solar paper.pdf

8/19/2019 Solar Paper.pdf

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Sustainability: Roadways and Solar Power Technology, a Revisit1

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Rajarajan Subramanian5

Pennsylvania State University at Harrisburg6777, W Harrisburg Pike7236, Olmsted Building8Middletown, PA - 170579Tel: 717-948-6488; Fax: 717-948-6502; Email: [email protected]

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Word count: 3,960 words text + 10 figures x 250 words (each) = 6,460 words2223

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28Submission Date: August 1, 201529


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ABSTRACT1

Glaring sun has always been an obvious source of energy and recently the focus of solar energy2enthusiasts has been on roadways and roadside areas to produce electricity. The solar panels on3 pavement markers are used to light the roads to guide the vehicles during night time. The solar4 panels are used as pavements for the roadways that cater to the needs of pedestrians, bicyclists5

and motorists. The “Photovoltaic Solar panels installed on the side of the roadways in different6 ways can be used to harness the solar energy available aplenty in nature. Photovoltaic (PV) cells7work by using semi-conductors to absorb light and create a flow of electrons. The advantages of8using the solar powered paneled roadways are not immediately felt right after the construction.9In the long run, the capital cost invested in solar panels can be reaped fully. The solar10 photovoltaic panels can be placed on the sides of the road beyond shoulder areas, on the sound11 barrier walls and on the bridge structures also. This paper deals with the current status of12technology related to the solar panels that are being used as pavements and the solar panels13installed along the roadside, on sound barrier walls and on bridge structures. This paper also14discusses the pros and cons of deriving electrical power out of roadway solar technology and the15feasibility of using such solar energy technology as this paper features it.16

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Keywords: Solar Energy, Photovoltaic, Solar Panels, Solar Powered Pavement Markers, Solar21Paneled Pavement, Photovoltaic Noise Barrier22

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INTRODUCTION 1The sun is the brightest star that is closer to us in the solar system. People across cultures2worshipped Sun for a very long time. No life can thrive without the presence of sun’s impact on3this planet. The sun’s powerful ray of light and radiation are always the sources of energy for4more than hundreds of centuries. Even if the clouds hide the sun from our view, the radiation5

from sun warms the earth the whole day and this energy can be used in the right way to produce6 electricity.7

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As new inventions of tools, instruments, electronic gadgets and toys are in place that uses9electricity as energy to operate, the energy needs started growing exponentially. As the energy10needs continue to grow, the surrounding environment is polluted with more carbon dioxide by11 burning the fossil fuels and it is high time that an alternative type of renewable energy has to be12sought. Solar energy is the biggest source of renewable energy on the planet. Solar Energy has13 penetrated our lives through homes, offices, gardens and streets. Also, it protects the environment14and helping us to save money on our electricity bills.15

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The notable invention of all the applications of the sunlight, is the photovoltaic cells that convert17 light energy into electricity. For the past few years, the residential buildings have been using the18solar energy to save money and to protect our environment. Recently, the concept of using the19solar energy from our roads that we travel on is picking up speed.20

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The solar powered Light Emitting Diode (LED) pavement markers can be embedded on the22 pavement. Also, there has been a growing trend of getting solar energy from solar panels23 pavement. Solar panels comprising of photovoltaic cells can be embedded on the pavement to24create electricity that can be used for the lighting the roads during night as well as for powering25the homes by connecting the solar cells to the national grid of electricity. Besides using the26 photovoltaic solar panels on the road, they can be used along the roadside as well as over the27

roadways as the roof cover. On either case, electricity can be produced and used for roadway28 lighting as well as for powering homes.2930

If the construction of any building is combined with a solar project then generally the cost of31fuel, delivery costs, and the cost of operating the conventional energy system can be saved32 because sunlight is freely available. In recent years, tax credits and other incentives by local and33federal governments have helped reducing the overall cost of solar energy projects. These cost34savings cover the high initial cost of solar panels and the accessories with a reasonable rate of35return and manageable risk to the investor. Recently, more and more investors serve the solar36market by combining utility cost savings, tax credits and other allowances given by local and37federal governments to construct cost effective projects. 38

39 SOLAR ENERGY ON THE PAVED AREAS40

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Solar Raised Pavement Markers (SRPM)42

