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Enabling Technology Project

Superconducting Electric Power Equipment Using Liquid Hydrogen Cooling

Outline of the area

Hiroyuki Ohsaki
Professor, The University of Tokyo

The energy system utilizing hydrogen as fuel or energy carrier is expected to greatly reduce the emission of CO2, and various research and development is being conducted. In this project, an energy equipment system integrating the hydrogen technology and the superconductive technology, in which hydrogen is utilized in the form of liquid hydrogen also as extremely low temperature refrigerant, is developed as innovative low carbon technology. The superconductive electrical equipment with liquid hydrogen cooling is expected to be technology to improve the efficiency and to lower the CO2 emission in the system and are largely progressed. These include the superconductive power generator with liquid hydrogen cooling applicable for the power generation system utilizing the hydrogen turbine and the controlling system for electrical system in which the fuel battery and the super conductive energy storage such as SMES (Superconducting Magnetic Energy Storage) are combined as an energy storage device suppressing the output power fluctuations of the renewable energy.
Hence, focused on the superconductive coil with liquid hydrogen cooling at a technical level for equipment application, a project is conducted by organically cooperating the various technologies from the applicable low cost superconductive long-length superconductive wires based on MgB2 wires, REBCO superconductive wires and so on, to the cryogenic technology by liquid hydrogen and the equipment systems technology such as magnets and rotators, thereby accelerating the research and development for practical use.

JAXA Noshiro Rocket Testing Center

This center is also utilized as a field for Joint Research with Universities promoted by JAXA (Japan Aerospace Exploration Agency), and a lot of collaborative research is conducted, such as the test for thermal hydraulics of liquid hydrogen, in cooperation with Kyoto University.

MgB2 superconducting coil

This coil is a small one which is experimentally produced by using MgB2  superconducting wires prepared with the PIT (power-in-tube) method. The MgB2  superconducting wires are relatively easy to make in a long length without using expensive rare earth metals, and are promising for practical use. Incidentally, the MgB2  that shows a super conductive phenomenon was found by Akimitsu et al. in 2001 in Japan.


Development of Low-Cost REBCO Coated Conductors

Kaname Matsumoto
Professor, Graduate School of Engineering, Kyushu Institute of Technology

For superconducting equipment with liquid hydrogen cooling, longlength superconducting wire with high performance needs to be developed at a low cost, in addition to the improvements of the superconducting engineering and cryogenics. In the present work at ALCA, the artificial pinning center technology, in which high Jc is demonstrated at 77K by artificially introducing crystal defects of the nano-scale to rare earth based high temperature superconducting wire, is newly applied at 10 to 30K to achieve the improvement of the wire performance by several tens of times over. By using the artificial pinning center technology, the necessary thickness of superconducting film can be reduced to a fraction of the conventional one, and as a result, drastic cost reduction in wire manufacturing can be established.

Development of low-cost REBCO coated conductors


Development of High Performance MgB2 Long Conductors

Hiroaki Kumakura
Senior Scientist With Special Missions, High temperature superconducting wires group, National Institute for Materials Science

Based on the development for MgB2 superconducting wires in the past ALCA project, we develop 100m-1km long class single-and multi-filamentary MgB2 superconducting wires applying an internal Mg diffusion process with the filaments composed of an intermediate B powder layer and an Mg core at the center. We investigate the prepared superconducting wires in detail, such as the microstructure of filaments and the local critical-current variations, and give feedback on the manufacturing process of superconducting wires. As such, we are aiming to develop a high-performance and low-cost MgB2 superconducting wire with the applicable level criticalcurrent property at the temperature of liquid hydrogen (20K) and at 5T in magnetic field. Further, long developed superconducting wires will be supplied to the Hamajima group and the Shirai group in ALCA Enabling Tech.

Development of high performance MgB2long conductors

Cross sectional photograph (prior to heat treatment) Diameter: 0.88 mm

Development of high performance MgB2 long conductors

A 100m-long class single core MgB2 superconducting wire having iron sheath (covering) has been manufactured. In the future, highly stable longitudinal MgB2 superconducting wire having copper (alloy) coating will be developed, based on the same technique.


Development of Liquid Hydrogen Cooled MgB2 Superconducting Power Apparatus

Yasuyuki Shirai
Professor, Graduate School of Energy Science, Kyoto University

The issue is for low carbon technology based on the superconductive equipment with liquid hydrogen cooling and the hydrogen and electricity coordinated energy infrastructure based on it to be the key. We attempt to promote the introduction of a large renewable energy source by lowering the introducing hurdle of the hydrogen energy with positive utilization of the liquid hydrogen cooling, and by enhancing the flexibility of the more complex power system from introducing the high performance and high efficiency superconductive equipment. In the present ALCA research, we conducted development of elemental technology of superconductive equipment with liquid hydrogen cooling and its cooling system, investigation of the property of the superconductive wire for liquid hydrogen cooling, and the review of an effect upon introducing the hydrogen and electricity coordinated energy system.

Development of liquid hydrogen cooled MgB2 superconducting power apparatus
One example of superconductive power generators with liquid hydrogen cooling and hydrogen and electricity coordinated energy infrastructure

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