Second-generation HTS Wire for Wind Energy Applications Venkat Selvamanickam, Ph.D. Department of Mechanical Engineering Texas Center for Superconductivity University of Houston, Houston, TX SuperPower Inc. Symposium on Superconducting Devices for Wind Energy February 25, 2011 – Barcelona, Spain 1 Symposium on Superconducting Devices for Wind Energy – February 25, 2011 – Barcelona, Spain
Superconductivity can have a wide range of impact on wind energy • Light-weight, higher-power, direct drive turbines – Preferred for off-shore wind energy for economy & less maintenance – Less than 500 tons for 10 MW compared to ~ 900 tons for conventional direct drive – More efficient, especially at part load – High air-gap flux density
• Superconducting Magnetic Energy Storage to address intermittency – Very efficient, short-term storage, complementing other storage methods
• Low-loss, long-distance power transmission from remote areas – Much reduced right of way (25 ft for 5 GW, 200 kV compared to 400 feet for 5 GW, 765 kV for conventional overhead lines)
• Fault Current Limiters and Fault Current Limiting Transformers
• Built-in fault current limiting capability while benefiting from high efficiency • Liquid nitrogen coolant is also dielectric medium (no oil) eliminates the possibility of oil fires and related environmental hazards
Symposium on Superconducting Devices for Wind Energy – February 25, 2011 – Barcelona, Spain
2
2G HTS wire: Great potential for applications • Second-generation (2G) HTS- HTS is produced by thin film vacuum deposition on a flexible nickel alloy substrate in a continuous reel-to-reel process Æ very different from mechanical deformation & heat treatment techniques used for Nb-Ti, Nb3Sn and 1G HTS wires – Only 1% of wire is the superconductor – ~ 97% is inexpensive Ni alloy and Cu – Automated, reel-to-reel continuous manufacturing process – Quality of every single thin film coating can be monitored on-line in real time !
40 μm Cu total 2 μm Ag
1 μm YBCO - HTS (epitaxial) 100 – 200 nm Buffer 20μm Cu
50μm Ni alloy substrate
20μm Cu Symposium on Superconducting Devices for Wind Energy – February 25, 2011 – Barcelona, Spain
2G HTS wires provide unique advantages
YBCO (H//c)
YBCO (H//ab)
Nb3Sn (Internal Sn)
Nb3Sn (Bronze)
< 0.1 mm
• 2G HTS wires provide the advantages of high temperature operation at higher magnetic fields. • Mechanical properties of 2G HTS wires are also 20μm Cu superior NbTi
50μm Hastelloy 20μm Cu
800
2
non-Cu Jc ( A/mm )
100000
10000 SP 2G HTS High Je
600
100 0
5
10
15
20
25
Applied Field ( Tesla )
30
35
Stress (MPa)
1000
400 High Strength 1G HTS Low Je
200 Nb3Sn Moderate Je
Low Strength 1G HTSModerate Je
0 0
0.1
0.2
Symposium on Superconducting Devices for Wind Energy – February 25, 2011 – Barcelona, Spain Strain (% )
0.3
0.4
0.5
4
Advantages of IBAD MgO-MOCVD based 2G HTS wires • Use of IBAD MgO as buffer template provides the choice of any substrate – High strength (yield strength > 700 MPa) – Non-magnetic, high resistive (both important for low ac losses) – Ultra-thin (enables high engineering current density) – Low cost, off-the-shelf • High deposition rate and large deposition area by MOCVD – enable high throughput • Precursors are maintained outside deposition chamber – Long process runs (already shown 50+ hours)
< 0.1 mm
20μm Cu
2 μm Ag 1 μm YBCO - HTS (epitaxial) ~ 30 nm LMO (epitaxial) ~ 30 nm Homo-epi MgO (epitaxial) YBCO ~ 10 nm IBAD MgO
100 nm
LaMnO3
50μm Hastelloy substrate 20μm Cu
MgO (IBAD + Epi layer) Y2O3 Al2O3
Symposium on Superconducting Devices for Wind Energy – February 25, 2011 – Barcelona, Spain Hastelloy C-276
5
