This presentation covers relationship of energy and power. It also covers basics of solarenergy

1. Energy Basics
31-08-2016 IEC-803 ENERGY BASICS BY DR N R KIDWAI, INTEGRAL UNIVERSITY 1

2. Force, Power and Energy
•As per Newton’s second law, the force (F) is related to the acceleration (a) of
a body of mass m ,
•F = ma
The unit of force is Newton (N), named after Isaac Newton (1642-1727).
Newton is defined as the force required to accelerate the mass of 1 kg at an
acceleration rate of 1 m/s2,
hence 1 N = 1 kg·m/s2.
31-08-2016 IEC-803 ENERGY BASICS BY DR N R KIDWAI, INTEGRAL UNIVERSITY 2

3. Force, Power and Energy
•Energy (E), is given as integration of product of force times distance,
𝐸 = 𝐹 𝑠 . 𝑑𝑠
•where s denotes distance. Energy is usually measured in the unit of Joule (J),
named after the English physicist James Prescott Joule (1818-1889), which it
defined as the amount of energy required applying the force of 1 Newton
through the distance of 1 m, 1 J = 1 Nm.
•Human require 10000 KJ energy per day = 2390 Kcal
•1cal=4.184J
31-08-2016 IEC-803 ENERGY BASICS BY DR N R KIDWAI, INTEGRAL UNIVERSITY 3

4. Force, Power and Energy
• Power (P), is rate of doing work, or, which is equivalent, the amount of energy
consumed per time unit. It is related to energy as,
𝐸 = 𝑃 𝑡 . 𝑑𝑡
where t denotes the time. The power is usually measured in Watt (W), after the Scottish
engineer James Watt (1736-1819). 1 W = 1 J/s
31-08-2016 IEC-803 ENERGY BASICS BY DR N R KIDWAI, INTEGRAL UNIVERSITY 4

5. Force, Power and Energy
1 J is a small amount of energy compared to the human energy consumption. Therefore,
in the energy markets, often the unit Kilowatt hour (kWh) is used.
1kWh = 1000Wh×3600 s/h = 3600000 Ws = 3600000 J = 3600 KJ
Average Male body require 2.78 KWH energy per day
•the amounts of energy in solid state physics,, are very small. So electron volt is used,
which is the energy a body with a charge of one elementary charge (e = 1.6×10−19 C)
gains or looses when it is moved across a electric potential difference of 1 Volt (V),
1eV = e×1V = 1.6×10−19 J.
31-08-2016 IEC-803 ENERGY BASICS BY DR N R KIDWAI, INTEGRAL UNIVERSITY 5