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The Unite Kingdom and the other European countries have been using the SRPMs for more44than 20 years. In U.K they are called “LED Road Studs” (as shown in Figure 1) and they45contain small solar panels and emit LED light to illuminate roadways during night time. Just a46


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few hours of daylight will provide enough battery power to last days - more than enough to1ensure the system operates all year round whatever the weather and wherever the location in2the world. The solar panel road studs have been installed in over 120 roads in the U.K and in3the Noord-Holland Province of the Netherlands (1).4

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FIGURE 1. SRPMs along the curve on the center line and on the shoulder 89

Generally, the LED RPMs increase the visibility of intersections during low-visibility10conditions (e.g., darkness and inclement weather). Illumination of intersection approaches and11crossings helps improve road user recognition of intersection location and features. At12intersections with vertical or horizontal curves causing limited sight distance for traffic13entering the intersection, LED RPMs activated by vehicle detectors can help provide advance14notification to drivers of potential vehicle conflicts as shown in Figure 2.15

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In U.S.A, the Oregon Department of Transportation (ODOT) did a test study and submitted17report (FHWA OR-RD-08-07) on its findings. SRPMs were installed in two locations and18 performed satisfactorily. However, after ODOT became aware of the range of markers19available and the potential issues related to poor performance, it was decided in October 200620that a more comprehensive study was needed. This study included laboratory testing and field21observations.22

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2FIGURE 2. Solar LED Raised Pavement Marker installed at intersection to guide3

turning movements4

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The Washington State Department of Transportation (WSDOT) did a study on Solar Powered6LED technology along a 2 mile section of State Route 530 that has a history of run-off-the-7road collisions. This study was conducted over a period of five years. The solar-powered road8reflectors that WSDOT has installed contain an LED that will automatically light up under9dark conditions to provide an estimated 10 times greater visibility for drivers than the10traditional retro-reflective markers. WSDOT will consider investing in additional test areas on11other roadway surfaces or situations depending on the test results of the tests and the funding12

availability. (2).1314

Advantages of SRPMs15

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SRPMs can be used for the visibility of drivers on both directions of travel on the roadways.17Also, advanced guidance could be provided by SRPMS to the passing and no passing zones.18 Nature of the changing terrain and curves ahead can be alerted to the drivers by the19introduction of SRPMs. Improved and sustainable night and adverse weather guidance can be20 provided (fog, rain, ice, skiff of snow etc.) because of their internal illumination rather than21retro reflectivity.22

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Guidance is maintained during winter months regardless of the condition of the painted24markings and they are fully compatible with snow removal operations. Night accidents can25 be reduced considerably.26

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Disadvantages of SRPMs28

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Some of the current recessed RPM’s are not visible/apparent in the rain or adverse weather30


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conditions and their subsurface mounting cause’s sight distances to be erratic and1foreshortened. The reflective surface of the stud is well below the road surface and it takes2considerable time after a weather event to clear them and again it becomes ineffective when3needed most.4

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When clear of debris or water, the reflective surfaces are short lived and despite their6subsurface mounting, they still require frequent replacement. In addition, the groove7foreshortens site distances and they are viable only during good weather. Dynamic loading,8high-speeds and lateral forces significantly foreshorten raised pavement marker service life on92 lanes highways. (3)10

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SOLAR PANELS EMBEDDED ON THE PAVEMENT12

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Solar Panels on the Walkway Pavement14

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The world’s first Solar Paneled Pavement (SPP) has been installed at George Washington16

University in Ashburn, Virginia (US). Designed by Building Integrated Photovoltaics (BIPV)17specialists the pavement panels are slip-resistant and semi-translucent for optimum aesthetic18appeal and functionality. The SPP generates approximately 400 Wp. In total 27 panels (Figure 3)19have been used in the pavement design which has been integrated into a popular Solar Walk20 between two of the university’s buildings, Innovation Hall and Exploration Hall.21

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FIGURE 3. Solar panels used on walkway.26

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In 2012, the Solar Walk was completed with design features suggested by the then students of the28George Washington University. The idea behind SPP is simple: sunlight falling on the road29surface is absorbed by solar cells and converted into electricity – the road surface acts as a large30

solar panel (Figure 4). The electricity generated in this way will find practical applications in31street lighting and putting the electric power on the national electricity grid.32

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FIGURE 4. Solar panels walkway after completion.34

