142016341 Executive Summary

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Salient features

Location

iState Odisha

iiLocality Indic heights, Bhubaneswar

iii Name of College IIDR

Area for SPV Plant

i Length4.572m

ii Width3.048 m

iii Location Western side of college building

SPV Power Plant

i Output 2.4kWp

ii No. of modules 6

iii No. of modules in series3

iv No. of parallel combination 2

v DC BUS 1 No.

4. Technical details of a SPV Module

(a) PV Module type Poly crystalline

(b) PV Module

I Model no SVL-1210

SVL-2169

(c) Electrical Parameter

I Maximum Power 100 Wp

ii Rated Current5.88 A

iiiRated Voltage 17.0 V

iv Short Circuit Current6.35 A

v Open Circuit Voltage 21.0 V


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5. Mounting Arrangement

I MountingFixed Type

ii Surface azimuth angle of PV Module 180

iii Tilt angle(slope) of PV Module 32.1

6. Inverter/ Power Conditioning Unit (PCU)

i Number of units 1

ii Rated Capacity 2.4 kWp

iii Input Voltage range 48 V (Max.)

iv Output Voltage 220 V AC

v Frequency 50 Hz

vi Efficiency 94%

7. Grid Connection Details

I Electrical parameters for interconnection 220 V, 1Ph ,50 Hz

11. Construction Time 40hour


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1. INTRODUCTION:

Harnessing of non polluting renewable energy resources to control green house

gases is receiving impetus from the government of India. The solar mission, which ispart of the National Action Plan on Climate Change has been set up to promote thedevelopment and use of solar energy in for power generation and other uses withthe ultimate objective of making solar energy competitive with fossil-based energyoptions. The solar photovoltaic device systems for power generation had beendeployed in the various parts in the country for electrification where the gridconnectivity is either not feasible or not cost effective as also some times inconjunction with diesel based generating stations in isolated places andcommunication transmitters at remote locations. With the downward trend in thecost of solar energy and appreciation for the need for development of solar power,solar power projects have recently been implemented. A significant part of the largepotential of solar energy in the country could be developed by promoting gridconnected solar photovoltaic power systems of varying sizes as per the need andaffordability coupled with ensuring adequate return on investment.

Renewable energy sources occur in nature which are regenerative or inexhaustiblelike solar energy, wind energy, hydropower, geothermal, biomass, tidal and waveenergy. Most of these alternative sources are the manifestation of solar energy asshown figure 1.1.


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Figure 1.1 Renewable sources of energy.

India is implementing one of the worlds largest programmes in renewable energy.

The country ranks second in the world in biogas utilization and fifth in wind powerand photovoltaic production. Renewable sources contribute to about 5% of the totalpower generating capacity in the country.

1.1 IDEAS ON RENEWABLE ENERGY:

Renewable energy is energy which comes from natural resource such as sunlight,wind, tides & geothermal heats.In other words Renewable is natural energy which

doesn't have a limited supply, which can be used again & again, and will never runout.

About 16% of global final energy consumption comes from renewables, with 10%coming from traditional biomass, which is mainly used for heating, and 3.4% fromhydroelectricity.

New renewables (small hydro, modern biomass, wind, solar, geothermal, and biofuels) accounted for another 3% and are growing very rapidly.The share of renewables in electricity generation is around 19%, with 16% of global electricitycoming from hydroelectricity and 3% from new renewables.

Renewable energy replaces conventional fuels in four distinct areas: electricitygeneration, hot water/space heating, motor fuels, and rural (off-grid) energyservices.

In other word renewable energy is also known as nonconventional energy source.

1.1.1 ADVANTAGES OF RENEWABLE ENERGY:

The major advantage of renewable energy is that it is renewable & so will never runout.

Renewable energy facilities generally require less maintenance than the traditionalgenerators.

More importantly these are environment friendly because it produces little or nowaste products like carbon dioxide or other chemical pollutants.


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Renewable energy projects can also bring economic benefits to many regional areas.These economic benefits may be from the increased use of local services as well astourism.

1.2 TODAYS SCENARIO:

From the end of 2004, worldwide renewable energy capacity grew at rates of 10

60% annually for many technologies.

For wind power and many other renewable technologies, growth accelerated in

2009 relative to the previous four years. More wind power capacity was added

during 2009 than any other renewable technology.

However, grid-connected PV increased the fastest of all renewables technologies,

with a 60% annual average growth rate. In 2010, renewable power constituted about

a third of the newly built power generation capacities.

By 2014 the installed capacity of photovoltaic will likely exceed that of wind, but due

to the lower capacity factor of solar, the energy generated from photovoltaic is not

expected to exceed that of wind until 2015.

1.3 IDEAS ON SOLAR ENERGY:

Solar energy is energy that is present in sunlight. Solar energy technologies include

solar heating, solar photovoltaics, solar thermal electricity and solar architecture,

which can make considerable contributions to solving some of the most urgent

problems the world now faces. Solar technologies are broadly characterized as either

passive solar or active solar depending on the way they capture, convert and

distribute solar energy. Active solar techniques include the use of photovoltaic

panels and solar thermal collectors to harness the energy. Passive solar techniques

include orienting a building to the Sun, selecting materials with favourable thermal

mass or light dispersing properties, and designing spaces that naturally circulate air.

1.4 TYPES OF TECHNOLOGY ASSOCIATED WITH SOLAR ENERGY:

1.4.1 Solar power plants


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Solar power plants strive to converting, either directly using photovoltaic(PV), or

indirectly using Concentrated solar power systems (CSP). Concentrated solar power

systems use lenses or mirrors and tracking systems to focus a large area of sunlight

into a small beam. Photovoltaic converts light into electric current using the

photoelectric effect.

