Future prospects of high T-c superconductors-coated conductors and their applications

The research and development of high-temperature superconducting wires, especially yttrium-based coated conductors (CCs), and their energy applications have been expected to reduce CO2 emissions. This article reviews recent progress in this area, mainly focusing on the results obtained by national projects in Japan. The I-c (critical current) x L (wire length) value of CCs has been improved to reach 466,752 A m (572 A/cm-W, 816 m), which exceeds that of Bi-system wires. CCs have also been improved in terms of in-field performance and AC loss reduction to meet market requirements. Power applications such as superconducting magnetic energy storage (SMES) systems, power cables and transformers have been developed using CCs in the current project. Because of fundamental research on high-capacity power cables, a low AC loss of 0.8 W/m-ph at 3 kA and 73.7 K was achieved. System design and fundamental research were performed on a 2GJ-class SMES system and a 20 MVA-class transformer. Based on the technologies developed by the end of the current project (FY2012), the innovation process of those applications will reach the implementation stage, where the long-term reliability tests will be performed. The process is expected to reach the penetration and propagation stage around 2020. (C) 2012 Elsevier B.V. All rights reserved.