The concept of solar panels embedded pavement for producing electricity is an out of the box5idea to implement. The "Embedded solar panel pavements" consist of individual panels with6three layers: a top layer of high-strength, textured glass that provides traction for vehicles, an7array of solar cells beneath that for gathering energy, and a base plate that distributes the8collected power (4).9

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Advantages of using Solar Walkway11

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Besides being used for walking purpose, solar panels produce electricity to light the sides of the13walkway and hence safety is enhanced. If they produce more electricity than needed for walkway14facilities and amenities then the solar panels can be connected to the national electric grid to15supply electricity to homes, other buildings and roadways. In the long run, the capital cost into16this type of project can be recovered.17

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Disadvantages of using Solar Walkway19

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Keeping it dust and snow free demands more constant maintenance work. Initial cost is higher21than the investment made on regular concrete pedestrian walkway.22

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Solar panels on parking lots and low volume roads24

An Idaho-based Solar Roadways, a private company obtained the Federal Highway25Administration (FHWA) contract for a project on Solar Road Panel prototype in 2009 (Figure265). It would integrate features such as LED lights and heating elements into structurally27engineered road panels. The glass panels that they used were tested in various University28testing laboratories and they all exceeded the properties such as compressive strength, impact29strength, friction test, etc. could be similar to the guidelines set forth in the specifications for30 pavements. It is implied that the glass panels can be manufactured to bear the dynamic loads31of trucks, cars, buses and different types of heavy vehicles. Figure 4 depicts a driveway made32


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of solar panels that could be effectively used during day time and that energy can also be1connected to the national electric grid (5).2

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FIGURE 5. Solar Road Panels prototype on Parking lot.4

As the artist envisions, the solar panels can also be embedded on the driveways and local5streets as in Figure 6. 6

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FIGURE 6. Solar Panels for Driveways.8

Solar Panels on Bike path9

In Netherlands, a new solar powered bike path (Figures 7 & 8) has been opened in the10 November of 2014. Bike users feel that there is no difference between the regular bike path11


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and the solar powered one. The power generated by this bike path is connected to the national1 power grid and can be used by the users that are connected by the national grid. The project in2the town of Krommenie in Netherlands is being called the world's first public road that3includes embedded solar cells.4

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FIGURE 7. Solar panels that form the Bike path.6

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FIGURE 8. Solar panels Bike path after completion8

Recently it has been found that the bike path is producing more electricity than anticipated.9The crystalline silicon solar cells are encased in two layers of tempered safety glass, mounted10in a concrete housing. The equipment is part of pre-built concrete slabs that the company says11have been refined in years of testing. The company says it's been a challenge to produce12energy-producing slabs that are both durable and ride able by thousands of cyclists a day. "It13has to be translucent for sunlight and repel dirt as much as possible," the company says. "At14


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the same time, the top layer must be skid resistant and strong enough in order to realize a safe1road surface" (6).2

Advantages of using the pavements with Embedded Solar Panels3

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The pavement solar panels can produce electricity by connecting them to the national power5grid and hence be used for homes. Carbon footprint on this planet is reduced. They minimize6the need for space for electricity generation and distribution. More area is available for use,7 because the total length of U.S roadways is around 4 million miles. Even though the initial8cost is higher, in the long run, the capital investment could be recovered.9

Disadvantages of using the pavements with Embedded Solar Panels 10

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It is more expensive to build the pavements with solar panels rather than without them.12Durability of these glass roads are yet to be seen, because it will have to deal with heavy13

dynamic loads such as Semi-trailer trucks, Construction equipment, buses, heavy machinery14and cars. In addition, the cost of repairing these solar panels is likely more expensive than it15would be for fixing ordinary, asphalt roads. During rain and adverse weather, the solar16roadways can collect lot of dirt and need to be cleaned periodically.17

The company says it could utilize a type of self-cleaning glass to keep the surface clear of dirt18

and grime, but this process is not yet proven. Because the solar panels lie flat instead of being19

angled to take optimal advantage of the sun, the path's panels will produce about 30 percent less20

power than similar panels might produce on a rooftop.2122

Solar Energy along the Paved Roadways2324

On the side of the roadways beyond the shoulder areas, within the Right of Way, the available25

area can be used for installing solar panels to produce electricity by connecting them to the26

