It covers all the basic aspects regarding Solar Energy and it is well supported with visuals .

1. Solar Energy: The
Ultimate Source Of Energy
Efforts By: GaurangEfforts By: Gaurang
(X-D 20)(X-D 20)

2. The SunThe Sun
 yellow dwarf star in the centeryellow dwarf star in the center
of the solar systemof the solar system
 diameter = 1,392,000 kmdiameter = 1,392,000 km
 mass = 2×10mass = 2×103030
kg,kg,
 99.86% of the solar system’s total mass99.86% of the solar system’s total mass
 ¾ hydrogen, the rest is mostly helium¾ hydrogen, the rest is mostly helium
 primary source of energy in the earthprimary source of energy in the earth

3. What is Solar Energy?What is Solar Energy?
 Originates with theOriginates with the
thermonuclear fusionthermonuclear fusion
reactions occurring inreactions occurring in
the sun.the sun.
 Represents the entireRepresents the entire
electromagneticelectromagnetic
radiation (visible light,radiation (visible light,
infrared, ultraviolet, x-infrared, ultraviolet, x-
rays, and radio waves).rays, and radio waves).

4. Advantages and DisadvantagesAdvantages and Disadvantages
 AdvantagesAdvantages
 All chemical and radioactive polluting byproducts ofAll chemical and radioactive polluting byproducts of
the thermonuclear reactions remain behind on thethe thermonuclear reactions remain behind on the
sun, while only pure radiant energy reaches thesun, while only pure radiant energy reaches the
Earth.Earth.
 Energy reaching the earth is incredible. By oneEnergy reaching the earth is incredible. By one
calculation, 30 days of sunshine striking the Earthcalculation, 30 days of sunshine striking the Earth
have the energy equivalent of the total of all thehave the energy equivalent of the total of all the
planet’s fossil fuels, both used and unused!planet’s fossil fuels, both used and unused!
 DisadvantagesDisadvantages
 Sun does not shine consistently.Sun does not shine consistently.
 Solar energy is a diffuse source. To harness it, weSolar energy is a diffuse source. To harness it, we
must concentrate it into an amount and form that wemust concentrate it into an amount and form that we
can use, such as heat and electricity.can use, such as heat and electricity.
 Addressed by approaching the problem through:Addressed by approaching the problem through:
1) collection, 2) conversion, 3) storage.1) collection, 2) conversion, 3) storage.

5. How much solar energy?How much solar energy?
The surface receives about 47% of the total solar
energy that reaches the Earth. Only this amount is
usable.

6. Power TowersPower Towers
“Solar One”,
Barstow,
California ,
1,800 sun-
tracking
mirrors reflect
heat to a
central
collector

7. Solar Panels in UseSolar Panels in Use
 Because of their current costs, onlyBecause of their current costs, only
rural and other customers far awayrural and other customers far away
from power lines use solar panelsfrom power lines use solar panels
because it is more cost effectivebecause it is more cost effective
than extending power lines.than extending power lines.
 Note that utility companies areNote that utility companies are
already purchasing, installing, andalready purchasing, installing, and
maintaining PV-home systemsmaintaining PV-home systems
(Idaho Power Co.).(Idaho Power Co.).
 Largest solar plant in US,Largest solar plant in US,
sponsored by the DOE, served thesponsored by the DOE, served the
Sacramento area, producing 2195Sacramento area, producing 2195
MWh of electric energy, making itMWh of electric energy, making it
cost competitive with fossil fuelcost competitive with fossil fuel
plants.plants.

8. Efficiency and DisadvantagesEfficiency and Disadvantages
 Efficiency is far lass than theEfficiency is far lass than the
77% of solar spectrum with77% of solar spectrum with
usable wavelengths.usable wavelengths.
 43% of photon energy is used43% of photon energy is used
to warm the crystal.to warm the crystal.
 Efficiency drops asEfficiency drops as
temperature increases (fromtemperature increases (from
24% at 0°C to 14% at 100°C.)24% at 0°C to 14% at 100°C.)
 Light is reflected off the frontLight is reflected off the front
face and internal electricalface and internal electrical
resistance are other factors.resistance are other factors.
 Overall, the efficiency isOverall, the efficiency is
about 10-14%.about 10-14%.
 Cost of electricity from coal-Cost of electricity from coal-
burning plants is anywhere b/wburning plants is anywhere b/w
8-20 cents/kWh, while8-20 cents/kWh, while
photovoltaic power generation isphotovoltaic power generation is
anywhere b/w $0.50-1/kWh.anywhere b/w $0.50-1/kWh.
 Does not reflect the true costs ofDoes not reflect the true costs of
burning coal and its emissionsburning coal and its emissions
to the nonpolluting method ofto the nonpolluting method of
the latter.the latter.
 Underlying problem is weighingUnderlying problem is weighing
efficiency against cost.efficiency against cost.
 Crystalline silicon-moreCrystalline silicon-more
efficient, more expensive toefficient, more expensive to
manufacturemanufacture
 Amorphous silicon-half asAmorphous silicon-half as
efficient, less expensive toefficient, less expensive to
produce.produce.

