Transcript Superconductivity UK

Superconductivity UK
Commercial superconductors,
Cryogenics and Transformers
Dr. Philip Sargent, Diboride Conductors Ltd.
This Talk
• Materials Review and price predictions
• BSCCO
• MgB2
• YBCO
• Cryogenics considerations
• Superconducting Transformers
Commercial Wire & Tape
• Commercial production:
• Niobium alloys (NbTi, Nb3Sn
etc)
• B2223 / silver tape - 1st Generation HTS
• Pre-commercial:
• MgB2
• Industrial laboratory:
• YBCO 2nd Generation HTS “coated conductor”
Key issues for power applications
• Overall current density • Cost!
Je of conductor, not
just of superconductor
• Performance in field
• Multiple filaments for
AC applications
• Anisotropy of Jc with
respect to field
direction
• Conductor itself
• Cooling (AC losses)
• Scalability of
fabrication
• Mechanical
• Strength, bend radius
HTS –perovskite ceramics
Ba
Cu
O
Y
Ba
B2223 - Bi2Sr2Ca2Cu3O
YBCO - YBa2Cu3O7
Engineering Implications
• Requires near single-crystal microstructure
by complex processing,
• Oxide requires furnace treatment in
controlled oxygen atmosphere, in silver,
• Highly anisotropic resulting tape:
• Along and across tape,
• Sensitive to magnetic field direction!
AMSC & Sumitomo
• AMSC &
Sumitomo have a
reciprocal licensing
agreement
American Superconductor 55 filament
(B2223) tape
Sumitomo (B2223) tape
AMSC B2223 Manufacturing Plant
 Larger billets, Process automation, Longer
strands, Multi-dies, Faster line-speed,
Combination of process steps
 Began volume production in early 2003
 Full capacity could be 20,000 km/year, now
900 km/year
Price/Performance $/kA.m
• How much does it cost to buy the wire to carry
1000 Amps a distance of 1m?
• Copper: 6 $/kA.m – 22 $/kA.m depending on
current density (400 – 100 A/cm2)
• Superconductors typically quoted at Jc and at 77K
and either zero magnetic field or “self field”.
• Cryogenic OFHC copper can be 0.06 $/kA.m.
• NbTi is approx. 0.9 $/kA.m in liquid helium.
Price/Performance $/kA.m
Price/Performance Ratio, $/kA-m
1200
$/kA.m
1000
800
600
World’s First HTS Wire
Manufacturing Plant
Opened By AMSC
400
200
0
1995
200 $/kA.m
1996
1997
1998
1999
2000
2001
2002
2003
2004
Reduced Manufacturing Costs ($/m) and Increased Wire
Performance (current carrying capacity)
B2223 & Commercial Products
• At $50/kAm (77K) price/performance ratio
significant markets would be enabled (it was
thought in ~1999):
−
−
−
−
−
Utility Generators (>100MVA)
Ship Propulsion Motors and Generators (>5MW)
Wind Turbine Generators (>4MW)
Urban T&D Power Cables
Industrial Magnetic Processing
Bought and shut down
by AMSC in 2002
• Significant worldwide industry in B2223
American Superconductor, Innova, Nordic Superconductor,
Sumitomo Electric, Vacuumschmelze, Trithor
Magnetic Field
• High magnetic field reduces current
carrying capacity
• Lower temperatures enhance current
carrying capacity
• Transformers, cables and FCLs are low
magnetic field devices
• B2223 at 27K carries twice the current, so
$/kA.m reduces to 100 $/kA.m.
Diboride & YBCO
• YBCO and similar compounds have had
research worth $$billions devoted to their
physics and processing.
• MgB2 was discovered in January 2001;
physics now entirely understood.
• Both can be made in:
• Tape geometry
• Massive lumps for new motor designs
Magnesium Diboride
Mg
B
Mg
B
s
Mg
B
Mg
39K
p
Magnesium Diboride
~ 400 $/kg
Making Diboride tape
Tube filling with
MgB2 powder
Wire drawing
and/or rolling
Flat rolling
Long lengths can
be now fabricated
Cu-sheathed tape
transverse cross irregular cross section
section
Simple sintering ~700C
In situ B+Mg with Fe barrier in Monel Sheath
With iron –tough to make multifilament- most likely be cabled ,
(twisted) monofilaments for low AC loss conductor, working on
Outer sheaths of Monel, Cu/Ni, and Cu to improve stabilization.
Hyper Tech Research
Magnesium Diboride (MgB2 )
• Advantages
• No weak-link effects, low anisotropy
• Easy to fabricate wires, films: <$10/kA.m potential
• Challenges
• Tc < 40 K (77 K applications like cables, transformers not
viable)
• High field applications such as NMR not viable
• Possible applications in 20-30K range for modest
field environments, e. g., rotating machinery
YBCO Coated Conductor
• Rolled, textured Nickel tape (Ni-W)
• Oxide buffer layer, preserves texture
• YBCO (or analogue, e.g. HoBCO), preserves texture
• Near “single crystal” 100s of metres long
• <$10/kA.m potential, but extraordinary plant cost
YBCO
Ni tape
Oxide buffer
layer deposition
YBCO
YBCO
precursor
YBCO
oxygenation
and conversion
YBCO Coated Conductor tape
• Active programs in US, Japan and Europe
• Examples of results in 2001:
•
122 A (75 K) over 1 m by LANL
− World record for meter length
•
50 A over 10 m by Fujikura
− World record for 10 meter length
•
Over 60 m :Fujikura
− World’s longest processed tape
YBCO CC Technical Issues
• Adequate uniformity over length
• Stability to over-currents or cracks
• Adequate current in MOD films
• Mechanical properties – spalling, cracking
• Stability of metal-oxide epitaxial interface
• Deposition rate for ion beam and laser processes
• Thicker than 3 micron YBCO ?