National grid. It is good that the unused land found great use to produce renewable energy in an27

efficient way.28

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European countries such as Germany, Netherlands and Switzerland have utilized unused spaces30on the side of roads for 20 years. But, in the United States although not large in capacity, an31interesting solar roadside project has been undertaken in the state of Oregon. In December 2008,32the first solar highway project in U.S started in Oregon State that began to produce electricity33

and it was fed into the national electricity grid. A solar array mounted on the ground with 59434solar panels that produces 104 kilowatt (DC) power is located at the interchange of Interstate 535and Interstate 205 south of Portland, Oregon. Solar energy created by the solar array feeds into36the national electricity grid during the day, in result running the meter backwards for energy37needed at night to illuminate the interchange during night through a Solar Power Purchase38Agreement with Portland General Electric (PGE) (Oregon Department of Transportation) (7).39

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In Europe, the noise barriers are used for installing solar panels to produce electricity. The land41


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strip along a road infrastructure can be used for noise abatement as well as for the placement of1PV modules to create electricity. PV on noise barriers does not require special land resources and2the costs for mounting structures can be shared between the PV system and the noise barrier.3Various PVNB technologies have already been implemented and tested. Particularly the use of4 bifacial modules may enhance the potential of photovoltaic noise barrier (PVNB). The first5

PVNB came into use in Europe in 1989 and is located in Switzerland in the municipality of6 Domat/Ems. Only a few years later other countries followed that example and build the first7PVNB in their country.8

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The glass surface of a PV module can only be applied for sound reflection. In situations where10absorption of sound is required a cassette or a zigzag model has to be applied, enabling a11combination of sound reflection and sound absorption. Because PV current cells operate most12efficiently at lower temperatures great care should be taken in the design of sound absorption13cassettes to allow sufficient cooling of the PV modules. In layered or zigzag arrangements14(Figure 9), the positioning of modules has to be such that (partial) shading is avoided at all times.15Contamination from vehicles on the motorway can have a negative impact on performance if the16modules are mounted too low and near the surface of the road.17

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FIGURE 9. Zigzag patterns of solar panels on the sound barrier walls21

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Successful use of PVNB requires a close cooperation between sound and PV experts, as well as23of the road authorities and the financiers of the PV system. To achieve cost reductions for the PV24

part of the project integrated systems are to be preferred to retrofit systems. With fully integrated25 PVNB systems, a clear understanding of the cost substitution should be aimed for. In an ideal26situation, the noise barrier and the PV plant should be planned and realized at the same time as a27single project (8).28

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The world’s largest PV sound barrier with a capacity of 500 kWp was installed at Freising in30Germany, next to the Munich Airport and is operational since September 2003. A new ceramic31 based PV module was developed and tested. 338 kWp of the installed PV capacity was realized32


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with ceramic based PV modules in a pilot production. The main objective of this Germany1 project was to demonstrate and promote an innovative multiple-function solar photovoltaic2technology for utilization as PV module and as novel construction element for the sound barrier3and for the construction industry. The total power capacity of the Freising sound barrier adds up4to 500 kWp at a length of approximately 1 km (9).5

6 Solar Panels installed beyond the shoulder areas7

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The first solar project built along a major highway right-of-way on the East Coast of the United9States has begun producing energy to power the town of Carver’s water-treatment plant in the10State of Massachusetts.11

Built along Route 44 (as shown in Figure 10) on an easement awarded by the state to the town,12the 99-kilowatt project makes use of the highway’s east-west orientation to erect an array of13south-facing solar panels in a nearly ideal location in terms of power-generating efficiency. The14600-foot-long series of linked panels went on line earlier this month, after NStar examined and15

approved its connection to the power grid. When the solar array produces more power than16

needed by the water- treatment plant, the surplus will be sold to the grid. When the plant needs17more than the panels are producing, the utility will provide it.18

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FIGURE 10. Roadside solar panel arrays 2122

For Carver, a town in Massachusetts, the renewable power supply will save about $3,000 a23month in electricity costs. State officials said the Route 44 solar project is a viable good project24helping the town while promoting the state’s goal of expanding sustainable energy sources25(Knox, 2012).26

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Advantages of Roadside Solar Panels28

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Savings on electricity bill can be achieved by using solar panels on the right of way, otherwise30


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not used. Solar panels produce clean energy and it makes use of unused space. More revenue can1 be made with the extra solar energy that can be used by connecting the panels to the national2electric grid.3

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Disadvantages of Roadside Solar Panels5