1.4.2 Solar heating:

House with solar panels for heating and other needs in Jablunkov and other foreigncountries. The sun may be used to heat water instead of electricity or gas. There aretwo basic types of active solar heating systems based on the type of fluid either

liquid or air that is heated in the solar energy collectors. (The collector is thedevice in which a fluid is heated by the sun.) Liquid-based systems heat water or anantifreeze solution in a "hydronic" collector, whereas air-based systems heat air inan "air collector. Both air and liquid systems can supplement forced air systems.

1.4.3 Solar cells:

Solar cells can be used to generate electricity from sunlight. It is a device thatconverts lightenergy into electrical energy. Sometimes the term solar cell is reserved

for devices intended specifically to capture energy from sunlight, while the term photovoltaic cell is used when the light source is unspecified. Solar cells have manyapplications. They have long been used in situations where electrical power from thegrid is unavailable, such as in remote area power systems, Earth- orbiting satellitesand space probes, consumer systems, e.g. handheld calculators or wrist watches,remote radiotelephones and water pumping applications.

1.4.4 Solar water pumps:-

Earlier, DC (direct current) motors had to be used for solar power units because thephotovoltaic (PV) cells produce DC current. Since the power produced by the PVcells fluctuates with the intensity of the sunshine, it had to be used to chargebatteries first and then the batteries used to run the DC motors.
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2.SOLAR PHOTOVOLTAIC SYSTEM (PVS): 2.1 INTRODUCTION

Photovoltaic power generation is a method of producing electricity using solar cells.A solar cell converts solar optical energy directly into electrical energy. A solar cell is

essentially a semiconductor device fabricated in a manner which generates a voltagewhen solar radiation falls on it.

In semiconductor, atoms carry four electrons in the outer valence shell, some of which can be dislodged to move freely in the materials if extra energy is supplied.Then, a semiconductor attains the property to conduct the current. This is the basicprinciple on which the solar cell works and generates power.

2.2SOLAR CELLS:

Solar cells are the building block of PV system. . It is a form of photoelectric cell

which, when exposed to light, can generate and support an electric current without

being attached to any external voltage source.

Solar cells produce direct current electricity from sun light, which can be used to

power equipment or to recharge a battery.

The first practical application of photovoltaics was to power orbiting satellites and

other spacecraft, but today the majority of modules are used for grid connected

power generation. In this case an inverter is required to convert the DC to AC.

Cells require protection from the environment and are usually packaged tightly

behind a glass sheet. When more power is required than a single cell can deliver,

cells are electrically connected together to form photovoltaic modules, or solar

panels.

Solar cells are often electrically connected and encapsulated as a module .

Photovoltaic modules often have a sheet of glass on the front (sun up) side, allowing

light to pass while protecting the semiconductor wafers from abrasion and impact

due to wind-driven debris, rain, hail, etc. Solar cells are also usually connected in

series in modules, creating an additive voltage.

Connecting cells in parallel will yield a higher current; however, very significant

problems exist with parallel connections.

For example, shadow effects can shut down the weaker (less illuminated) parallel

string (a number of series connected cells) causing substantial power loss and even


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damaging the weaker string because of the excessive reverse bias applied to the

shadowed cells by their illuminated partners.

Strings of series cells are usually handled independently and not connected in

parallel, special paralleling circuits are the exceptions. The efficiency of a solar cell may be broken down into reflectance efficiency,

thermodynamic efficiency, charge carrier separation efficiency and conductive

efficiency. The overall efficiency is the product of each of these individual

efficiencies.

The cost of a solar cell is given per unit of peak electrical power.

High-efficiency solar cells are of interest to decrease the cost of solar energy. Many

of the costs of a solar power plant are proportional to the panel area or land area of

the plant.

A higher efficiency cell may reduce the required areas and so reduce the total plant

cost, even if the cells themselves are more costly.

Materials presently used for photovoltaic solar cells include monocrystalline silicon,

polycrystalline silicon, amorphous silicon, cadmium telluride, and copper indium

selenide .

Many currently available solar cells are made from bulk materials that are cut into

wafers between 180 to 240 micrometers thick that are then processed like other

semiconductors.

2.3 SEMICONDUCTOR MATERIALS FOR SOLAR CELLS:

2.3.1Monocrystalline silicon (c-Si):

Monocrystalline silicon often made using the Czochralski process. Single-crystal wafer

cells tend to be expensive, and because they are cut from cylindrical ingots, do not

completely cover a square solar cell module without a substantial waste of refined

silicon. Hence most c-Si panels have uncovered gaps at the four corners of the cells.

2.3.2Polycrystalline silicon or multicrystalline silicon, (poly-Si or mc-Si):

Polycrystalline silicon or multicrystalline silicon , (poly-Si or mc-Si):made from cast

square ingots large blocks of molten silicon carefully cooled and solidified. Poly-Si

cells are less expensive to produce than single crystal silicon cells, but are less


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The cells must be connected electrically to one another and to the rest of the

system. Popular photovoltaic panels, in terrestrial applications typically use MC3

(older) or MC4 connectors to facilitate easy weatherproof connections.

Cells must also be protected from mechanical damage and moisture. Most solarpanels are rigid, but semi-flexible ones are available, based on thin-film cells.

Electrical connections are made in series to achieve a desired output voltage and/or

in parallel to provide a desired current capability.

Depending on construction, photovoltaic panels can produce electricity from a range

of frequencies of light, but usually cannot cover the entire solar range (specifically,

ultraviolet, infrared and low or diffused light). Hence much of the incident sunlight

energy is wasted by solar panels, and they can give far higher efficiencies if

illuminated with monochromatic light.

Therefore, another design concept is to split the light into different wavelength

ranges and direct the beams onto different cells tuned to those ranges.This has been

projected to be capable of raising efficiency by 50%.

2.4.1 Crystalline silicon modules:

Most solar modules are currently produced from silicon photovoltaic cells. These aretypically categorized as monocrystalline or polycrystalline modules.

2.4.2 Rigid thin-film modules:-

In rigid thin film modules , the cell and the module are manufactured in the same

production line.

2.4.3 Flexible thin-film modules:-

Flexible thin film cells and modules are created on the same production line by

depositing the photoactive layer and other necessary layers on a flexible substrate .

