News Release
February 17, 2022
The World’s First Demonstration Test to Install a Tri-axial
Superconducting Cable System into a Commercial Plant
Grid Completed－Expected to cut over 95% of transmission loss by applying it to plants with highpower usage－
New Energy and Industrial Technology Development Organization (NEDO)SWCC SHOWA CABLE SYSTEMS CO., LTD.
BASF Japan Ltd.
Translation of Japanese NEDO news release posted on December 6, 2021

The New Energy and Industrial Technology Development Organization (NEDO),SWCC Showa Cable Systems Co., Ltd. (SWCC), and BASF Japan Ltd. (BASF) havecompleted the world’s first demonstration test of a tri-axial superconducting cablesystem installed in a commercial chemical plant’s grid at BASF Japan’s Totsuka site
(Totsuka Ward, Yokohama City). The test was carried out from November 2020 to
September 2021 under the Strategic Innovation Program for Energy Conservation
Technologies.
As a result of this test, it was verified that the system is capable of supplying power
continuously and stably for about one year. It was also verified that cooling cables
using liquid nitrogen is reliable and safe thereby maintaining a superconducting stateeven during extremely hot weather when cooling is difficult. Additionally, the test wassuccessful in reducing the installation and operating costs of the system by using
existing facilities.
By adopting the system in a plant that uses more than 30 MW of large-scale powercompared to conventional systems, there is a possibility of losses during powertransmission being reduced by more than 95% and the effect of reducing CO 2
emissions has also been confirmed.
These results prove that the system can contribute to a decarbonized society as anefficient power transmission system.

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February 17, 2022

Source: Prepared by NEDO based on the digital map published by the Geospatial Information Authority of Japan

Figure 1. Cabling layout at installation site
1．Overview
The effective use of electric power has become an urgent issue, with the need to reduce greenhousegas emissions as a countermeasure to global warming. As a highly efficient power supply technologythat does not cause power loss due to its zero electrical resistance, superconductivity technology has
attracted a lot of attention from various fields such as electric energy, electronics, medicine, andtransportation. However, in order to maintain a superconducting state, the technology must be kept
cool with liquid nitrogen, and the like. Therefore, it was necessary to establish a low-cost operational
technology for practical use.
Against this backdrop, NEDO has been promoting the Strategic Innovation Program for Energy
Conservation Technologies*1 with the aim of building an energy-saving economy and society andstrengthening industrial competitiveness in Japan. In this program, Showa Cable Systems Co., Ltd.
(SWCC) and BASF Japan Ltd. (BASF) completed a demonstration test in September 2021 at BASF
Japan’s Totsuka site, which they had been jointly carrying out since November 2020*2.
A low cost and compact tri-axial superconducting cable system developed from FY2017 to FY2018
was installed*3 for the test. As a result, it was verified that the system is capable of supplying power
continuously and stably for about one year. It was also verified that cooling cables using liquid nitrogenis reliable and safe thereby maintaining a superconducting state even during extremely hot weather
when cooling is difficult. Additionally, the test was successful in reducing the installation and operating
costs of the system by using existing facilities.
The energy-saving effect of installing the system will be even greater when applying it to a grid thatenergizes a large current. Therefore, it is expected that it will be applied to factories that use large
amounts of electricity, bus bars in power plants, and in the future, to the infrastructure of smart cities.
In plants that handle cold heat, such as liquid nitrogen, the cold heat can be used for cooling,eliminating the need to install a chiller, making the system relatively low-cost to operate and highlyeffective to install. By replacing a conventional cable with the system in plants that use more than 30
MW of large-scale power, there is a possibility that losses during power transmission can be reducedby more than 95%. The effect of reducing CO2 emissions has also been confirmed, therefore provingthat this cable system can contribute to a decarbonized society as an efficient power transmission

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February 17, 2022
system.
2．Results of this project(1) Development of a low-cost, compact cable systemInpractical

application

development(FY2017–FY2018),

alow-cost,compact,

tri-axial

superconducting cable for general plants was developed, as shown in Figure 2. The concentricarrangement of the three conducting phases results in a net cancellation of the magnetic fields during
normal operation. As a result, the amount of coated conductor used can be reduced to one-third ofthat of single-core cables, and the total cost of coated conductor can be reduced to two-thirds. In
addition, by using a tri-axial type, a single cable is used to achieve a compact and flexible structure.

Figure 2. Tri-axial superconducting cable
Conventional single-core cables require six terminals to supply power to each of the three-phase
ACs independently. On the other hand, the tri-axial superconducting cable has only two terminals by
arranging the electrodes coaxially, resulting in a compact shape as shown in Figure 3.

Figure 3. Terminal of tri-axial superconducting cable
In conjunction with the tri-axial structure of the cable, the interconnection also adopted a coaxial
cable joint structure that was developed from existing technology. As a result, a compact shape withan outer diameter of 340 mm was achieved, as shown in Figure 4. A cable joint technology with low

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February 17, 2022
electrical resistance was established, making it possible to extend the cable.

Figure 4. Cable joint of tri-axial superconducting cable
A subcooled cooling system that was jointly developed by Air Water Inc. and SWCC, as shown in
Figure 5, was adopted in this test. In this cooling system, liquid nitrogen stored in a sealed container
is depressurized to cool it to minus 200°C using the latent heat of evaporation when the liquid changes
to gas. The concept of the design is to use liquid nitrogen, which the plant has in large quantities, asa refrigerant, and recover nitrogen gas exhausted to reduce pressure for reuse in the plant.
Since the tri-axial superconducting cable system is used with constant cooling, it is necessary toconstantly monitor the status of liquid nitrogen used for cooling. In this test, sensors to measurepressure, temperature, flow rate, and liquid level were arranged at both terminals, and this data wasmanaged by a monitoring system. A function to switch the power transmission circuit in case ofemergency has also been added.

