Moving Towards the Sun : A Report on Photovoltaic Cells by Pooja Chowdhury

8/12/2019 Moving Towards the Sun : A Report on Photovoltaic Cells by Pooja Chowdhury

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ByPoojarini ChowdhuryROLL NO. 100127270

This report has been prepared to spread awareness of the need of photovoltaic cells, the present

technologies used and the probable expansions in this field. This will contribute to a rapid

development of world-class, costcompetitive photovoltaics (PV) for sustainable electricity

production. It identifies the major technical and non-technical barriers to the uptake of the

technology and outlines a strategic research agenda designed to ensure a breakthrough of PV

and an increase in deployment in the world. It has the potential to play an important role in the

transition towards a sustainable energy supply system of the 21st century and to cover a significant

share of the electricity needs of world.

This paper intends to provide a succinct definition of photovoltaic technology, its working, current

scenario around the world, new innovative building integrated PV design, and accurately unify

efficiency, shipment, cost and pricing data.

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M.Arch Sustainable Architecture Studies, University of Sheffield

MOVING TOWARDS THE SUN

A REPORT ON PHOTOVOLTAIC CELLS


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MOVING TOWARDS THE SUN: A REPORT ON PHOTOVOLTAIC CELLS

iiARC 6840 | RENEWABLE ENERGY | 100127270

TABLE OF CONTENTS

1 Background Study 11.1 Need for Renewable Energy 1

1.2 Current Status of Renewable Energy 1

1.3 Report 3

2 Solar Energy 5

3 PV Technology 7

3.1 Introduction and Working 7

3.2 Brief History 7

3.3 PV Array Systems 8

3.3.1 Grid Connected System 83.3.2 Off Grid System 9

3.3.3 Hybrid Systems 10

3.4 PV Modules 10

3.4.1 Crystalline solar cells (c-Si) 10

3.4.2 Amorphous Solar Cells (thin-film solar cell) 11

3.4.3 Other Types 11

4 Current Applications of PV Modules 13

4.1 Residential 13

4.2 Commercial 134.3 Rural and Remote Applications 14

4.4 Industrial 14

4.5 Other 15

4.6 Common Application Overview 15

5 Critical Evaluation of Solar Energy and PV Technology 15

5.1 Advantages 15

5.2 Disadvantages 16

6 Current Scenario: PV Market Development 17

6.1 Situation in the European Union 206.2 Situation in Japan 21

6.2.1 Situation in China 22

6.3 Situation in India 23

6.3.1 Situation in the USA 24

6.3.2 Situation in Other Countries 25

7 PV Market 26

8 Emerging and New Technologies 27

9 Designing with PVs 2810 Building Integrated PV and other Design Innovations 30

10.1 PV Skylights 30


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10.1.1 A Case Study of Mont Cenis Academy, Germany 30

10.2 PV Integrated Insulated Glass/Curtain Walls 31

10.2.1 A Case Study of the Cellophane House 31

10.3 PV Tiles/Paving 32

10.4 PV Decks 32

10.5 PV Lit Urban Spaces 33

10.6 Solar Textiles 33

10.7 Portable Solar Tree 34

10.8 Miscillaneous: Vehicles 34

10.9 Miscillaneous: faade Tiles 35

11 Future Ventures: Under Progress 36

11.1 Noceras Leaf 36

11.2 Liquid Solar Array 36

11.3 Nano Materials 37

11.4 Solar Nantennas 37

11.5 Tensile Solar Shade 38

11.6 PV Water Heating Panels 38

11.7 AquaSun Floating Solar Panels 39

11.8 Other Ideas 40

12 Conclusion 41

13 References 42


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LIST OF FIGURES

Figure 1: Total greenhouse gas emissions 1

Figure 2: Energy distribution 1

Figure 3: Fuel shares of the world's energy supply, 2000 2

Figure 4: Money invested in renewable sources of energy 2

Figure 5: Power generated from energy sources in 2010 3

Figure 6: World solar energy map 4

Figure 7: Categories of solar energy generation 5

Figure 8: PV module 6

Figure 9: BOS module 6

Figure 10: Working of a grid-connected PV system 7

Figure 11: Solar powered lamppost 8

Figure 12: Working of an off-grid PV system 8

Figure 13: Working of an off-grid PV system (RES, 2010). 9

Figure 14: Exploded view of a crystalline PV module 9

Figure 15: Section of thin-film solar cells 10

Figure 16: CIGS Module 10

Figure 17: Thin film vs. crystalline production 11

Figure 18: PV integrated in railings 12

Figure 19: PV exterior wall faade 12

Figure 20: PV integrated with elements of architecture 12

Figure 21: PV used for water pumps in rural areas 12

Figure 22: PV used in artificial satellites 14

Figure 23: Energy payback time of PV modules 15

Figure 24: PV production around the world 16

Figure 25: Graph tabulating Table 2 values 17

Figure 26: World annual solar PV production 1985-2009 18

Figure 27: Regional manufacturer shipment 1997-2007 18

Figure 28: Solar cell manufacturing business in China 21

Figure 29: Chinese PV industry forecast of production capacity 22


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LIST OF TABLES

Table 1: Comparative study of PV systems 11

Table 2: Advantages and disadvantages of materials used for PV modules 11

Table 3: Annual solar PV power production by country 2002-2009 17

Table 4: Regulatory framework countries in the EU & Switzerland, 2004 19

Table 5: Characteristics of emerging generation solar cells 27

ABBREVIATIONS

AC Alternating Current

a-Si Amorphous Silicon

BIPV Building Integrated Photovoltaic Systems

CAES Compressed Air Energy Storage

CdTe Cadmium Telluride

CIGS Copper Indium Gallium Diselenide

CIS Copper Indium Diselenide

CPV Concentrated Photovoltaics

c-Si Crystalline Silicon

CSP Concentrating Solar Power

DC Direct Current

EPIA European Photovoltaic Industry Association

ESCOs Energy Service Companies

EU European Union

MDBs Multilateral Development Banks

PV Photovoltaics

R&D Research and Development

RED IEA Renewable Energy Department

SHC Solar Heating and Cooling


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1 BACKGROUND STUDY

1.1 NEED FOR RENEWABLE ENERGY

The demand for fossil fuels (coal, oil & gas) has been rising for decades, and the 20th

century saw a rapid twentyfold increase in its use. With the climate hazard it causes,

the depletion of sources due to demand and need to ensure long-term security of

energy supply; there is an obligation to consider ways of reducing the carbon

footprint and sourcing energy from renewable resources (Peel Energy, 20101).

It is due to these reasons the UN proposed the Kyoto Protocol, that the member

countries are obligated to reduce the green house gas emissions by an average of

5.2 percent by 2012 (UNFCC, 19972) and 30 percent by 2020.

Figure 8: Total greenhouse gas emissions (UNFCC, 20063).

1.2 CURRENT STATUS OF RENEWABLE ENERGYChanges in renewable energy markets,

investments, industries, and policies have been

so rapid in recent years that perceptions of the

status of renewable energy can lag years

behind the reality. Renewables comprised fullyone-quarter of global power (Figure 2) capacity

from all sources and delivered 18 percent of

global electricity supply in 2009(REN21, 20104).

Investment in sustainable energy is rapidly

increasing, with $70.9 billion (Figure 4), which is

43% more than previous years (UNEP, 20075).

1Available on http://www.peelenergy.co.uk/frodsham-/benefits [Viewed on 26 May 2011].

2Available on http://unfccc.int/resource/docs/convkp/kpeng.pdf [Viewed on 26 May 2011].3 UNFCC, 2006. Available on http://news.bbc.co.uk/1/hi/6098922.stm [Viewed on 26 May2011].4REN21. 2010. Renewables 2010 Global Status Report(Paris: REN21 Secretariat).

Figure 9: Energy distribution, 2009

(REN21, 2010).


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Figure 10: Fuel shares of the world's energy supply, 2000 (IEA, 20026).

Figure 11: Money invested in renewable sources of energy (SEFI, 20077).

From Figure 4 it can be clearly seen that majority of the money is being used for the

development of wind energy, while only 16 percent is used to develop solar energy.

By seeing the potential of solar energy, there is need for solutions and for it to bedeveloped further.

