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Superconducting Magnetic Energy Storage (SMES) for Improved Power
Quality
Shuki Wolfus, Alex Friedman, Yasha Nikulshin, Eli Perel & Yosi Yeshurun
Institute of Superconductivity, Department of Physics Bar-Ilan University
Ø Circulating current in a coil generates magnetic field, B
Ø The energy stored in space is proportional to B2
2 2
Energy in Coils
E = 12LI 2
If the coil is superconducting, its current doesn’t decay The coil becomes an energy storing device
Limitations:
Ø Switching voltage and efficiency
Ø Winding insulation / coil breakdown
3 3
High-Power Capability
V = L dIdt
Power capability of the SMES depends on its discharge rate
9 P. TixadorInstitut Néel, G2Elab
2011 ESASSummer school
Energy and power densities
Ragone chart:
Performance
comparison
of storing
devices
Performances
0,001
0,01
0,1
1
10
100
1000
104
105
0,01 0,1 1 10 100 1000Mass
spe
cific
power
(kW
/kg)
Mass specific energy (Wh/kg)
Super
capacitor
Batteries
Dielect
ric
capa
cito
r
SMES
Batteries
Fly-
wheel
10 P. TixadorInstitut Néel, G2Elab
2011 ESASSummer school
SMES application
0,001
0,01
0,1
1
10
100
1000
104
105
0,01 0,1 1 10 100 1000Mass
spe
cific
power
(kW
/kg)
Mass specific energy (Wh/kg)
Super
capacitors
Batteries
Dielect
ric
capa
cito
rs
SMES
Batteries
Performances
Disch
arg
ing
time
Power
SMESHigh power
supercaps
Hours
Seconds
MinutesHigh power flywheels
Ni-Cd batteries
Lead-acid batteries
Lo
ng
du
ra.
fly
wh
.
Li-ion batteries
NaS batteriesHigh energy
supercaps
Pumped
hydro
CAES
Metal-air
batteriesFlow batteries
100 MW100 kW1 kW
www.electricitystorage.org
4 4
SMES Power Density
Comparison to other energy storage technologies
P. Tixador, ESAS 2011
5 5
SMES Applications
SMES main advantage is in the high-power short-time regime
9 P. TixadorInstitut Néel, G2Elab
2011 ESASSummer school
Energy and power densities
Ragone chart:
Performance
comparison
of storing
devices
Performances
0,001
0,01
0,1
1
10
100
1000
104
105
0,01 0,1 1 10 100 1000Mass
spe
cific
power
(kW
/kg)
Mass specific energy (Wh/kg)
Super
capacitor
Batteries
Dielect
ric
capa
cito
r
SMES
Batteries
Fly-
wheel
10 P. TixadorInstitut Néel, G2Elab
2011 ESASSummer school
SMES application
0,001
0,01
0,1
1
10
100
1000
104
105
0,01 0,1 1 10 100 1000Mass
spe
cific
power
(kW
/kg)
Mass specific energy (Wh/kg)
Super
capacitors
Batteries
Dielect
ric
capa
cito
rs
SMES
Batteries
Performances
Disch
arg
ing
time
Power
SMESHigh power
supercaps
Hours
Seconds
MinutesHigh power flywheels
Ni-Cd batteries
Lead-acid batteries
Lo
ng
du
ra.
fly
wh
.
Li-ion batteries
NaS batteriesHigh energy
supercaps
Pumped
hydro
CAES
Metal-air
batteriesFlow batteries
100 MW100 kW1 kW
www.electricitystorage.org
Ideal for handling power quality issues
P. Tixador, ESAS 2011
6 6
PQ Cost to EU Economy
European Power Quality Survey Report
7
www.leonardo-energy.org
caused by poor PQ is 4% of annual turnover. The services model The model estimation of wastage caused by poor PQ is 0,1419% of annual turnover. Statistical bias is real danger in research like this, especially in terms of how representative the study is of the target universe. This was however resolved once the random and statistically based samples were checked. The regression analysis applied to this PQ Survey project proved that the samples and models are large and good enough to conclude that the variation explained by the model is not due to chance and that the relationship between the model and the dependent variable - annual PQ costs - is very strong. The charts in Figure 1 present the cost extrapolations of wastage caused by the range of PQ phenomena throughout the sectors investigated in EU-25: PQ cost is characterized by disturbance type (absolute value in € bln and % value of total cost) and cost components.
