Hi h T t S d tiHigh Temperature Superconducting...

Hi h T t S d tiHigh Temperature Superconducting Transmission:

Losses and other Considerations

Dr. Michael Gouge, ORNL

GCEP Advanced Electricity Infrastructure Workshop

Stanford University

November 1, 2007

Superconductivity is not newp y

• Superconductivity discovered in 1911Superconductivity discovered in 1911 in the element mercury

• metallic superconductors (for magnets):magnets):– materials are NbTi, Nb3Sn

• operation in liquid helium– 4 K or -452 F – “low temperature superconductors”

• medical imaging (MRI) & research g g ( )magnets

• fusion and accelerator magnets

2

Superconductors: Electricity p yflows without loss of energy

O di d t l tOrdinary conductor: electronsmoving at random lose energy in

collisions, generating heat.

Superconductor: electrons moving in pairs don’t collidein pairs don’t collide,

generating no heat and losingno energy!

4

How Cold is Cold, and What is “High-Temperature?” g p

321-321

5

The Electricity Chain

hydrowind solar digital

electronics

coalgas

heatmechanical

motion electricity

communication

power grid

transportationmotion

fuel cells lighting

grid

industrynuclearfission

fuel cells g gheating

refrigeration35% of primary energy

production delivery use

transportation petroleum chain ⇒ 29% of primary energy

Basic Energy SciencesBasic Energy Sciences Workshop on Superconductivity May 8Workshop on Superconductivity May 8--11, 200611, 2006

transportation petroleum chain ⇒ 29% of primary energy

The Great Enabler

% primary energy devoted to electricity production

30

40

20

30

%

10 QuickTime™ and aTIFF (Uncompressed) decompressor

are needed to see this picture.

1880 20201920 1940 1960 1980 20000.0

1900


source: EPRI

DOE Superconductivity for Electric S t PSystems Program

– Develop & Demonstrate Equipment

• Transmission & Distribution– Power Cables– Transformersa s o e s– Fault Current Limiters

• Rotating Electric Machines– Generators (MVA)Generators (MVA)– Motors (HP)– Synchronous Condensers (MVAR)

• Magnets• Magnets– Medical Imaging– Separation & Processing

R&D

8

– R&D

Potential to Impact Existing Technologies and Opportunities for Novel Applicationspp pp

• Significant efficiency benefits to the national electricity infrastructure.

HTS motor is 50% smaller and lighter

. . .and losses are cut in half

HTS cable carries 3-5 x the current

HTS transformers are non-flammable (do not use oil) and more efficient

9

Transforming the Grid: Efficiency and Environment

deliveryproduction

deliveryuse

HTS cablesFraction of resistance

Preferred power flow routeLow impedance ⇒ easier regulation

HTS generatorsHigh power density ⇒ 1/2 size weight

Low impedance ⇒ easier regulation

HTS motorsHigh power density⇒ 1/2 size, weight

⇒ 1/2 size, weight

1/2 to 2/3 the losses

high efficiency down to 5% of

TransformersHigh power density ⇒ 1/2 size, weight h t ti

1/2 losses at high speedHigh efficiency at low

speed

the rated load

withstand voltage and reactive power fluctuations

⇒ cheaper construction

1/2 the losses

No flammable or contaminating transformer oil

Replacement of industrial motors could save 1% of total electricity use = 4

GW


transformer oilSite in urban areas

Efficiency and Environment

electricityelectricityproduction electricity

deliveryelectricity

use

incandescent~ 5% efficient

Solid state> 50% efficient

Lighting ~ 22% of electricity use

51% produced from coal

63% primary energy lost

2 Gt CO2/yr

7-10% transmitted energy lost

= 40 GW

Clean electrical energy

electric motors ~ 64% of electricity use

2 Gt CO2/yr34% of CO2 emissions

Clean electrical energy

Contaminating and flammabletransformer oil

Urban restrictions on substationsTransportation 72% energy lost


72% energy lost 31% CO2 emissions

High Temperature Superconducting (HTS) Generators: Modest efficiency savings but over a

large fraction of electricity generated

From final report: p“GE believes that the economic breakpoint for a utility class HTS generator will be a based loaded unit rated above 500 MW At these higherrated above 500 MW. At these higher ratings, the fixed costs, such asthe refrigeration and other auxiliary equipment, can be amortized over a greater efficiency benefit.”

• Typical efficiency savings for

GE 100 MVA HTS GeneratorDesign

Typical efficiency savings for larger units are 0.35-0.55%.• For a 575 MVA GE unit, the loss savings was 2 GW – 0.35%.