2.5 SOLAR ARRAYS:

A photovoltaic array (or solar array ) is a linked collection of solar panels.


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The power that one 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 .

Most PV arrays use an inverter to convert the DC power produced by the modules

into alternating current that can power lights, motors, and other loads. The modules in a PV array are usually first connected in series to obtain the desired

voltage; the individual strings are then connected in parallel to allow the system to

produce more current. Solar panels are typically measured under STC (standard test

conditions) or PTC (PVUSA test conditions), in watts.

Typical panel ratings range from less than 100 watts to over 400 watts.The array

rating consists of a summation of the panel ratings, in watts, kilowatts, or

megawatts.

3. SOLAR TRACKER& MPPT:

A solar tracker is a device that orients various payloads toward the sun. Payloads can

be photovoltaic panels, reflectors, lenses or other optical devices.

3.1 Basic concept on Solar tracking system:-

Sunlight has two components, the "direct beam" that carries about 90% of the solar

energy, and the "diffuse sunlight" that carries the remainder - the diffuse portion is

the blue sky on a clear day and increases as a proportion on cloudy days.

As the majority of the energy is in the direct beam, maximizing collection requires

the sun to be visible to the panels as long as possible.

The energy contributed by the direct beam drops off with the cosine of the angle

between the incoming light and the panel. In addition, the reflectance (averaged

across all polarizations) is approximately constant for angles of incidence up to

around 50, beyond which reflectance degrades rapidly.

a. Types of Solar Tracker:

Photovoltaic trackers can be classified into two types: standard photovoltaic (PV)

trackers and concentrated photovoltaic (CPV) trackers.


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Beside these two again we can classified solar tracker in to two types considering its

axis: Single axis trackers & Dual axis trackers.

3.1.1 Non-concentrating photovoltaic (PV) trackers:-

In flat-panel photovoltaic (PV) applications, trackers are used to minimize the angle of

incidence between the incoming light and a photovoltaic panel.

This increases the amount of energy produced from a fixed amount of installed

power generating capacity.

In standard photovoltaic applications, it is estimated that trackers are used in at least

85% of commercial installations greater than 1MW from 2009 to 2012. Photovoltaic panels accept both direct and diffuse light from the sky. The panels on

standard photovoltaic trackers always gather the available direct light.

The tracking functionality in standard photovoltaic trackers is used to minimize the

angle of incidence between incoming light and the photovoltaic panel. This increases

the amount of energy gathered from the direct component of the incoming light.

3.1.2 Concentrated photovoltaic (CPV) trackers:-

In concentrated photovoltaic (CPV) and concentrated solar thermal (CSP) applications

trackers are used to enable the optical components in the CPV and CSP systems.

The optics in concentrated solar applications accept the direct component of sunlight

light and therefore must be oriented appropriately to collect energy.

Tracking systems are found in all concentrator applications because such systems do

not produce energy unless oriented closely toward the sun. The optics in CPV modules accept the direct component of the incoming light and

therefore must be oriented appropriately to maximize the energy collected. In low

concentration applications a portion of the diffuse light from the sky can also be

captured.

The tracking functionality in CPV modules is used to orient the optics such that the

incoming light is focused to a photovoltaic collector.


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CPV modules that concentrate in one dimension must be tracked normal to the sun in

one axis. CPV modules that concentrate in two dimensions must be tracked normal to

the sun in two axes.

I. Single axis trackers:-

Single axis trackers have one degree of freedom that acts as an axis of rotation. The

axis of rotation of single axis trackers is typically aligned along a true North

meridian. It is possible to align them in any cardinal direction with advanced

tracking algorithms. There are several common implementations of single axis trackers. These include

horizontal single axis trackers (HSAT), vertical single axis trackers (VSAT), tilted

single axis trackers (TSAT) and polar aligned single axis trackers (PSAT).

The orientation of the module with respect to the tracker axis is important when

modeling performance.

II. Horizontal single axis tracker (HSAT):-

The axis of rotation for horizontal single axis tracker is horizontal with respect to the

ground. The posts at either end of the axis of rotation of a horizontal single axis

tracker can be shared between trackers to lower the installation cost.

Field layouts with horizontal single axis trackers are very flexible.

The simple geometry means that keeping all of the axis of rotation parallel to one

another is all that is required for appropriately positioning the trackers with respectto one another.

Horizontal trackers typically have the face of the module oriented parallel to the axis

of rotation. As a module tracks, it sweeps a cylinder that is rotationally symmetric

around the axis of rotation.

In single axis horizontal trackers, a long horizontal tube is supported on bearings

mounted upon pylons or frames.


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The axis of the tube is on a north-south line. Panels are mounted upon the tube, and

the tube will rotate on its axis to track the apparent motion of the sun through the

day.

III. Vertical single axis tracker (VSAT):-

The axis of rotation for vertical single axis trackers is vertical with respect to the

ground. These trackers rotate from East to West over the course of the day. Such

trackers are more effective at high latitudes than are horizontal axis trackers.

Field layouts must consider shading to avoid unnecessary energy losses and to

optimize land utilization. Also optimization for dense packing is limited due to the

nature of the shading over the course of a year.

Vertical single axis trackers typically have the face of the module oriented at an angle

with respect to the axis of rotation. As a module tracks, it sweeps a cone that is

rotationally symmetric around the axis of rotation.

IV. Tilted single axis tracker (TSAT):-

All trackers with axes of rotation between horizontal and vertical are considered

tilted single axis trackers. Tracker tilt angles are often limited to reduce the wind

profile and decrease the elevated ends height off the ground.

Field layouts must consider shading to avoid unnecessary losses and to optimize land

utilization.

With backtracking, they can be packed without shading perpendicular to their axis of

rotation at any density. However, the packing parallel to their axis of rotation is

limited by the tilt angle and the latitude.

