STRENGTHENING THE GRID Effect of High-Temperature Superconducting Power Technologies on Reliability, Power Transfer Capacity, and Energy Use Richard Silberglitt Emile Ettedgui Anders Hove Science and Technology Policy Institute R Prepared for the Department of Energy The research described in this report was conducted by RAND’s Science and Technology Policy Institute for the Department of Energy under contract ENG- 9812731. Library of Congress Cataloging-in-Publication Data Silberglitt, R. S. (Richard S.) Strengthening the grid : effect of high temperature superconducting (HTS) power technologies on reliability, power transfer capacity, and energy use / Richard Silberglitt, Emile Ettedgui, and Anders Hove. p. cm. Includes bibliographical references. “MR-1531.” ISBN 0-8330-3173-2 1. Electric power systems—Materials. 2. Electric power systems—Reliability. 3. High temperature superconductors. I. Ettedgui, Emile. II. Hove, Anders. III.Title. TK1005 .S496 2002 621.31—dc21 2002021398 RAND is a nonprofit institution that helps improve policy and decisionmaking through research and analysis. RAND® is a registered trademark. RAND’s pub- lications do not necessarily reflect the opinions or policies of its research sponsors. Cover illustration by Stephen Bloodsworth © Copyright 2002 RAND All rights reserved. No part of this book may be reproduced in any form by any electronic or mechanical means (including photocopying, recording, or information storage and retrieval) without permission in writing from RAND. Published 2002 by RAND 1700 Main Street, P.O. Box 2138, Santa Monica, CA 90407-2138 1200 South Hayes Street, Arlington, VA 22202-5050 201 North Craig Street, Suite 102, Pittsburgh, PA 15213 RAND URL: http://www.rand.org To order RAND documents or to obtain additional information, contact Distribution Services: Telephone: (310) 451-7002; Fax: (310) 451-6915; Email: [email protected] iii Preface Power transmission constraints resulting from the slow growth of transmission systems relative to the large growth in the demand for power have played a major role in higher electricity prices and reduced reliability in many areas across the United States in recent years. This report summarizes the results of two RAND studies that investigated the potential effect of high-temperature superconducting (HTS) technologies on the U.S. power grid. In the first study, which was supported by the U.S. Department of Energy (DOE) and performed under the auspices of RAND’s Science and Technology Policy Institute, RAND reviewed the evolution of the U.S. electricity market under deregulation, identified electricity transmission constraints, and made engineering comparisons between conventional power components and those based upon HTS technologies. That study was begun in July 2000 and concluded with this report. In the second study, which was supported by the National Renewable Energy Laboratory, RAND analyzed the effects of HTS transmission cables in realistic grid situations using power-flow simulations performed for RAND by PowerWorld Corporation. HTS cable manufacturer Pirelli Cables and Systems provided engineering data required for these simulations. The second study was conducted from June 2001 to January 2002. This report integrates the results of those two studies to draw conclusions concerning ways in which HTS cables could be deployed in the future to increase grid reliability and power transfer capacity. This report also compares the energy use and acquisition and operating costs of HTS and conventional power technologies. This report should be of interest to individuals and organizations that generate, transmit, distribute, use, or regulate electric power, all branches of government that deal with electric power systems, and individuals and organizations that sponsor or perform research and development on superconducting and related technologies. Originally created by Congress in 1991 as the Critical Technologies Institute and renamed in 1998, the Science and Technology Policy Institute is a federally funded research and development center sponsored by the National Science Foundation and managed by RAND. The Institute’s mission is to help improve public policy by conducting objective, independent research and analysis on iv policy issues that involve science and technology. To this end, the Science and Technology Policy Institute • supports the Office of Science and Technology Policy and other Executive Branch agencies, offices, and councils • helps science and technology decisionmakers understand the likely consequences of their decisions and choose among alternative policies • helps improve understanding in both the public and private sectors of the ways in which science and technology can better serve national objectives. Science