Figure 1: Extrapolation of PQ cost to EU economy in LPQI surveyed sectors
90
80
70
60
50
40
30
20
10
0TotalServicesIndustry
4,2
0
4,1
53,4
2,1
51,2
1,31,10,2
6,4
1,84,6
86,5
1,5
85REMARKSStandard errorof estimation:industry +/-5% basedon regression only and+/- 2,54% variancecorrected services+/-12,93%, +/-11,91%respectivelyBanks excluded
PQ cost in EU>150 bln €
Flicker unbalance earthing and EMCSurges and transientsHarmonicsLong interruptionsDips and short interruptions
30,1
2,9
64
0,4
63,6
37,9
2
36
44,6
3,3
41,3
2,20,91,4
TotalServicesIndustry
Other costEquipmentProcess slowdownWIPLabor
PQcost
inbln€
J. Manston & R. Targosz European Power Quality Survey Report, 2008
7 7
Industries sensitive to PQ disturbances
J. Manston & R. Targosz European Power Quality Survey Report, 2008
European Power Quality Survey Report
17
www.leonardo-energy.org
Figure 10: LPQI survey, PQ disturbance frequency, dips, interruptions, surges and
transients
These are annualised data giving the frequency of disturbances per sector. In this figure one metals company claiming short interruptions every day has been filtered to avoid distorting the overall picture.
Figure 11: LPQI survey, Frequency – annual time occurrence in %, harmonics,
flicker
8 8
Technology Challenges
Ø Magnetic Design (field intensity, stored energy, coil configuration, stray fields, foot print…)
Ø Cryostat and magnet cooling (conduction vs. liquid cooling, heat flow, heat drain, maintenance…)
Ø Superconductor (wire development, AC losses, quench
protection, stabilization…)
Ø Power electronics (logic, switching, components, losses, algorithm, control…)
27 P. TixadorInstitut Néel, G2Elab
2011 ESASSummer school
I
ToroidSolenoid
Magnet topologies
Magnet
28 P. TixadorInstitut Néel, G2Elab
2011 ESASSummer school
SMES magnet topology
Simple structure Stray fieldSOLENOID High stored energy Large coils
per conductor unit
TOROID Low stray fields Lower stored energy Smaller unit coils per conductor unit
Mechanical structure
Mechanics: very importantSMES magnets subject to strong Lorentz forces,
If not properly handled, rated performances not achieved.
Magnet
9 9
BIU’s HTS SMES (Old)
Main achievements: Ø World’s first LN2 cooled operating HTS SMES 3-phase, 400 V, 1 kJ, 20 kW Ø Special geometry Iron core increased energy gain reduced self field Ø Novel converter circuit
Simultaneous charge & discharge increased device power
Ministry of National Infrastructure - Israel Electric Company (IEC)
10 10
BIU’s New SMES
Features
Ø 1MJ, 1MW
Ø Solenoid design with field shielding
Ø New, state-of-the-art MgB2 superconducting wires
Ø Conduction cooling at 10K
11 11
BIU’s New SMES
!500$
!400$
!300$
!200$
!100$
0$
100$
200$
300$
400$
500$
0$ 0.005$ 0.01$ 0.015$ 0.02$ 0.025$ 0.03$
V$corrected$
Reference$
V$Interrupted$
12 12
Worldwide SMES Projects - China
1-MJ/0.5-MVA SMES that incorporates Bi-2223 wire. Baiyan substation in Gansu Province since 2011
A. Wolsky, “A roadmap to future use of HTS by the power sector”, 2012
13 13
Chubu Electric - Japan
19MJ/10-MVA SMES that incorporates NbTi wire. 2007
14 14
Brookhaven, ABB, SuperPower & Huston Univ. - USA
1.7MJ/10-kVA SMES for military micro-grids . 2015
15 15
Hybrid SMES - The Futuristic Vision
1362 IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY, VOL. 21, NO. 3, JUNE 2011
LIQHYSMES—A Novel Energy Storage Concept forVariable Renewable Energy Sources Using Hydrogen
and SMESMichael Sander and Rainer Gehring
Abstract—A new energy storage concept is proposed that com-bines the use of liquid hydrogen (LH2) with Superconducting Mag-netic Energy Storage (SMES). The anticipated increase of the con-tribution of intermittent renewable power plants like wind or solarfarms will substantially increase the need for balancing demandsand supplies from seconds to several hours or even days. LH2 withits high volumetric energy density is the prime candidate for largescale stationary energy storage but balancing load or supply fluctu-ations with hydrogen alone is unrealistic due to the losses related tothe re-conversion into electricity and also due to the response timesof the flow control. To operate the hydrogen part more steadilysome short-term electrical energy storage will be needed. Here aSMES based on High Temperature Superconductors (HTS) is pro-posed for this purpose which could be operated in the LH2 bath.With this approach the cryogenics-related costs for the SMES arewidely cut. The concept is introduced. Simple simulations on thebuffering behavior and comparisons of different plant types arepresented.
