• Energy Research
• University of North Texas close

The magnetically confined kinetic-energy storage ring (MCKESR) is a new, fundamental type of energy-storage device. Energy is stored as kinetic energy in mass circulated at high velocity around a circular loop. The constraining force necessary to keep the circulating ring from flying apart is provided by radial, inwardly directed forced exerted along the perimeter of the loop by magnetic fields. The magnets and ring are contained in a tunnel, which may be buried in the ground. Levitational support against gravity is also provided by magnetic fields. Energy insertion or extraction is similar to that for a synchronous motor.

There is a need to generate magnetic fields both above and below 1 megagauss (100 T) with compact generators for laser-plasma experiments in the Beamlet and Petawatt test chambers for focused research on fundamental properties of high energy density magnetic plasmas. Some of the important topics that could be addressed with such a capability are magnetic field diffusion, particle confinement, plasma instabilities, spectroscopic diagnostic development, material properties, flux compression, and alternate confinement schemes, all of which could directly support experiments on Z. This report summarizes a two-month study to develop preliminary designs of magnetic field generators for three design regimes. These are, (1) a design for a relatively low-field (10 to 50 T), compact generator for modest volumes (1 to 10 cm3), (2) a high-field (50 to 200 T) design for smaller volumes (10 to 100 mm3), and (3) an extreme field (greater than 600 T) design that uses flux compression. These designs rely on existing Sandia pulsed-power expertise and equipment, and address issues of magnetic field scaling with capacitor bank design and field inductance, vacuum interface, and trade-offs between inductance and coil designs.

The cost of superconducting magnets and the refrigerators needed to keep them cold can be estimated if one knows the magnet stored energy and the amount of refrigeration needed. This report updates the cost data collected over 20 years ago by Strobridge and others. Early cost data has been inflated into 1991 dollars and data on newer superconducting magnets has been added to the old data. The cost of superconducting magnets has been correlated with stored energy and field-magnetic volume product. The cost of the helium refrigerator cold box and the compressors needed to keep the magnet cold can be correlated with the refrigeration generated at 4.5K. The annual cost of 4.5K refrigeration can be correlated with 4.5K refrigeration and electrical energy cost.

By various theorems one can relate the capital cost of superconducting magnets to the magnetic energy stored within that magnet. This is particularly true for magnet where the cost is dominated by the structure needed to carry the magnetic forces. One can also relate the cost of the magnet to the product of the magnetic induction and the field volume. The relationship used to estimate the cost the magnet is a function of the type of magnet it is. This paper updates the cost functions given in two papers that were published in the early 1990 s. The costs (escalated to 2007 dollars) of large numbers of LTS magnets are plotted against stored energy and magnetic field time field volume. Escalated costs for magnets built since the early 1990 s are added to the plots.

The original goal of this Phase II Superconductivity Partnership Initiative project was to build and operate a prototype Magnetic Resonance Imaging (MRI) system using high temperature superconductor (HTS) coils wound from continuously processed dip-coated BSCCO 2212 tape conductor. Using dip-coated tape, the plan was for MRI magnet coils to be wound to fit an established commercial open geometry, 0.2 Tesla permanent magnet system. New electronics and imaging software for a prototype higher field superconducting system would have added significantly to the cost. However, the use of the 0.2 T platform would allow the technical feasibility and the cost issues for HTS systems to be fully established. Also it would establish the energy efficiency and savings of HTS open MRI compared with resistive and permanent magnet systems. The commercial goal was an open geometry HTS MRI running at 0.5 T and 20 K. This low field open magnet was using resistive normal metal conductor and its heat loss was rather high around 15 kolwatts. It was expected that an HTS magnet would dissipate around 1 watt, significantly reduce power consumption. The SPI team assembled to achieve this goal was led by Oxford Instruments, Superconducting Technology (OST), who developed the method of producing commercial dip coated tape. Superconductive Components Inc. (SCI), a leading US supplier of HTS powders, supported the conductor optimization through powder optimization, scaling, and cost reduction. Oxford Magnet Technology (OMT), a joint venture between Oxford Instruments and Siemens and the world’s leading supplier of MRI magnet systems, was involved to design and build the HTS MRI magnet and cryogenics. Siemens Magnetic Resonance Division, a leading developer and supplier of complete MRI imaging systems, was expected to integrate the final system and perform imaging trials. The original MRI demonstration project was ended in July 2004 by mutual consent of Oxford Instruments and Siemens. Between the project start and that date a substantial shift in the MRI marketplace occurred, with rapid growth for systems at higher fields (1.5 T and above) and a consequent decline in the low field market (<1.0 T). While the project aim appeared technically attainable at that time, the conclusion was reached that the system and market economics do not warrant additional investment. The program was redirected to develop BSCCO 2212 multifilament wire development for high field superconducting magnets for NMR and other scientific research upon an agreement between DOE and Oxford Instruments, Superconducting Technology. The work t took place between September, 2004 and the project end in early 2006 was focused on 2212 multifilamentary wire. This report summarizes the technical achievements both in 2212 dip coated for an HTS MRI system and in BSCCO 2212 multifilamentary wire for high field magnets.

