Superconducting Cables in Grid:Implementation of Superconducting Cables

Source: Fat Knowledge [1]

Prepared by Prajeshkumar Solanki and Aqpik Peter

The Algonquin Centre for Construction Excellence,Algonquin College

Ottawa, Ontario

15 April 2014

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Transmission Line Superconductors:

Replacing Regular Conductors with Superconductors

Prepared by Prajeshkumar Solanki and Aqpik Peter

Prepared for Prof. Jordan Smith

in partial fulfillment of the

requirements of ENL2019T-410:

Technical Communication for Engineering Technologies

The Algonquin Centre for Construction Excellence,

Algonquin College

Ottawa, Ontario

15 April 2014

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Declaration of Sole Authorship

We, Aqpik Peter and Prajeshkumar Solanki, confirm that the following work submitted for assessment in ENL2019T-410 (Technical Communication for Engineering Technologies) is expressed entirely in our own words, except where acknowledged otherwise. The use of work by other authors-be they words, ideas, numerical data, figures, tables, photographs, etc.—whether quoted, paraphrased, or reproduced, is properly cited at the point of use. The original sources of cited work may be located using the IEEE-style bibliographical entries in the References page at the back.

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Executive Summary

In this report, we will compare regular transmission lines to superconducting transmission lines. To get superconductors into its superconducting state, you need to cool it to about -196 degrees Celsius which we would use liquid hydrogen mixed together in a conduit underground. Using superconductor is a major bonus because there would be zero resistance in the line that would be able to transfer extremely high wattage though the generation system. Our transmission system today are used with towers and power line poles that are exposed to weather which is another disadvantage because certain climates increases the resistance in the conductors and that would increase the power load and make the generation system less efficient.

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Contents

Declaration of Sole Authorship . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . iExecutive Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . iiTable of Contents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . iiiIndex of Figures and Tables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . iv1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

1.1 Purpose . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11.2 Background . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11.2.1Problem Background . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21.2.2Solution Background . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21.3 Exclusion Elaboration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31.4 Content Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31.5 Reader Benefit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

2 Problem Elaboration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32.1 Losses due to Resistance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42.2 Stability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52.3 Environmental and Safety Issues . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

3 Solution Elaboration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73.1 Superconducting Cables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83.2 Production of the superconductors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93.3 Lifespan . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

4 Feasibility Study . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 104.1 Cost Benefit Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 104.2 Logistical Feasibility . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 104.3 Scheduling Feasibility . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . 11

5 Comparative Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 115.1 Alternative Solutions Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 125.2 Criteria Elaboration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 125.3 Comparative Analysis Table . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 135.4 Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

6 Conclusions and Recommendations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 156.1 Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 156.2 Recommendations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

Glossary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20Appendices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

Superconducting cable Benefits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

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Index of Tables and Figures

Figures

1. Superconducting cable schematic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . i2. Power loss over transmission line . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83. Power loss. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84. Hurricane Impacts. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95. Bird Deaths By High voltage lines. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

Tables

1. Superconductors vs Regular Conductors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 2. Criteria for alternative to superconducting cables . . . . . . . . . . . . . . . . . . . . . . . . . . .16 3. Superconducting cable benefits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

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1 Introduction

1.1 Purpose

In this report, we will be talking about the feasibility of replacing overhead

transmission line with liquid hydrogen cooled superconductors placed

underground in conduits as a means to minimize the resistance losses and

make the transmission a lot more efficient and vastly increasing the lifespan of

the system. By making operational grid with the superconductors, we will

right away diminish the losses due to resistance and we could use the liquid

hydrogen as fuel for the future cars. This report was prepared for Professor

Jordan Smith in partial fulfillment of the requirements of ENL2019T-410:

Technical Communication for Engineering Technologies.

1.2 Background

With the higher demand of electricity vastly increasing in North-America each

year, we need a whole new power grid system that will be much more

efficient, cost saving as well as environment friendly. As we all know that a lot

of power is being wasted because of the less efficient power transmission

lines, so a lot of work has to be done to minimize the losses by introducing the

superconductors in the grid. With an increasing demand for an alternative to

fossil fuels, we have to invest our interests in solar, wind, agricultural biomass

and advance nuclear power technology [2].

1.2.1 Problem Background

In the past, about 11 years ago North America saw a major power

outage that pushed the region into the darkness of stone era.

Around 120 million people in the area suffered huge losses due

power failure. This was due to the outdated 20th century power grid

system that lacks in the area of efficiency and interruption free

operation. A conventional transmission line system consists of

aluminum or other alloys as their conductors, which runs via

overhead lines through towers. The main problem with this system

is losses, either it’s due to resistance or weather or other means, it

is not efficient and safe.