6. Energy
Law of conservation of Energy says “Energy can neither be created nor destroyed”
Only form of energy can be changed
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7. Solar Energy
The amount of sunlight striking the earth’s atmosphere continuously is 1.75 x 105 TW
Considering a 60% transmittance through the atmospheric cloud cover, 1.05 x 105 TW
reaches the earth’s surface continuously
If the irradiance on only 1% of the earth’s surface could be converted into electric energy
with a 10% efficiency, it would provide a resource base of 105 TW, while the total global
energy needs for 2050 are projected to be about 30–40 TW.
The present state of technologies is such that solar cell efficiencies have reached to 20%,
with concentrating PVs at about 40% and solar thermal system efficiencies of 40–60%.
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8. Solar Energy
Solar systems, including solar thermal and photovoltaics, offer environmental advantages
over electricity generation using conventional energy sources.
The benefits fall into two main categories: environmental and socioeconomically issues.
Environmental benefits:
Reduction of the emission of the greenhouse gases (mainly CO2, NOx) and of toxic gas
emissions (SO2, particulates)
Reclamation of degraded land
Reduced requirement for transmission lines within the electricity grid
Improvement in the quality of water resources
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9. Solar Energy
Socioeconomic benefits:
Increased regional and national energy independence
Creation of employment opportunities
Restructuring of energy markets due to penetration of a new technology and the
growth of new production activities
Diversification and security (stability) of energy supply
Acceleration of electrification of rural communities in isolated areas n Saving foreign
currency
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10. Solar Energy
It is worth noting that no artificial project can completely avoid some impact to the
environment.
The negative environmental aspects of solar energy systems :
Pollution stemming from production, installation, maintenance, and demolition of the
systems
Noise during construction n Land displacement
Visual intrusion
These adverse impacts present difficult but solvable technical challenges.
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11. Solar Energy
oldest large-scale application known to us is the burning of the Roman fleet by
Archimedes, the Greek mathematician and philosopher (287–212 B.C.). The burning glass
of Archimedes composed of 24 mirrors, which conveyed the rays of the sun into a
common focus and produced an extra degree of heat.
Amazingly, the very first applications of solar energy refer to the use of concentrating
collectors, In 18 centuries. Solar furnaces capable of melting iron, copper, and other
metals were being constructed of polished iron, glass lenses, and mirrors.
The first commercial solar plant was installed in Albuquerque, New Mexico, in 1979. It
consisted of 220 heliostats and had an output of 5 MW.
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12. Solar Energy
Becquerel discovered the photovoltaic effect in selenium in 1839.
The conversion efficiency of the “new” silicon cells, developed in 1958, was 11%,
although the cost was prohibitively high ($1000/W), present cost ($1/W).
The first practical application of solar cells was in space, where cost was not a barrier,
since no other source of power is available
in the 1960s resulted in the discovery of other photovoltaic materials such as gallium
arsenide (GaAs). These could operate at higher temperatures than silicon but were much
more expensive
The materials most commonly used is solar PV cells are silicon (Si) and compounds of
cadmium sulphide (Cds), cuprous sulphide (Cu2S), and gallium arsenide (GaAs).
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13. Solar Energy
Amorphous silicon (a-Si) is a glassy alloy of silicon and hydrogen (about 10%).
Amorphous silicon cells are composed of silicon atoms in a thin homogenous layer rather
than a crystal structure.
Amorphous silicon absorbs light more effectively than crystalline silicon, so the cells can
be thinner. (thin film PV technology).
Amorphous silicon can be deposited on a wide range of substrates, both rigid and
flexible, which makes it ideal for curved surfaces and “foldaway” modules.
Amorphous cells are, however, less efficient than crystalline-based cells, with typical
efficiencies of around 6%, but they are easier and therefore cheaper to produce.
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14. Solar Energy
Several properties make it an attractive material for thin film solar cells:
1. Silicon is abundant and environmentally safe.
2. Amorphous silicon absorbs sunlight extremely well, so that only a very thin active
solar cell layer is required (about 1 m as compared to 100  m or so for crystalline
solar cells), thus greatly reducing solar cell material requirements.
3. Thin films of a-Si can be deposited directly on inexpensive support materials such as
glass, sheet steel, or plastic foil.
A number of other materials, such as cadmium telluride (CdTe) and copper indium
diselenide (CIS), are now being used for PV modules. These can be manufactured by
relatively inexpensive processes, in comparison to crystalline silicon technologies, yet
they typically offer higher module efficiencies than amorphous silicon.
31-08-2016 IEC-803 ENERGY BASICS BY DR N R KIDWAI, INTEGRAL UNIVERSITY 14

15. Solar Energy Applications
Electricity Generation:
Solar PV systems
 Off grid or stand alone
 Grid Connected
Solar Desalination: To purify water through heating, evaporation and condensation.
Solar Drying: drying an agricultural product is to reduce its moisture contents to a level
that prevents deterioration within a period of time regarded as the safe storage period.
 Passive solar buildings: buildings that include, as integral parts of the building,
elements that admit, absorb, store, and release solar energy and thus reduce the need
for auxiliary energy for comfort heating
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16. Solar Energy
The sun is a sphere of intensely hot
gaseous matter with a diameter of 1.39
x 109 m
The sun is about 1.5 x 108 km away
from earth,
as thermal radiation travels with the
speed of light in a vacuum (300,000
km/s), after leaving the sun solar
energy reaches our planet in 8 min and
20 s.
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17. Solar Energy
As observed from the earth, the sun disk forms an angle of 32 min of a degree
The sun has an effective black-body temperature of 5760 K.
The sun’s total energy output is 3.8 x 1020 MW, (63 MW/m2 of the sun’s surface)
The earth receives only a fraction of the solar radiation, equal to 1.7 x 1014 kW; however,
even with this small fraction, it is estimated that 84 min of solar radiation falling on earth
is equal to the world energy demand for one year (about 900 EJ).
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