Solar Energy

Solar Energy
(The Ultimate Renewable Energy
Resource)
Representators:
• Muhammad Imran (Roll No-11380)
• Danyal Anjum (Roll No-9715)
• Muhammad Asqalan (Roll No-9408)
• Talha Pervaiz (Roll No-10663)

What’s solar energy?
• Solar energy originates with the thermonuclear fussion reactions
occurring in the sun.
• Represents the entire electromagnetic radiation(visible
light,infrared,ultraviolet,x-rays and radio waves).
• This energy consists of radiant light and heat energy from the sun.
• Out of all energy emitted by sun only a small fraction of energy is
absorbed by the earth.
• Just this tiny fraction of sun’s energy is enough to meet all our power
needs.
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How much Solar energy?
The surface receives about total 47% of the total solar energy that reaches the
earth only this amount is usable.
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Defination:
• The most precise definition is that energy from the sun.
• It is the radiation from the sun that is capable of producing
heat,cause chemical reaction or generating electricity.
• It is the largest source of energy received on earth,but its intensity on
the earths surface is very low.
• Solar energy is becoming the ultimate source because of its non-
polluting character.
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Even the energy demand met by using solar energy is very less
but this is increasing in present time.
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Why Solar Energy?
• The fossils fuel are non-renewable energy resources so we can not
depend on them forever.
• No harmful emissions are released into the air when electricity is
produced by solar panels.
• It is non-polluting and silent source of electricity and also low
maintenance and long lasting energy.
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Electricity from Solar Energy:
• Solar power is described as conversion of sunlight into
electricity.Sunlight could be changed into electricity
with the use of
-Directly using PV or Photovoltaics
-Indirectly by CSPs
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Photovoltaics:
• Converting solar energy directly into electrical energy.
• Devices used are called solar panels.
• Solar panel is a group of solar cells.
• Solar cell works on the principle of photoelectric effect.
8

Structure of a Solar Cell:
A typical solar cell is a multi-layered unit consisting of a:
• Cover-a clear glass or plastic layer that provide outer protection from the
elements.Transparent adhesives holds the glass to the rest of the solar cell.
• Anti-reflective coating-This substance us designed to prevent the light that
strikes the cell from bouncing off soo that the maximum energy is absorbed
into the cell.
• Front contact-Transmits the electric current.
• N-type semi-conductor layer-This is the thin layer of silicon which has been
mixed(process called doping) with phosphorus.
• P-type semi-conductor layer-This is the thin layer of silicon which has been
mixed or bored with boron.
• Back Contact-Transmits the electric current. 9