and Technology Policy Institute research focuses on problems of science and technology policy that involve multiple agencies. In carrying out its mission, the Institute consults broadly with representatives from private industry, institutions of higher education, and other nonprofit institutions. Inquiries regarding the Science and Technology Policy Institute may be directed to: Helga Rippen Director Science and Technology Policy Institute RAND 1200 South Hayes Street Arlington, VA 22202-5050 Phone: (703) 413-1100 x5574 Email: http://www.rand.org/scitech/stpi/ Web: http://www.rand.org/centers/stpi v Contents Preface ................................................. iii Figures ................................................ vii Tables ................................................. ix Summary................................................ xi Acknowledgments ........................................ xv Acronyms ............................................. xvii Symbols ............................................... xxi 1. INTRODUCTION...................................... 1 2. THE EVOLUTION OF THE U.S. ELECTRICITY TRANSMISSION GRID: TRANSMISSION CONSTRAINTS ..................... 7 Electricity Market Restructuring ........................... 8 HTS Cables and Today’s Transmission Grid ................... 9 Increased Utilization of the Grid ...........................11 Transmission and Efficient Power Markets ....................13 Major U.S Transmission Constraints ........................15 Technology Alternatives: High-Voltage Direct Current and Flexible AC Transmission System Devices .......................21 3. POTENTIAL IMPACT OF HTS CABLES ON GRID RELIABILITY AND AVAILABLE TRANSFER CAPACITY ...................25 Simulations of the Downtown Chicago Transmission Grid ........26 Simulations of California’s Path 15 Transmission Circuit ..........34 4. ENGINEERING COMPARISONS BETWEEN HTS CABLES AND CONVENTIONAL TRANSMISSION CABLES AND CONDUCTORS .......................................39 Comparison Between HTS Cables and 138 kV Conventional Underground Cables ................................39 Description and Limitations of the Analysis .................40 Energy Loss Comparison of HTS and XLPE Cables ............41 Life-Cycle Cost Estimates for HTS and XLPE Cables ...........46 Comparison Between HTS Cables and 230 kV Conventional Overhead Lines ....................................52 Description and Limitations of the Analysis .................52 Energy Loss Comparison of HTS Cables and Overhead ACSR Transmission Lines .................................55 Life-Cycle Cost Estimates for HTS Cables and ACSR Transmission Lines............................................ 56 5. ENGINEERING COMPARISONS BETWEEN HTS AND CONVENTIONAL ENERGY STORAGE SYSTEMS AND TRANSFORMERS .....................................63 vi Flywheel Energy Storage Systems ..................... 63 Description and Limitations of the Analysis ................. 63 Energy Use Comparison of Flywheel and Battery Energy Storage Systems ......................................... 64 Life-Cycle Cost Estimates for a FESS and a BESS .............. 70 HTS Transformers ..................................... 72 Description and Limitations of the Analysis ................. 72 Energy Loss Comparison of HTS and Conventional Transformers ..................................... 73 Life-Cycle Cost Estimates for HTS and Conventional Transformers ..................................... 78 Superconducting Magnetic Energy Storage ................... 80 Comparing SMES and FESS Performance ................... 80 Potential Uses of SMES ................................ 81 6. CONCLUSIONS AND FEDERAL ACTION PLAN .............. 85 Conclusions .......................................... 85 Federal Action Plan for HTS Research and Development ......... 86 Appendices A. TECHNICAL CHARACTERISTICS AND DEMONSTRATION STATUS OF HTS POWER TECHNOLOGIES .................. 89 B. PARAMETRIC RELATIONSHIPS FOR ENERGY LOSS AND LIFE- CYCLE COST COMPARISONS OF SUPERCONDUCTING AND CONVENTIONAL CABLES AND CONDUCTORS ............ 103 C. PARAMETRIC RELATIONSHIPS FOR COMPARISON OF THE ENERGY USE OF FLYWHEEL ENERGY STORAGE SYSTEMS AND BATTERY ENERGY STORAGE SYSTEMS .............. 111 D. PARAMETRIC RELATIONSHIPS FOR COMPARISON OF ENERGY USE AND LIFE-CYCLE COST OF HTS AND CONVENTIONAL TRANSFORMERS ...................... 113 vii Figures 2.1 Status of Electricity Market Restructuring .................. 8 2.2 Areas of the United States in Which Major Transmission Constraints Have Been Identified ........................21 3.1 Portion of Downtown Chicago Grid Showing Area of Interest and Contingency Area, Commonwealth Edison Control Area Within MAIN Transmission Grid Shown in Inset .............27 3.2 Portion