Tilted single axis trackers typically have the face of the module oriented parallel to

the axis of rotation. As a module tracks, it sweeps a cylinder that is rotationally

symmetric around the axis of rotation.

V. Polar aligned single axis trackers (PASAT):-


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This method is scientifically well known as standard method mounting a structure whichsupports a telescope. The tilted single axis is aligned to the polar star.

It is therefore called polar aligned single axis tracker (PASAT). In this particular

implementation of a tilted single axis tracker the tilt angle is equal to the latitude of theinstallation. This aligns the tracker axis of rotation with the earths axis of rotation.

VI. Dual axis trackers:-

Dual axis trackers have two degrees of freedom that act as axes of rotation. These

axes are typically normal to one another. The axis that is fixed with respect to the

ground can be considered a primary axis. The axis that is referenced to the primary

axis can be considered a secondary axis.

There are several common implementations of dual axis trackers. They are classified

by the orientation of their primary axes with respect to the ground.

Two common implementations are tip-tilt dual axis trackers (TTDAT) and azimuth-

altitude dual axis trackers(AADAT).

Dual axis trackers allow for optimum solar energy levels due to their ability to follow the sun

vertically and horizontally. No matter where the sun is in the sky, dual axis trackers are able

to angle themselves to be in direct contact with the sun.

VII. Tip tilt dual axis tracker (TTDAT):-

A tip tilt dual axis tracker is so-named because the panel array is mounted on the tip of along pole. Normally the east-west movement is driven by rotating the array around the top

of the pole.

On top of the rotating bearing is a T- or H-shaped mechanism that provides vertical

rotation of the panels and provides the main mounting points for the array. The posts

at either end of the primary axis of rotation of a tip tilt dual axis tracker can be

shared between trackers to lower installation costs.

Field layouts with tip tilt dual axis trackers are very flexible. The simple geometry

means that keeping the axes of rotation parallel to one another is all that is required

for appropriately positioning the trackers with respect to one another.


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Normally the trackers would have to be positioned at fairly low density in order to

avoid one tracker casting a shadow on others when the sun is low in the sky. Tip-tilt

trackers can make up for this by tilting closer to horizontal to minimize up-sun

shading and therefore maximize the total power being collected. The axes of rotation of tip tilt dual axis trackers are typically aligned either along a

true north meridian or an east west line of latitude. It is possible to align them in any

cardinal direction with advanced tracking algorithms.

VIII. Azimuth-altitude dual axis tracker (AADAT):-

An azimuth altitude dual axis tracker has its primary axis vertical to the ground. Thesecondary axis is then typically normal to the primary axis.

They are similar to tip-tilt systems in operation, but they differ in the way the array isrotated for daily tracking. Instead of rotating the array around the top of the pole, AADAT

systems typically use a large ring mounted on the ground with the array mounted on a series

of rollers.

The main advantage of this arrangement is the weight of the array is distributed over aportion of the ring, as opposed to the single loading point of the pole in the TTDAT.

This allows AADAT to support much larger arrays. Unlike the TTDAT, however, the AADATsystem cannot be placed closer together than the diameter of the ring, which may reduce

the system density, especially considering inter-tracker shading.

3.2 Maximum power point tracking:

Maximum power point tracking (MPPT) is a technique that grid tie inverters, solar

battery chargers and similar devices use to get the maximum possible power from

one or more solar panels.

Solar cells have a complex relationship between solar irradiation, temperature and

total resistance that produces a non-linear output efficiency known as the I-V curve.


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It is the purpose of the MPPT system to sample the output of the cells and apply the

proper resistance (load) to obtain maximum power for any given environmental

conditions.

Figure 3.1 I-V curve

Photovoltaic cells have a complex relationship between their operating environment

and the maximum power they can produce.

The fill factor, abbreviated FF , is a parameter which characterizes the non-linear

electrical behavior of the solar cell. Fill factor is defined as the ratio of the maximum

power from the solar cell to the product of Open Circuit Voltage V oc and Short-Circuit Current I sc.

For any given set of operational conditions, cells have a single operating point where

the values of the current (I) and Voltage (V ) of the cell result in a maximum power

output.

These values correspond to a particular load resistance, which is equal to V / I as

specified by Ohm's Law. The power P is given by P=V*I. A photovoltaic cell has an

approximately exponential relationship between current and voltage.
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From basic circuit theory, the power delivered from or to a device is optimized

where the derivative (graphically, the slope) dI/dV of the I-V curve is equal and

opposite the I/V ratio (where d P/dV =0). This is known as the maximum power point

(MPP) and corresponds to the "knee" of the curve.

A load with resistance R=V/I equal to the reciprocal of this value draws the maximum

power from the device. This is sometimes called the characteristic resistance of the

cell.

This is a dynamic quantity which changes depending on the level of illumination, as

well as other factors such as temperature and the age of the cell. If the resistance is

lower or higher than this value, the power drawn will be less than the maximumavailable, and thus the cell will not be used as efficiently as it could be.

Maximum power point trackers utilize different types of control circuit or logic to

search for this point and thus to allow the converter circuit to extract the maximum

power available from a cell.

4. SOLAR POWER SYSTEM:

Solar power system can be classified as following types depending on the connection

to the system

1.On grid system

2.Off grid system(Stand-alone system)
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fossil fuels. Even though the sun doesn't always shine, any installation gives a

reasonably predictable average reduction in carbon production and use.

4.2 Off-grid sytem:-

The term off-grid refers to not being connected to a grid, mainly used in terms of

not being connected to the main or national transmission grid in electricity. In

electricity off-grid can be stand-alone systems (SHS) or mini-grids typically to

provide a smaller community with electricity. Off-grid electrification is an

approach to access electricity used in countries and areas with little access to

electricity, due to scattered or distant population. It can be any kind of electricity

generation. The term off-the-grid (OTG) can refer to living in a self-sufficient

manner without reliance on one or more public utilities.

