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Literature Review

This is the Literature Review Page for my project topic on PV+Noise barrier systems

Notes

• The first PV+Noise barrier (PVNB) system was installed in Switzerland in the year 1989. Major of the installations of such type of systems are in Europe majorly in Germany, Switzerland and Netherlands. Only 2 installations in China and Australia are located outside Europe.

• The types of module design can be classified as Retrofit and Integrated designs.

1. Top mounted
2. Shingles
3. Cassette
4. Horizontal Zig Zag
5. Bifacial

PV on Noise Barriers

Nordmann, T. and Clavadetscher, L., 2004. PV on noise barriers. Progress in Photovoltaics: research and applications, 12(6), pp.485-495.

The paper present the concept of PV modules mounted on noise barriers. The paper gives a short overview of the state of art and progress made in the use of PVNB in Europe. The paper also demonstrates the prototype of module designs of PVNB.

1. The mounting of PV modules on the noise barriers along the road and rails provides the benefits of dual use of built up land, energy generation in highly congested and high usage areas and easy access for construction and maintenance.
2. The different types of module design that have been implemented and tested for more than 2 years in Europe are:
   • Cassette
   • Zig Zag
   • Shingles
   • Bifacial
3. The cassette and Zig and zag module uses a combination of both sound reflection and sound absorption techniques. Also careful considerations are given to avoid shading effect in these type of designs.
4. The bifacial modules consists of solar cells on either side of the module design. Thus one side of the module gets exposed to the morning sun while the other side is exposed to the evening sun thereby increasing the energy output compared to a single side oriented PV module.

Estimation of environmental benefits, cost benefits and system description of PVNB installed along a metro line in China

Gu, M., Liu, Y., Yang, J., Peng, L., Zhao, C., Yang, Z., Yang, J., Fang, W., Fang, J. and Zhao, Z., 2012. Estimation of environmental effect of PVNB installed along a metro line in China. Renewable Energy, 45, pp.237-244.

The paper presents the system description, environmental benefit evaluation and cost evaluation for PV+Noise barrier module installed along a urban metro line in China.

SYSTEM DESCRIPTION:

• The project is a PVNB installed along the metro transit infrastructure in Shanghai. The length of the section of transit line under consideration is 360m.
• Sound reflection properties of Noise barriers are achieved by using the solar cell modules itself.
• The angle between the direction normal to the path of barrier and south direction was 67º. Thus the orientation of the PV module was not ideal for mounting it. The modules were mounted in the vertical plane configration.
• Amorphous Silicon (a-Si) solar cells were considered due to their high light absorption rate. Easier and cheaper manufacturing process.
• The PV modules were grid connected using a DC junction box, Inverter and AC distribution box.
• The total no of PV modules used along the length is 223, out of which 216 are identical and remaining 7 are used to adjust the voltage output.
• Also in Shanghai due to dirt accumulation the PV output power is reduced by 10%.

FORECASTED ENERGY

• The energy forecast are based on the formulas presented in the book "Photovoltaic Solar Energy Generation" by A. Goetzberger V.U. Hoffmann and Klein and Theilacker model of solar radiation.
• The calculated values of total annual average radiation is 763.2 kWh/sq.m, peak hours of solar is 763.2. The annual energy output is of the order of 4274~5495 kWh. The capacity factor is of the order of 7.13% which is primarily due to the 67º orientation of PV modules from the polar south.

ENVIRONMENTAL BENEFITS

• The term EPBT (Energy Payback Time) is used to understand the overall benefits the PV system connected to grid brings to the environment. It is defined as,

     EPBT = ENERGY(Invested) / ENERGY(PV)

• The typical value of EPBT calculated is 5.4 years, which is very small compared to the entire lifespan of the PV module system of 20-30 years.
• Also the cost savings in terms of pollution control costs is of the order of 455-1300$/kg of gas emission prevented.

Photovoltaic Integration with tunnel shaped sound barriers

Schirone, L. and Bellucci, P., 2000. On photovoltaics integration in tunnel-shaped sound barriers. In Photovoltaic Specialists Conference, 2000. Conference Record of the Twenty-Eighth IEEE (pp. 1644-1647). IEEE.

The Paper talks about the Acoustic Photovoltaic panel for a tunnel shaped sound barrier system. Also the paper focuses on the Balance of system configurations.