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1.2.2 Solution Background

To overcome the modern era transmission system problems and

losses, we must look for an alternative way to provide efficient and

reliable solution. Our solution is to implement Superconducting

transmission lines through conduits in which liquid hydrogen would

flow as a coolant to get the conductor at its superconducting state.

Superconductors are more efficient than regular conductor because

there is no electrical resistance and would run on direct current

(DC).

1.3 Exclusion Elaboration

This report doesn’t elaborate the materials used up to make the underground

conduits in which the superconductor cables run. Also the report doesn’t

consist of the cost of the maintenance which could be done while the grid is

operational. The materials used in the superconducting cables may differ and

in this case they are just in a testing phase, so the actual metal used as

superconductor may be changed in the future.

1.4 Content Summary

In this report we will check the feasibility of implementing the superconducting

cables in the grid and check the various aspects to totally change the

conventional grid system so that we will prevent losses as well as we protect

the environment. Chapter three will elaborate the solution to the implement

the whole new system of superconducting cables. Chapter four will check

about the feasibility and the cost analysis involved in this project. Fifth chapter

will be on comparative analysis between the superconducting cables and the

conventional wire systems. The following chapter will elaborate the conclusion

for making this system operation and will include the recommendations to

fulfill the demand of the project.

1.5 Reader Benefit

This study report is meant to provide brief knowledge about implementing

superconducting cables in the grid over conventional cables. The institutions

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which generate electricity like power stations will definitely get a clear idea of

saving the losses and making their distribution safe and worthy. In this

developed world, we never want to be left out without power, so we need a

reliable solution to the modern era transmission problems. We came up with

an idea of using the superconducting cables instead of the regular cables, so

it will almost totally diminish the losses due to resistance and will be mostly

maintenance free. This will solve the problems like unstable grid, black-outs,

environmental issues like bird deaths due to overhead lines moreover it will be

a lot safer for humans as it won’t be exposed in the open air. Another major

benefit will be liquid hydrogen, which runs through the cables. We will be able

to use the liquid hydrogen as our fuel so this will be totally futuristic idea.

2 Problem Elaboration

The modern era problem of transmission is losses and unreliability. In the recent

times we have seen huge blackouts and millions of people left without power. The

problem with the conventional system that we are using right now is that it is filled

with lot of losses, unstable and not being the environmental friendly. As being

exposed open in the air, it has several other issues too related to it. Being not safe,

more space consuming and not at all efficient enough are the drawbacks of the

conventional transmission line grid system. In order to overcome these problems we

have to figure some way out to provide people a safer and more importantly cost

saving solution of what we think this project will deliver.

2.1 Losses due to Resistance

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We use special conductors in a conventional transmission lines with a really low

resistivity but it is still not good enough to prevent losses [3].

Figure 2. Power Loss in a transmission lines over 1000kms Source: Stanford University [3].

Figure 3. Various Power Loss Source: Stanford University [3].

2.2 Stability

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The main issue of this regular or contemporary transmission system is the

stability. As we all know the normal transmission lines are open to air and have

to deal with the weather. When the storms, hurricanes, cyclones come it uproots

the towers, leaving the grid broken. For example in 2008 Hurricane Gustav left

huge population without power because it destroyed the whole towers in the

transmission lines.

Figure 3. Hurricane Impacts Source: The Times-Picayunea [4].

2.3 Environmental and Safety Issues

Every year millions of birds are being killed by the high voltage lines. This is a

worldwide problem [5]. An estimated 174 million birds are killed in the USA only

every year [5]. This will in turn raise serious environmental issues and will

collapse the balance of nature and lot of endangered species will extinct. If we

talk about safety this system is pretty unsafe to work on. For the technicians who

work on the overhead transmission lines, a lot of care should be taken because

of the high chances of electrocution.

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Figure 5. Bird deaths by high voltage lines Source: Reta [5]

3 Solution Elaboration

Our report is to figure out the effective way to minimize the losses as well as make

the transmission lines environmental friendly. On top of that we will get the liquid

hydrogen as fuel for the futuristic cars. The main logic to implement these lines was

to save power and give the stability to the grid to prevent power outages. This

system can be implemented in any type of topographies as it runs underground

ducts which carry huge liquid hydrogen cooled superconducting cables. Setting up

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the superconducting grid will in turn save millions of dollars in a long run and will be

long lasting, maintenance free system.