Figure 4.3 off-grid PV system with battery charger

5. Charge controller:

A charge controller , charge regulator or battery regulator limits the rate at which

electric current is added to or drawn from electric batteries.The terms "charge

controller" or "charge regulator" may refer to either a stand-alone device, or to control


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circuitry integrated within a battery pack, battery-powered device, or battery recharger.

It prevents overcharging and may prevent against overvoltage, which can reduce battery

performance or lifespan, and may pose a safety risk. It may also prevent completely

draining ("deep discharging") a battery, or perform controlled discharges, depending onthe battery technology, to protect battery life.

5.1 TYPES OF CHARGE CONTROLLER:

Solar charge controller basically divided in to two types : stand alone charge

controller & integrated charge controller.

Stand-alone charge controllers:

I. Charge controllers are sold to consumers as separate devices, often in

conjunction with solar or wind power generators, for uses such as RV, boat,

and off-the-grid home battery storage systems.

II. In solar applications, charge controllers may also be called solar regulators.

Some charge controllers / solar regulators have additional features, such as a

low voltage disconnect, a separate circuit which powers down the load when

the batteries become overly discharged.

III. A series charge controller or series regulator disables further current flow

into batteries when they are full.

IV. A shunt charge controller or shunt regulator diverts excess electricity to an

auxiliary or "shunt" load, such as an electric water heater, when batteries are

full.

V. Simple charge controllers stop charging a battery when they exceed a set

high voltage level, and re-enable charging when battery voltage drops back

below that level.

VI. Pulse width modulation (PWM) and maximum power point tracker (MPPT)

technologies are more electronically sophisticated, adjusting charging rates

depending on the battery's level, to allow charging closer to its maximum

capacity.


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VII. Charge controllers may also monitor battery temperature to prevent

overheating. Some charge controller systems also display data, transmit data

to remote displays, and data logging to track electric flow over time.

Integrated charge controller circuitry :-

I. Circuitry that functions as a charge regulator controller may consist of several

electrical components, or may be encapsulated in a single microchip, anintegrated circuit (IC) usually called a charge controller IC.

II. Charge controller circuits are used for rechargeable electronic devices such as

cell phones, laptop computers, portable audio players, and uninterruptible

power supplies, as well as for larger battery systems found in electric

vehiclesand orbiting space satellites.

III. Charge controller circuitry may be located in the battery-powered device, in a

battery pack for either wiredor wireless [(inductive) charging, inline with the

wiring, or in the AC adapter or other power supply module.

Modern multi-stage charge controllers:

Most quality charge controller units have what is known as a 3 stage charge

cycle that goes like this :

1)BULK:- During the Bulk phase of the charge cycle, the voltage gradually rises to

the Bulk level (usually 14.4 to 14.6 volts) while the batteries draw maximum

current. When Bulk level voltage is reached the absorption stage begins.

2)ABSORPTION:- During this phase the voltage is maintained at Bulk voltage level

for a specified time (usually an hour) while the current gradually tapers off as the

batteries charge up.


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3)FLOAT:- After the absorption time passes the voltage is lowered to float level

(usually 13.4 to 13.7 volts) and the batteries draw a small maintenance current

until the next cycle.

Figure 5.1 Block diagram of charge controller

5.1.1 How it Works:-

I. The principle behind a solar charge controller is simple. There is a circuit to measure

the battery voltage, which operates a switch to divert power away from the battery

when it is fully charged.

II. Because solar cells are not damaged by being short or open-circuits, either of these

methods can be used to stop power reaching the battery.

III. A controller which short-circuits the panel is known as a shunt regulator , and that

which opens the circuit as a series regulator .


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IV. Optionally there may also be a switch which automatically disconnects the power

from the appliances or loads when the battery voltage falls dangerously low. This is

known as a low-voltage disconnect function.

Figure 5.2 circuit diagram of charge controller

6. LOCATION:

INDIC Institute is situated in the southern most side of chandaka reserve forest at Muktapur

village, Khurda District ODISHA. INDIC Institute is a B-Tech engineering college (approved by

AICTE and affiliated to BPUT).The location of the site is shown in the Exhibit I.


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7. SITE DESCRIPTION:

The western side of college building Is open space. The lay out of the space is shown in the

Exhibit II. An area of about 150 sq f. is vacant which could be used for SPV installation of

2.4 kWp. It is proposed to utilize the vacant area available on the western for installation of

2.4 kWp which could serve as a grid connected demonstration system and could be used for

collection of data for analysis on the of availability of solar power.

8. EXISTING POWER SUPPLY ARRANGEMENTS:

8.1 SESU SUPPLY

The power requirement for INDIC institute is nearly 180 kva. The power received at 11

kV level and step down to 440 V.

8.2 EMERGENCY POWER SUPPLY

DG set of 1x180 kVA capacity has been installed for providing back up supply to

important services like lifts, corridor lights, chairman & Members office and essentiallighting in the building during the period of load shedding.

9. FUNCTIONAL DESCRIPTION OF SPV POWER SYSTEM:

9.1 The solar PV system shall be designed with either mono/ poly crystalline silicon

modules or using thin film photovoltaic cells or any other superior technology having

higher efficiency.

9.2 Three key elements in a solar cell form the basis of their manufacturing technology.

The first is the semiconductor, which absorbs light and converts it into electron-hole

pairs. The second is the semiconductor junction, which separates the photo-generated

carriers (electrons and holes), and the third is the contacts on the front and back of the

cell that allow the current to flow to the external circuit. The two main categories of


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technology are defined by the choice of the semiconductor: either crystalline silicon in

a wafer form or thin films of other materials.

9.3 The grid interactive roof top solar PV system generally comprises the following

equipment.