1. Owing to the circular nature of the barriers the PV modules are mounted on a variable surface orientation. Thus the tilt angles for each parallel group of PV cells will be different.
2. The APV consists of the lower substrate which helps to reduce the sound propagation, while the PV module is mounted on top of it. Considerations have to be given to the heat dissipation of the PV modules so that overheating of the PV cells can be avoided.
3. The BOS for such type of PV module configration shall be capable to take care of the different modules mounted at different tilt angles.
4. One type is the one in which each APV is equipped with an independent inverter which can be directly be connected to the grid. Different surface orientation is not an issue since each panel is fitted with maximum power point trackers and are shunt connected on the AC side. Also safe operation and soft performance degradation is achieved.
5. An option for the 3 phase or single phase AC-APV panels, is the internal connection of the PV module with the inverter to form a 3 phase line. The output of the inverter can be either star connected for 3 phase AC or shunt connected for single phase AC. However, the major drawbacks of this system is the losses due to ac currents in the low voltage circuit and the inverter will not be easily accessible.

Photovoltaic Noise Barrier in Canada

Remmer, D. and Rocha, J., 2005, August. Photovoltaic noise barrier-Canada. In SESCI 2005 Conference.

The paper is a study about the potential of the PVNB systems for Canada. The Ontario province of Canada was considered to study the potential of PVNB. The paper also talks about the various PVNB designs, the noise barrier legislation and standards of Canada.

• In the Ontario province of Canada, there are approximately a total of 15,000 kms of transportation network. However, the southern part of Ontario has a high concentration of roads and population which is a high potential for building Noise Barrier integrated PV.
• Out of the total highway length of Ontario, 40-50 % are oriented in the East-West Direction, 25-35% in the North-South direction and 15-25% in the South-East,North-East,South-West or North-West orientation.
• Thus major of the highways are best suited for the ideal South oriented PV panels. For highways that already have sound barriers, we can use the retro-fitting technologies of Shingles and Top mounted PVNB. For the N-S oriented roads, the bifacial PVNB technology can be used.
• In Ontario, there are an existing 155kms of noise barriers constructed already and every year approximately 5kms are added. The sound barriers are majorly made up of concrete and the rest are constructed using wood or metal. For noise barriers located outside the city areas noise barriers with reflection properties can be used. Thus for sound reflection use, we can use standard PV modules wherein the transparent substrate acts as the reflecting component.
• The annual solar irradiation in Ontario was estimated using the RETScreen model for PV projects. The results showed that the maximum average yearly irradiation of 1.55Mwh/sq.m-yr is received for a tilt angle of 30-45º. Also for the N-S oriented roads the maximum average yearly irradiation is around 1.4Mwh/sq.m-yr for a flat oriented PV Panel.
• The maximum energy yield by using PVNB technology in existing noise barriers in Ontario was calculated to be around 20 GWh/yr. However, this value did not include an shadowing effects due to trees and other structure around the noise barrier.
• One major reason for absence of PVNB technology in Canada is due to the high noise limit set at 55dB by the Govt. This is higher than the WHO standard of 45dB and European standard of around 40-49dB. Thus implementation of stringent rules will lead to addition of more PVNB technology in Canada.
• Also for integration of PV and Noise barrier systems new standards are needed to be formulated since the existing noise barrier standards do not consider PV integrated noise barrier system.

Integrated PV Noise Barriers: Six innovative 10kWp Testing Facilities a German/Swiss Technological and Economical success story

Nordmann, T., Reiche, K., Kleiss, G., Frölich, A. and Goetzberger, A., 1998, July. Integrated PV noise barriers: six innovative 10 kWp testing facilities, a German/Swiss technological and economical success story!. In 2nd World Conference and Exhibition on Photovoltaic Solar Energy Conversion, Vienna, Austria (pp. 2486-2491).

The paper presents the monitoring results of 6 different types of PVNB modules installed in Germany and Switzerland. In terms of monitoring, the PV and noise damping properties of all the modules were compared using the same monitoring hardware.

• PVNB GERMANY (A96 Highway Munich) Cassette Type- 9.9kWp

1. Highly integrated design and easily mountable.
2. The performance ratio which is measure of the PV modules energy output performance was measured. The values varied between 0.55 (July) and 0.79 (February).
3. The major reason for poor performance was due to inefficient heat dissipation. The module design caused the module operating temperature to reach 51.9° celsius in summer wheres the module temperature was about 30.9° celsius in February.
4. Also another reason for the performance index to be on the lower side was due to the self shading effects caused by the upper module on the lower module.
5. Another reason was the damage to the panels due to vandalism.