6They need protection from the theft by criminals. Capital and Maintenance costs need to be7monitored. Especially when the panels are deposited with dirt and dust from road traffic use, then8they need constant cleaning and additional facilities to prevent theft. Vehicle accidents may cause9solar panels gets disturbed.10

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CONCLUSIONS AND RECOMMENDATIONS12

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Solar panels can be used on the roadway pavements as well as along the roadside. The pros and14cons are to be weighed in before taking decision on the selection of the right type of solar project15that can be used on our roadways taking into consideration the different projects that were16

exhibited in this report.1718

The advantages and disadvantages of using Roadway pavement solar energy and Roadside solar19energy are listed as below:20

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Advantages22

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Overall, clean energy, less environmental pollution can be achieved. In the long run of use, cost24can be brought down. Safety of the roadway at night can be improved. During the winter period,25the icing of pavement and bridges can be avoided. Entire roadway can be lighted with the26roadside solar panels creating electricity. If done right, the whole country can be electrified by27

using solar panels along the roadway.28

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Disadvantages 30

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Initial and maintenance costs may be very high. When the glass is scratched, it may collect dirt32or dust and may become useless because it loses its transparency. Scratch proof glasses are very33expensive. During accidents, the repaving may be a very costly affair. To keep the storm water34away from roadway is important and it may involve costly procedures to keep the water away.35Theft and vandalism may render the roadside solar panels more expensive to afford better36 protection.37

38Recommendations 39

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The SRPM has to be improved to provide viability of use under any severe weather conditions.41Solar panels can be used on driveways of Single or Multifamily Homes. The solar panels can be42installed on the roof of the structure that can cover the entire roadways. They can be placed on43the rails of the bridges too.44

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REFERENCES1

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1. Pearson G, (2006), “Solar studs open road to brighter future after test success”,3http://www.ukroads.org/webfiles/Solar%20studs%20open%20road%20to%20bri4ghter%20future%20after%20test%20success.pdf Published in the year 2006 and5

accessed on January 24, 2015.6 2. Bradley B. (2014), “Alternative Uses of Highway Right of Way”,7http://www.fhwa.dot.gov/real_estate/publications/alternative_uses_of_highway_r 8ight-of-way/rep03.cfm#ref29 Published and updated on September 5, 2014 and9accessed on January 24, 2015.10

3. Dornsife C. (2010), “WSDOT Solar Powered Centerline Delineation Test”11http://www.bhspi.org/BPpapers/files/HSG_WSDOTSR530_synop_101020.pdf 12

Highway Safety Group Washington SR 530, 2.25 miles segment, MP 32.75 to1335.00, 2010 and accessed on January 26, 2015.14

4. Balp N. (2013), “George Washington University debuts Solar Walk on the15Virginia Science and Technology Campus”, http://gwtoday.gwu.edu/gw-debuts-16

solar-walk-virginia-science-and-technology-campus, Published on October 1,17 2013 and accessed on January 24, 2015.185. Brusaw S. (2015), “Solar Roadways”,19

http://www.solarroadways.com/intro.shtml, January 5, 2015, and accessed on20January 26, 2015.21

6. Tobal K. (2014), “Netherlands Installs World's First Solar Bike Path”,22http://www.renewableenergyworld.com/rea/news/article/2014/11/netherlands-23installs-worlds-first-solar-bike-path, November 14, 2014, and accessed on24January 26, 201525

7. Ponder D, Proudfoot J, Carson F, and Gina F. (2012), “Alternative uses of26Highway Rights-of-Way”, Transportation Research Record , a Transportation27Research Board Journal, Report No. 2270, 2012.28

8.

Nordmann T. and Luzi C, (2004), “PV on Noise Barriers”, Progress in29Photovoltaics: Research and Applications, 2004; Vol. 12:485–495, TNC30Consulting AG, Erlenbach, Switzerland, (DOI: 10.1002/pip.566)31

9. M. Grottke, T. Suker, R. Eyras, J. Goberna, O. Perpinan, A. Voigt, A. Thiel, M.32Spendel, K. Gehrlicher, G. Frisen, R. Gambi and K. Kellner, “PV SOUNDLESS –33WORLD RECORD “ALONG THE HIGHWAY” – A PV SOUND BARRIER34WITH 500 KWP AND CERAMIC BASED PV MODULES”,35http://www.nanfor.com/demos/isofoton/corporate/material/pdf/ponencias/04.pdf 36 published in 2003 and accessed on August 1, 2015.37