Successful scale-up of IBAD-MOCVD based 2G HTS wires • 500 m 2G HTS wire first demonstrated in January 2007 (crossed 100,000 A-m) • 1,000 m 2G HTS wire first demonstrated in July 2008 (crossed 200,000 A-m) • Crossed 300,000 A-m in July 2009 with 1,000 m wire. • 1,400 m lengths are now routinely produced. • High throughput processing (>> 100 m/h* in IBAD & buffer processes, > 100 m/h* in other processes) • Manufacturing capacity of few hundred km/year *4 mm wide equivalent
) 320,000 m A ( 280,000 h t g240,000 n e L200,000 * t n e160,000 rr u C120,000 l a ic ti 80,000 r C 40,000
0
1,065 m
90 A-m to 300,330 A-m in seven years
1,030 m
935 m 790 m 595 m
427 m 322 m 206 m 1 m 18 m 97 m 158 m 62 m 1 0 v o N
2 0 -l u J
3 0 -r a M
3 0 v o N
4 0 g u A
5 0 -r p A
5 0 c e D
Symposium on Superconducting Devices for Wind Energy – February 25, 2011 – Barcelona, Spain
6 0 g u A
7 0 -r p A
8 0 n a J
8 0 p e S
9 0 y a M
6
Meeting application requirements for HTS wire: Superior performance in operating conditions Application
Operating Field (Tesla)
Operating Temp. (K)
Key requirements
Wire needed per device (kA-m)
0.01 to 0.1 (ac) 0.1 to 1 (DC)
70 to 77
Low ac losses (ac) High currents (dc)
40,000 to 2,500,000
1 to 3
30 to 65
In-field Ic
2,000 to 10,000
Transformers
0.1
65 to 77
Low ac losses
2,000 to 3,000
Fault current limiters
0.1
65 to 77
Thermal recovery High volts/cm
500 to 10,000
2 to 30 T
4 to 50
In-field Ic
2,000 to 3,000
Cables Generators
SMES
7 Symposium on Superconducting Devices for Wind Energy – February 25, 2011 – Barcelona, Spain
Wire price-performance is the key factor for commercialization • Today’s 2G wire (4 mm wide, copper stabilized) : 100 A performance at 77 K, zero applied magnetic field, Price $ 30-40/m = $ 300-400/kA-m. • At this price, cost of wire for typical device project (other than cable) > $ 1 M (more expensive than the typical cost of the device itself !) Cost of wire for a 500 km cable project = $ 20 M (~ cost of cable project itself !) Metric Price
Today $ 300 400/kA-m
Customer requirement < $ 100/kA-m*
For commercial market entry (small market)
< $ 50/kA-m*
For medium commercial market
< $ 25/kA-m*
For large commercial market
Four to 10-fold improvement in wire price-performance needed ! *at operating field and temperature Symposium on Superconducting Devices for Wind Energy – February 25, 2011 – Barcelona, Spain
Need for wire performance improvements • Ten-fold reduction in price essentially impossible with $/m cost reduction. • Increasing amperage is key to reaching price ($/kA-m) targets • Opportunity to substantially increase self-field critical current in 2G wire by increasing film thickness – HTS is still only 1 to 3% of 2G wire compared with 40% in 1G wire and is the only process that needs to be changed in 2G wire for high critical current
• Opportunity to significantly modify in-field critical current performance of 2G wire – Numerous possibilities of rare-earth, dopant, nanostructure modifications to tailor in-field critical current
Symposium on Superconducting Devices for Wind Energy – February 25, 2011 – Barcelona, Spain
9
SuperPower-UH 2G wire development strategy • SuperPower’s technology operations consolidated in Houston which enabled total focus on manufacturing in Schenectady. Manufacturing objectives • High yield, high volume operation • On-time delivery of highquality wire • Incorporate new technology advancements
Manufacturing Operations in NY SuperPower Manufacturing at Schenectady, NY
Technology in Houston
SP staff @ Houston
UH research staff
Technology objectives • High performance wires • Highly efficient, lower cost processes • Advanced wire architectures • Successful transition to manufacturing
CRADAs Customers National Labs
Best of both worlds : strong and concentrated emphasis on technology development & manufacturing Symposium on Superconducting Devices for Wind Energy – February 25, 2011 – Barcelona, Spain