• …but must have that 10 $/kA.m process!
B2223 (1G) to YBCO (2G)
Price/Performance $/kA.m
Price/Performance Ratio, $/kA-m
1200
$/kA.m
1000
800
600
World’s First HTS Wire
Manufacturing Plant
Opened By AMSC
400
200
0
1995
200 $/kA.m
1996
1997
1998
1999
2000
2001
2002
2003
2004
Reduced Manufacturing Costs ($/m) and Increased Wire
Performance (current carrying capacity)
ORNL Model
Assumed by analogy with other fibres
B2223/YBCO Wire cost ($/kA.m)
Magnesium Diboride
Performance
Technology ‘S’ Curves
Effort
Power Technologies
HTS g2
17y
MgB2
Performance
75y
HTS g1
Copper-Iron
2003
Effort
Conclusions:
Superconductors for AC Power
• HTS G1:
• B2223 tape
• Diboride:
• MgB2 wire
• HTS G2:
• YBCO CC tape
AC Power Superconductors
Refigeration Energy Consumption
Energy Consumption
Carnot Thermodynamics
Higher running costs =
Higher
Lower
Higherrunning
cryogenic
capitalrunning
costs
Highercosts,
magnetic
field costs,
lower wire costs
uses more wire
capability
0
20
40
Temp (K)
60
80
Temperatures
Liquid Phase at 1 atmosphere
CO
N
O
Ne
H
Cryogen Gap
He
0
20
40
T (K)
60
80
Cryogenic Cooling Costs
70.4x
Ideal Energy Consumption
4K
27K
Carnot
Sterling
80.00
EC
60.00
10.1x
40.00
2.9x
20.00
0.00
0
20
30
14x
9x
40
Temp (K)
60
80
77K
Cryogenics
• High AC power is intrinsic to transformers
• Cables have high losses: so need cryogens
• Conduction-cooled designs need exploring
20-24K and 27K-60K for other applications
• Thermal reservoirs need investigating to
peak-shave cryogenics capital costs
• Reducing the capital cost of cryogenics is as
important as their efficiency for grid markets
Cooling & Purchase Costs
• There is a trade-off between cryogenic capital cost
•
•
•
•
and materials capital cost – colder running means
less material required but more cryogenics.
The cheaper the superconductor, the higher the
optimum operating temperature.
Comparing different materials therefore requires a
whole-system comparison
Competition between materials is application
dependent
Transport applications are always more attractive
Cost “Prediction”
Source: Mulholland et al, DOE June 2003
Cryogenic Patents
Cryogenic Cooling System patents filed in the U.S.
18
Cryogenic Cooling System Patents
16
Cryocooler
14
12
10
8
6
4
2
20
02
20
00
19
98
19
96
19
94
19
92
19
90
19
88
19
86
19
84
19
82
19
80
19
78
19
76
0
19
74
Number of Patents Filed
20
Year
Qi3 Limited (2003)
Targets
• Copper: 6 – 22 $/kA.m (400 to 100 A/cm2)
• B2223: 100 $/kA.m (at 27K)
Device
kA/cm2 Tesla
Static
105
Transformer
Cables
105
$/kA.m
1.4
15
<0.1
10 ?
Dick Blaugher, NREL
ABB HTS Transformer
100 MVA, 225 / 20 kV
•
•
•
•
•
oil free, liquid nitrogen 68K
20% lower weight
80% lower load losses
5% smaller volume
Short circuit reactance 50% of
conventional
•
25% over-loadability without
accelerated ageing
• 150% first cost
• 90% lifecycle cost
• Short circuit current limitation in first
half wave, self restoring FCL
5
m
11 m
135 000
kg
Other HTS Transformer Benefits
• Reduced need for load tap changer
units
• Reduced system VAR requirements
• Reduction in capacitor banks
• With a generator, reduced VAR enables
additional generator capacity so
reduced capital cost of generator
ABB Conclusions
•With current costs for energy and equipment, an open loop
refrigeration system is the most economical.
•The mechanical refrigeration industry is not currently able to meet
performance targets required for a commercial Utility product.
–Cryocoolers are too expensive, maintenance intervals are too
short, and production methods are not cost effective.
–The number of competitors in the field is limited, and the
companies are generally small operations.
–Production scale-up and comprehensive global service could
be problematic
Near term market too small to justify continuation
of project!
Waukesha/ORNL Project
• Waukesha 24.9kV to
•
•
•
•
4.2kV
$10m project
2x overload capability
FCL capability
1 MVA pilot at 25K with
cryocooler
Transformers
Lifetime Cost of Ownership in $/kW
Cu (330 K)
MgB2 (25 K)
60
HTS (68 K)
200$/kAm
5
Cryo
-
25
34
Wire
5
50
5
Total
65
80
50
@ 300 A/cm2
Losses
2000 ABB SPI Phase I Analysis
10
Adapted from Paul Grant EPRI
ORNL HTS Transformer
• High utilization and
high cryocooler
efficiency required
to get energy
savings (RAND)
• Feasible with 10year payback if
<15$/kA.m at 77K.
(Lawrence Assc.)
Energy Efficient Transformers
•
•
•
•
•
•
High-copper section designs
Domain-refined steels
Ultra-thin iron laminations
High-field (1.7T) iron alloy core
Metallic glass or amorphous iron core
Lowest first-cost purchasing prevents
adoption of any of these technologies.
www.efficient-transformers.org
Primary Benefit
• The primary benefit in a
superconducting transformer is the
Fault Current Limiting capability.
• Therefore, make FCLs first!
Thankyou
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