12 12

Design

Cable cross-sectional view• Co-axial cable features:

– Magnetic field shielded (HTS outer shield).B th d t d

Liquid Nitrogen Coolant

Inner Cryostat Wall

Copper Shield Wire

Outer Protective Covering

Liquid Nitrogen Coolant

Inner Cryostat Wall

Copper Shield Wire

Outer Protective Covering

– Both conductor and dielectric are wrapped from tapes.

– Cryogenic dielectric reduces size and

Copper Core

High Voltage Dielectric

HTS Shield Tape

Coppe S e d e

HTS Tape

Copper Core

High Voltage Dielectric

HTS Shield Tape

Coppe S e d e

HTS Tape

reduces size and increases current carrying capacity.

– Flexible cable to allow reeling Outer Cryostat Wall

Thermal “Superinsulation”

Outer Cryostat Wall

Thermal “Superinsulation”

g• New tri-axial design is

most compact superconducting cable concept:– Minimizes use of HTS

tape– Requires minimum

surface area for cryostat-lower heat load

13 13

lower heat load

HTS cables are attractive in niche applications like NYC to deliver high current (power) in a small duct spaceto deliver high current (power) in a small duct space• 9 three-phase copper circuits, each

in a 6 inch duct– copper conductors de-rated due to

heating in adjacent ducts• One three-phase tri-axial cable in 10

Copper

inch duct• At constant current can increase

capacity by increasing voltageHTS

William Street & Fulton

14 14

William Street & Fulton Sreet, New York City

(2003)

HTS cables have loss reductions relative to copper d t b t th ibl k t i llconductors but the accessible market is small

• Transmission (~138 kV and above) ( )About 12 percent (160,000 miles) of all power lines are transmission lines.For most utilities, over 99% of transmission lines are overhead. An equivalent underground transmission line can cost 5 to 15 times the cost of an overhead transmission line but there is a growing market.g gHTS cables are now several times more expensive than copper underground cables so there only an incentive to install HTS cables in the transmission grid in niche applications or where there are strong aesthetic considerations.

• Distribution (~69 kV and below)Distribution ( 69 kV and below)About 88 percent of all power lines.Generally the capacity of these lines are low (less than 20 MVA) and the load factor variable so it is not attractive for HTS cables.There may be some applications for HTS cables at 35-69 kV and 2-4 kAThere may be some applications for HTS cables at 35 69 kV and 2 4 kA (100’s of MVA) but this market will not impact national grid losses much.

15 15

Why HTS Transformers?• From power generation to end user there are 8-9% losses. Much

of this is in transformers.• 80% of losses in transformers are load loss, which HTS ,

application makes almost negligible.• Need for efficient delivery of electric power will continue to grow

world wide.

2000

2500

U.S. Power Transformers (10+MVA)

1000

1500

2000

Units

00

500

5 10 15 20 25 30

34,800

Age of Transformers in Years

16 16

HTS Motors: Reduced losses in end use

17 17

Superconductivity can reduce losses in ti t i i d dgeneration, transmission and end use

• The loss reduction is evaluated for the HTS component prelative to the copper or aluminum conductor it replaced.

• There is a cryogenic penalty which must be taken into account. Typically for 1 watt removed at 77 K it requiresaccount. Typically for 1 watt removed at 77 K it requires 10-12 watt of electrical input power at room temperature.

• The cryogenic losses are normally much less than the efficiency gain for larger devices This sets a thresholdefficiency gain for larger devices. This sets a threshold for HTS grid component size:– 100-300 MVA for HTS generators

10 20 MVA f HTS t f– 10-20 MVA for HTS transformers– ~5 MVA (6700 HP) for HTS motors

18 18

General refrigeration cycleg y

H t j ti QHeat rejection Q hto ambient at T h

QFluid expansion to reduce

temperature Work done onprocess fluid

Power in via compressor or drive unit

QHX

Power produced and lost to ambient.

10-20 watt at 300 K

Heat absorptionQc watts at Tc

ch

cCarnot TT

T−

=η

HTS load at ~Tc ( ) Carnotreal .3-.1 ηη ×≈1 watt at 77 K

19 19

Cycle efficiency vs. capacity at Top

20 20

Typical cryogenic heat loads

Heat rejection Q hto ambient at T h

Q

Heat absorptionQc watts at Tc

Fluid expansionto reduce

temperature

Work done onprocess fluid

Power in viacompressoror drive unit

QHX

Power produced and lost to ambient.

