multiple companies were entrusted with a task (operation test of high-temperature superconducting DC power transmission systems) by Japan's Ministry of Economy, Trade and Industry (METI), the association was formed as an operating body. In addition to the two firms, Sumitomo Electric Industries Ltd and Chubu University participated in it.

In the operation test, a superconducting cable whose electrical resistance becomes zero when it is cooled with liquid nitrogen (-196°C) will be used. It was developed by Sumitomo Electric. By transmitting DC electricity with the superconducting cable, energy loss at the time of power transmission is expected to be drastically reduced, compared with conventional systems that transmit alternating-current (AC) electricity with metal cables.

In Phase 1, the "Ishikari Data Center" of Sakura Internet and a solar power plant that the company will build in an area adjacent to the data center will be connected by using about 500m-long superconducting cables. The data center has already been equipped with a "high-voltage direct-current (HVDC) power transmission system." And its power utilization efficiency has been improved by reducing the number of AC/DC conversions from three to one at the time of using commercial AC power for servers.

In the operation test, DC power transmitted from the solar power plant will be directly input into the HVDC power transmission system and used for operation of the data center.

The trend of actively using electricity generated with renewable energy for operation of data centers, which consume a large amount of electricity, has been followed by many companies, especially the US- and Europe-based leading IT firms including Google Inc and Apple Inc. And the efforts of Sakura Internet are part of this trend.

Sakura Internet intends to make wide use of renewable energy-derived electricity in Hokkaido. For example, it is planning to connect the Ishikari Data Center to Wakkanai City (Hokkaido), where there are many wind power generation facilities, by using superconducting cables in or after 2020.