Outline • Higher performance in operating conditions of interest • Low ac loss wires • Improving yield and reducing cost
Symposium on Superconducting Devices for Wind Energy – February 25, 2011 – Barcelona, Spain
11
Goal
1000
8 Research MOCVD Pilot MOCVD
7
Increasing Ic
6
Jc (MA/cm2)
Critical current (A/cmwidth)
Need for higher amperage production wires
5
2016 – 1000 A
4 3
2014 – 750 A/cm 2012 – 500 A/cm
2 1
800 600 400 200 0 0
1 2 3 Thickness (µm)
0
• Address problems with decreasing current density with thickness HTS film thickness • High currents without significantly Now Ic up to 375 A/cm (150 A/4 mm) in long lengths increasing film thickness by increasing current density (Jc) SP 0
M3 714
0.5
1
1.5
2
2.5
3
3.5
– Microstructural improvement (texture, secondary phases, a-axis, porosity) – Pinning improvement (interfacial & bulk defects)
• Opportunity to reduce factor of two difference between pilot and research MOCVD systems Symposium on Superconducting Devices for Wind Energy – February 25, 2011 – Barcelona, Spain
12
Improvement in critical currents of thick film coated conductors with higher rare earth content 6 77K
2
Jc (MA/cm )
5 0T 1T, //ab 1T, //c 1T, min
4 3 2 1 0 0.9
1.1
1.3
1.5
1.7
1.9
Gd+Y
Symposium on Superconducting Devices for Wind Energy – February 25, 2011 – Barcelona, Spain
13
Improved pinning by Zr doping of MOCVD HTS wires • Systematic study of improved pinning by Zr addition in MOCVD films at UH. • Two-fold improvement in in-field performance achieved !
Process for improved in-field performance successfully transferred to manufacturing at SuperPower Symposium on Superconducting Devices for Wind Energy – February 25, 2011 – Barcelona, Spain
Large improvements in in-field Ic of Zr-doped wires
100 A/4 mm
100 A/4 mm achieved at 65 K, 3 T in Zr-doped wire compared to 40 K, 3 T in undoped wire 165 A/4 mm achieved at 40 K, 5 T in Zr-doped wire compared to 18 K, 5 T in undoped wire Symposium on Superconducting Devices for Wind Energy – February 25, 2011 – Barcelona, Spain
Large improvements in in-field Ic of Zr-doped wires 65 K 3T
40 K 3T
18 K 3T
Undoped wire
0.27
1.02
2.13
Doped wire
0.73
1.99
3.50
Retention factor of doped wire is higher by
2.7
1.9
1.6
2.64
2.23
Retention of 77 K, zero field Ic
77 K zero-field Ic of 2009 undoped wire = 250 A/cm 77 K zero-field Ic of new doped wire = 340 A/cm
Retention factor of doped wire including higher zero field Ic is higher by
Symposium on Superconducting Devices for Wind Energy – February 25, 2011 – Barcelona, Spain
3.71
Superior performance at 4.2 K in recent Zr-doped MOCVD production wires 60
Production wire 1.1 µm thick HTS film Ic (77 K, 0 T) = 310 A/cm
50
1000 Ic - 4mm width (A)
Jc, MA/cm2
40
T=4.2K
30
20
10
0 0
20
40
60
80
T, K
Jc @ 4.2 K (A/4 mm)
2009
2010
10 T, B ⊥ wire
201
310
20 T, B ⊥ wire
118
183
5 T, B || wire
1,219
1,893
10 T, B || wire
1,073
1,769
100
undoped, B perp. wire undoped, B || wire FY'09 Zr-doped, B perp. wire FY'09 Zr-doped, B || wire FY'10 Zr-doped, B perp. wire FY'10 Zr-doped, B || wire
1
10 B (T)
Measurements by V. Braccini, J. Jaroszynski, A. Xu,& D. Larbalestier, NHMFL, FSU
In-field performance of Zr-doped production wires improved by more than 50% in high fields at 4.2 K Symposium on Superconducting Devices for Wind Energy – February 25, 2011 – Barcelona, Spain
Benefit of Zr-doped wires realized in coil performance Coil properties
With Zr-doped wire
With undoped wire
Coil ID
21 mm (clear)
12.7 mm (clear)
Winding ID
28.6 mm
19. 1 mm
# turns
2688
3696
2G wire used
~ 480 m
~ 600 m
Wire Ic
90 to 101 A
120 to 180 A
Field generated at 65 K
2.5 T
2.49 T