Working of a Solar Cell:
• Photoelectric Effect
oWhen a light of certain frequency falls on the surface of metal Electrons
will absorb the energy.
oIf incident energy is greater than the work function of the metal then
the photo electrons wil be emmited and
oExcess energy is converted into the kinetic energy of electron.
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oWhen solar panels are placed in the sunlight,photons will strike the
surface and emits electrons.
oAs a result electron hole pair is created in the solar cell.
oWhen external circuit is connected to the solar cell,electrons flow in the
circuit and the current is generated.
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Types of Solar Electric Systems:
The stand alone system
• Stand alone or off-grid solar power system consists of solar panels and a
battery bank.
• Used in rural areas and regions where there is no access to the utility grid.
• Very good at giving economical electricity.
Grid-tie solar system
• Very useful for homes that are already linked to the utility grid.
• Primary advantage is the cheap process of utility.
• The system used to be weired with an inverter that creates ac
electricity,which is needed for linking to the utility grid.
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Stand alone or Off grid solar system:
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Grid-connected solar system:
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Uses of Solar Energy:
• Heaters
• Cars
• Lights
• Satellites
• Dryers
• Calculators
Commercial Use:
• On an office building,roof areas can be covered with solar panels.
• Remote buildings such as schools,communities can make use of solar energy.
• In developing countries,this solar panels are very much useful.
• Even on the highways,for every five kilometers solar telephones are used.
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Applications of Solar Energy:
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Developing Solar Panel in Pakistan:
• In Pakistan about 65% of the population lives in some 50,000 villages dispersed
around the country.
• Many of the villages are far from the main transmission lines of the national grid
because of their relatively small population.
• It is not usually economically viable to connect these villages to grid.
• Solar energy has great potential in areas of Pakistan that receive high solar
radiation throughout the year.
• For e.g 19 mega joules of solar energy per square meter is received everyday.
• The nation wide average is 5.5 kwh/mess/day.
• Enough energy potential for solar energy because there are 250-300 sunny days
per year.
• Continuos cloudy days are rare.
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Advantages Of Solar Power:
Advantage To Pakistan:
• The power source of sun is absolutely free.
• The production of solar energy produces no pollution.
• The technological advancements in solar energy systems have made them extremely
cost effective.
• Most systems do not require any maintenance during their lifespan,which means you
never have to put money into them.
• Solar energy systems are now designed for particular needs.for instance,you convert
your outdoor lighting to solar.the solar cells are directly on the lights and can’t be
seen by anyone.at the same time,you eliminate all costs associated with running your
outdoor lighting.
• Solar energy can be used in remote areas where it is soo expensive to extend the
electricity power grid.
• It is estimated that the world oil reservers will last for upcoming some years.on the
other hand solar energy is infinite(forever) till sun. 19

Advantages Of Solar Power:
Advantage To Pakistan:
• Solar energy can be used in remote areas where it is soo expensive to
extend the electricity power grid.
• It is estimated that the world oil reservers will last for upcoming some
years.on the other hand solar energy is infinite(forever) till sun.
• Solar cells are long lasting sources of energy which can be used
almost anywhere.
• Solar cells are also totally silent.
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Disadvantages of Solar Energy:
• Location-the location of solar panels is of major importance in the
generation of electricity.Areas which remains mostly cloudy and foggy will
produce electricity but at a reduced rate and may require more panels to
generate enough electricity homes.Houses which are covered by
trees,landscapes or other buildings may not be suitable enough to
produce solar power.
• Pollution-most of the photovoltaic panels are made up of silicon and other
toxic metals like mercury,lead and cadmium.Pollution in the environment
can also degrade the quantity and efficiency of photovoltaics cells.New
innovative technologies can overcome the worst of these effects
• Reliability-unlike other renewable source which can also be operated
during night,solar panels prove to be useless during night which means
you have to depend on the local utility grid to draw power in the night.
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• Inefficency-since not all the light from the sun is absorbed by the solar panels
therefore most solar panels have a 40% efficiency rate which means 60% of the
sunlight gets wasted and is not harnessed.
• Installation areas-for home users,a solar energy installation may not require
huge space but for big companies,a large area is required for the system to be
efficient in providing a source of electricity.
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Current Solar Power plants functioning
in Pakistan:
• SOLAR ENERGY PAKISTAN LTD(THATTA,SINDH)
• DACC LLC SOLAR(SINDH)
• WAH INDUSTRIES LIMITED SOLAR(TAXILA,PUNJAB)
• THE ACCESS SOLAR(PUNJAB)
• CWE SOLAR(CHOLISTAN)
• BAKHSH ENERGY SOLAR(KASUR)
• ROSHAN POWER SOLAR
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Better ways of usage:
• Government should take measures and see that solar lights are used as street
lights in all the areas
• We can place solar panels in the barren lands instead of keeping it away
uselessly.
• We can also keep these solar panels in the deserts,where we can make use of
this energy with the help of a rechargeable battery.
• Efficency of solar panels depends on the range of frequencies of light that
strike the surface.so they can give higher efficiency if we split the light into
different frequency ranges and direct the beams onto the cells tuned to these
frequencies.
• Building a new home is the best time to design and orient the home to take
the advantage of the sun’s rays.
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