10. Knox R. (2012), “Carver welcomes solar array”,38http://www.bostonglobe.com/metro/regionals/south/2012/08/29/carver-roadside-39solar-project-town-new-route-energy-40savings/5Ydy05kbZl8ywaUdaens9J/story.html, August 30, 2012, Accessed on41January 26, 2015.42
http://www.ukroads.org/webfiles/Solar%20studs%20open%20road%20to%20brighter%20future%20after%20test%20success.pdfhttp://www.ukroads.org/webfiles/Solar%20studs%20open%20road%20to%20brighter%20future%20after%20test%20success.pdfhttp://www.fhwa.dot.gov/real_estate/publications/alternative_uses_of_highway_right-of-way/rep03.cfm%23ref29http://www.fhwa.dot.gov/real_estate/publications/alternative_uses_of_highway_right-of-way/rep03.cfm%23ref29http://www.bhspi.org/BPpapers/files/HSG_WSDOTSR530_synop_101020.pdfhttp://www.bhspi.org/BPpapers/files/HSG_WSDOTSR530_synop_101020.pdfhttp://gwtoday.gwu.edu/gw-debuts-solar-walk-virginia-science-and-technology-campushttp://gwtoday.gwu.edu/gw-debuts-solar-walk-virginia-science-and-technology-campushttp://www.solarroadways.com/intro.shtmlhttp://www.renewableenergyworld.com/rea/news/article/2014/11/netherlands-installs-worlds-first-solar-bike-pathhttp://www.renewableenergyworld.com/rea/news/article/2014/11/netherlands-installs-worlds-first-solar-bike-pathhttp://www.nanfor.com/demos/isofoton/corporate/material/pdf/ponencias/04.pdfhttp://www.nanfor.com/demos/isofoton/corporate/material/pdf/ponencias/04.pdfhttp://www.bostonglobe.com/metro/regionals/south/2012/08/29/carver-roadside-solar-project-town-new-route-energy-savings/5Ydy05kbZl8ywaUdaens9J/story.htmlhttp://www.bostonglobe.com/metro/regionals/south/2012/08/29/carver-roadside-solar-project-town-new-route-energy-savings/5Ydy05kbZl8ywaUdaens9J/story.htmlhttp://www.bostonglobe.com/metro/regionals/south/2012/08/29/carver-roadside-solar-project-town-new-route-energy-savings/5Ydy05kbZl8ywaUdaens9J/story.htmlhttp://www.bostonglobe.com/metro/regionals/south/2012/08/29/carver-roadside-solar-project-town-new-route-energy-savings/5Ydy05kbZl8ywaUdaens9J/story.htmlhttp://www.bostonglobe.com/metro/regionals/south/2012/08/29/carver-roadside-solar-project-town-new-route-energy-savings/5Ydy05kbZl8ywaUdaens9J/story.htmlhttp://www.bostonglobe.com/metro/regionals/south/2012/08/29/carver-roadside-solar-project-town-new-route-energy-savings/5Ydy05kbZl8ywaUdaens9J/story.htmlhttp://www.nanfor.com/demos/isofoton/corporate/material/pdf/ponencias/04.pdfhttp://www.renewableenergyworld.com/rea/news/article/2014/11/netherlands-installs-worlds-first-solar-bike-pathhttp://www.renewableenergyworld.com/rea/news/article/2014/11/netherlands-installs-worlds-first-solar-bike-pathhttp://www.solarroadways.com/intro.shtmlhttp://gwtoday.gwu.edu/gw-debuts-solar-walk-virginia-science-and-technology-campushttp://gwtoday.gwu.edu/gw-debuts-solar-walk-virginia-science-and-technology-campushttp://www.bhspi.org/BPpapers/files/HSG_WSDOTSR530_synop_101020.pdfhttp://www.fhwa.dot.gov/real_estate/publications/alternative_uses_of_highway_right-of-way/rep03.cfm%23ref29http://www.fhwa.dot.gov/real_estate/publications/alternative_uses_of_highway_right-of-way/rep03.cfm%23ref29http://www.ukroads.org/webfiles/Solar%20studs%20open%20road%20to%20brighter%20future%20after%20test%20success.pdfhttp://www.ukroads.org/webfiles/Solar%20studs%20open%20road%20to%20brighter%20future%20after%20test%20success.pdf

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