Same level of high-field coil performance can be achieved with Zr-doped wire with less zero-field 77 K Ic, less wire and larger bore Symposium on Superconducting Devices for Wind Energy – February 25, 2011 – Barcelona, Spain
Goals for further performance improvements • Two-fold improvement in in-field performance achieved with Zr-doped wires • Further improvement in Ic at B || c : Now 30% retention of 77 K, zero field value at 77 K, 1 T ; Goal is 50%. • Improvement in minimum Ic Æ controlling factor for most coil performance : Now 15 to 20% retention of 77 K, zero field value at 77 K, 1 T ; Goal is first 30% and then 50% • Together with a zero-field Ic of 400 A/4 mm at 77 K, self field Æ 200 A/4 mm at 77 K, 1 T in all field orientations. • Achieve improved performance levels at lower temperatures too (< 65 K) Critical current (A/4 mm)
200 Standard MOCVD‐based HTS tape MOCVD HTS w/ self‐assembled nanostructures
100
Goal
10x
77 K, 1 T
c‐axis
10 0
30
60
90
120
150
180
210
Angle between field and c‐axis (°) Symposium on Superconducting Devices for Wind Energy – February 25, 2011 – Barcelona, Spain
240
Ongoing research in pinning improvements • Raise minimum Ic in angular dependence – Most defects in Zr-doped MOCVD wires are directional, BZO nanocolumns along the c-axis (with splay) and RE2O3 precipitate arrays along the a-b plane. – Create new defect structure that is not directional or modify existing defect structure to be isotropic
• Determine contribution of different defect structures at lower temperatures and higher fields
200
Critical current (A/4 mm)
– Create a splay in defects along a-b plane to broaden the peak in Ic at B || a-b just like the peak at B || c
Standard MOCVD‐based HTS tape MOCVD HTS w/ self‐assembled nanostructures
100
Goal
10x
c‐axis
10 0
30
60
90
120
150
180
210
Angle between field and c‐axis (°)
Symposium on Superconducting Devices for Wind Energy – February 25, 2011 – Barcelona, Spain
240
Multiple strategies to enhance in-field performance : higher Ic, more isotropic • Superconductor process modification – Chemical modifications in MOCVD to modify defect density, orientation and size. • Influence of film thickness on in-field Ic of Zr-doped films • Influence of rare earth type and content • Influence of Zr content at fixed rare-earth type and content • Influence of other dopants • Influence of deposition rate
• Buffer surface modification buffer prior to superconductor growth • Post superconductor processing modification such as post annealing etc. Symposium on Superconducting Devices for Wind Energy – February 25, 2011 – Barcelona, Spain
2
Improvement with Zr in thicker films
All samples were of composition Y0.6Gd0.6BCO Improvement in in-field critical current of Zr-doped wires increases with film thickness
Symposium on Superconducting Devices for Wind Energy – February 25, 2011 – Barcelona, Spain
In-field performance of Zr-doped films is drastically modified by rare earth content Zr content maintained at 7.5% in all three samples
c‐axis
Y1.2
(Y,Gd)1.5
20 nm Fewer defects along a‐b plane in Y1.2 ; defects prominent along a‐b plane in (Y,Gd)1.5 Symposium on Superconducting Devices for Wind Energy – February 25, 2011 – Barcelona, Spain
Thick film multilayers of Zr doped (Y,Gd)1.5 and (Y,Gd)1.2 compositions • 7.5% Zr doping. 0.7 µm HTS film deposited in each pass. • Zero-field and in-field performance measured after each pass.
Symposium on Superconducting Devices for Wind Energy – February 25, 2011 – Barcelona, Spain
Multfilamentary 2G HTS tapes for low ac loss applications 2
• So far, there is no proven technique to repeatedly create high quality mulfilamentary 2G tapes. Also, adds substantial cost.
ac loss (W/m)
• Filamentization of 2G HTS tapes is desired for low ac loss applications.
