A 17 slides PPT made by School Students for a Physics Project on Sources Of Energy. Hope It Will Help your Purpose!

1. Solar
And
Geothermal
Energy

2. What is Energy?
• Energy is the property that must be transferred to an object in
order to perform work on – or to heat – the object, and can be
converted in form, but not created or destroyed.
• Living organisms require available energy to stay alive, such as the
energy humans get from food.
• Civilisation gets the energy it needs from energy resources such as
fossil fuels, nuclear fuel, or renewable energy.
• The processes of Earth's climate and ecosystem are driven by the
radiant energy Earth receives from the sun and the geothermal
energy contained within the earth.

3. Solar Energy
• Solar energy is radiant energy emitted by the sun.
• Solar energy is an important source of renewable energy and its
technologies are broadly characterized as either passive solar or
active solar depending on how they capture and distribute solar
energy or convert it into solar power.
• Active solar techniques include the use of photovoltaic systems,
concentrated solar power and solar water heating 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.

5. Potential of Solar Energy
• The Earth receives 174 petawatts (PW) of incoming solar radiation
(insolation) at the upper atmosphere.
• Approximately 30% is reflected back to space while the rest is
absorbed by clouds, oceans and land masses.
• The spectrum of solar light at the Earth's surface is mostly spread
across the visible and near-infrared ranges with a small part in the
near-ultraviolet.

7. Conversion
• The conversion of energy from sunlight into electricity, either
directly using photovoltaics (PV) is known as Solar energy.
• Concentrated solar power systems use lenses or mirrors and
tracking systems to focus a large area of sunlight into a small beam.
Photovoltaic cells convert light into an electric current using the
photovoltaic effect.
• The photovoltaic effect is the creation of voltage or electric current
in a material upon exposure to light and is a physical and chemical
property/phenomenon.

8. • Silicon, which is used for making solar cells, is abundant in nature
• but availability of the special grade silicon for making solar cells is
limited.
• The entire process of manufacture is still very expensive, silver used for
• interconnection of the cells in the panel further adds to the cost. In spiteof
the high cost and low efficiency, solar cells are used for many scientificand
technological applications.
• The principal advantages associated with solar cells are that they have no
moving parts, require little maintenance and work quite satisfactorily
without the use of any focussing device. Another advantage is that they
can be set up in remote and inaccessible hamlets or very sparsely
inhabited areas in which laying of a power transmission line may be
expensive and not commercially viable.

10. Q.WHATISGEO-THERMALENERGY?
Sol. Geothermal energy is heat energy generated and stored in the Earth. Thermal energy is the energy that
determines the temperature of matter. The geothermal energy of the Earth's crust originates from the original
formation of the planet and from radioactive decay of materials (in currently uncertain but possibly roughly
equal proportions). The geothermal gradient, which is the difference in temperature between the core of the
planet and its surface, drives a continuous conduction of thermal energy in the form of heat from the core to the
surface.

11. Q.HowDoesGeo-Thermal Energygettoworking?
Sol."Geo"means"fromtheearth," and"thermal"means"heat,"sothistypeofenergyisfoundundertheearth.Thehotlavafrom
a volcano and the hot steam from a geyser both come from underground heat and we can use that same type of heat in our
homes.
Here'showitworks:aboutfourfeetunderground,thetemperatureoftheearthstaysthesameallyearlong,about55degrees.
A geothermal heating system uses pipes buried more than four feet deep in the earth. That is another reason why it's important
foradultstocall811beforetheydigintheiryardsotheydon'thitburiedpiping.
Thesystempumpsaliquidthroughthepipestoabsorbtheheatandbringsitbackindoors.Adevicecalleda"heatexchanger"
takestheheatfromtheliquidandusesittoheattheairinsidethehome.
Ageothermalsystemcancoolyourhouseduringthesummer,too!Itjustworksinreverse,absorbingtheheatfromtheairinside
yourhomeandmovesitbackintotheearth.
Ageothermalheaterisalsoveryenergy-efficient.Almostnoneoftheenergyusediswasted,soithelpskeepheatingbillsverylow

13. PROSOFUSINGGEO-THERMALENERGY
• It only requires heat from the earth to work, a virtually limitless supply.
• It is a domestic source of energy found throughout the world.
• It is simple and reliable, not like solar or wind energy.
• It has the smallest land footprint of any other power source.
• It doesn’t require fuel to operate.
• New technologies are making geothermal energy available in more places.

14. CONSOFUSINGGEO-THERMALENERGY
• High costs to construct geothermal plants.
• Sites must be located in prime areas, requiring long distance transmission, which is often costly.
• The introduction of water is considered wasteful and possibly harmful to the environment.
• Emissions of sulfur dioxide and silica are often an issue.
• The process of drilling into heated rock is problematic.
• Geothermal plants other than binary only work with a minimum 350 degree F (150 C) temperature.

15. Q.WhatCountriesuseGeo-Thermal Energythemost?
Sol.ThelargestgroupofgeothermalpowerplantsintheworldislocatedatTheGeysers,ageothermalfieldinCalifornia, United
States.Asof2004,fivecountries(ElSalvador,Kenya,thePhilippines,Iceland,andCostaRica)generatemorethan15%oftheir
electricityfromgeothermalsources.

16. INDIAANDGEO-THERMALENERGY
Plans to build India's first geothermal power plants are underway. Indian states Gujarat, Chhattisgarh, Andhra Pradesh, Orrisa
and West Bengal are the first of many to announce interest in developing the BRIC country's first geothermal energy plant, with
power capacity in the range of 3MW to 5MW.
The news follows reports in July that the Ministry of New and Renewable Energy of India (MNRE) plans to set up a geothermal
energy policy later this year to guide future projects.
"We are proactive on the geothermal front. A draft policy on geothermal energy is ready" – an MNRE official said.

17. THANKYOU!
MADEBY:-KATHANDESAI,SARTHAKJAIN,SARTHAKCHHABRA,AGRIMSINGHandANIKETPERAI
FormoreinformationaboutGeothermalandSolarEnergyvisit:-http://www.kidsdiscover.com/teacherresources/whats-good-and-whats-bad-about-geothermal-energy/