Figure 5. Subcooled cooling system(2) Confirmed the ease of cable installation and energy-saving effects by carrying out this test at anactual plant.

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February 17, 2022
A special condition of this test was that it was necessary to use the plant’s existing facilities, so thecable was installed on an existing rack, which is located about 5 meters above the ground. Therefore,
it was necessary that the cable was bent 90 degrees (bending radius 1.5 meters) at four locations asshown in Figure 7, but the flexibility of the cable allowed it to be installed without any problems.
Although the flow path of liquid nitrogen becomes narrower at bends with a compact cable, it can flow
over long distances (approximately 400 meters round trip) in the system without any problems,confirming that it can be used for complex plant layouts.

Figure 6. Tri-axial superconducting cableinstallation in an existing rack(5 meters high)Figure 7. Bending parts of tri-axial
superconducting cable(90 degrees, bending radius 1.5 meters)

Reduced heat penetration due to the compactness of parts such as cables, terminals andintermediate connections, and the energy-saving effect of utilizing the existing liquid nitrogen storage
in the plant were almost exactly as designed. Based on the results of this test, a comparison wasmade between the power transmission loss generated over a period of one year by energizing a 1,000
m-long tri-axial superconducting cable and a conventional cable (CV cable) with 3,000 A of a threephase AC (Figure 8). This comparison shows that replacement with this tri-axial superconducting
cable system is expected to reduce the amount of power loss generated with the conventional cableby 95%.

Figure 8. Comparison of annual power transmission loss
In this test, power was supplied without incident for about one year, and the stable circulation ofliquid nitrogen was confirmed despite extremely hot weather. Conventional liquid nitrogen pumps
require overhauling every few months, but a liquid nitrogen pump developed in this project has
achieved accident-free and maintenance-free operation for about one year. This means that theNews Release
February 17, 2022
maintenance of the liquid nitrogen pump can be carried out in conjunction with regular plantinspections, proving its high practicality.
In addition, as a result of constant monitoring throughout the test period by a monitoring systemdeveloped for this test, the effectiveness of the tri-axial superconducting cable system was confirmed,
and it was also confirmed that the monitoring system can be unmanned.
By applying the system to plants, significant energy-saving effects can be expected. Figure 9 shows
the relationship between the initial investment payback period and energy savings when the system
is installed. Each bubble is color-coded to indicate the presence and type of cooling system being
used, and the size to indicate the number of alternative lines. For example, if the initial investment
payback period is set at 10 years or less, 1,080 lines (about 300 sites) will be targeted. Among thoselines, there are 420 lines (about 190 sites) that use liquid nitrogen (green bubbles) and 30 MW ofelectricity. The annual energy saving would be about 110 kL in crude oil equivalent, indicating that theinitial investment can be recovered in about 8 years.

Figure 9. Relationship between the initial investment payback period and energy savings
A video of the demonstration test is available on the NEDO Channel, NEDO's official YouTubechannel, from 1:00 p.m. JST on Monday, December 6.
The world’s first demonstration test to install a superconducting cable into a commercialplant system was completed
https://www.youtube.com/watch?v=VyCUbPG_qRw&list=PLZH3AKTCrVsVzmrljRdMW4ppYDHkVlai&index=3
3. Future plans
Through this demonstration test, NEDO, SWCC, and BASF verified the installation method andoperational management method at a private plant, as well as the energy-saving effects, and obtained
results as expected. Work will continue towards the practical application of the system and link theresults to the reduction of greenhouse gas emissions through the effective use of electric energy toachieve a decarbonized society.

[Notes]*1 Strategic Innovation Program for Energy Conservation Technologies
Research and development items: Development and Demonstration/Development of a Low-Cost Triaxial Superconducting
Power Cable for In-Plant Use
Period: 2017 - the end of October 2021
Project participant: SWCC Showa Cable Systems Co., Ltd.
Project participant's contractors: BASF Japan Ltd., Air Water Inc., Kyushu University, Tohoku University*2 Reference: NEDO news release, June 12, 2019, “World's first demonstration test of tri-axial superconducting cable tobe started at a private plant”
https://www.nedo.go.jp/news/press/AA5_101132.html*3 Reference: NEDO news release, November 11, 2020, "World's first installation of tri-axial superconducting cables in aprivate plant.”
https://www.nedo.go.jp/news/press/AA5_101377.html

4．For more information, please contact:(Inquiries related to this news release)
NEDO Energy Conservation Technology Department, Development Group I
Contact persons: Kinoshita, Iwamoto TEL:+81-44-520-5281
Strategy Section Business Strategy Planning Dept.
SWCC SHOWA HOLDINGS CO., LTD.
TEL：+81-44-223-0520
Communications
BASF Japan Ltd.
TEL: +81-3-5290-2510
Email: communications-jp@basf.com(For inquiries related to superconducting cable system technologies and products)
Superconducting Applied Products and Development Section
Research & Development Center
SWCC SHOWA CABLE SYSTEMS CO., LTD.,
TEL: +81-42-773-7163