This document provides an overview of superconducting magnetic energy storage (SMES). It discusses the history and components of SMES systems, including superconducting coils, power conditioning systems, cryogenic units, and control systems. The operating principle is described, where energy is stored in the magnetic field created by direct current flowing through the superconducting coil. Applications include providing stability and power quality for the electric grid. Challenges include the large scale needed and cryogenic cooling required to maintain superconductivity.

1. Superconducting Magnetic
Energy Storage
Presented by-
Tanvir Ahmed Toshon

2. Outline
• Superconductivity
• Introduction
• History
• Components
• Operating Principle
• Applications & Market

3. Superconductivity
• Superconductivity is a phenomenon of exactly zero electrical
resistance and expulsion of magnetic fields occurring in certain
materials when cooled below a characteristic critical temperature.
• Discovered by Dutch physicist Heike Kamerlingh Onnes on April 8, 1911
in Leiden, South Holland.
• It is characterized by the
Meissner effect.
• Typically two types:
 Type I
 Type II

4. What is SMES?
• SMES is an energy storage system that stores energy in the form
of dc electricity by passing current through the superconductor
and stores the energy in the form of a dc magnetic field.
• The conductor for carrying the current operates at cryogenic
temperatures where it becomes superconductor and thus has
virtually no resistive losses as it produces the magnetic field.
• The magnetic field is created by flow of direct current through
the coil.
• In this state the current in a coil can flow for infinite time. This
can also be seen from the time constant of a coil τ = L/R,
where R goes to zero and τ then goes to infinity.

5. Historical Review of SMES
• 1969: First concept was proposed by Ferrierin in
France.
• 1971: Research performed in University of Wisconsin
in the US.
• This research led to construction of the first SMES
device.
• High temperature superconductors (HTS) appeared
commercially in late 90s.
• 1997: first significant size HTS-SMES was developed
by American Superconductors. Then it was
connected to a scaled grid in Germany.

6. Components of SMES system
• Superconducting coil
with the magnet
• The power conditioning
system (PCS)
• The cryogenic system
• The control unit

7. Superconducting Coil
• Main part of a SMES system
• Most superconducting coils are wound using conductors which are
comprised of many fine filaments of a niobium-titanium (NbTi) alloy
embedded in a copper matrix.
• The Size of the coil
depends upon the
energy storage
requirement and coil
geometry.
• Typically 2 type:
 LTS
 HTS

8. Power Conditioning System
• Interface between the superconducting magnet and AC power system.
• Three configurations available:
 Thyristor based PCS.
 Voltage source converter based PCS.
 Current source converter based PCS .

9. Cryogenic Unit
• The superconducting SMES coil must be maintained at a temperature sufficiently low to maintain a
superconducting state in the wires.
• Commercial SMES today this temperature is about 4.5 K (-269°C, or -452°F) (for LTS)
• Reaching and maintaining this temperature is accomplished by a special cryogenic refrigerator that uses
helium as the coolant or liquid nitrogen in case of HTS.
• The refrigerator consists of one or more compressors for gaseous helium and a vacuum enclosure called a
“cold-box”, which receives the compressed, ambient-temperature helium gas and produces liquid
helium/nitrogen for cooling the coil .
• Since it affect the overall efficiency and cost of SMES system, the loss components such as cold to warm
current leads, ac current, conduction and radiation etc. should be minimized to achieve a higher efficient
and less costly SMES system.

10. Control system
• Establishes a link between power demands from the grid and power
flow to and from the SMES coil.
• Receives dispatch signals from the power grid and status of the coil.
• Maintains system safety and sends system status information to the
operator.
• Modern systems are tied to the internet to provide remote observation
and control.

11. SMES system grid connected
configuration
Controller
Coil Protection
Cryogenic
System
VCoil
ICoil
Dewar
Power Conversion System
CSI
or
VSI + dc-dc chopper
Transformer Bypass
Switch Coil
AC
Line

12. Operating Principle
• The operation of SMES is based on the fact the a current will continue to flow
in a superconductor even after the voltage across it has been removed.
• A superconducting coil that is cooled below its critical superconducting
temperature has negligible (zero) resistance. Thus the current will continue to
flow in it.
• The stored energy is inductive: 𝐸 =
1
2
𝐿𝐼2
• The coil carries a current at any state of charge
• Charging Phase: Since the current flows only in one direction, the PCS must
produce a positive voltage across the coil to store energy. This increases the
current.
• Discharging Phase: the PCS are adjusted to make the system look like a load
across the coil by producing a negative voltage causing the coil to discharge.

13. Applications of SMES
• System stability: SMES can reduce low frequency
oscillations to enhance transmission capacity and
boost voltage stability.
• Power quality: SMES systems can offer energy for
flexible AC transmission (FACTS).

14. Application of SMES
• Paper industry
• Motor vehicle assembly
• Petrochemical Refineries
• Chemical & pharmaceutical Companies

15. Advantages of SMES
• SMES systems have the ability of fast response
• They can switch from charge to discharge state (vice
versa) within seconds.
• The absence of moving parts and high cycling
efficiency are some additional advantages
• It can be deployed in places where other
technologies such as pumped hydro or compressed
air are not feasible

16. Common Challenges
• Main drawback of the SMES technology is the need of large
amount power to keep the coil at low temperature, combined
with the high overall cost for the employment of such unit.
• To achieve commercially useful levels of storage, around
1 GW.h (3.6 TJ) a SMES installation would need a loop of
around 100 miles (160 km).
• Another problem is the infrastructure required for an
installation. Until room temperature superconductors are
found, the 100 mile (160 km) loop of wire would have to be
contained within a vacuum flask of Helium/liquid nitrogen. This
in turn would require stable support, most commonly
envisioned by burying the installation.

17. Comparison with other Technologies

18. Market Analysis
• It has been estimated that, the total cost to the US businesses of the lost
productivity is a staggering $15-30 billion per year.
• It is estimated that, over 100 MW of SMES units are now operation in
worldwide.
• The global market for SMES is projected to reach US$64 million by 2020.
• At the larger scale, the projected development of a 100 MWh load leveling
system could be implemented during 2020-30.
• The cost of storage system is in the range of $85-125K per MJ while the cost of
power conversion system is in the range of $150-$250 per KW.

19. References
• https://en.wikipedia.org/wiki/Superconductivity
• http://www.climatetechwiki.org/technology/jiqweb-ee
• http://www.library.utoronto.ca/iip/journal/MAIN4/cowles.htm
• http://paginas.fe.up.pt/~ee04109/Documentos%20e%20imagens/36%20-
%20An%20Overview%20of%20SMES%20Applications%20in%20Power.pdf
• http://www.superpower-inc.com/content/superconducting-magnetic-energy-
storage-smes
• http://vtb.engr.sc.edu/vtbwebsite/downloads/publications/IEEE%20Sustainabl
e%20energy-published%20paper.pdf
• http://www.slideshare.net/biswajitcet13/superconductivity-
15348460?related=1
• https://www.chuden.co.jp/english/corporate/press2007/0615_1.html
• http://www.slideshare.net/GlobalIndustryAnalystsInc/superconducting-
magnetic-energy-storage-smes-systems-a-global-strategic-business-report

20. Questions??