Supercharging the Electric Grid The Promise of High-Temperature Superconductivity Tommi Makila Iowa Department of Natural Resources
Presentation outline Superconductivity background, history Electric power sector applications Future of the technology: promises, challenges
What is superconductivity? Electricity without resistance; there are no energy losses Happens only at very low temperatures in known materials
What is high-temperature superconductivity? Low temperature: below 23 K (-418 F) High temperature: above 23 K Significance of 77K (-321 F) Inexpensive liquid nitrogen can be used as a coolant
History of superconductivity 1911: Superconductivity discovered 1957: BCS Theory 1962: First commercial superconducting wire 1986: First HTS material discovered 1987: HTS at 92K 1994: 1st generation HTS wire in kilometerlengths 2003: 2nd generation HTS wire in ten-meter lengths
Theory of superconductivity BCS (Bardeen, Cooper, Schrieffer) Theory first widely accepted theory to explain superconductivity (1957) current carried by pairs of electrons known as Cooper pairs does not fully explain high-temperature superconductivity
Theory of superconductivity Graphs courtesy of Pirelli.
Superconductivity is here! Magnetic Resonance Imaging (MRI) Maglev trains High-energy particle accelerators (Fermilab, CERN) Pictures: Intermagnetics General Corp. and Railway Technical Research Institute.
State of the U.S. grid Aug. 14, 2003: 50 million lost power, over $6 Billion in losses Grid based on early 20th century technology Grid investment not keeping up with growth in electricity generation and demand Picture courtesy of SuperPower.
Transmission constraints in the Midwest Top MISO constraints causing economic curtailments: Chronic constraints limiting economic transactions: 10 1 3 7 5 2 14 4 6 6 18 15 19 13 17 11 16 9 12 Maps courtesy of Midwest ISO.
HTS applications for electric power industry Generators Power cables Transformers Fault current limiters Energy storage Electric motors Graph: HowStuffWorks.com
Power cables No dc losses, low ac losses Carries 3-5 times more current than same size conventional cable Ideal for crowded urban areas Challenges: price, reliability Status: Demonstration project success mixed; new projects in the works Picture courtesy of Nexans.
Power cables Main cable types warm dielectric cold dielectric tri-axial Picture courtesy of Ultera TM.
Transformers 3-6% of generated electricity lost to transformer inefficiencies HTS could reduce losses 50% Up to 50% smaller in size No flammable, toxic oil needed Status: Waukesha developing demonstration model Picture courtesy of SuperPower.
Generators Greater efficiency (0.35-0.55 % gain) Smaller size (up to 2/3 smaller than conventional) Large, established market Status: GE developing 100 MVA generator Picture courtesy of SuperPower.
Electric motors Greater efficiency Smaller, lighter Primary application: large motors over 1,000 hp Status: 6,700 hp motor built for US Navy by American Superconductor Challenge: current technology fairly competitive (efficient and reliable) Picture courtesy of American Superconductor.
Fault current limiters New type of device Limits size and duration of fault current very fast protects equipment in the system Status: SuperPower to install 138 kv limiter at a utility substation by 2006 Picture courtesy of SuperPower.
Energy storage Increases system reliability and efficiency less interruptions = large financial savings Superconductive Magnetic Energy Storage energy stored in superconducting coils can provide several MW for several seconds Flywheels HTS bearings can decrease hourly losses from 3-5% to 0.1% Picture courtesy of American Superconductor.
HTS wire Key to most HTS applications! Challenge of making wire: HTS materials are brittle ceramics First generation HTS wire lots of silver needed, making it expensive Applications being developed with 1st generation wire Picture courtesy of American Superconductor.
Manufacturing 1 G wire -- powder-in-tube method Graphs courtesy of American Superconductor.
HTS wire 2nd generation wire (coated conductors) metal strips are coated with HTS thin films different techniques being developed for depositing HTS material challenge: continuous long-length production needs to be cheaper than 1G wire; lower price key to HTS application success Picture courtesy of SuperPower.
Manufacturing 2 G wire -- liquid-metal-organic deposition Graphs courtesy of American Superconductor.
HTS wire Graph courtesy of American Superconductor.
HTS technology benefits Improved efficiency = $ savings current losses of 7-10% could be cut in half Improved power quality & system reliability Environmental benefits less pollution because of less generation less materials (including toxic materials) in equipment no above-ground lines improved order of generation dispatch
What obstacles does the technology face? Competitively priced wire Reliable, less costly cooling systems High-voltage insulation in low temperatures More automated production processes Practical experience needed (demonstration projects)
What is being done to advance the technology 10,000 researchers worldwide U.S., Japan and Europe competing DOE s Superconductivity Program for Electric Systems started in 1988 Superconductivity Partnership Initiative (demonstration projects) Accelerated Coated Conductor Initiative (second generation wire development)
What is being done to advance the technology Manufacturers Laboratories Universities Utilities
When will commercially viable products be available? Difficult to predict Wire: 2nd generation wire market entry expected 2005-2010 Cable expected to be first application to enter market, followed by motors, generators and transformers
Market projections Projected U.S. Market for HTS Devices (millions of dollars) 2000 1500 1000 500 Motors Generators Transformers Cables 0 2011 2013 2015 2017 2019 2021 2023 2025 Source: U.S. Department of Energy.
Resources IDNR folders: more information, links Iowa Department of Natural Resources http://www.iowadnr.com/energy/hts/ U.S. Department of Energy http://www.electricity.doe.gov/
Contact: Tommi Makila Iowa Department of Natural Resources Tel. 515.281.8852 Email: tommi.makila@dnr.state.ia.us This material was prepared with the support of the U.S. Department of Energy (DOE). However, any opinions, findings, conclusions or recommendations expressed herein are those of the authors and do not necessarily reflect the views of the DOE.