Index Terms—AC loss, energy storage, high-temperature super-conductors, hydrogen, superconducting magnets.
I. INTRODUCTION
A SUBSTANTIAL increase of the contribution of renew-able energy sources to both mobility and electric power
is anticipated for the next decades, and this will also increasethe need for balancing supplies and demands. For both fields,hydrogen (H2) produced in electrolytic processes could, to-gether with fuel cells (or gas turbines & generators), becomea generally applicable fuel and energy carrier of unlimitedavailability. A combined plant for liquid hydrogen productionand electrical energy storage is proposed which uses liquidhydrogen (LH2) as the bulk energy carrier. Superconductingmagnetic energy storage (SMES) e.g. based on 123-HTSCoated Conductors (CC) or Bi-2223-HTS which both could beoperated at LH2 temperature, allows operating the hydrogenpart more smoothly [1], [2]. The LH2 could thus not only beused for very compact energy storage but also for cooling theSMES [3]. With this approach the cryogenics-related costsfor the SMES are widely cut. Fig. 1 shows the concept forsuch a LIQHYSMES hybrid plant (combination of LIQuidHYdrogen and SMES). It consists of three major parts: the
Manuscript received August 01, 2010; accepted October 05, 2010. Date ofpublication November 11, 2010; date of current version May 27, 2011.
M. Sander is with Karlsruhe Institute of Technology (KIT), Institute forTechnical Physics (ITEP), Hermann-von-Helmholtz-Platz 1, 76344 Eggen-stein-Leopoldshafen, Germany (e-mail: [email protected]).
Color versions of one or more of the figures in this paper are available onlineat http://ieeexplore.ieee.org.
Digital Object Identifier 10.1109/TASC.2010.2088359
Fig. 1. Concept of the LIQHYSMES Hybrid Plant consisting of three majorparts: the Electrochemical Energy Storage (EES), the Superconducting Mag-netic Energy Storage (SMES) and the Power Conversion & Control Unit (PCC).
Electrochemical Energy Storage (EES), the SMES and thePower Conversion & Control Unit (PCC). All three units haveto be strictly based on modularity, so that, depending on thecurrent operating requirements, blocks of e.g. electrolyzer orfuel cells can be switched on or off on a minute time scale.The electrical energy storage may be further combined with theproduction of H2 fuel in compressed or liquid form.
Table I gives the major plant parameters like power, energyand the loss assumptions which have been used to crudely simu-late the buffering behavior of a simplified LIQHYSMES modelplant. For comparison, also estimates for a SMES based on NbTiwires (e.g. incorporated in an inner LHe tank shielded by theLH2 tank), are given. A first estimate of the anticipated plantscharacteristics is presented in the following.
II. RAMPING LOSSES OF THE SMES
The conductor losses in the SMES are estimated as follows:Since the ramping processes considered here are very slow(447 sec), eddy current and coupling losses are neglected here.As could be shown in [4], for high magnetic fields and veryslow changes the hysteretic magnetization losses of CC arewell approximated by the critical state model, and the transportlosses can be neglected. At high magnetic fields the individualCC tapes e.g. in a Roebel cable, are essentially decoupled[5], i.e. mutual interactions among neighbor tapes are muchsmaller than those with the central coil field. Consequently,the locally occurring volumetric losses don’t explicitly depend
1051-8223/$26.00 © 2010 IEEE
M. Sander and R. Gehing, IEEE TRANS. ON APPL. SUPERCON., 21, 1362 (2011)