HTS Component Heat load, Top C bl ( h ) 3 4 kW/k t 65 80 K

HTS load at ~Tc

Cable (per phase) 3-4 kW/km at 65-80 K

Transformer (10-100’s MVA) 100-1000 W at 60-80 K

Motors (5,000-40,000 HP) 50-100’s W at 50-65 K

Generators (400-1500 MW) 100-1000 W at 50-65 K

Fault Current Limiters ~ kW’s at 50-80 K

SMES, magnetic separation, 10-100’s W at 50-65 K

21 21

MRI, etc.

Insert more efficient HTS i h i i idcomponents into the existing grid

• Analysis from EC and Japan:– Assign threshold component rating for HTS

t h l i ti (MW MVA HP)technology insertion (MW, MVA, HP)– Specify efficiency improvement taking into account

the cryogenic penaltythe cryogenic penalty– Assume a fraction of the total market is penetrable– Calculate annual energy savings in TWh– Convert to MMT of carbon dioxide (region specific)

22 22

Results from EU StudyComponent Threshold

ratingLosses

relative to conventional

Annual Energy Savings

CO2 Reduction

Generator 100 MW 0.5 10.4 TWh

Transformer 12.5 MVA 0.5 20.7 TWh

Total 31 TWh 14.7 MMTTotal(1.2% of total generation)

(average over all generation)

(20% of Kyoto reqr.)

Teemu Hartikainen et al., “Reductions of greenhouse gas emissions by utilization of superconductivityin electric-power generation,” Applied Energy, 78, pages 151-158, (2004).

23 23

Results from Japanese StudyComponent Threshold

ratingLosses

relative to conventional


CO2 Reduction

conventionalGenerator Efficiency

improved by 0.5%6.4 TWh 3.0 MMT

Transformer Efficiency improved by 0.125-0.25%

13.0 TWh 1.0 MMT

Motors 1 MW Efficiency 5 0 TWh 0 4Motors 1 MW Efficiency improved by 2%

5.0 TWh 0.4

Total 24.4 TWh 4.4 MMT

S. Morozumi, “Potential of energy conservation by superconductive applications,” Physica C, 357-360, pages 20-24, (2001).

24 24

y , , p g , ( )

Results from Japanese Study: benchmark to U.S.

S Morozumi “Potential of energy conservation by superconductive applications ”

The multiples of contribution of superconductive applications to energy conservation andCO2 reduction in the USA are compared to Japan (Japan is defined as 1 in each case).

25 25

S. Morozumi, Potential of energy conservation by superconductive applications, Physica C, 357-360, pages 20-24, (2001).

Insert more efficient HTS i h i i idcomponents into the existing grid

• Analysis for U.S.– Same general approach as EU, Japan– 4,055 TWh of electricity generated in 2005, y g– Assume 9.5% of generated electricity is lost (EIA 2006)– Assign threshold component rating for HTS technology insertion

(MW, MVA, HP)– Specify efficiency improvement taking into account the cryogenic

penalty– Assume a fraction of the total market is penetrable– Calculate annual energy savings in TWh– Convert to MMT of carbon dioxide (5.4 MMT/GW-year)

26 26

U.S. Similar Approach

Component Threshold rating

Losses relative to conventional


CO2 Reduction

SavingsGenerator 400 MW Efficiency

improved by 0.4%13.0 TWh

Transformer 10 MVA Efficiency improved by 0.2%

25.6 TWh

5 MW Effi i 12 8 TWhMotors 5 MW Efficiency improved by 1.9%

12.8 TWh

Total 51.4 TWh 31.8 MMT (average Total ( gover all generation)

27 27

R&D, energy savings and policy can accelerate insertion 3-4 HTS can accelerate insertion

• HTS Conductors– Optimize conductor design to meet grid applications

tapes carry the same current as this 400-A copper cableg g

– Reduce manufacturing costs an order of magnitude – Reduce ac losses

• Cooling systems– Lower cost: from $100 to $25/watt at ~ 65-80 K Pulse-tube

copper cable

– higher efficiency (20-30% of Carnot) and high reliability cryocoolers• High voltage/low temperature electrical insulation

materials– Dielectric materials that meet application needs

cryocooler

– Make cryogenic electrical engineering routine• DOE-Office of Electricity is supporting HTS R&D

and realistic grid demonstrations• Need an incentive for utilities and end users to

switch to HTS grid devices– Annual electricity savings is a start….– CO2 reduction credit?

R e s is ta n c eis fu t ile .

28 28

Reconfigure the Gridoror

Was Edison right?