Ongoing Market and industry trends include:

Wind power New growth in off shore development; the growing popularity

of distributed, small scale grid-connected turbines; and new wind projects in

a much wider variety of geographical locations around the world and within

countries. Firms continue to increase average turbine sizes and improve

technologies, such as with gearless designs.

Biomass power Biomass power plants exist in over 50 countries around the

world. Several European countries are expanding their total share of powerfrom biomass: Austria (7%), Finland (20%), and Germany (5%). Biogas for

power generation is also a growing trend in several countries.

Grid-connected solar PV Industry has been responding to price declines

and rapidly changing market conditions by consolidating, scaling up, and

moving into project development. Thin-film PV has experienced a rapidly

growing market share in recent years, reaching 25%. Increase in utility scale

5 Aitken, D.W. (ISES), 2010. Transitioning to a Renewable Energy Future. Available at

http://www.ises.org/shortcut.nsf/to/wp [Viewed on 26 May 2011].6 IEA, 2002. Renewables in Global Energy Supply. Available in Transitioning to a RenewableEnergy Future, 2010.7UNER, 2010. Global Trends in Sustainable Energy Investment.

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1.3 REPORTThis report goes in depth into solar photovoltaic (PV) technology: its current status,

advancements and will predict its future development in the world. The

developments in a few countries have been studied further in detail.

It primarily helps understand the technology and why it is important to develope it

further, over other renewable energy sources in this era.


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2 SOLAR ENERGYSolar power refers to the use of the suns energy for electricity production and has

abundant reserves. Using only 1% of the total available amount of solar radiation

would be enough to meet the entire global demand for energy.

Figure 13: World solar energy map (Nijs, 2010).

The total amount of solar energy reaching the earths surface represents several

thousand times the world total energy consumption; the technical potential of

converting solar energy directly into electricity is greater than 4,40,000TWh/year i.e.

about four times the earths total energy consumption. Moreover, solar energy

power generation produces no carbon dioxide and therefore is a purely green

energy form. It provides a viable alternative to fossil fuels for power generation

(FNCHN, 2011). The advantages of using solar energy include:

Minimal negative environmental impact by reducing air & water pollution

and greenhouse gas emission. Silicon (material used for creating solar

modules) is entirely benign and available in abundance.

Never exhausting source of energy.

Relatively low operating & maintenance cost. Minimal labour requirements.

Protection against volatile electricity prices.

Stable and independent power source (Floyd Associates, n.d.).

Due to the dilemma between meeting the growing demand for energy and

protecting the environment, solar energy power generation has become a

mainstream endeavor (FNCHN, 20109).

9Available on http://news.fnchn.com/Bright_prospects_for_thin_93943.aspx [Accessed on 20May 2011].


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Presently solar energy is harnessed with the help of photovoltaics (PV) systems to

produce electricity, solar collectors to heat water and room spaces, concentrated

solar power/thermal (CSP/CST) for electrical and thermal purpose. Off the above,

CSP/CSTs are relatively new technologies, while PVs are the most widely used

(FNCHN, 2011).

Figure 14: Categories of solar energy generation (edited by Author).


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3 PV TECHNOLOGY

3.1 INTRODUCTION AND WORKING

Electricity is produced from sunlight through a processcalled solar photovoltaics. Photovoltaic cells are made

of semi-conducting materials, so when the sunlight

strikes, it is converted into electricity. The amount of

useful electricity generated is proportional to the

intensity of light energy, which falls into the conversion

area.

PV cells use direct sunlight and diffused solar radiation

to produce electricity. Thus, even if the sky is overcast

electricity is produced. To determine the PV electricity

generation potential for a particular site, it is importantto assess the average total solar energy received over

the year. Despite its advanced technical capabilities, a

PV system will not generate electricity at night, but the

system is able to store collected energy in a battery for

use during non-daylight hours.PV systems consist of two major subsystems of

hardware: PV modules (Figure 8) and the Balance-of-

System (BOS) (Figure 9). PV modules house an array of

solar cells that deliver direct current (dc) power,

whereas BOS equipment include components needed for mounting, cabling,

battery, charge controller, dc/ac inverter and other components, power

conditioning and site-specific installation. It is noted that the BOS-costs also include

labourto build a turnkey system.

The PV industry is growing worldwide at an amazing pace. Over 560MWp of PV

modules were manufactured and sold worldwide in 2002. The average rate of

growth of the industry in the beginning of this Millennium has been 36.6%,

representing more than a doubling every two years, and it increased by 44% in 2002.

The value of worldwide PV sales is projected to grow to more than US$ 27.5 billion in

2012.

3.2 BRIEF HISTORYThe foundation for modern PV technology was laid in the early 1950s, when

researchers at Bell Telephone Laboratories discovered and developed crystalline

silicon solar cells. Although at the same time attempts were made to commercialize

silicon solar cells on a larger scale, it took until the 1980s before markets were

developed to warrant production at any significant scale. From then on, laboratory

and commercial PV technology development has shown steady progress. This has

led to a portfolio of available PV technology options at different levels of maturity,

and experience that can be expressed by a robust learning curve (price reduction

vs. cumulative production of commercial PV).

Figure 8: PV module.

Figure 9: BOS module.


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3.3 PV ARRAY SYSTEMSPV generates electricity in over 100 countries and continues to be the fastest

growing power-generating technology in the world. Even though it is the most

expensive of the solar technologies in terms of energy production, it is the most

versatile, simplest to install and cheapest to maintain.

The power that one PV module can produce is seldom enough to meet

requirements of a home or a business, so the modules are linked together to form

an array.Based on the location, requirement and application the PV array system can be

divided into gridconnected and offgrid types. The working and current scenario of

these systems is mentioned below, in brief. The systems are built at or close to the

point of use to avoid the cost and risk of failure of infrastructure.

3.3.1 GRID CONNECTED SYSTEMA grid-connected system is connected to a large independent grid (typically the

public electricity grid) and feeds power into the grid. Grid connected systems vary in

size from residential (2-10kWp) to solar power stations (up to 10s of GWp). In the case

of residential or building mounted grid connected PV systems, the electricity

demand of the building is met by the PV system. Only the excess unused electricity is

fed into the grid. The electricity to be fed into the grid requires to be converted to

AC by an inverter (Figure 10).

Figure 10: Schematic diagram of the working of an grid-connected PV system (Solar Shop,

200610).

Between 2004 and 2009, grid-connected PV capacity increased at an annual rate

of 60 percent. An estimated 7GWp of grid-tied capacity was added in 2009,

increasing the existing total by 53 percent to 21GWp (ISES, 201011).

10 Available at http://www.mysolarshop.co.uk/Solar-panel-diagrams-i-95.html [Accessed on27 May 2011].


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3.3.2 OFF GRID SYSTEMThis system refers to a selfsufficient type, which

does not rely on drawing supplemental power

from the electrical utility. These systems consist of

a PV array, control and safety equipment, a

battery bank (weight and type of battery is

based on whether the appliance is portable or

not), and usually an inverter (Figure 12). It varies

in sizes and is usually attached directly to the

appliance, with its other hardware embedded

within the unit (e.g. traffic lights, street lamps,

watches, calculators, etc.).

Off-grid system proves to be advantageous in

remote and rural places where the electrical grid

may not be able to reach. Though, this system

would only be able to provide basic electricity needs to small households.

Figure 12: Schematic diagram of the working of an off-grid PV system (Solar Shop, 2006).In 2009 the off-grid PV system accounts for an additional 3-4GW above the capacity

of the grid-connected system.

11 Aitken, D.W. (ISES), 2010. Transitioning to a Renewable Energy Future. Available athttp://www.ises.org/shortcut.nsf/to/wp [Viewed on 26 May 2011].

BATTERIES

Figure 11: Solar powered lamppost.


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3.3.3 HYBRID SYSTEMSThese are created when the PV system is combined

with another source of power (biomass

generator/wind turbines/diesel generator) (Figure 13),

to ensure a consistent supply of electricity. This systemmay or may not be linked to the grid (RES

Group, 201012).

Figure 13: Schematic diagram of the working of an off-grid PV system (RES, 2010).