9. Uses Of Solar EnergyUses Of Solar Energy
1.1. Architecture and PlanningArchitecture and Planning::
Sunlight has influenced building design since the beginning ofSunlight has influenced building design since the beginning of
architectural historyarchitectural history. Advanced solar architecture and urban planning. Advanced solar architecture and urban planning
methods were first employed by the methods were first employed by the GreeksGreeks and and ChineseChinese, who, who
oriented their buildings toward the south to provide light andoriented their buildings toward the south to provide light and
warmthwarmth. Urban heat islands (UHI) are metropolitan areas with higher. Urban heat islands (UHI) are metropolitan areas with higher
temperatures than that of the surrounding environmenttemperatures than that of the surrounding environment. A. A
straightforward method of counteracting the UHI effect is to paintstraightforward method of counteracting the UHI effect is to paint
buildings and roads white and plant trees. Using these methods,buildings and roads white and plant trees. Using these methods, aa
hypothetical "cool communities" program in hypothetical "cool communities" program in Los AngelesLos Angeles has has
projected that urban temperatures could be reduced by approximatelyprojected that urban temperatures could be reduced by approximately
3 °C at an estimated cost of US$1 billion, giving estimated total3 °C at an estimated cost of US$1 billion, giving estimated total
annual benefits of US$530 million from reduced air-conditioningannual benefits of US$530 million from reduced air-conditioning
costs and healthcare savings.costs and healthcare savings.

10. 2.2. Agriculture and Horticulture:Agriculture and Horticulture: AgricultureAgriculture and and
horticulturehorticulture seek to optimize the capture of solar energy seek to optimize the capture of solar energy
in order to optimize the productivity of plants. in order to optimize the productivity of plants.
GreenhousesGreenhouses convert solar light to heat convert solar light to heat, enabling year-, enabling year-
round production and the growth (in enclosedround production and the growth (in enclosed
environments) of specialty crops and other plants notenvironments) of specialty crops and other plants not
naturally suited to the local climate.naturally suited to the local climate. Primitive greenhousesPrimitive greenhouses
were first used during Roman times to producewere first used during Roman times to produce
cucumberscucumbers year-round for the Roman emperor year-round for the Roman emperor TiberiusTiberius
.. The first modern greenhouses were built in Europe in The first modern greenhouses were built in Europe in
the 16th century to keep exotic plants brought back fromthe 16th century to keep exotic plants brought back from
explorations abroad.explorations abroad.[34][34]
Greenhouses remain an important Greenhouses remain an important
part of horticulture today, and plastic transparentpart of horticulture today, and plastic transparent
materials have also been used to similar effect in materials have also been used to similar effect in
polytunnelspolytunnels and and row coversrow covers..

11. 3. Water Treatment:3. Water Treatment:
Solar distillation can be used to make saline or Solar distillation can be used to make saline or
brackish waterbrackish water potable. The first recorded instance potable. The first recorded instance
of this was by 16th-century Arab alchemists. Aof this was by 16th-century Arab alchemists. A
large-scale solar distillation project was firstlarge-scale solar distillation project was first
constructed in 1872 in the constructed in 1872 in the ChileanChilean mining town of mining town of
Las Salinas. The plant, which had solar collectionLas Salinas. The plant, which had solar collection
area of 4,700 marea of 4,700 m22
, could produce up to 22,700 L per, could produce up to 22,700 L per
day and operated for 40 years.day and operated for 40 years.

12. Darmstadt University of Technologyin
Germany won the 2007 Solar Decathlon
in Washington, D.C. with thispassive
house designed specifically for the humid and
hot subtropical climate.[22]
Greenhouses like these in the Westland
municipality of the Netherlands grow
vegetables, fruits and flowers.
Solar Water Disinfection in IndonesiaSolar Water Disinfection in Indonesia

13. Final ThoughtFinal Thought
 Argument that sun provides power only during the dayArgument that sun provides power only during the day
is countered by the fact that 70% of energy demand isis countered by the fact that 70% of energy demand is
during daytime hours. At night, traditional methodsduring daytime hours. At night, traditional methods
can be used to generate the electricity.can be used to generate the electricity.
 Goal is to decrease our dependence on fossil fuels.Goal is to decrease our dependence on fossil fuels.
 Currently, 75% of our electrical power is generated byCurrently, 75% of our electrical power is generated by
coal-burning and nuclear power plants.coal-burning and nuclear power plants.
 Mitigates the effects of acid rain, carbon dioxide, andMitigates the effects of acid rain, carbon dioxide, and
other impacts of burning coal and counters risksother impacts of burning coal and counters risks
associated with nuclear energy.associated with nuclear energy.
 pollution free, indefinitely sustainable.pollution free, indefinitely sustainable.

14. SourcesSources
 http://www.solarenergy-solarpower.comhttp://www.solarenergy-solarpower.com
 http://www.wikipedia.orghttp://www.wikipedia.org
 http://www.google.comhttp://www.google.com
 Google ImagesGoogle Images
 the world of science, vol 10, technology ofthe world of science, vol 10, technology of
changechange
 Tell Me Why ??Tell Me Why ??