Cryogenic Efficiency

1
Cryogenic Efficiency Losses in AC Power Machines

• Dr. Philip Sargent MIM MBCS CDipAF CEng.
• Diboride Conductors Ltd.

2
Power Superconductors
3
Power Superconductors
4
Cost of Capital when the superconductor is
costly
Lower capital costs, Expensive capital
Lower running costs, Cheap capital, Cheap
superconductor
5
Constraint Liquid Cryogens
Optimal Range
LOX!
6
Engineering Needs

• Generators, Transformers, Cables, FCLs, Motors,
  Grid conditioning, power storage
• Capital cost is most important for all of these
  in deregulated power markets
• Why superconductors?
• Higher power density, 100x the current
• Smaller
• Lighter (MgB2 is 1/3 the density of Copper)
• Cheaper to buy and install
• Cheaper to operate
• Entirely new capabilities (FCLs)

7
HyperTech CTFF for MgB2
CONTINUOUS TUBE FORMING AND FILLING (CTFF)
8
Boron Chemistry

• Pyrometallurgy Mg B heat
• Powder in tube in situ
• Powder in tube ex situ
• Powder in tube ex situ Mg
• Powder in tube HIP
• CVD Mg diborane
• Electrochemistry Mg-borates in KCL
• Other chemical routes ??

9
Materials Requirements

• Magnetic Fields 2-5 T (except cables)
• AC use requires T gt 20 K (cryogenic cost)
• Materials parameters
• Low cost 10 /kA.m
• Practical volumes Je (Jc 105 A/cm2 )
• Low AC losses W/kA.m at 50Hz.
• Flexible, low Je / strain sensitivity

10
Targets

• Copper 6 22 /kA.m (400 to 100 A/cm2)
• Bi2223 100 25 /kA.m (2002 2005)

Device kA/cm2 T /kA.m
Motor 105 4 10
Generator 105 4 10
Transformer 8.104 0.5 - 2 lt10
FCL 8.104 0.2 10
Cable 7.104 lt0.5 10-100
Dick Blaugher, NREL
11
Market Segmentation
12
Competitive Costs
Wire /kA.m Cost Driver
NbTi (4.2 K, 2 T) 0.90 Materials (Nb)
Nb3Sn (4.2 K, 10 T) 10 Materials (Nb)
Bi-2223 (25 K, 1 T) 25 Materials (Ag)
Y-123 (25 K, 1 T) 4 Capital Plant
MgB2 (25 K, 1 T) 0.8 3.6 ? Capital Plant
Paul Grant EPRI
13
Comparative Performance
"Sokolowski Plot" of HTSC Wire Performance and
Cost
10000
10
1 /kAm
100
NbTi
4.2K, 2T
1,000
1000
Nb
Sn
3
4.2K, 12-15 T
Operating Current, Ic (A)
100
Y-123 IBAD 77K, 0T
Bi-2223 77K,0T ASC 50
Bi-2223
77K, 0T
10
NKT Target
1
1000
100
10
1
0.1
Cost (/m)
Paul Grant EPRI
14
Transformers a big prizeCost of Ownership in
/kW
Cu (300 K) _at_ 300 A/cm2 HTS (68 K) MgB2 (25 K)
Losses 60
Cryo -
Wire 5
Total 65
2000 ABB SPI Phase I Analysis
Paul Grant EPRI
15
First Major Applications

• Current Leads? No.
• FCLs ? New capabilities!
• Transmission Cables ?
• Distribution Cables ?
• Dielectric thermal AC lossses
• Transformers ? 98 efficient.
• Generators ?
• Power stations,Wind turbines?
• Non-Utility Power Applications
• Motors
• 68 of industrial power
• Half of that over 750kW
• Power electronics Cryogenics

16
Materials Changeovers
Materials Changeovers
17
Technology S Curves
18
Power Technologies
75y
16y
MgB2
Performance
HTCs
Copper-Iron
2002
Effort
19
Conclusions

• Necessary Partner Technologies
• Cryogenics, not 99.999 reliable
• Power electronics, why use AC if DC can do it?
• Motors
• Higher power density, 100x the current
• Smaller, Lighter
• Cheaper to buy and install
• Transport ships, trains
• Environmentally friendly
• Prefer wire not tape!

12 April 2002