3.4 PV MODULESPhotovoltaic (PV) technologies, also commonly known as solar cells, are solid-state

semiconductors. These solar cells are arranged in arrays to produce more than

100W of power. The properties and efficiency13of the module depend on the type

of solar cell used. The following list represents the three main technologies currently

used to create solar cells:

3.4.1 CRYSTALLINE SOLAR CELLS (C-SI)

It is the most common type of solar panels as it is widelyavailable, hence represents about 90 percent of the

market today (RES, 201014). Crystalline Silicon modules

are made by slicing silicon ingot into wafers, processing

these wafers into solar cells, electrically

interconnecting the cells, and enclosing it within a

glass (Figure 14) and metal frame(PV-TRAC, 2005). 36

individual cells would be required to produce a

12 Available at http://www.res-group.com/resources/about-solar-energy.aspx [Accessed on27 May 2011].13Efficiency of a solar cell is the ration of the electrical power output to the light power input.It is a percentage value (Nijs, J., n.d.).14 Available at http://www.res-group.com/resources/about-solar-energy.aspx [Accessed on27 May 2011].

Figure 14: Exploded view of a

crystalline PV module.


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continuous voltage of 20 Volts (http://www.mysolarshop.co.uk/-i-74.html [Accessed

on 20 May 2011]). They are very efficient in good light conditions and have an

overall efficiency of about 12 to 17 percent (RES, 2010).With the low silicon utilisation,

the modules energy payback time (which is usually several years) is much shorter

than the module lifetime.

3.4.2 AMORPHOUS SOLAR CELLS (THIN-FILM SOLAR CELL)Thin-film modules are made by

coating and patterning entire sheets

of low-cost glass, plastic or stainless

steel sheets with micro-thin layers of

photosensitive conducting materials,

followed by encapsulation (Figure

1515). The panel is formed in one

sheet where cells are not visible. They

are the cheapest solar panels in

market (PV-TRAC, 2005). It can be

highly efficient in material utilisation,

has low labour requirements, and uses comparatively little energy in the

manufacturing process which results in lower production costs, but are not as

efficient (in performance) as the other types, although this has improved in recent

years and they can be a practical alternative to panels made with silicon cells (PV-

TRAC, 2005). The price advantage is counterbalanced by substantially lower

efficiency rates of 5 to 13 percent (RES, 2010). They are most often seen in small solar

panels like those in calculators or garden lamps, and give the most efficient

performance in low light intensity (http://www.mysolarshop.co.uk/-i-74.html[Accessed on 20 May 2011]).

3.4.3 OTHER TYPESThe other types include cadmium telluride (CdTe) and

copper indium gallium deselenide (CIGS), which are

usually found in a thin-filmed form (Figure 16). The problem

of these other technology (cadmium telluride) is that it

contains Cadmium, which is toxic and affects people the

same way mercury does. Another drawback is that theefficiency of the CdTe cell is 15% while that of the CIGS

cell is 20% (http://www.moodia.com/article/thin-film-solar-

panels-photovoltaic-energy [Accessed on 20 May 2011]).

The PV solar industry has seen rapid development in

recent years all around the world. The global output of PV batteries reached

10,700MWp in 2009. Thin film solar cells contributed 1,700MWp, accounting for 15.9%

of the total. This proportion will be further increased in the future. Its application can

be seen in solar energy batteries (FNCHN, 2011).

15 Source http://www.greenoptimistic.com/2010/07/06/amorphous-silicon-solar-cells-hydrogen-efficiency/ [Viewed on 28 May 2011].

Figure 15: Section of thin-film solar cells.

Figure 16: CIGS Module


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Table 3: Comparative study of PV systems (Nijs, 201016. Editted by Author).

Table 4: Advantages and disadvantages of materials used for PV modules (Stephens, 200817).

Figure 17: Thin film vs. crystalline production (Stephens, 2008).

16 Nijs, J., 2010, Photovoltaic Solar Energy: Present and Future [Online]. Available athttp://www.clubofrome.at/events/lectures/58/pdf1.pdf [Accessed on 23 May 2011].17 Stephens, S., 2008. Solar Energy: Future Trends and Technologies [Online]. Available atwww.solaramericacommunities.energy.gov/pdfs/2008_annual_meeting/Solar-Energy-Future-

Trends-and-Technologies.pdf [Viewed on 23 May 2011].

TECHNOLOGY CRYSTALLINE SILICON THIN FILM

IMAGE

Source: http://renewablepowersolarenergy.com/solar-panels/solar-panel-blog

[Accessed on 23 May 2011]CELL TYPES Monocrystalline Polycrystalline

Amorphous

crystallineCIGS CdTe

MANUFACTURING

PROCESS

Feedstock, contacts, module

design

Depositing processes, substrate,

encapsulate

LAB EFFICIENCY 24.7 % 13 % 18.8 % 17 %

INDUSTRIAL

EFFICIENCY 12 17 % 6 10 % 9 13 % 9 12 %

MARKET SHARE 90 95 % 5 % 3 %

SUBSTRATE BENEFITS DIFFICULTIES

GLASS Excellent barrier, smooth, thermal

expansion, vacuum compatible.

Rigid, heavy weight.

FLEXIBLE Low weight, durability, removable,

potential low cost with high throughput.

Curling, stress, poor

adhesion.

POLYAMIDE Monolithic integration. Worst efficiency, low

temperature deposition.

FLEXIBLE METAL High deposition temperature. Pin hole (roughness),

impurity diffusion.


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4 CURRENT APPLICATIONS OF PV MODULES

The capability of PV to be utilised in certain

applications under current economic and

technical conditions depends on thegeographical location and the climatic

zones, as well as cost. PV generators are

generally a good solution for basic needs in

rural applications to improve living standards.

To solve the problems associated with

intermittency and dispersion, hybrid solutions

can be implemented combining the use of

the full range of renewables, solar,

hydropower, wind in coastal areas, and

biomass. Lower cost and increased

performance PV will ensure that uptake in all

markets is increased in the future (PV-TRAC,

2005).

4.1 RESIDENTIALThe number of PV installations on buildings

connected to the electricity grid has grown in

recent years. In solar systems connected to

the electricity grid, the PV system supplieselectricity to the building, and any daytime

excess may be exported to the grid. Batteries

are not required because the grid supplies

any extra demand. However, to be

independent of the grid supply, battery

storage is needed to provide power at night.

Holiday homes without access to the

electricity grid can are more cost-effectively

than if the grid was extended to reach the

location. Remote homes in sunny locations

can obtain reliable electricity to meet basic

needs with a simple system comprising of a PV

panel, a rechargeable battery to store the

energy captured during daylight hours, a

regulator (or charge controller), and the

necessary wiring and switches. Such systems

are often called solar home systems (SHS).

Figure 19: PV exterior wall facade.

Figure 18: PV integrated in railings.

Figure 20: PV integrated with elements ofarchitecture.

Figure 21: PV used for water pumps in

rural areas.


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4.2 COMMERCIALThe vertical walls of office buildings provide several opportunities for PV

incorporation, as well as sunshades or balcony railings incorporating a PV system.

Sunshades (Figure 20) may have the PV system mounted externally to the building,

or have PV cells specially mounted between glass sheets comprising the window

(Figure 19).

4.3 RURAL AND REMOTE APPLICATIONSThousands of dwellings around the world are too far from the grid to be connected,

but they can benefit from PV generated electricity for lighting, television,

refrigeration, etc. Remote buildings, such as schools, community halls, and clinics,

can benefit from solar energy. In developing regions, central power plants can

provide electricity to homes via a local wired network, or act as a battery chargingstation where members of the community can bring batteries to be recharged.

PV systems can be used to pump water (Figure 21) in remote areas as part of a

portable water supply system. Specialized solar water pumps are designed for

submersible use or to float on open water. Large-scale desalination plants can also

be PV powered using an array of PV modules with battery storage.

Decentralised rural electrification (DRE) in developing countries concerning about

1.7 billion people in the world according to official IEA figures, aims to meet:

Basic needs: potable water, water for livestock, refrigeration and lighting for

a dispensary.

Improved quality of life: residential lighting, telephone service, radio and

television and community lighting (street lighting, schools, meeting halls,

etc.).

Small-scale motorisation for development: pumping for farming irrigation,

vegetable gardening, storage, motorisation for mills, presses, small craft

industries, etc.

