2. Outline
Introduction(Present Scenario in India)
Background on Solar Light
Types of Solar cell
How a Silicon-Based Solar Cell Works
How a Dye-Sensitized Cell Works
Comparison
Summary
3. Introduction :
Energy-starved India is becoming a vibrant market for renewable energy.
This bodes well for a country that has often seen its industrial and
economic growth inhibited by a truncated supply of conventional power.
Currently faces energy shortage of 8 % & a peak demand shortage of
11.6 %.
In order to sustain a growth rate of 8 %, it is estimated that the power
generation capacity in India would have to increase to 306 GW in the
next 10 years which is 1.7 times current levels.
Grid-connected renewable power accounts for as much as 20.2 GW – or
11% – of India's 182.3 GW of installed power capacity.
◦ The majority share (55% or 99.8 GW ) – by coal-based thermal power.
◦ Gas-fired thermal power, (10% or 17.7 GW),
◦ Hydropower (21% or 38.7 GW) and nuclear 2.6% with 4780 MW.
◦ India just had 2.12 megawatts of grid-connected solar generation
capacity
4. Under the 11th Five Year Plan (ended March 2012), Only 52 GW of the
78.6 GW originally envisaged has been added,.
The 10th Plan (2002-07) only saw a meagre 21.2 GW capacity added,
against a target of 41.1 GW.
The 12th Plan (2012-17) now aims for a capacity addition of 103.3 GW
which includes commensurate transmission and distribution capacities.
Clean energy investments in India reached a record US$10.3bn in 2011, up
52% from the US$6.8bn invested in 2010 .This was the highest growth
figure of any significant economy in the world, with the country accounting
for 4% of global investments in clean energy. The large growth was driven
by a 7-fold increase in funding for grid-connected solar projects.
Solar photovoltaic (PV) power plants totalling over 180 MW were set up in
the country and off-grid installations of over 50 MW were completed as
well.
5. What is Solar Energy?
Energy produced by the Sun
Conversion of Sunlight into usable energy such as
electricity and heat.
◦ Clean(No green house gases),
◦ renewable source of energy,
◦ Decentralization of power
Photovoltaic (solar) panel
◦ Saving eco-systems and livelihoods.
Harnessed by solar collection
methods such as solar cells & Concentrators
Conversion of Sunlight into usable energy such as
electricity and heat.
Set of solar panels
6. Energy from the Sun is Abundant
Solar power systems installed in the areas defined by the
darkdisks could meet the world's current Total energy
demand
7. Solar Panel Use Today
Solar panels being tested on
WalMart store
Solar panels on Microsoft
building
8. Photovoltaic Solar Cells
Generate electricity directly
from sunlight
2 Main types:
– Single-crystal silicon Silicon Based Solar Cell
(traditional)
Widespread
Expensive to manufacture
– Dye-sensitized (“nano”)
Newer, less proven
Inexpensive to manufacture
Flexible
Dye Sensitized Solar Cell
10. Solar Cells are Converters of
Energy
Solar cells are devices that take light energy as
input and convert it into electrical energy
11. A Little Background on Light
Different colours of light have different wavelengths and different
energies
12. Absorption of Light by Atoms
Absorption occurs only when the energy of the
light equals the energy of transition of an
electron
Single
electron
transition in
an isolated
atom
13. Absorption of Light by Ionic
Compounds
Electrons can jump between “bands”
Incident light with energy >= than the “band
gap” energy can be used to excite the
electrons
14. So What Does this Mean for Solar
Cells ?
In dye-sensitized solar cells
– Talk about highest occupied
molecular orbital (HOMO) and
lowest unoccupied molecular
orbital(LUMO)
In single-crystal silicon
solar cells
– Talk about “conduction band”
(excited states) and “valence
band”(ground states)
15. How a Silicon-Based Solar Cell
Works
Light with energy greater than the band gap energy of Si
is absorbed
Energy is given to an electron in the crystal lattice.
The energy excites the electron; it is free to move.
A positive “hole" is left in the electron’s place.
This separation
of electrons and
holes creates a
voltage and a
current.
16. Silicon-Based Solar Cell
Attributes
Expensive
– Made in high vacuum at high heat
– High manufacturing costs
Need TLC
– Fragile, rigid, thick
Long return on investment
– Takes 4 years to produce energy savings
equivalent to cost of production
17. How a Dye-Sensitized Cell
Works
Light with high enough energy excites electrons in dye
molecules
Excited electrons infused into semiconducting TiO2,
transported out of cell
Positive “holes” left in dye molecules
Separation of excited electrons and “holes” creates a
voltage and hence current.
18.
19. Dye-Sensitized Solar Cells
Relatively inexpensive
– Made in non-vacuum setting mainly at room temperature
– Relatively simple manufacturing process
Need little TLC
– Thin, lightweight, flexible
Short return on investment
– Takes approx 3 months to produce energy savings
equivalent to cost of production
20. Dye-Sensitized and Silicon-based
Solar Cells Compared
Dye-Sensitized Traditional
Relatively Expensive
inexpensive
– Need little TLC – Need TLC
– Short return on – Long return on
investment investment
21. Summary
The DSSC has a number of attractive
features.
Although its conversion efficiency is less than
the best thin-film cells, in theory
its price/performance ratio should be good
enough to allow them to compete with fossil
fuel electrical generation by achieving grid
parity.
North-western University researchers
announced a solution to a primary problem of
DSSCs, short useful life of the device.. The
current efficiency is about half that of silicon
cells, but the cells are lightweight and
potentially of much lower cost to produce.
22. Further Reading
Konarka Technologies (Graetzel cells) http://www.konarkatech.com/
PV Power Resource Site http://www.pvpower.com/
US DOE Photovoltaics http://www.eere.energy.gov/pv/
Key Center for Photovoltaic Engineering
http://www.pv.unsw.edu.au/
National Center for Photovoltaics http://www.nrel.gov/ncpv/