A Presentation given on Photon 2k18 in our college Madanapalle Institute of Technology and Science, in the Stream of Physics. this slide explains briefly the various Renewable energy Sources available to us, their classification, and focuses more on the Photo Voltaic Cells.

1. PHOTON_2k18
Emerging Trends in Renewable Energy
Photo Voltaic Technology
Author : M. Praveen Kumar Reddy
mail : 17691a03d2@mits.ac.in

2. INTRODUCTION
Renewable Energy Resources:
 The Energy Resources which can be generated
continuously in nature and are inexhaustible.
Eg. wood, solar energy, wind energy, tidal
energy, hydropower, biomass energy, bio-fuels,
geo-thermal energy and hydrogen. They are
also known as non-conventional sources of
energy and they can be used again and again in
an endless manner.

3. Solar Energy
• Sun is the ultimate source of energy, directly or indirectly
for all other forms of energy. The nuclear fusion reactions
occurring inside the sun release enormous quantities of
energy in the form of heat and light. The solar energy
received by the near earth space is approximately
1.4 kJ s-1 m-2 known as solar constant.
• Traditionally, we have been using solar energy for drying
clothes and food-grains, preservation of eatables and for
obtaining salt from sea-water. Now we have several
techniques for harnessing solar energy. Some important
solar energy harvesting devices are discussed here.

4. Solar Cells
 They are also known as Photo Voltaic cells or
PV cells. Solar cells are made of thin wafers of
semiconductor materials like silicon and
gallium.

5. Working
When solar radiations fall on them, a potential
difference is produced which causes flow of
electrons and produces electricity.
Silicon can be obtained from silica or sand, which
is abundantly available and inexpensive.
By using gallium arsenide, cadmium sulphide or
boron, efficiency of the PV cells can be improved.
The Potential Difference produced by a single PV
cell of 4 cm2 size is about 0.4 to 0.5 volts and
produces a current of 60 milli Amperes.

6. Solar Batteries
 A group of solar cells joined together in a
definite pattern form a solar panel which can
harness a large amount of solar energy and can
produce electricity enough to run street-light,
irrigation water pump etc.

7. Types of Solar Cells
First
Generation
PV Cells
Second
Generation
PV Cells
Third
Generation
PV Cells

8. First Generation PV Cells
 About 200μm thick
 A simple p-n junction is the essence of most solar cells.
 Made from wafers of crystalline silicon, sliced from large
ingots.
 Can take up to a month to complete.
 Use a single, simple junction between n-type and p-type
silicon layers, which are sliced from separate ingots.
 n-type ingot is made by heating chunks of silicon with small
amounts of phosphorus, antimony, or arsenic as the dopant,
while a p-type ingot would use boron as the dopant.
 Slices of n-type and p-type silicon are then
fused to make the junction.

9. Second Generation PV Cells
 Popularly known as Thin Film Solar Cells (TFSC) or Thin
Film Photo Voltaics(TFPV),
 100 times thinner than First Generation PV Cells.
 Generally made from amorphous silicon (a-Si)
 Cadmium-Telluride (Cd-Te) and Copper Indium Gallium
Diselenide (CIGS) are the other materials used.
 They are extremely thin, light, and flexible,
 They can be laminated onto windows, skylights, roof tiles,
and all kinds of substrates including metals, glass,
and polymers (plastics).
 More Flexible but less Efficient.

10. Third Generation PV Cells
 Comes with the efficiency of the First Generation PV
Cells (30% or more).
 More likely to be made from materials such as
amorphous silicon, organic polymers (making
Organic Photo Voltaics, OPVs), perovskite crystals.
 Feature multiple junctions.
 Cheaper, more efficient, and more practical than
either first- or second-generation cells.

11. Efficiency
S. No PV Cell Efficiency (%)
1.. First Generation PV Cells 15 – 20
2. Second
Generation PV
Cells
a-Si 7
Cd-Te 11
CIGS 7 – 12
3. Third Generation PV Cells 30

12. Uses
• Solar cells are widely used in calculators,
electronic watches, street lighting, traffic
signals, water pumps etc.
• They are also used in artificial satellites for
electricity generation.
• Solar cells are used for running radio and
television also.
• They are more in use in remote areas where
conventional electricity supply is a problem.

13. Concentrator PV Cells

14. Concentrator PV Systems
 Concentrator PV Systems use optics to reduce
the cell area from 2 to more than 1000 times.
Class of CPV Typical
Concentration
Ratio
Tracking Type of Converter
High
Concentration PV
(HCPV)
300 – 1000 Two – Axis III – V Multi
Junction Cells
Low Concentration
PV (LCPV)
<100 One or Two Axis c-Si or Other Cells

15. CPV systems
 Shifts the major system cost from the cell to
the optics.

16. Efficiency Comparison
Single Junction Cell
 Single Junction Cells
respond to a Portion of the
Solar Spectrum.
Multi Junction Cell
 Multi Junction Cells use multiple
materials to more fully match the
Solar Spectrum.

17. Evolution

18. Printable Solar Panels
 More Flexibility at lower cost.
 Can be printed anywhere (walls, windows, roller
blinds, shade umbrellas and even tents).
 Cost effective but less efficient (10%).
 Commonwealth Scientific and
Industrial Research
Organization (CSIRO) is on
research to develop highly efficient
Printable Solar Cells.

19. Revolutionary Steps
Applied Science and Technology I and II
Generation PV :
Lower Si feedstock prices.
Thinner Si wafer Technology.
Thin Films.
Improved Processing.
Improved Performance.
Advanced integration packaging.

20. Revolutionary Steps
Transformational Science and Technology (II
Generation PV) :
Thin Films.
Concentrators.
Organics.
Si wafers <100μm.
Si cells beyond 25% efficiency.

21. Revolutionary Steps
Fundamental Science III Generation PV :
Quantum dots.
Nanotechnology.
Multi-multi-junctions.
Thermo Photonics.
Intermediate Band.
Bio-inspired.