4.4 INDUSTRIALFor many years, solar energy has been the power supply choice for industrial

applications, in form of telecommunication relays, cathodic protection, tele-

measurements, and all applications for which the electrical consumption is small

compared to grid connection like parking meters even in towns, or emergency

phones along highways

Solar energy is also frequently used for transportation signaling, such as offshore

navigation buoys, lighthouses, aircraft warning light structures, and increasingly in

road traffic warning signals. Solar is used to power environmental monitoring

equipment and corrosion protection systems for pipelines, wellheads, bridges, and

other structures. For larger electrical loads, it can be cost-effective to configure a

hybrid power system that links the PV with a small diesel generator.


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4.5 OTHERAs its initial purpose, PVs are still being used to

power artificial satellites (Figure 22).

Thin filmed PV sheets are usually used for

consumer applications like watches,

calculators, garden lights, alarm devices, etc.

4.6 COMMON APPLICATION OVERVIEWPV systems are sometimes best configured with a small diesel generator in order to

meet heavy power requirements in off-grid locations. With a small diesel generator,

the PV system does not have to be sized to cope with the worst sunlight conditions

during the year. The diesel generator can provide back-up power that is minimizedduring the sunniest part of the year by the PV system. This keeps fuel and

maintenance costs low (SMRA, 201018).

The major cost element for thin films is the capital for equipment and materials, and

the cost of the materials will be the key to achieving low overall module costs in the

long term. The price of standard PV modules is currently approximately 3 !/W. This

could be reduced to 2 !/W by 2010, 1 !/watt-peak in 2020 and 0.5 !/W in 2030.

5 CRITICAL EVALUATION OF SOLAR ENERGY AND PV TECHNOLOGY

5.1 ADVANTAGES Solar energy is a locally available renewable resource. It does not need to

be imported from across the world. This reduces environmental impacts

associated with transportation and also reduces our dependence on

imported oil. And, unlike fuels that are mined and harvested, when we use

solar energy to produce electricity we do not deplete or alter the resource.

PV modules require minimal energy to be manufactured or installed hence

qualifies as a green technology.

A PV system is flexible in type. It can be constructed to any size based on

energy requirements. Furthermore, it can be enlarged or moved if the energy

need changes.

PVs are flexible in use, hence can be part of a consumer product, mounted

on building roofs, integrated in a building skin or assembled into large power

stations. Due to this, it can serve energy needs in dispersed and isolated

communities.

It can be designed to be very robust and reliablewhile at the same time it is

quiet and safe.

Visuallyunobtrusive.

PV fits well in the existing infrastructure and it offers possibilities to make

intelligent matchesbetween electricity supply and demand.

18Available at http://www.solarbuzz.com/going-solar/using/uses [Accessed on 27 May 2011].

Figure 22: PV used in artificial satellites.


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PV cells were originally developed for use in space, where repair is extremely

expensive, if not impossible. PV still powers nearly every satellite circling the

earth because it operates reliably for long periods of time with virtually no

maintenance.

PV can supply a substantial part or even the majority of our future electricity

needs. For example, in Europe, fitting the total surface of south-oriented roofs

with PV equipment would enable full coverage of our electricity needs. This

illustrates that.

The economic benefits of a growing commercial PV sector are already

proving a reality and have led to strong global competition (PV-TRAC, 2005).

5.2 DISADVANTAGES Although reliable PV technology is already available today, it needs further

development, especially to reduce the costof electricity produced.

Toxicchemicals, like cadmium and arsenic, are used in the PV (amorphous)production process. These environmental impacts are minor and can be

easily controlled through recycling and proper disposal.

Solar energy is more expensive to produce than conventional sources of

energy due to the cost of manufacturing PV devices, and also the

equipment efficiency. As the conversion efficiencies continue to increase

and the manufacturing costs continue to come down, PV will become

increasingly cost competitive with conventional fuels.

Solar power is a variable energy source, thus may not be able to produce

power all the time, this could lead to an energy shortage if a lot of a region's

power comes from solar power (CetOnline19).

Figure 23: Energy payback time of PV modules (EPVEC, 200620).

19 Available at http://www.cetonline.org/Renewables/PV_pro_con.php [Viewed on 28 May2011].20Alsema, de Wild, Fthenakis, 2006.21stEuropean PV Energy Conference, Dresden.

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23/50



6 CURRENT SCENARIO: PV MARKET DEVELOPMENT

PV cell manufacturers produced a record 10,700 megawatts of PV cells globally in

2009, a 51 percent increase from the year before. While growth in 2009 slowed from

the remarkable 89 percent expansion in 2008, it continued the rapid rise of an

industry that first reached 1,000 megawatts of production in 2004. By the end of 2009,nearly 23,000 megawatts of PV had been installed worldwide, enough to power 4.6

million U.S. homes. Solar PV, the worlds fastest-growing power technology, now

generates electricity in more than 100 countries (Roney, 201021).

Figure 24: PV production around the world (IEA, 201022).

This success has been generated by a combination of market stimulation and

intensive research and development in Japan, the USA and Europe, over the last 10

years. Prices have been reduced by three times since 1990. Cumulative worldwide

installations were estimated to 2.2 GW by the end of 2003, with Europe standing at

560 MW.

21 Eco Economy Indicators: Solar Power [Online]. Available on http://www.earth-policy.org/indicators/C47/ [Accessed on 28 May 2011].22International Energy Agency, 2010. Technology Roadmap: Solar photovoltaic energy.

Z HISTORICAL FIGURES EPIA MODERATE SCENARIO


24/50



Table 3: Annual solar PV power production by country 2002-2009 (EPI, 2010).

Figure 25: Graph tabulating Table 2 values (EPI, 2010).

It is today public policy and political leadership, rather than either technology or

economics that are required to move the widespread application of solar energy

technologies and methodologies forward. The technologies and economics will all

improve with time, but they are sufficiently advanced at present to allow for major

penetrations of solar energy into the mainstream energy and societal infrastructures.

And significant goals can be now set with confidence for major percentage

improvements in energy efficiency and increases in solar and renewable energy

applications for the next 50 years, at which time the world should be receiving over

50 % of all energy needs from locally available environmental resources, with most of

EUROPEAN

UNION

COUNTRY 2006 2007 2008 2009 2010 2011 2012 2013

Belgium 2 18 48 100 70 80 90 100

Czech

Republic0 3 51 80 90 110 140 170

France 8 11 46 250 340 600 900 1000

Germany 850 1100 1500 2000 2000 2300 2600 3000

Greece 1 2 11 35 100 100 100 100

Italy 13 42 258 400 600 750 950 1250

Portugal 0 14 50 40 50 100 160 230

Spain 88 560 2511 375 500 500 550 800

Rest of EU 12 17 28 120 140 200 300 450

RESTOFTHE

WORLD

China 287 210 230 400 500 700 1000 1100

India 145 207 342 340 1000 1200 1500 2000

Japan 12 20 45 80 100 300 600 1000

South Korea 12 20 40 50 60 80 120 300

USA 20 43 274 100 150 220 300 400

Rest of the

world

153 125 126 250 300 300 300 350

TOTAL 1603 2392 5559 4620 6000 7540 9610 12250


25/50



these being from direct and indirect uses of solar energy. There are no resource

limitations to this scenario.

Figure 26: World annual solar PV production 1985-2009 (EPI, 201023).

Figure 27: Regional manufacturer shipment 1997-2007 (Navigant, 2008).

This section of the report will give a general overview of the current status of PV

technology in a few countries, and how the government is aiming to expand and

develop it further. This will clearly show the importance and demand of PV systems,

although only very recently its importance has been realized.

23 Earth Policy Institute, 2010. Eco-Economic Indicators: Solar Power [Online]. Available athttp://www.earth-policy.org/indicators/C47/ [Viewed on 28 May 2011].

0

500

1,000

1,500

2,000

2,500

3,000

3,500

4,000

1995 1998 2001 2004 2007 2010

Megawatts

China

TaiwanJapan

United States

Germany


26/50



6.1 SITUATION IN THE EUROPEAN UNIONSolar PV accounted for about 16 percent of all new electric power capacity

additions in Europe in 2009. While the US dominated in venture capital and private

equity, EU-27 attracted the significant public market investment in 2006: $5.7 billion.

This is partly due to the higher awareness of climate change and the role of

renewable energy and energy efficiency in the EU, who ratified the Kyoto Protocol.