I. SPV Power Source

II. Inverter (PCU)

III. Mounting Structure

IV. AC and DC Cables

V. Earthing equipment /material

VI. Junction Boxes or combiners

VII. Instruments and protection equipment

9.4 Photovoltaic solar system use the light available from the sun to generate electricityand feed this into the main electricity grid or load as the case may be. The PV panels

convert the light reaching them into DC power. The amount of power they produce is

roughly proportional to the intensity and the angle of the light reaching them. They are

therefore positioned to take maximum advantage of available sunlight within siting

constraints. Maximum power is obtained when the panels are able to 'track' the sun's

movements during the day and the various seasons. However, these tracking

mechanisms tend to add a fair bit to the cost of the system, so a most of installations

either have fixed panels or compromise by incorporating some limited manual

adjustments, which take into account the different 'elevations' of the sun at various

times of the year. The best elevations vary with the latitude of the load location.

9.5 The power generating capacity of a photovoltaic system is denoted in Kilowatt peak

(measured at standard test conditions of solar radiation of 1000 W per m2). A common

rule of thumb is that average power is equal to 20% of peak power, so that each peak


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kilowatt of solar array output power corresponds to energy production of 4.8 kWh per

day (24 hours x 1 kW x 20% = 4.8 kWh)

9.6 Solar photovoltaic modules can be developed in various combinations depending upon

the requirements of the voltage and power output to be taken from the solar plant.

No. of cells and modules may vary depending upon the manufacturer prudent practice

10. SOLAR INVERTER:

I. A controller which short-circuits the panel is known as a shunt regulator , and

that which opens the circuit as a series regulator .

II. Optionally there may also be a switch which automatically disconnects the

power from the appliances or loads when the battery voltage falls

dangerously low. This is known as a low-voltage disconnect function.

III. It is a critical component in a photovoltaic system, allowing the use of

ordinary commercial appliances. Solar inverters have special functions

adapted for use with photovoltaic arrays, including maximum power point

tracking and anti-islanding protection.

IV. Many different types of inverter can be used in a solar power system. There

are dedicated inverters for solar power available, but what's important is that

the correct inverter is used for the job it has to do.

V. This job is converting a certain amount of power from low voltage DC to 230

Volts AC to power mains appliances. The right inverter will deliver enough

power but will be no bigger than necessary, and will have the right output

waveform .

10.1 Classification:-

Solar inverters may be classified into three broad types: standalone inverters, grid

tied inverters & battery backup inverters.

1. Stand-alone inverters :-


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I. Stand-alone inverters , used in isolated systems where the inverter draws its DC

energy from batteries charged by photovoltaic arrays.

II. Many stand-alone inverters also incorporate integral battery chargers to replenish

the battery from an AC source, when available. Normally these do not interface inany way with the utility grid, and as such, are not required to have anti-islanding

protection.

III. Unlike grid-tie inverters, stand-alone inverters use batteries for storage.As these

types of inverters are not connected to the grid, they do not have anti-islanding

protection equipments.

IV. As there is a risk of back-feed from the load, circuit breakersare provided at the load

side for protection.Stand-alone inverter power ratings range from about 250 W to

5000 W for residential systems and if the power output is greater than the individual

inverter rating, many inverters can be connected.

V. Battery banks connected to the inverters operate at 12 V, 24V or 48V so that the

inverter can operate at hundreds of amps of current at full load. In stand-alone

inverters, the installers usually must install the dc main bonding jumper as most

inverters do not have the arrangement.

Applications Of Standalone inverter:

I. Stand-alone inverters are mostly used in conjunction with renewable energy sources

like solar panels or wind turbines powering residential and industrial buildings in

remote locations.

II. They are also used in battery operated vehicles and electric boats where AC power is

required for the operation.

2. Grid-tie inverters:

I. Grid-tie inverters are designed to shut down automatically upon loss of utility supply,

for safety reasons. They do not provide backup power during utility outages.

II. A grid-tie inverter (GTI) or synchronous inverter is a special type of power inverter

that converts direct current (DC) electricity into alternating current (AC) and feeds it

into an existing electrical grid.


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III. GTIs are often used to convert direct current produced by many renewable energy

sources, such as solar panels or small wind turbines, into the alternating current

used to power homes and businesses.

IV. The technical name for a grid-tie inverter is "grid-interactive inverter". Grid-interactive inverters typically cannot be used in standalone applications where utility

power is not available.

V. During a period of overproduction from the generating source, power is routed into

the power grid, thereby being sold to the local power company. During insufficient

power production, it allows for power to be purchased from the power company.

Typical operation of grid-tie system:-

I. Inverters take DC power and invert it to AC power so it can be fed into the electric

utility company grid. The grid tie inverter must synchronize its frequency with that of

the grid (e.g. 50 or 60 Hz) using a local oscillator and limit the voltage to no higher

than the grid voltage.

II. A high-quality modern GTI has a fixed unity power factor, which means its output

voltage and current are perfectly lined up, and its phase angle is within 1 degree of

the AC power grid.

III. The inverter has an on-board computer which will sense the current AC grid

waveform, and output a voltage to correspond with the grid.

IV. Grid-tie inverters are also designed to quickly disconnect from the grid if the utility

grid goes down. This is a requirement that ensures that in the event of a blackout,

the grid tie inverter will shut down to prevent the energy it produces from harming

any line workers who are sent to fix the power grid.

V. Properly configured, a grid tie inverter enables a home owner to use an alternative

power generation system like solar or wind power without extensive rewiring and

without batteries.

VI. If the alternative power being produced is insufficient, the deficit will be sourced

from the electricity grid.

VII. The inverters may use the newer high-frequency transformers, conventional low-

frequency transformers, or without transformer.


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VIII. Instead of converting direct current directly to 120 or 240 volts AC, high-frequency

transformers employ a computerized multi-step process that involves converting the

power to high-frequency AC and then back to DC and then to the final AC output

voltage.

How an Inverter works:-

I. Most people are familiar with the idea of a transformer . A transformer is a device

that converts one voltage into another, so why do we need an inverter? Well the

problem with a transformer is that it can only work with alternating current or AC.

The power from the battery in a solar power system is direct current or DC.

II.

Roughly, what an inverter does is to turn this DC into AC by rapid transistorisedswitching, and then use a transformer to convert it to the correct AC voltage.