29 29

Enable efficient, reliable two-way power flow via HTS DC cablesflow via HTS DC cables

• Since there are effectively no resistive losses, HTS DC cables can carry 10-100 t t th ti l

Conventional cable 300-1000 A

100 x greater current than conventional cables

• For fixed power in a range of 20-500 MVA, this allows the DC voltage to be

12 cm

, greduced from 100-150 kV to 10’s of kV

• This simplifies the converter station, reduces its volume and cost and increases the reliability of the DC

LN

increases the reliability of the DC network HTS Tapes

Dielectric

Vacuum/MLI

HTS dc cable 10,000-50,000 A

DC network with

30 30

HTS backbones

HTS DC Cable: A potential solution for growing power delivery needs of computing facilities

• ORNL Leadership Computing Facility is advancing:Cray XT3 Jaguar – 250 TF in 2007

Motivation

– Cray XT3 Jaguar – 250 TF in 2007– Cray Baker – 1-PF in 2008– Expansion to “exa-scale” systems considered

• Expect significant increase in power demand (30 MW) facility upgrade neededdemand (30 MW) facility upgrade needed

• DOE is interested in addressing efficiency issues for data centers

• No resistive loss increase efficiency, reduce CO2 footprint.• Single high power density cable reduce footprint and

Benefits of HTS DC cable

Single high power density cable reduce footprint and environmental impact

• DC power ready to integrate with computers• Relocate auxiliary power equipment outdoors

d li i t i bl

31 31

31

OAK RIDGE NATIONAL LABORATORYU. S. DEPARTMENT OF ENERGY

SSM_0609

reduce cooling requirement, increase usable space

North American Transmission RegionsEASTERN470 GW

103 control areas

Four major independent asynchronous networks, tied together only by DC interconnections:1. Eastern Interconnected Network – all regions east of the Rockies except ERCOT and Quebec portion of the NPCC reliability council.

Four major independent asynchronous networks, tied together only by DC interconnections:1. Eastern Interconnected Network – all regions east of the Rockies except ERCOT and Quebec portion of the NPCC reliability council.2. Quebec – part of the NPCC reliability council.3. Texas – the ERCOT reliability council.4. Western Interconnected Network – the WSCC reliability council.

2. Quebec – part of the NPCC reliability council.3. Texas – the ERCOT reliability council.4. Western Interconnected Network – the WSCC reliability council. Source: Arrillaga (1998)Source: Arrillaga (1998)

From the U.S. - Scientific American - July 2006 Paul Grant EPRIPaul Grant, EPRI

Cryogenic superconductingCryogenic, superconductingconduits could be connectedinto a “SuperGrid” that wouldsimultaneously deliver dc electrical power and hydrogen fuel….hydrogen fuel….

33

Japanese vision: HTS dc and solar, wind farms

34 34

Ryosuke Hata, Dr., Eng.Sumitomo Electric Industries, Ltd.ISIS-16

More details

35 35

ConclusionsConclusions

• Substitution of conventional generatorsSubstitution of conventional generators, transformers and large motors with their HTS counterparts can:HTS counterparts can:– save up to 14.7, 4.4 and 31.8 MMT of CO2 in

EU Japan and U SEU, Japan and U.S.• Reconfiguration of the grid can save more

but requires a major paradigm shift inbut requires a major paradigm shift in technology and policy.

36 36

Thank you yand

Extra slidesExtra slides

37 37

• From T. J. Blasing 1 kW-hr = 605 g of CO2; for 1 year 5.3 MMT for 1 GW• 2005 total generation is 4055 106 GW-hr: average over year is 463 GW: produces 2330 MMT of g g y p

CO2 or 5.0 MMT/GW• T&D losses of 7-10% of generated power about 40 GW producing 230 MMT of CO2: for I year this

is 5.8 MMT/GW• 64% of energy generated in the US is converted by electric motors--approximately half of this is

converted by motors greater than 1,000 hp• About 70% of the 1000 horsepower and above motor market is a viable target for HTS motors.• An HTS motor will have half the losses (or less) of a conventional motor of the same rating. The

size of the HTS motor will also be smaller. Consider a 6000 horsepower motor example. The ti l hi h ffi i i d ti t ill b 96 6% ffi i t hil th HTS t ill bconventional, high efficiency induction motor will be 96.6% efficient while the HTS motor will be

98.5% efficient (including the power loss associated with the HTS coil cryocooler system as a loss for the HTS motor). This 1.9% efficiency improvement results in a savings for the customer approaching $50,000 per year.

