In the United States the program to develop power applications of superconductivity is led by the Department of Energy Office of Energy Efficiency and Renewable Energy (DOE EERE), which has by far the largest U.S. program. It gains some support from the Electric Power Research Institute (EPRI) program and programs in the Defense Advanced Research Projects Agency (DARPA) and the Navy. The U.S. program has historically been large, but the uncertainties of the present program are considerable. This uncertainty is a major concern at present, since the technology is in the midst of a major thrust to address real utility applications.
There are two very well defined parallel thrusts in the U.S. program. The first focuses on development of HTS conductors. This thrust is based on a firm belief, which panelists found during our visits to be entirely shared by the Japanese and European research community, that the conductor is the critical element for the whole of HTS technology. However, conductors need devices to justify tackling the manifold problems of scaling up for production, and developing devices is the second thrust. Thus, a parallel program emphasizing both conductors and devices can develop effective and rapid feedback for the technology. These same two parallel thrusts characterize the U.S., Japanese, German, and Swiss programs.
A significant characteristic of the U.S. program is that it is more aggressively focused on early device demonstrations than that in either Germany or Japan. In both of those countries there is a greater sense that superconductivity is bound to be an important 21st century technology and that today's work can proceed in a measured and confident way. By contrast, the U.S. program is hustling along, trying to make HTS applications occur in the 20th century. A significant component of this effort has been an extremely effective linkage between the U.S. industry, national laboratories, and universities. This has been remarked upon specifically by members of Japanese study missions to the United States.
The DOE EERE program serves as the primary benchmark against which to compare the German and Japanese programs. The principal element of the DOE EERE program strategy is that there are both wire and systems technology components. Twenty-three companies, six national laboratories, and ten universities collaborate on the wire component within a legal framework that provides for intellectual property protections. The systems part of the program is carried out through the Superconductivity Partnership Initiative (SPI). This involves four industry-led teams, each of which is committed to substantial cost-sharing and to commercialization of the technology on which they are working.
Even a brief review of this program is impressive, considering that it was only in 1990 that the prospect of a reasonable conductor made from an HTS material was first demonstrated. Demonstration devices of real significance have come remarkably quickly in these past seven years, including a 200 horsepower industrial motor (Fig. 1.2), a 50 m, 1,800 ampere power cable, and a 2.4 kV fault-current limiter. These units have all been based on HTS conductors made from the (Bi,Pb)2Sr2Ca2Cu3Ox (BSCCO-2223) compound. Conductors made from BSCCO have been advancing very strongly since 1995, and these advances are not yet fully incorporated into the devices. Even more promising for conductor technology is that 1995-1996 brought genuine possibilities of second-generation conductors based on biaxially textured YBa2Cu3O7-[delta](YBCO).
Fig. 1.2. World-record 200 hp HTS motor tested by Reliance/DOE team in early 1996.
These developments use a technique first developed in Japan by Fujikura but since developed further in important ways by Los Alamos and Oak Ridge National Laboratories (LANL, ORNL). Table 1.1 summarizes the program and its thrusts and successes since its inception in 1990.
Achievements of the DOE Power Applications Program