• PVNB GERMANY Shingles Type- 9.1 kWp

1. The Shingles type design is a highly compact and retrofit design. Thus in this prototype design we can the energy output/metre of road is more.
2. The performance ratio varies between 0.59(January)-0.7(May). The average module operating temperature is moderate due to the air convection which helps to reduce the module temperatures.
3. However, this module also suffers from the self shading effects. The lower placed module outputs are reduced due to the shading effect of the upper modules. The maximum loss due to shading is about 4%.

• PVNB GERMANY Zig-zag Type-10.08 kWp

1. In this type of design the PV modules are stacked in alternating planes of PV panels and noise absorbing surface. The design offers an aesthetic look.
2. The PV panels are however tilted at an angle of 75° against an optimum tilted angle of 35°. This affects the energy ouptut of the PV panels considerably.
3. Also, the installation of these modules takes a long time unless they are pre-fabricated in factory.
4. The performance index varies between 0.69 (july)- 0.79 (February).
5. Also the self shading effect is avoided due to the high inclination angle of the PV panels.

• PVNB Switzerland(A1 Motorway) Type Bifacial- 10kWp

1. This is a patented design of TNC Germany. This prototype module design is favourable for roads oriented North-South.
2. The panels are placed vertically along the sides of the highway and it offers the highest level of integration possible in terms of PV and noise barrier capabilities.The PV module itself is the noise damping structure.
3. The PV Panels located on either side of the module helps to capture the suns irradiation from frontside(East) and backside(West). However the output on the backside is lower compared to the frontside. The performance ratio of the module varies between 0.69-0.56.

• Noise Protection properties.

1. In order to understand the Noise protection offered by the different module design, the modules were tested as per ISO 10847, which deals with In-situ determination of insertion loss of outdoor noise barriers of all types.
2. Of the above mentioned module designs, the zig-zag and cassette type offer sound absorbing properties. The shingle and bifacial act as the sound reflecting modules.
3. The sound protection features of different type of modules can be summarized as below,

** Insertion loss is measured 20 m behind the Noise barrier

COMBINING PHOTOVOLTAICS AND SOUND BARRIERS- A FEASIBILITY STUDY

De Schepper, Ellen, et al. "Combining photovoltaics and sound barriers–A feasibility study." Renewable energy 46 (2012): 297-303.

The paper talks about the economic and ecological feasibility of a Photovoltaic noise barrier. The hypothetical case study is of highway E313 in Tuilt region of Belgium.

1. PVNB is an alternative technique for space constraint PV structures.
2. The cost benefit analysis of the PVNB system were evaluated based on the net present value, internal rate of return, payback period and discounted payback period. Also the ecological benefits was expressed in terms of monetary gains. The economic and ecological benefit of PV structure and noise barrier were evaluated together and separately.
3. The Solar panel assessment

The cost benefit analysis of the Solar panel showed that the panels are profitable with an IRR of 8.07%. Also the payback period of the system is around 9.7 years. The benefits of reduced CO2 in terms of monetary gains is small but is important to gain green current certificate which majorly affects the profitability of the PV Panels.

1. Noise Barrier Assessment

The noise barrier only has ecological benefits to it. To calculate the monetary value of the ecological benefits from the noise barrier, stated preference and revealed preference of the customers was used. In stated preference the amount of money that any customer was willing to pay to change the quality of noise environment around them was used to calculate the monetary gain. In revealed preference, customer behaviour is observed using data on housing price and noise loads. By using the Hedonic pricing method the degree of how much people are willing to pay more can be evaluated. The results of Hedonic pricing can be described in terms of noise sensitivity depreciation index (NSDI) which is the house price drop per db increase in sound level.The noise barrier for a 25 year lifetime has a chance of being profitable. Also a significant amount of investment on the noise barrier can be recovered by the ecological benefits of reduced noise nuisance.

1. PVNB Assessment:

The PVNB as a whole is profitable with an IRR of 5.67% and payback period of 12 years. However the major factor influencing the profitability is the presence of Green Current Certificates and government subsidy on solar projects.