III. Depending on how this is done, the result can be either a sine wave like the mains or

a modified sine wave which approximates to the mains.

b. PROTECTION AND CONTROL:

I. Inverter shall be provided with islanding protection to isolate it from the grid in case

of no supply, under voltage and over voltage conditions so that in no case there is any

chance of accident.

II. In addition to above, PV systems shall be provided with adequate rating fuses, fuses

on inverter input side (DC) as well as output side (AC) side for overload and short

circuit protection and disconnecting switches to isolate the DC and AC system for

maintenances are needed.

III. Fuses of adequate rating shall also be provided in each solar array module to protect

them against short circuit

11. ARRANGEMENT :


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The general layout arrangement of the SPV panels is shown in the drawing given at

Exhibit III and installation details of the panels are shown in the Exhibit IV.

12. ESTIMATES OF COST:

Based on the normative cost adopted by CERC the cost is estimated as Rs.1.77 Lakh.

13. PROCEDURE TO INSTALL A SOLAR POWER PLANT:

There are seven steps involved in designing a successful solar PV installation

Scoping of the project

Calculating the amount of solar energy available

Surveying the site

Calculating the amount of energy needed

Sizing the solar system

Component selection and costing

Detailed design

Step 1 Scoping of the project

I. As with any project, you need to know what you want to achieve. This basically

involves detailing what you want from the captive PV installation, once installed.

II. Do you want it to completely provide your day time electricity usage? Or do you

want it to support a part of your usage? To start with, the scope of the project can

be simple and later as we progress we can flesh it out to suit the requirements.

III. Defining the scope is in fact the most important step because once the basic scope iswrong, we might not be able to get the system do, what we exactly want it to do.


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Step2 - Calculating the amount of solar energy available

I. Solar insolation is the amount of electromagnetic energy (solar radiation) incident on

the surface of the earth. Basically that means how much sunlight is shining down on

the area under consideration.

II. The values are generally expressed in kWh/m 2/day. This is the amount of solar

energy that strikes a square metre of the earth's surface in a single day. Of course

this value is averaged to account for differences in the days' length. There are

several units that are used throughout the world.

III. By knowing the insolation levels of a particular region one can determine the

number of PV modules that are required. An area with poor insolation levels willneed a larger number of PV modules than an area with high insolation levels. Once

the regions insolation level is known, one can more accurately calculate collector

size and energy output.

IV. The typical thumbrule that is used for the amount of electricity that solar PV can

produce is as follows: On average, 1 W of solar PV, at current crystalline silicon panel

efficiencies, can produce about 4 Wh of electricity per day. This is however only an

average estimate and based on the location, this could be a bit lower or higher thanthe average.

Step 3 Surveying the site

I. A site survey basically consists of a brief interview with the developer to get a feel

for their electricity needs and a physical inspection of the proposed array site to see

if it is suitable for solar. When a qualified photovoltaic design professional visits a

potential solar site, he or she has many things to watch out for.

II. Primarily, they will be checking the roof's orientation (azimuth) and solar access.

Orientation refers to the direction the roof faces - directly south is ideal, with some

leeway to the Southwest or Southeast.

III. Solar access quantifies the percentage of time when the proposed array location will

be receiving the full unshaded power of the sun during different days of the year.

IV. A shady roof might disqualify a site from receiving incentive money from the state,

and is not a responsible choice for solar anyway. There are ways to get around shade


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issues - either by looking at alternate sites, trimming or removing trees, or by using

micro-inverters in the system design rather than one large central inverter.

Step 4 - Calculating the amount of energy needed

I. The next big task for any photovoltaic system designer is to determine the

system load. This load estimate is one of the key factors in the design and cost of

the stand-alone PV system.

II. A simple way to determine the approximate ceiling for the solar PV system

capacity for all electricity needs is as follows:

1. Find out your total monthly electricity consumption. Lets say it is 100000 kWh

2. Divide it by 30 to get an approximate daily consumption. In the example, it is

about 3300 kWh.

3. Using the thumb rule that 1 W of solar PV can approximately produce 4 Wh of

electricity per day, you can determine the approximate maximum solar PV capacity

you will require to power all your systems using solar PV. In this case, if the total

daily consumption of electricity is 3300 kWh, you will require a maximum of 3300/4

= 825 kW.

4. It is however very unlikely that you would require such a high capacity for solar

PV as you will need solar PV primarily as a backup power source, perhaps as a

replacement for diesel based power generation.

Ceiling for the solar PV required for complete diesel replacement

5. In most cases, you will be using solar only as a backup power source to replace

diesel based power production.

6. One simple way to determine the amount of solar PV for this purpose is to determine

the total amount of electricity you produce using diesel every month. In the example

provided, out of the 100000 kWh of total electricity you consume every month, lets


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say 10% or 10000 kWh is generated from diesel gensets. This provides you the ceiling

for the solar PV system capacity for complete diesel replacement. In this case, it is 82.5

kW.

7. As a thumb rule, one litre of diesel produces 4 kWh, so you can also compute theabove with the data for the amount of diesel used every month.

While estimating the load, the designer should consider energy conserving

substitutes for items that are used often. Identifying large and/or variable loads and

determining if they can be eliminated or changed to operate from another power

source will save cost.

Step 5 Sizing the system

From the results obtained in step 2 and step 4, we can determine the size of the

solar system that will be needed to power the site. The necessary systems involved

in the setting up of captive power plants are:

1) Array(collection of solar PV modules)

2) Charge controllers

3) Batteries

4) Inverters

5) Mounting systems

PV array sizing Array sizing is determined by taking into account the daily energy

requirement (in Kilowatt hours) and average daily peak sunshine hours in the design month.

No part of a PV array can be shaded. The shading of small portions of a PV module

may greatly reduce output from the entire array. PV modules connected in series

must carry the same current.


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If some of the PV cells are shaded, they cannot produce current and will become

reverse biased. This means the shaded cells will dissipate power as heat, and over a

period of time failure will occur.