The vector potential and the magnetic field have been derived for an arrays of quadrupole magnets with thin Cos(2{theta}) current sheet placed at r = R.{sup bc}. The field strength of each coil within the array, varies purely as a Fourier sinusoidal series of the longidutinal coordinate z in proportion to {omega}{sub m}z, where {omega}{sub m} = (2m-1){pi}/L, L denotes the half-period, and m = 1,2,3 etc. The analysis is based on the expansion of the vector potential in the region external to the windings of a linear 3D quad, and a revision of that expansion by the application of the 'Addition Theorem' from that around the coil center to that around any arbitrary point in space.

Work is reported on the development of superconducting tokamak poloidal field system (TPFS) program. Progress is discussed on the design of the 20 MJ, 50 kA, 7.5 T superconducting pulsed energy storage coil to be operated in a bipolar mode from +7.5 T to -7.5 T in an energy transfer period of 1.5 to 5 s in 1982 followed by extensive cyclic testing. The facility to conduct the tests uses a traction motor energy transfer system and a nonconducting dewar. Status of the hardware development for the TPFS program is presented. Current interrupter development and testing for protection and energy transfer circuits are also presented. The 400 kJ METS coil test results are given.

A 30 MJ superconducting magnetic energy storage (SMES) system was designed and developed for application in the Western US Power System to damp power oscillations that limit high voltage ac transmission. The system is in place at the Bonneville Power Administration (BPA) Tacoma Substation and has been in an experimental use for over a year. Extended operations of the unit have been undertaken with success. The physical, electrical, and operational features of the SMES system are given.

The inherently high storage efficiency, instantaneous dispatch capability and multi-function uses of superconducting magnetic energy storage (SMES) are attributes that give it the potential for widespread application in the electric utility industry. Opportunities appear to exist where SMES at a given location could provide multiple benefits either simultaneously or sequentially as system conditions dictate. These benefits, including diurnal storage and system stability and dynamic control enhancement, increase the application potential of SMES to a larger number of opportunities than might be justified by the value of its diurnal storage capability alone. However, the benefits an individual utility may realize from SMES applications are strongly influenced by the characteristics of the utility system, the location of the SMES unit and the timing of its installation in the system. Such benefits are typically not evaluated adequately in generic studies. This paper summarizes results of case studies performed by Pacific Northwest Laboratory (PNL) with funding provided by the Bonneville Power Administration (BPA) and the Electric Power Research Institute (EPRI). The derivation of SMES benefits and costs are described and benefit/cost (B/C) ratios are compared in system-specific scenarios of interest to BPA. Results of using the DYNASTORE production cost model show the sensitivity of B/C ratios to SMES capacity and power and to the forecast system load. Intermediate-size SMES applications which primarily provide system stability and dynamic control enhancement are reviewed. The potential for SMES to levelize the output of a wind energy complex is also assessed. Most of the cases show SMES to provide a positive net benefit with the additional, sometimes surprising indication, that B/C ratios and net present worth of intermediate-size units can exceed those of larger systems.