A number of EU countries offer generous incentives to promote renewable energy

(such as the German feed-in tariff) and are starting to do so with efficiency. These

factors help to explain why investors in the EU have been particularly ready to pour

money into renewable energy, and why companies there have reached a relatively

mature stage in their development. The European PV production in 2003 reached

200MW, which represents approximately 26% of the worldwide PV production. The

installation of PV in Europe in 2003 represents 34% of the world PV market. The market

has grown in Europe at a consistent rate compared with other large markets (Japan

and USA). In contrast, the intensity of technological development efforts and theincrease in production capacity are much lower in Europe than in Japan (EPI, 2010).

Table 4: Regulatory framework for a few countries in the EU and Switzerland from 2004 (PV-

TRAC, 2005).

The present situation of the regulatory framework for photovoltaics in Europe may be

described as being very heterogeneous with substantial differences between theMember States and their time planning. One of the worst signals to the market is a

COUNTRY FRAMEWORK

Austria Feed-in tariff paid for 20 years with cap of 15MW, but only for systemsinstalled in 2003 and 2004 (cap was already reached after four weeks).

When power < 20 kW, cost equals 0.6!/kWh.

When power > 20kW, cost equals 0.47!/kWh.

Denmark No specific PV programme, but settlement price for green electricity.

France Feed-in tariff: 0.15!/kWh for systems 30kW) and

0.54!/kWh (>100 kW), for faade integration there is an additional

bonus of 0.05!/kWh.

Greece Feed-in tariff: 0.08!/kWh on islands and 0.07!/kWh on the mainland.Grants for 40-50% of total cost. Holds only for commercial applications

>5 kW, no grants for domestic applications.

Sweden No specific PV programme. Electricity certificates for wind solar,biomass, geothermal and small hydro. Energy tax exemption.

Switzerland Net metering with feed-in tariff of min. 0.15CHF/kWh (0.10!/kWh);investment subsidies in some cantons; promotion of voluntary measures

(solar stock exchanges, green power marketing).

United Kingdom Investment subsidies in the framework of a PV demonstrationprogramme. Reduced VAT.


27/50



continuous change of conditions, which does not give the security needed for

investors (PV-TRAC, 200524).

Germany (the leading country in the EU) installed a record 3,800MW of PV in 2009,

more than half the 7,200MW added worldwide. This brought Germanys overall PV

generating capacity to 9,800MW, nearly three times as much as the next closest

country, Spain. Already in the first half of 2010, Germany added another 3,800MW.While Germany has played a major role in advancing PV and driving down costs, its

importance will decline as other countries step up their demand and reduce the

industrys reliance on a single market. After its record-breaking year in 2008, the

Spanish PV market plummeted to an estimated 70MW added in 2009, due to a cap

on subsidies after the national solar target was exceeded. But, there were other

sunny spots in Europe. Italy came in a distant second after Germany, installing 710

MW and more than doubling its 2008 additions due to high feed-in tariffs and a good

national solar resource; such strong growth is expected to continue.

6.2 SITUATION IN JAPANWith 49 percent of the world production in excess of their domestic market, Japan is

an exporter of PV. Japanese manufacturers have increased their investments in

production. The countrys contribution, between 1995 and 2002, had risen from 21-

49percent and looks to grow even higher (EPI, 2010). Although after the recent

disasters, the contribution has drastically reduced to 14 percent. The Japanese

government has, over the last ten years, implemented a coherent long-term PV

policy including R&D, demonstration tests, market deployment and promotion. This

continuity makes the implementation of PV, both in manufacturing and marketing,

very effective. Standardisation issues are being addressed, and PV is being activelypromoted through the Residential PV System Dissemination Programme. In addition,

the Government has implemented programmes for the introduction of new energy

directed at local governments and private entrepreneurs.

The Japanese PV2030 roadmap outlines possible development routes leading to

50-200GW of PV in 2030 (baseline case 100 GW). The technical potential is estimated

to be 8 000 GW. Research and development is aimed at reaching break-even with

household electricity prices in 2010 (0.17!/kWh), business electricity prices in 2020

(0.10 !/kWh), and industry prices in 2030 (0.05 !/kWh). Japan has a net metering

(~0.2 !/kWh) scheme complemented by a relatively low subsidy (only 12%).

Implementation is successful, and at the end of 2003 some 180000 systems were

installed with a total capacity of 700 MW (PV-TRAC, 2005).

24Photovoltaic Technology Research Advisory Council, 2005.A Vision for PhotovoltaicTechnology[Online]. Available at:

http://technologies.ew.eea.europa.eu/technologies/resourc_mngt/energy_save_renewbls/p

hotovoltaics/vision-report-final.pdf/ [Viewed on 24 April 2011].


28/50



6.2.1 SITUATION IN CHINAChinas solar PV industry has been growing rapidly and the country now ranks first in

the world in exports of PV cells. While China now manufactures more than a third of

the worlds PV cells, 95% of it is exported and only 5% used within country since most

Chinese consumers cannot afford the technology. Domestic output of PV cellsexpanded from less than 100 MW in 2005 to 2GW in 2008, experiencing a 20-fold

increase in four years (Sicheng Wang, 2008), due to a demand from the international

PV market, especially Germany and Japan. In 2008, Chinas cumulative PV installed

capacity was 150 MW (National Energy Administration, 2009). Some 40% of this

demand is met by independent PV power systems that supply electricity to remote

districts not covered by the national grid. Market shares of solar PV for

communications, industrial, and commercial uses have also increased. BIPV systems,

as well as large-scale PV installations in desert areas, are being encouraged by the

Chinese government, which began providing a subsidy of RMB 20 (USD 2.93) per

watt for BIPV projects in early 2009. It is likely that the 2010 and 2020 national targets

for solar PV (400 MW and 1 800 MW, respectively) announced in 2007 will be

significantly increased. Experts predict that Chinese installed capacity could reach 1

GW in 2010 and 20 GW in 2020 (CREIA, 2009).

The country, being a global powerhouse for PV, is currently dependent on imported

feedstock; this can be seen from Figure 28. This will change by 2015, due to intense

investment in silicon refining capacity by 2012, and the country will become a net

exporter of every element of the PV chain by 2020. Investment in Chinese solar

companies total $1.1 billion in 2006 $638 million of Venture Capital & Private Equity,

plus $466 million of public market fund raising (PV-TRAC, 2005). China announced

that it has doubled its target goal for solar power generation over the next decadein an effort to decrease dependency on nuclear power due to the recent Japan

crisis. The National Development and Reform Commission announced that China is

aiming to complete enough solar installations to provide a solar power capacity of

10GW by 2015 and 50GW by the end of the decade. This bold green move is a huge

step that should encourage the use of clean energy sources across the country.

Figure 28: Solar cell manufacturing business in China (SolarPlaza, 200525).

25Alternative Energy Magazine.Available at:http://www.altenergymag.com/emagazine.php?issue_number=06.02.01&article=solarplaza

[Viewed on 28 May 2011].

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China is expected to publish a five-year blueprint soon that will outline supportive

policies for the solar power industry. The shift to clean power will also bode well for

the countrys overall health, as they have registered some of the globes worst air

and water quality following three decades of unrestrained growth and its resulting

pollution. The country is anticipating an investment of several hundred billion dollars,

and it hopes that by 2020 it will generate a full 15% of its energy from renewable

sources (Alternative Energy Magazine, 201126).

Figure 29: Chinese PV industry forecast of production capacity (SolarPlaza, 2009).

While PV remains relatively expensive as a form of generation, China will continue to

focus on capitalising on other countries generous feed-in tariffs (New Energy

Finance, 2010).

Additional details:

232 projects -- totaling 290 MW -- to be built at major industrial sites where

carbon heavy manufacturers will consume all of the electricity generated.

35 projects -- totaling 306 MW -- to be built as utility-scale solar parks, whose

output will flow into Chinas transmission grid.

27 projects -- totaling 46 MW -- to be built by independent producers in

remote, powerless regions.

6.3 SITUATION IN INDIAAt present, only 9 percent of the energy utilised in India are from renewable sources,

i.e. sun and wind (Figure 3027).

26Available at:http://www.altenergymag.com/emagazine.php?issue_number=06.02.01&article=solarplaza

[Viewed on 28 May 2011].27PV Group, 2009. The Solar PV Landscape in India: An Industry Perspective[Online]. Availableat http://www.solarindiaonline.com/pdfs/The_Solar_PV_Landscape_in_India1.pdf [Viewed on

28 May 2011].

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The application spread for

PV in India is very different

from the global mix of solar

applications. Instead, it

almost entirely (97 percent)

comprises of off-grid and

small capacity applications

(street lighting, traffic

signal, domestic power

back-up, etc.).