3.1 Superconducting Cables

The superconducting cables consist of superconductors. Superconductors are

mix alloy of several metals or compound which below a certain temperature get

the superconductivity and have zero resistance [6]. Figure 5 shows the structure

of the superconducting cable. Superconducting cables can be used in any kind

of topographies as it has thermal insulation so no matter if it’s hot or cold the

cable can withstand everything. It can carry huge currents and cryogenic liquid

hydrogen fuel in the conduits which will be delivered to the vehicle fueling

stations. The superconductors are really thin layer of metal which can carry

unusually high amount of current without any resistance. The cable consists of

two superconducting wires at +/-50Kv and 50Kamps current without any

significant losses [7]. This kind of cables can carry 5 GW of power hundreds of

kilometers [7].

Figure 1. Super Conductor

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Source: Fat Knowledge [1]

3.2 Production of the superconductors

The production of the hydrogen cooled superconducting cables is in a testing

phase right now. Scientist are coming up with the different types of metal alloys

as superconductors and trying to make a less costly and more efficient cables.

The Russian scientists have made a superconducting cable of 26mm diameter

and 12mm cavity in it for the liquid hydrogen to flow. They are well in progress to

make a bigger diameter cable which can carry liquid hydrogen 200-220 g/s and

able to carry 25MW of power [8]. The USA made 100m flexible superconducting

cable 3cm diameter pipe for 1m/s liquid hydrogen to flow with an overall

diameter of 10cm which can carry 5000v, 2000amps and 10MW dc power with

variable loads and current [9].

3.3 Lifespan

Though superconducting cables is an impressive concept a lot of research to be

done on it. Fairly new technology, so it promises the longer life span but no

research is done yet on the longevity of the superconducting cables.

Table 1. Superconductors vs. Regular conductors

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Source : Randolf miller’s introduction to superconductors [10]

4 Feasibility Study

We are so much used to overhead transmission lines despite knowing the fact that

there are lot of losses. Superconducting cables would save a lot of losses in the long

run and payback the costs of implementation. A lot of research has proven that

superconducting cables can play a big role in the power sector. Recent studies have

shown us that it could carry huge currents. As being underground and not exposed

to the open air, the cable is more environmental friendly and safe.

4.1 Cost Benefit Analysis

The metals used to form the super conductors are easily available and are pure

metal or metal alloys [10]. The American Superconductor figured out that the

superconducting cable system would cost $8 million per mile for the single pipe

carrying 5000Megawatts and $13 million for the double pipe carrying 10000MW

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[11]. The conventional transmission towers and lines would cost roughly $7-10

million per mile [11].

4.2 Logistical Feasibility

There are two basic types of superconductors, one is pure metals and another is

metal alloys. These metals are easily available so they can be produced on large

scales in the industries. The production of cryogenic hydrogen is little bit

expensive at the moment. At present the hydrogen comes from the steam

reforming of methane and consists of carbon. The scientists are working to

produce hydrogen by separating it from the water [9]. Superconducting cables

have no impact on environment as they are placed underground. There won’t be

any corona effect due oxidation, the conductors are totally concealed in lot of

layers. As being a new concept a lot of more development is to be done. People

will appreciate this new development and because of its benefits.

4.3 Scheduling Feasibility

There are lot of technical choices and challenges ahead like in cryogenic fuels

and vacuums, dielectric materials being held under lot colder condition and cable

designs. We could still in around 10 years of time frame, will be able to operate

10-20km line to solve the transmission problems [9]. By 2050 we will be able to

set up around 40 sections each 100kms long [9].

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5 Comparative Analysis

In the following chapter we will discuss about the alternatives to the hydrogen cooled

superconducting cables. Unfortunately at this moment no other alternative is

available to the superconducting cables. There are other types of superconductors

which could be used in the cables but not the whole new technology that replaces

this idea. We could use different coolants to make material superconductive like

Liquid Nitrogen and Helium.

5.1 Alternative Solutions Description

Liquid nitrogen has a little bit higher boiling point at about 77Kelvins or -196C.

When insulated from the heat, the liquid nitrogen could be transported and

stored. The Liquid Nitrogen is also an explosive gas, when handled carelessly, it

could create a disaster. Another alternative is liquid helium which has a boiling

point of 4.2K also acts as coolant in the various applications.

5.2 Criteria Elaboration

Following subsections will briefly elaborate the criteria.

5.2.1 Stable System

The main concern of the modern era transmission is the stability. Nobody wants

to be left out without power. People need the stable system that will not be

affected by weather or any other factors. Our idea of superconducting cable

system will fulfill all the demands of the modern era, providing stability and

won’t be affected by rain, snow, heat and storms as it is situated underground.

5.2.2 Minimal Losses

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The losses caused by the resistance in the conductor are the main concern in

the transmission lines. Our solution for this problem is superconducting cables,

which has almost no resistance hence being cost saving.

5.2.3 Safety and Eco-friendly

If we consider the criteria there’s a clear choice, underground cables are not

exposed in the open air. As being covered in concealed pipes, there are no

chances are getting electrocuted.