However, since it is impossible to prevent occasional shading, the use of by passdiodes around series - connected modules is recommended.

Controllers - Charge controllers are included in most photovoltaic systems to protect the

batteries from overcharge or excessive discharge.

Overcharging can boil the electrolyte from the battery and cause failure. Allowing

the battery to be discharged too much will cause premature battery failure and

possible damage to the load.

The controller is a critical component in your PV system. Thousands of rupees of

damage may occur if it does not function properly. In addition, all controllers cause

some losses (tare loss) in the system. One minus these losses, expressed as a

percentage, is the controller efficiency.

The cost of the controller increases rapidly as the current requirement increases.

Controllers for 12-volt and 24-volt systems with currents up to 30 amperes are

available at a reasonable cost. Controllers with 30- 100 amperes are available but 2-5

times more expensive. Controllers that will switch currents over 100 amperes are

usually custom designed for the application. One way to work with currents over 100

amperes is to connect controllers in parallel. It is often less expensive to use five 20-

ampere rated controllers in parallel than one 100-ampere unit.

The controller must be installed in a weather resistant junction box and can be

located with other components such as diodes, fuses, and switches. Excessive heat

will shorten controller lifetime so the junction box should be installed in a shaded

area and venting provided if possible.

Controllers should not be mounted in the same enclosure with batteries. The

batteries produce a corrosive environment that may cause failure of electronic

components.


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Battery sizing - To determine the size of the battery storage required for a stand-

alone PV system, it is required to make a number of decisions.

Before making these choices, one should study and understand battery parameters

and the concept of system availability. First, you must choose the amount of back-up

energy you want to store for your application.

This is usually expressed as a number of no sun days, in other words, for how many

cloudy days must your system operate using energy stored in batteries. There is no

right answer to this question. It depends on the application, the type of battery,

and the system availability desired.

Inverters - Power conditioning units, commonly called inverters, are necessary in any

stand-alone PV system with ac loads. The choice of inverter will be a key factor in

setting the dc operating voltage of your system.

When specifying an inverter, it is necessary to consider requirements of both the dc

input and the ac output. The choice of inverter will affect the performance,

reliability, and cost of your PV system. Usually, it is the third most expensive

component after the array and battery.

The selection of the inverter input voltage is an important decision because it often

dictates the system dc voltage .

An inverter should be installed in a controlled environment because high

temperatures and excessive dust will reduce lifetime and may cause failure.

The inverter should not be installed in the same enclosure with the batteries

because the corrosive gassing of the batteries can damage the electronics and the

switching in the inverter might cause an explosion. However, the inverter should be

installed near the batteries to keep resistive losses in the wires to a minimum.

Mounting structures- Ground mounting of PV arrays is recommended for stand-

alone systems. Regardless of whether you buy or build the mounting structure make

sure it is anchored and the modules are restrained.


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Many module manufacturers and distributors sell mounting hardware specifically

designed for their modules.

This hardware is intended for multiple applications and different mounting

techniques and considerations like wind loading have been included in the design.Using this mounting hardware is the simplest and often the most cost effective.

Customized array mounting structures can be expensive.

Others- It is important to select wire, connectors, and protection components such

as switches and fuses that will last for twenty years or more.

To obtain this long life, they must be sized correctly, rated for the application, and

installed carefully. Connections are particularly prone to failure unless they are

made carefully and correctly.

Step 6 Component selection and costing

Once the various components have been sized, the next important step is the

selection and costing of the components.

There are many players in the market vying to establish their products. At

thisjuncture, the system developer has to select components by taking into account

factors like technical specifications, reliability, and lifetime of the components in

addition to the cost.

Investment for the solar modules is for a period of 25 years, so selecting a high

efficient solar panel is of prime importance. The manufactures of the batteries claim

a lifetime of about 7 years, whereas inverters guarantee at most 2 years. As can be

seen from these numbers, selection becomes a crucial part of the captive solar PV

installation.

Step 7 Detailed design


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Now that the major components have been sized and selected, it is time to consider

how to interconnect everything as a working system.

The detailed design is the more actionable form of the captive solar PV installation.

The system developer accumulates all the data collected from the previous 6 stepsand prepares a layout of the installation on paper. The developer removes obvious

engineering fallacies and prepares a corrected version of the layout on paper.

The confirmed design will have all the necessary data like the average consumption

per day(kWh), the insolation levels at the area under consideration(in hours) , the

optimal plant size, the area required for the same, the number of panels required to

be installed in that area, the number of charge controllers, batteries, inverters

required for the determined plant size, the cost of all the components and many

more intricate details like the viability of installing tracking systems etc.

Stand-alone PV systems will be reliable power producers for more than two decades

if properly sized for the application, engineered well, and installed carefully. PV

arrays for stand-alone systems are installed in many unique and innovative ways.

However, there are common issues involved in any installation, whether the array is

fixed or tracking, mounted at ground level, or on a pole or building.

14. Preventive Maintenance

The integral part of any completed installation is the periodic checks that are

recommended for any stand-alone PV system so that little problems can be found

and corrected before they affect system operation. The system should be checked

soon after installation when it is presumably operating well.


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CONCLUSION:

Power generation & efficient distribution is the prime need of the day.

To explore the new avenues to sustain the ever increasing demands is the present

challenge.

This is a provoking seminar topic. To make this type of topic is really feasible for us. I

wish this topic motivate you all and made us think for our future generation.


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REFERENCE:

Butti, Ken; Perlin, John (1981). A Golden Thread (2500 Years of Solar Architecture and Technology) .

Van Nostrand Reinhold. Carr, Donald E. (1976). Energy & the Earth Machine . W. W. Norton& Company.

Halacy , Daniel (1973). The Coming Age of Solar Energy . Harper and Row.

www.wikipedia.com/solarenergy
http://www.wikipedia.com/solarenergyhttp://www.wikipedia.com/solarenergyhttp://www.wikipedia.com/solarenergy

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