• If $1 Billion of HTS motors are sold worldwide each year about one third of these sales would beIf $1 Billion of HTS motors are sold worldwide each year, about one third of these sales would be in the United States. Factoring in the energy efficiency improvement of the HTS motors over conventional motors, the $333 Million in HTS motor sales in the Unites States results in an annual savings (from this one year of motor sales) due to the efficiency improvement provided by HTS motors of $41 Million (about 0.6 Billion kW-hr at $0.07 /kW-hr). Taking a typical large motor life

f 25 d l k t diti th ti i t ll d b d f l t ill bof 25 years, under normal market conditions, the entire installed based of large motors will be replaced by HTS motors over a 25 year period. It is expected that this transition will be faster as energy costs continue to climb. With a conversion of all large electric motors that are candidates for HTS technology the annual energy savings, in the United States alone, will be over $1 Billion (25 years of motor sales adding at least an additional $41 Million in energy savings each

38 38

( y g $ gy gyear).

• Energy losses in the U.S. T&D system were 7.2% in 1995, accounting for 2.5 quads of primary energy and 36.5 MtC. Losses are divided such that about 60% are from lines and 40% are from transformers (most of which are for distribution).

• The EIA estimates that transmission and distribution losses in the United States averaged about 9 percent of electricity generated in 2005.

39 39

The Power Grid

6

5

4

TransmissionInvestment

4

3

2

1

$B

Source: Cambridge Energy Research Associates

200019801970196019501940 19900

capacity50% growth

reliabilityblackouts

efficiency / environment7-10% of power is lost in the grid

40 1GW l tsby 2030urban power bottleneck

cascadesquality

40 1GW power plants230 Mmt of CO2


Blackouts, Cascading Failures, and Quality

Insufficient regional generationRolling blackouts west coast

Brownouts east coast400 major outages 1984-1999

Grid congestion preventspower sharing

Local failures cascade2003 Northeast Blackout

508 generators tripped outCleveland ⇒ Toronto ⇒ NYC1800400 major outages 1984-1999 Cleveland ⇒ Toronto ⇒ NYC

7 minutes

600

1000

1400Requests for Relief from Power Exchanges

Requ

ests

10/yr

ency

1996 1998 2000 2002

200

North American Electric Reliability Council

1/yr

1/10yrs

1/100yrs

Freq

ue

I t t d t t 2/3 it l t i lit diti i

Not only outages, but qualityCustomers affected

1/100yrs

10K 100K 1M 10M

Report on 2003 North American Blackout,

https://reports energy gov/

Report on 2003 North American Blackout,

h // /

Digital power quality: 10% demand today ⇒ 30% by 2020

Internet data centers: 2/3 capital cost is power quality conditioningSemiconductor fab lines need steady voltage to fraction of a cycle

https://reports.energy.gov/ https://reports.energy.gov/


The grid cannot deliver digital quality power for the 21st century

Transforming the Grid: Superconducting Cable

5-fold more power than copper

same cross section

zero DC loss

100 f ld l C l h

Lower losses ⇒ longer transmission

Regional power sharingCross weather boundariesCross generation zones100-fold less AC loss than copper

high power density ⇒ small size

Cross generation zones

Generation at fuel source for distant transmission

Replace copper with superconductor

Use existing underground conduits

N Y k

HTS XLPE

XLPE

XLPE

138 kV

230 kV

345 kVLower voltageNo heatingNo impact on underground i f

New YorkCA

Transcontinental diurnal levelingIncrease efficiency and capacity

Only superconductors can achieve this HTS

XLPE

HTS XLPE

0 500 1000250 750

34.5 kV

69 kVinfrastructureEasier permitting


0 500 1000250 750Power Capacity (AC 3Φ, MVA)

Transforming the Grid: Superconducting Power Control

Fault current limiters Reactive power controlFault current limitersManage overload currents due to lightning, wind, component failure, dynamic power flow

Growing complexity ⇒ growing fault currents age

Reactive power control

reactive loadtransformers

g p y g g

R l

Volt

aReal loadresistive

Superconductors:

smart fault control

The wire is the controller

Resi

stan

ce IcReal power

Driven by grid: motor

Superconducting reactive power regulator

The wire is the controller

Fault current limited in half cycle ~ 10ms

Fast automatic reset when fault is cleared

CurrentDr n y gr m t r

Injects/absorbs reactive power: generator

Smart dynamic responseFast automatic reset when fault is cleared

Transparent when not active

Superconductors enable smart self-healing grid

Small, economic packageFirst commercial

superconducting grid technology


Superconductors enable smart self healing grid

Hi h T t S d tiHigh Temperature Superconducting...

Documents

Transcript of Hi h T t S d tiHigh Temperature Superconducting...