5.3 Comparative Analysis Table

Table 2. Criteria for alternative to conventional cables

Superconducting cables Conventional cables

Power loss 3% 9%

Storm/security risks No Yes

New land required No Yes

5.4 Results

The table illustrates that the superconducting cables are more preferable over

conventional transmission line. It doesn’t require new land and is not vulnerable

to the weather conditions.

5.4.1 Superconducting Cable Solution

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Superconducting cables consists of superconductors which are cooled by

cryogenic hydrogen which could be used as a fuel in cars. It will diminish the

losses and create a safer transmission system as well as eco-friendly too.

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6 Conclusions and Recommendations

6.1 Conclusions

The superconducting cables in grid system run through underground path as

they are not open to the air so there are no corona losses. There is no

electromagnetic field around the cable itself. Because it can carry huge amount

of currents while using really small diameter conductors, it is economically viable

solution. There will be close to zero maintenance costs associated with this

system. So we could conclude that we get a better solution of losses affiliated

with regular transmission lines and more over we get liquid hydrogen which is a

coolant in this case as a fuel for cars.

6.2 Recommendations

This report recommends that the implementation of this superconducting cable in

a grid will definitely bring the stability to the current grid system. This is highly

recommended for the power stations which generate electricity as they can

transmit large current over long distances in AC as well as DC. It is cost saving

and said to be a reliable and safe solution. It is specially recommended for the

regions where a lot of storms and hurricanes occur.

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Glossary

Superconductor: An element or compound or metal alloy, which at a certain temperature gains the zero resistivity are called superconductors [6].

MW: Megawatts, the unit in which power is measured.

KA: Kilo-amps, the unit in which current is being measured

Resistance: The opposition force in the substance to block the current flow is called resistance.

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References

[1] Fat Knowledge, "A Power Grid for the Hydrogen Economy," Fat Knowledge, 11 July 2006. [Online]. Available: http://fatknowledge.blogspot.ca/2006/07/power-grid-for-hydrogen-economy.html. [Accessed 14 April 2014].

[2] By Paul M. Grant, Chauncey Starr and Thomas J. Overbye, "www.scientificamerican.com," 26 June 2006. [Online]. Available: http://phe.rockefeller.edu/docs/SA_Supergrid.pdf. [Accessed 28 March 2014].

[3] C. Harting , "http://large.stanford.edu/," Stanford University, 24 October 2010. [Online]. Available: http://large.stanford.edu/courses/2010/ph240/harting1/. [Accessed 15 April 2014].

[4] Rebecca Mowbray, The Times-picayun, "www.nola.com," The Times-picayun, 05 September 2008. [Online]. Available: http://www.nola.com/hurricane/index.ssf/2008/09/entergy_works_to_bring_plants.html. [Accessed 15 April 2014].

[5] Reta, "http://retasite.wordpress.com/2014/01/08/altalink-transmission-line-kills-birds/," 8 January 2014. [Online]. Available: http://retasite.files.wordpress.com/2011/03/clarks-cartoon.jpg?w=497. [Accessed 15 April 2014].

[6] superconductors.org, "www.superconductors.org," 2 July 1999. [Online]. Available: http://superconductors.org/. [Accessed 15 April 2014].

[7] Bruno De Wachter, "www.leonardo-energy.org," 2 June 2007. [Online]. Available: http://www.leonardo-energy.org/superconducting-hydrogen-electricity-grid. [Accessed 15 April 2014].

[8] Anton Evseev, "www.pravda.ru," 26 March 2012. [Online]. Available: http://english.pravda.ru/science/tech/26-03-2012/120888-hybrid_superconducting-0/. [Accessed 15 April 2014].

[9] Brian Wang, "www.nextbigfuture.com," 24 june 2006. [Online]. Available: http://nextbigfuture.com/2006/06/other-tech-continental-supergrid-and.html. [Accessed 15 April 2014].

[10] Randolf joseph Muller, "www.wou.edu," 24 February 2011. [Online]. Available: http://www.wou.edu/~rmiller09/superconductivity/. [Accessed 15 April 2014].

[11] Rebecca Smith, "blogs.wsj.com," 13 May 2009. [Online]. Available: http://blogs.wsj.com/environmentalcapital/2009/05/13/moving-electricity-via-super-cold-cables-wins-influential-dc-ally/. [Accessed 15 April 2014].

[12] W.-H. Librarian, "www.wtech.org," September 1997. [Online]. Available:

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http://www.wtec.org/loyola/scpa/02_03.htm. [Accessed 10 April 2014].

Appendix: Superconducting Cables as Compare to Conventional Wires

Table 3: Superconducting cable Benefits

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Source: wtech.org [12]

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