unstriated
100 Hz
1
5.1 x
multifilamentary 0 0.00
0.01
0.02
0.03
0.04
0.05
Bac rms (T)
4 mm 5-filament tape, 4 mm wide (produced up to 15 m)
32-filament tape, 4 mm wide (difficult to make even 1 m lengths)
Symposium on Superconducting Devices for Wind Energy – February 25, 2011 – Barcelona, Spain
0.06
Goals in multifilamentary 2G HTS wire fabrication • Maintaining filament integrity uniform over long lengths (no Ic reduction) • Striated silver and copper stabilizer (minimize coupling losses) • Minimum reduction in non superconducting volume (narrow gap) and fine filaments HTS
Ag
Substrate Cu
A fully filamentized 2G HTS wire would need to have 20 – 50 µm of copper stabilizer striated ! Symposium on Superconducting Devices for Wind Energy – February 25, 2011 – Barcelona, Spain
Approach to make fully-filamentized 2G HTS wire Ag 1. Coat photoresist on silver
YBCO Photoresist Substrate
2. Transfer pattern from mask to photoresist
3. Electroplate copper
Cu
4. Remove remaining photoresist
5. Wet etch silver and HTS
X. Zhang and V. Selvamanickam, US 7,627,356 Symposium on Superconducting Devices for Wind Energy – February 25, 2011 – Barcelona, Spain
Approach to make fully-filamentized 2G HTS wire Cu
Ag
HTS
substrate
100 μm
Cu
1 mm
Fully-filamentized 2G HTS wire demonstrated, but still involves etching Symposium on Superconducting Devices for Wind Energy – February 25, 2011 – Barcelona, Spain
2
Alternate bottom-up approach being developed Striate buffer layer, then deposit REBCO. REBCO Buffer Stack Substrate
Substrate
Substrate
Prerequisites: 1.) ‘striation ‘phase’ needs favorable properties for minimal coupling 2.) no widening of ‘striation phase’ into REBCO 3.) No poisoning of REBCO (no diffusion barrier) 4.) No porosity or features that may initiate cracks 5.) Fully-filamentized silver and copper stabilizer Symposium on Superconducting Devices for Wind Energy – February 25, 2011 – Barcelona, Spain
Striation of buffer layers
500 µm
Mechanical striation with a diamond tip: Milling reveals ~1.8 micron depth 1 mm separation Width ~ 25 µm. Repeated experiments with load control : width decreased to 12 µm Symposium on Superconducting Devices for Wind Energy – February 25, 2011 – Barcelona, Spain
Striated buffer after MOCVD • REBCO texture typical of nonstriated tape • Striated texture polycrystalline, rough • No apparent widening of striation!
Symposium on Superconducting Devices for Wind Energy – February 25, 2011 – Barcelona, Spain
Cross section of striated region after MOCVD
Symposium on Superconducting Devices for Wind Energy – February 25, 2011 – Barcelona, Spain
Factor of five lower ac loss in multifilamentary wire made by bottom-up approach
SCR 5,6 – multifilamentary ; SCR 7ref – reference, no filaments
Symposium on Superconducting Devices for Wind Energy – February 25, 2011 – Barcelona, Spain
Improving yield through on-line vision QC in MOCVD • Vision inspection algorithms assign quality values to images taken every ~15 mm of the wire as it emerges from the MOCVD deposition chamber • Comparisons of ‘quality map’ with reference tape to discern process drift in real time Training from Reference Images No Partial Training
500
20
400
40
300
60
200
80
100
100 850
900
950
0 1,000 1,050 1,100 1,150 1,200 1,250 1,300
Absolute Position (m)
Real-time prediction of Ic during MOCVD process enabled by improved on-line Vision system Symposium on Superconducting Devices for Wind Energy – February 25, 2011 – Barcelona, Spain
Ic-1T (Amps)
Defect Code Value (%)
0
COVG Ic1T
Early detection of a-axis growth during MOCVD is valuable for high current wires 300
Predicted critical current (A)
Critical Current (A/cm)
Critical current predicted based on (006) XRD peak intensity 250 200 150 100 50 0
0
0.5
1
YBCO (200)/(006) ratio
1.5
400
Ic=4.95*counts (006)-125
300 200 100
y = 1.0007x - 0.0235 R² = 0.8411
0 0
100
200
300
400
Measured critical current (A)
Good correlation between measured Ic and (006) XRD peak intensity Symposium on Superconducting Devices for Wind Energy – February 25, 2011 – Barcelona, Spain
On-line XRD in new pilot-MOCVD system for real-time quality control
36
Symposium on Superconducting Devices for Wind Energy – February 25, 2011 – Barcelona, Spain
Significant improvement in quality of production wires in 2010 % wires >
2009
2010
250 A/cm
25%
60%
300 A/cm
8%
22%
Symposium on Superconducting Devices for Wind Energy – February 25, 2011 – Barcelona, Spain