Its large and diversified PV

industry consisting of ten

fully vertically integrated

manufacturers making

solar cells, solar panels and complete PV systems, and around 50 assemblers of

various kinds. Together, these companies supply around 200 MW per year of 30

different types of PV systems in three categories rural, remote area and industrial.

However, despite this strong industrial base, PV constitutes a small part of Indias

installed power generation capacity, with 2.7 MW grid- connected systems and 1.9

MW stand-alone systems in 2008 (Banerjee, 2008). There have been a number of

high-level government initiatives that have provided new momentum for PV

deployment in India, including:

The 2008 Action Plan on Climate Change included a National Solar Mission

that establishes a target

of generating 20 GW of

electricity from solar energy by 2020; the programme aims to boost annualPV power generation to 1 000 MW by 2017.

In 2008, the Ministry of New and Renewable Energy (MNRE) established a

target of 50 MW of capacity by 2012 to be achieved through its Generation

Based Incentives (GBI) programme. The GBI includes production incentives

for large solar power plants of INR 12 (USD 0.25) per kWh for PV power for up

to 50 MW of capacity, subject to a maximum 10 MW in any one state.

The Eleventh Five-Year Plan (2007-12) proposed solar RD&D funding of INR 4

billion (86.4M USD). The Working Group on R&D for the Energy Sector

proposed an additional INR 53 billion (1.15B USD) in RD&D for the Eleventh

Five-Year Plan, with the two largest topics being: research on silicon

production for PV manufacturing (total investment INR 12 billion [259M USD],

including the establishment of a silicon production facility) and research on

LEDs (INR 10 billion [216M USD], also including the establishment of a

manufacturing facility).

6.3.1 SITUATION IN THE USAThe third largest market in 2008 was USA, with 342MW of PV installations, including

292MW grid-connected PV. California, New Jersey and Colorado accounted for

more than 75% of the US grid-connected PV market. The US Senate voted to extend

the tax credits for solar and other renewable energies in 2008, and the Energy

Improvement and Extension Act of 2008 was approved.

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31/50



Department of Energy gave $117.6 million to accelerate the widespread

commercialization of solar energy technologies. $51.5 million was given for

Photovoltaic Development and $40.5 million for Solar Deployment (ISA, 201028). It

aims to support the U.S. PV industry in improving the cost-effectiveness,

performance, and reliability of its products; as well as the forming of partnerships

among national laboratories, industry and universities.

The ongoing deregulation process of power utilities has resulted in several

programmes being proposed and legislated at State level that affect photovoltaics.

These include Green pricing, set-asides for photovoltaics, net metering,

interconnection requirements, etc. Initiatives related to the promotion of

photovoltaics are individually adopted by the 50 states.

Figure 31: Evolution of PV technology in USA (Stephens, 200829).

The country added an estimated 470MW of solar PV in 2009, including 40MW of off-

grid PV, bringing cumulative capacity above the 1GW mark. California accounted

for about half of the total, followed by New Jersey with 57MW added; several other

states are expected to pass the 50MW per year mark in the near future.

6.3.2 SITUATION IN OTHER COUNTRIESOther strong markets included the Czech Republic, which saw a nine fold increase in

total capacity relative to 2008to 411 MWthanks to generous feed-in tariffs for

solar PV, although they are not likely to remain that high. The trend toward large-

scale (greater than 200 kilowatt) PV plants continued around the globe, with the

28 India Semiconductor Association, 2010. Solar PV industry 2010: Contemporary Scenaio andEmerging Trends.29Stephens, S., 2008. Solar Energy: Future Trends and Technology.


32/50



number of such plants exceeding 3,200 in 2009, up from roughly 2,450 the previous

year. These facilities totaled some 5.8 GW of capacity, more than five times the 2007

capacity, and accounted for more than a quarter of existing global PV capacity by

year-end. The majority of these plants are operating in Spain, Germany, and the

United States, although an increasing number are being installed in Asia and

elsewhere. A 950kW system in Cagayan de Oro City in the Philippines is reportedly

the largest in any developing country, and a 250kW system outside of Kigali in

Rwanda is the largest grid-connected PV system in sub-Saharan Africa. In the Middle

East, installation of Saudi Arabias first and largest PV system (2MW) on the roof of

King Abdullah University of Science and Technology was completed in May 2010.

7 PV MARKETThe solar PV industry saw major declines in module prices in 2009, by some estimates

dropping over 5060 percent from highs averaging $3.50 per watt in the summer of

2008. By December 2009, prices were falling below $2.00 per watt in some instances

(REN21, 2011).

To retain competitiveness, firms focused on increasing efficiency, reducing operating

costs, and increasing capacity utilization at factories. This marked resilient and

profitable industry players. Consolidation and scale-up also emerged as major

responses. For example, in the United States 2009 saw the closing of BP Solars PV

manufacturing facility. Simultaneously, the top 10 manufacturers were looking to

grow from 6.9 GW of manufacturing capacity in 2009 to 10.6 GW in 2010. Chinas

Jiangsu and Zhenjiang provinces, where more than 300 manufacturers compete for

contracts, are representative of the intense competition.

Many manufacturers responded to softening demand by broadening their market

positions into project development as well as manufacturing. A new project

subsidiary of Q-Cells, for example, had 100 MW of projects under construction in

Germany and Italy by the end of 2009, generating demand equivalent to 18

percent of Q-Cells annual module production. Suntech of China acquired an 86

percent stake in Global Solar Equity Funds, an entity created to provide equity to PV

projects. And First Solarsigned a memorandum of understanding (MOU) to build a

2GW project in China, the first 30MW of which is scheduled for completion in 2010. As

many manufacturers grow and buy their way into the project development business,

new business models are being created for project development and financing,

based on regional and local incentives and regulations. These models often look

more like real estate development than manufacturing or power-projectdevelopment businesses.

Thin-film PV manufacturing maintained its 25 percent production share in 2009,

despite losing its historical cost advantage over crystalline PV module prices. Of the

roughly 150 thin-film manufacturing firms thaXt existed in 2008, only about half (70)

were estimated to be active by early 2010, and only a handful continued to

produce at full capacity. First Solar led the industry, becoming the first PV

manufacturer to produce more than 1GW in a single year (1.1 GW in 2009). The rest

of the thin-film industry, notably Sharp and Showa Shell, produced a combined

500MW in 2009. The majority of thin-film firms purchase their production lines from

market leaders Applied Materials and Oerlikon Solar(REN21, 2011).


33/50



Figure 32: Market shares of top 15 solar PV manufacturers, 2009 (REN21, 2011).

The top 15 solar cell manufacturers produced 65 percent of the 10.7GW of cells

manufactured in 2009 (See Figure 32). Firms in China and Taiwan produced nearly

half (49 percent) of the global total, followed by Europe (18 percent), Japan (14

percent), and the United States (6 percent).

Even as the average size of PV projects increases, there is growing interest in very

small-scale, off-grid systems, particularly in developing countries. These systems

account for only some 5 percent of the global market, but sales and total capacity

have increased steadily since the early 1980s. In Africa, Asia, and Latin America, the

hunger for modern energy is driving the use of PV for mini-grid or gridless systems,

which in many instances are already at price parity with fossil fuels. Several hundred

megawatts of off-grid PV continue to be added globally every year, in bothdeveloped and developing countries (REN21, 2010).

8 EMERGING AND NEW TECHNOLOGIESA variety of other PV technologies and conversion concepts are the subject of

research. They are all aimed at low cost, high efficiency or a combination of the

two. New technologies are at various stages of development: from proof-of-principle

to pilot production.

A key factor in reducing of the cost of modules is connected with the manufacturing

processes used. In this context there is considerable interest in replacing singlecrystalline and polycrystalline semiconductor layers by nanostructured layers, which

may be deposited very cheaply, using experience from other sectors.

New technologies can be categorised as:

Options primarily aimed at very low cost (while optimising efficiency)

o Sensitised oxide cells

o Organic solar cells

o Other nanostructured materials.

Options primarily aimed at very high efficiency (while optimising cost)

o Multi-junction cells for use in concentratorso Novel conversion concepts.