Rapidly decreasing price of 2G HTS wire through technology advancements 10 m demo 100 m demo 500 m demo First year of pilot production
1,000 m demo
Creation of separate Manufacturing and R&D facilities
2 to 4x higher throughput
Symposium on Superconducting Devices for Wind Energy – February 25, 2011 – Barcelona, Spain
AP wire (Zr-doped) product introduction
Projected improvements in in-field performance of production wires through technology
• 10-fold improvement by combination of higher self-field critical current and improved retention of in-field performance through technical innovations. • Even at 4.2 K, 15 T, 2G HTS wire is comparable now with Nb3Sn wire. Opportunity to improve to be 10X better than Nb3Sn ! Symposium on Superconducting Devices for Wind Energy – February 25, 2011 – Barcelona, Spain
Significant price improvements projected through technological advancements Prototype device market c
Small commercial market Medium commercial market Large commercial market
• Price reduction due to improvements in zero-field critical current, retention of in-field critical current and cost reduction ($/m) • Applications that involve magnetic field benefit from the additional improvement factor in in-field Ic retention • IncreasingSymposium market opportunities with decreasing price at operating condition. on Superconducting Devices for Wind Energy – February 25, 2011 – Barcelona, Spain
Roadmap to realize large market potential Now to 2 years
30
Magnetic Field (T)
35
2G HTS ‐ demo market Niobium‐Tin LTS Niobium‐Titanium LTS
D
25
A. Cables, Transformers, Fault Current Limiters
20
B. Motors, Generators, Transportation, Aerospace
15
C. High‐field Magnets
10
D. High‐field Inserts
C
5
A
0 10
20
30
40
50
60
70
80
Magnetic Field (T)
D
25
15
C
D. High‐field Inserts, MR, High Energy Physics, Fusion Reactors
10
B A
0 0
10
20
30
D. High‐field Inserts
C 10 B
A 10
20
30
40
50
60
70
80
90
• Large market potential outside the capability of LTS wire.
C. High‐field Magnets, MR, High Energy Physics, Fusion Reactors
5
C. High‐field Magnets,
15
Temperature (K)
B. Motors, Generators, Transportation, Aerospace
20
A. Cables, Transformers, Fault Current Limiters B. Motors, Generators, Transportation, Aerospace
20
0
90
2G HTS ‐ Large market 5+ years 2G HTS ‐ Medium market 2G HTS ‐ Small market A. Cables, Transformers, Niobium‐Tin LTS Niobium‐Titanium LTS Fault Current Limiters
30
2 to 5 years
0
Temperature (K)
35
D
25
5
B 0
2G HTS ‐ Large market 2G HTS ‐ Medium market 2G HTS ‐ Small market Niobium‐Tin LTS Niobium‐Titanium LTS
30
Magnetic Field (T)
35
40 50 60 Temperature (K)
70
80
90
• Wide range of applications with broad operating conditions & unique requirements – need highly sophisticated & engineered wire. • Abundant opportunity to lead market capture through technology to improve wire performance and cost-profile
Symposium on Superconducting Devices for Wind Energy – February 25, 2011 – Barcelona, Spain
Applied Research Hub to accelerate technology transfer and commercialization • Formed in 2010 with $3.5 M funding from the state of Texas through the Emerging Technology Fund. Additional $3.8 M provided by UH. • The initial focus of the Applied Research Hub is on power applications of high temperature superconducting wire. SuperPower is the first industry partner • Labs now in UH campus expanding to 70-acre UH Energy Research Park • New pilot-scale MOCVD system procured and will be set up this summer. • SuperPower to establish Specialty Products Facility in UH Energy Research Park this summer Rapid transfer of technology advances to manufacturing to accelerate commercialization of HTS for wind energy and other applications Symposium on Superconducting Devices for Wind Energy – February 25, 2011 – Barcelona, Spain
Abundant potential for 2G HTS wires for several applications • 2G HTS wires have come a long way by combining complex materials with novel processes and equipment innovations. • Among all superconducting materials, 2G HTS wires are the most tunable Æ plenty of opportunities to meet goals through R&D. • Potential for large improvements in performance (critical current in operating condition) with modest price reduction ($/m) • Opportunities to tailor wire to meet complete specifications (ac losses, stabilization, mechanical properties) • Focused R&D effort underway along with maturing manufacturing operation for broad insertion of 2G HTS wire in several applications
Symposium on Superconducting Devices for Wind Energy – February 25, 2011 – Barcelona, Spain