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Some technologies, such as sensitized oxide and multi-junction cells, are more

mature and are gradually moving out of the laboratory phase while others are still in

the early stages of development. Organic (or plastic) PV is often considered a

high-risk, high-potential option. Working devices have been demonstrated, but

efficiencies are still low and sufficient stability has yet to be proven. Finally, novel

conversion concepts will be based on a variety of principles, and can be

considered to be at the fundamental research stage.

Table 5: Characteristics of emerging generation solar cells (ARIPT, 2007 30).

30 Applied Research Institute for Prospective Technologies, 2007. Emerging and NovelPhotovoltaic Texhnology. Working paper no.3.

TYPE OF SOLAR

CELLDESCRIPTION

PARAMETERS

EFFICIENCY IN

PRODUCTION(%)

LIFETIME

(yrs)

BAND

GAP (eV)

Multi Junction Higher efficiencies could be

achieved by using stacks of

semiconductors with different bandgaps. This technology makes better

use of the incoming light whereby

the conversion efficiency is

improved. It is the most promising

and the most expensive

technology.

21 - 36 - 0.7 3.4

Dye Sensitized

Photochemical

Solar Cells

The main material for solar cell used

is lowcost nanocrystalline titanium

dioxide with a large effective area

and organic dyes immersed in an

electrolyte. The advantage of dye

cells is that they can be produced

from inexpensive materials and by

simple production process. The

major challenge is to develop cells

and modules for powerapplications, as that poses for this

type of cells severe temperature

conditions. Though the stability

increased significantly, it still doesnot meet the standards of other

solar modules.

11 (0.25 cc)

and 8 on real

devices.

Low Variable

(depends

on

material

used)

Conductive

Organic

Polymer Cells

Device is based on the property of

some organic materials to beconductive: conjugated

polymers. Among the conductive

polymers investigated, the most

promising ones are the structures

containing fullerene (C60) as theacceptor material. Evident

advantages of this technology are

the expected lowcost

manufacturing and the possibility to

make solar cells by tailoring the

required properties by modifications

of the organic molecules.

Challenges are to increase small

area cell efficiencies and stability

under outdoor conditions.

>5 Low Variable

(dependson

material

used)


35/50



9 DESIGNING WITH PVS

Site Suitability the most important aspect to consider is the location of the site. The

solar installation must receive as much light as possible.

Estimating the outputs from different PV technologies Based on the country of site

the energy outputs can be calculated. This will be based on the tilt, orientation and

system efficiency. If the optimum angle is not achievable, over 90% of the maximum

annual energy can still be achieved at 10 degree and 50 degree tilts.

South-facing vertical facades generate around 70% of the maximum.

The effects of shade Shadows cast by tall trees and neighbouring buildings must be

kept in mind during the design process. The best location for solar PV is on the south-

facing roof or building sides. Minor shading can result in significant loss of energy

since the cell with the lowest illumination determines the operating current.

How to maximise the energy benefits of PV cells the more energy efficient the

building, the greater the benefit of the PV cells. Bear in mind that PV glass can often

provide thermal insulation as well since they can be made of low emissivity glass.

PV glass laminates and flexible thin film PV PV glass laminates are attractive and

well suited to facades and transparent rooftops. They can be fitted to standard

curtain walling structures and are suitable for any application where glass is used.

Thin-film PV is durable and flexible and is encased in a waterproof, self-cleaning

polymer. It can be used in unusual designs that exploit its flexibility.

How PV cells are affected by soiling The degree of soiling will depend on thelocation but usually dust accumulation and self-cleaning reach a steady state after

a few weeks. In extreme cases dust may cause a power reduction of about 10%. At

low tilts horizontal-glazing bars can trap debris, which could lead to shading of part

of the array. The design of the system should aim to minimise uneven soiling.

Lifetimes and warranties Most solar products have a lifetime of around thirty years.

Modules of all types usually have a twenty-year warranty, as do most thin-film

integrated products. Crystalline PV slates and PV glass laminates usually have a ten-

year warranty. These times are only a rough guide and should be checked for each

specific product.


36/50



10 BUILDING INTEGRATED PV AND OTHER DESIGN INNOVATIONS

This section of the report will cover the innovative PV applications in construction,

that contribute to the building or urban sustainability. A few of the applications are

of consumer goods or vehicles, which are out very recently.

10.1 PV SKYLIGHTSThe Skylight (Figure 33) system ensures an

optimized PV electrical generation

adding multifunctional passive

bioclimatic properties of thermal inner

comfort. Moreover, the air chamber of

the insulating glass guarantees best

thermal performance. In other words,

the skylight provides a multifunctionalsolution where not only energy is being

generated in-situ, but also natural

illumination is being provided

implementing solar control by filtering effect, avoiding infrared and UV irradiation to

the interior (enhancing thermal comfort and avoiding interior aging).

Source: http://www.onyxsolar.com/photovoltaic-skylight.html [Viewed on 29 May

2011].

10.1.1 A CASE STUDY OF MONT CENIS ACADEMY, GERMANYTotal roof area 12,600 sq.m.

PV area 9300 sq.m.

Standard PV roof panel 116mx278m (2802 no.s).

Standard PV facade panel 116mx240m (280

no.s).

Electrical power of each panel 192 to 416 Wp.

Incline angle of roof panel 5 degrees.

Incline angle of facade panel 90 degree.

No. of converters ca.600.

Total electrical power 1 Mwp.

Energy production 750,000 kwhReduction in carbon emission 12,000t/a Figure 16: PV integrated skylights

and facade of the building.

Figure 16: Roof fixing

detail.Figure 36: Exploded view of PV

block.

Figure 37: View of PV block.

Figure 33: PV Skylights.


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38/50



Figure 40: Exploded section of the double-skin wall.

10.3 PV TILES/PAVINGIt is made by a solar PV glass integrated over elevated ceramic and is completely

walkable. One of its main attractions is the variety of uses and the fact that it is

possible to place furnishing on it without losing space, as it happens when a

conventional PV panels are installed.

This PV pavement is a really appealing product for architects as it can be integratedin any project and environment without renouncing design and aestheticism. What

is more, it combines pasive elements (avoided CO2emmissions) with active

elements (power generation) reducing remarkably the building impact on the

environment.

10.4 PV DECKSPV decking, used in the promenade decks of Zadar (Croatia), is an integration of

the PV system and LED lights. These lights come on once the solar cells stop soakingenergy. Apart from being highly functional, it proves to be aesthetic as well.

INTERIOR

LAYER

IR LAYER WITH

FRAME

BUILDING

FRAME

OPERATING

LAYER

OUTER LAYER

WITH FRAME

Clear PET on

inner side ofinterior frame

IR blocking film Air cavity

vented toexterior

Clear PET with

PowerFilm PVmodules on

inner side of

exterior frame.

PET weather

barrier layerprinted with

diffusing

pattern

Figure 41: PV deck at Zadar, Croatia.


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10.5 PV LIT URBAN SPACESA relatively new concept is the PV integrated solar sheds (Figure 42) & street lamps. It

created uniqueness and a different identity to the congregational space.

The tree (Figure 44) is 23 feet high with 27 power-generating leaves. It generates

10,000kWh per year and saves over $165,000 over a 20-year period. When the sun isshining, the power generated can power 7 houses. Unlike regular streetlights, they

do not require costly underground wiring to install, and they are immune to

blackouts. The lights have 10 solar panels at the top of the branches, which charge

built-in batteries, which in turn power LEDs for illumination. Since LEDs generate direct

light, they emit much less light pollution when compared to conventional streetlights.

The built-in light detectors automatically turn the lights on after sun down.

10.6 SOLAR TEXTILESSolar fiber manufacturing paradigms may lead to lower manufacturing costs. Textile

geometry, due to texture and larger surface area, provide light trapping for higher

efficiencies. Multijunction geometries can be achieved with the weaving patterns,

and prove to be easier to install than rigid panels. They can be integrated with

technical textile such as carbon fiber composites.

Figure 45: Design prototype,

Danish Royal Institute of Art. Figure 46: PV integrated solarcurtains, Sheila Kennedy. Figure 47: Solar textile, byKonarka.

Figure 42: Public space with PV integrated solar

sheds, Rome (Behnisch Architects).

Figure 43: Solar tree exhibited in Vienna,

Austria.

Figure 44: Solar tree designed by Ross Lovegood, supported by Artemide & Sharp Solar.


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10.9 MISCILLANEOUS: FAADE TILESApart from being purely functional, PV tiles can be designed to enhance the

building faade to create an interesting feature.

Through laser cutting technology, the active area of the glass can be modified in

order to get different patterns and 100% customized designs, leading to spectacular

shapes and semi-transparency effects.

Do combine a pattern and a semi-transparency degree according to the pursued

design and to the energy requirements of the project.

Depending on the selected pattern or design, and the degree of semi-transparency,

peak power could decrease.

Figure 19: Innovative PV tiles for building facades.


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11 FUTURE VENTURES: UNDER PROGRESSThese technologies are still in a research phase, yet to be implemented and sold in

the market.

11.1 NOCERAS LEAFScientist Dr. David Nocera has

perfected a low-cost, artificial leaf-

like device that mimics

photosynthesis. Nocera hopes to

use his leaf to help make

individual homes capable of

becoming their own self-sufficient

power stations.

The leaf is made of silicon and uses

inexpensive nickel and cobalt

catalysts. Rather than producing

energy directly like a photovoltaic

cell, the leaf splits the water

molecule, which then produce

electricity for personal and

household use. The prototype can produce energy continuously for 45 hours without

any fluctuations.

Noceras leaf is ready for commercial production and distribution.

11.2 LIQUID SOLAR ARRAYSunengy has developed a new kind

of floating solar array, called a Liquid

Solar Array (LSA), which they believe

could be attached to hydroelectric

dams to increase their energy

output. The LSA (Figure 53) is a

floating platform with a series of

concentrated solar panels that have

the ability to track the suns

trajectory across the sky to garner

the most energy from available

daylight. Sunengy also believes their

floating solar array will be cheaper than conventional solar panels because of the

lack of expensive storm proof mounts and land acquisition costs.

(Source http://inhabitat.com/sunengy-develops-new-floating-liquid-solar-arrays-to-

maximize-energy-output-of-hydro-plants/ [Viewed 29 May 2011]).

Figure 53: LSA modules.

Figure 52: Microscopic view of Nocera's Leaf.


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11.3 NANO MATERIALSResearchers in the Netherlands have created a synthetic replacement for indium, an

extremely rare metal that has become a necessary ingredient in solar cells and

some organic light emitting diodes (OLEDs). The new material is made of carbon

nanotubes and plastic Nano particles, and researchers believe theyll be able to

achieve high levels of electrical conductivity with continued research. By replacing

a rare earth mineral with an engineered material, these researchers could also be

on the road to bringing down the high cost of creating solar cells.

(Source http://inhabitat.com/new-nano-material-could-replace-rare-earth-minerals-

in-solar-cells-and-oleds/ [Viewed 29 May 2011]).

Researchers at the MIT are utilizing viruses to enhance the efficiency of PV cells at

the microscopic level. In an article in the journal Nature Nanotechnology, the

scientists revealed that viruses could be used to organize carbon nanotubes in dye-

sensitized solar cells, reaping efficiency gains of a full third (Figure 54).

(Source http://inhabitat.com/mit-researchers-harness-viruses-to-improve-solar-

efficiency-by-a-third/ [Viewed 29 May 2011]).

11.4 SOLAR NANTENNASSolar efficiencies have increased incrementally over the past years, but they are still

hovering around 20%. However, an engineer from the University of Missouri claims to

have developed a flexible solar sheet that could revolutionize solar power by

soaking up over 90% of the suns energy. It is a thin, moldable solar sheet composed

of microscopic antennas called nantennas (Figure 55) that is able to harvest heat

and convert it into usable electricity. Best of all, he says that the technology could

be available to the general public within five years.

(Source http://inhabitat.com/mu-develop-solar-nantennas-that-can-capture-95-percent-of-solar-energy/ [Viewed 29 May 2011]).

Figure 20: Section of the proposed PV module.


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11.5 TENSILE SOLAR SHADEThe breathable fabric uses strips

of CIGS amorphous thin film solar

technology, which eliminates toxicmaterials and is relatively efficient in full sun

while tolerating shade well. The versatile

technology is perfect for site-specific

applications where conditions are often

changing. Modular in construction, Tensile

Solar can tolerate abuse and still work.

SMIT has developed four designsthe

saddle, the pole mount (Figure 56), the

tent, and larger architectural designs. The

concept is particularly appealing for

events that usually would use generators.

Pop up a tent, plug it in to a battery system

and youre good to go. They

visualize parking lots strewn with the

canopies (Figure 57), cooling cars down

and feeding the grid and maybe even

electric cars.

(Source http://inhabitat.com/new-tensile-

solar-shade-by-smit-will-juice-up-your-

summer-with-sun/ [Viewed 29 May 2011]).

11.6 PV WATER HEATING PANELSSolar panel manufacturer Solimpekis offering a hybrid solar panel that is capable of

providing both electricity and water heating from the same panel. The panels are

ideal for applications where there is limited roof space available, but both solar

electricity and solar hot water are desired. Even better, the combination of the two

Figure 55: Microscopic view of the solar nantennas.

Figure 56: Pole mount PV tensile canopy.

Figure 57: PV tensile canopy for parking

lots.


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functions actually improves the

efficiency of the electrical generation

of the photovoltaics.

These hybrid panels address a problem

most solar panels have: as photovoltaic

(PV) panels get hotter, they get less

efficient at generating electricity. A PV

panel is about 1% less efficient for every

3.5 degrees F temperature increase.

The Solimpeks panels address this by

using water to absorb excess heat and

keep the panels cooler. Water-cooling

is far more effective than air cooling,

making this a very effective combination. The heated water is then used to provide

the additional benefit of hot water for the building.

Testing has shown the efficiency of electrical generation to be as high as 28%while

at the same time producing 140-160 degree F water. This works out to an

improvement of 20% over a similar sized electric-only PV array, and without the

added hot water benefit, either.

Keeping the panels cooler has the additional benefit of extending their lifespan,

keeping them in service for a longer period of time. These panels will also be able to

pay back their installation cost more quickly since they are providing both electricity

and hot water.

(Source http://inhabitat.com/photovoltaic-solar-hot-water-panels-reap-multiple-

benefits/ [Viewed 29 May 2011]).

11.7 AQUASUN FLOATING SOLAR PANELSSolar panels take up a lot of

space, but Israeli

company Solaris Synergy

(working with French EDF

Group) have found a

solution: placing floating

solar panels on inland bodiesof water. The project,

called AquaSun, would not

only see the panels placed

on lakes and reservoirs, but

the panles would use the

water as a cooling system.

AquaSuns panels are made from silicon cells, which may be cheap but are also

prone to inefficiency caused by overheating. However by installing them on bodies

of water, this mitigates the problem. The floating panels, which would generate

200kw of clean energy, would also be adaptable to a regions energy requirements

with panels being added and removed when needed. AquaSun will not be installed

Figure 21: PV and Solar water heating panels.

Figure 59: Aquasun floating solar panels.


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in ecologically-sensitive areas or in open seas. Instead they would be installed on

reservoirs that are used for agriculture and industrial purposes.

A prototype has been designed and is set to be presented at the 4th International

Eilat-Eilot Renewable Energy Conference in Israel. Current plans aim to see AquaSun

installed for a nine-month test period in a basin at a hydro-electric facility in

southeastern France by the end of September 2011.

(Source http://inhabitat.com/aquasun-floating-solar-panels-to-be-deployed-in-

france/ [Viewed 29 May 2011]).

11.8 OTHER IDEAS Solar window with spray-on solar film claims to generate 300% more energy

than solar panels (http://inhabitat.com/solarwindow-with-clear-spray-on-film-

could-generate-300-more-energy-than-solar-panels/). Self-healing solar cells using carbon nanotubes ongoing research in Purdue

University (http://inhabitat.com/solar-cells-designed-to-self-repair-like-

plants/). Solar sailed micro-satellites by NASA NASA has launched these solar

powered satellites on an experimental basis. Its purpose is to clean space

debris (http://inhabitat.com/nasa-solar-powered-micro-satellite-will-clean-

space-debris/). PV tracking systems PV arrays that are connected to a device that orient

the PVs towards the sun direction.

Moving Towards the Sun : A Report on Photovoltaic Cells by Pooja Chowdhury

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Transcript of Moving Towards the Sun : A Report on Photovoltaic Cells by Pooja Chowdhury