Solar Photovoltaic Electricity
Indian Perspective-2010

• The Jawaharlal Nehru National Solar Mission,
is a major initiative of the Government of India
and State Governments to promote ecologically
sustainable growth while addressing India’s
energy security challenge.
• It will also constitute a major contribution by
India to the global effort to meet the challenges
of climate change.
• This is one of the several initiatives that are
part of National Action Plan on Climate Change.
The program was officially inaugurated in 2010
by Prime Minister of India, Manmohan Singh.

JAWAHARLAL NEHRU NATIONAL SOLAR MISSION
The deployments across the application segments is envisaged
as follows
TARGET
S.
No
Application Segment Phase 1
(2010-13)
Phase 2
(2013- 17)
Phase 3
(2017-22)
1 Solar Thermal
Collectors
7
Million sq.
metres
15
Million sq.
metres
20
Million sq.
metres
2 Off Grid Applications 200 MW 1000 MW 2000 MW
3 Grid power, including
Roof top and small
plants
1,100 MW 4000-10,000
MW
20000
MW

PV systems
• are easily transportable and Installable.
• can be used to generate electricity
where it will be used,
• even at locations the electric grid
doesn’t reach.
• PV is also modular, so installations can
be scaled to the appropriate size for a
given use

Small as well as medium scale
• PV’s scalability allows it to be used for both
large-scale power plants and to
• power handheld calculators, and it
distinguishes PV from fossil fuel based power.
• PV can be installed on buildings, parking lots
and other developed areas without interfering
with human activities.

Solar energy can be integrated into virtually
every part of Indian life—
• the homes we live in,
• the offices where we work,
• the farms and factories that produce the
products we buy, and
• the schools where our children learn.
• With creativity and sound public policy,
solar energy can make a major contribution
to India’s energy future.

In solar photovoltaics, sunlight is converted into
electricity using a device called solar cell
• A solar cell is a
semiconducting device
made up of silicon or
other materials, which
when exposed to
sunlight, generates
electricity.

Magnitude of the current generated
depends on

INDIA: Insolation: kWh per Sq-mt per day & Salinity> 1500 mg/l

The Thar
Desert in India
is also a
promising
location for a
solar energy.

An example of a complete set of beam normal
insolation data for a given location is shown in Figure

Capacities of SPV
modules
• SPV modules of various capacities are
available, and are being used for a variety of
applications. Theoretically, a PV module of
any capacity (voltage and current) rating can
be fabricated. However, the standard
capacities available in the country range from
5 Wp to 120 Wp. The voltage output of a PV
module depends on the number of solar cells
connected in series inside the module.

Science & technology of solar
Cells & Modules
Types of silicon solar cells
(Mono- crystalline, multi- crystalline, and
Amorphous, Thin film)
Energy efficiency

Energy efficiency
• A solar cell's energy conversion efficiency (η,
"eta"), is the percentage of power converted
(from absorbed light to electrical energy) and
collected, when a solar cell is connected to an
electrical circuit. This term is calculated using the
ratio of Pm, divided by the input light
irradiance under "standard" test conditions (E, in
W/m2) and the surface area of the solar
cell (Ac in m²).

Standard Current-Voltage (I-V) Curve
• The I-V Curve is an important technical aspect
of a solar module, the basis for understanding
all PV array design. It represents the possible
values of output current (I) and voltage (V)
that a solar module can deliver under specific
environmental conditions.

Standard Current-Voltage (I-V) Curve

Reading the I-V Curve
• If the module is outputting to a 12-volt
battery, you can determine the watts output
to the battery from the graph. Read up from
12 volts to the IV curve and then over to the
Amperes scale to find that the current output
would be about 5.9 amps. Since power (in
watts) equals voltage times current, this
means that the module would be outputting
into the battery at a rate of about 71 watts.

Solar cell Technologies: Some references

Development of solar cell technology

Important Components other than the PV Module
‘Balance of System’ (BOS)
• Batteries for Storage of Electricity
• Electronic Charge Controller
• Inverter
• Mounting structure and tracking device

Battery banks
• Batteries are charged during the day time
using the DC power generated by the
SPV module.
• The battery bank supplies power to loads
during the night or non-sunny hours.

Inverter fundamentals
• The inverters transform the DC power from
solar modules into AC power to match the grid
and be useful for most house loads.
• The inverter is a power conditioner that creates
pure sine wave power (AC.) This power is
cleaner than the grid because it is conditioned
right on site.

Maximum Power Point Tracking
(MPPT).
• Inverters also maximize the power output of the
solar array in a function known as Maximum
Power Point Tracking (MPPT). Solar modules
produce the power at the voltage they are
connected to.
• The maximum power point voltage changes as
the sun moves throughout the day and the
current (amps) gets higher and lower.
• This allows the inverter to produce the most
amount of power at any given time without frying
its circuitry.

Inverter failure
• Inverters are the one component that needs to be replaced
periodically. Most systems installed today use a single inverter
for the entire system, so when it fails, the whole system stops
providing electricity to the home.
• Possibly with an inverter for each panel or small group of
panels may be a solution. This has several advantages:
• If an inverter fails, only one panel of the system will be affected,
which will be reported in our daily monitoring.
• This allows for better scalability, in that we do not need to have
different inverter capacities for different system sizes.
• The efficiency of the system is improved, since DC loses more
energy than AC going through a wire.

Available space
• A crucial factor is having enough space in the sun
with the proper orientation.
• The average home needs about a 5 kW system to
offset their annual usage.
• To calculate the physical size of this system, you
can use this simple rule of thumb:
• 10 W / ft2 of space
• A 5 kW system covers about 500 ft2 of roof or
ground area.
• 5000 W / 10 W/ft2 = 500 ft2

Charge controllers/regulators -1
• Why do you need a controller?
• Main function is to fully charge a battery
without permitting overcharge. If a solar array
is connected to lead acid batteries with no
overcharge protection, battery life will be
compromised. Simple controllers contain a
relay that opens a charging circuit terminating
the charge at a pre-set high voltage and once
a pre-set low voltage is reached, closes the
circuit, allowing charging to continue.

Charge controllers/regulators - 2
• More sophisticated controllers have several
stages and charging sequences to assure the
battery is being fully charged. The first 70% to
80% of battery capacity is easily replaced. It is
the last 20% to 30% that requires more
attention and therefore more capacity.

Charge controllers/regulators -3
• The circuitry in a controller reads the voltage
of the battery to determine the state of
charge.
• Designs and circuits vary, but most controllers
read voltage to reduce the amount of power
flowing into the battery as the battery nears
full charge.

SPV Power Plant

solar electric generating plant
• The largest solar electric
generating plant in the
world produces a
maximum of 354
megawatts (MW) of
electricity and is located
at Kramer Junction,
California. It produces
electricity for the grid
supplying the greater
Los Angeles area.

Standards for balance of system
components

Located at the 19th Milestone on the Gurgaon–
Faridabad road just outside the boundary of Delhi.
• Solar cell testing
• Photovoltaic module
testing
• Testing of lighting systems
• SPV pump testing
• Battery testing for PV
applications
• Long-term performance
evaluation of PV modules
• Resource assessment
• Technology
demonstration &
assessment
• SPV power plant
• Research and
Development

PV power output management can be achieved with battery or other
electrochemical storage, pumped hydroelectric storage, or with diesel-
generator backup.

The top five in solar technology utilisation
for Solar PV Grid connected are:
Germany
Japan
U S A
Spain
France

Issues in managing solar electricity: References
• Denholm, P and R. M. Margolis, 2007, ‘Evaluating the
limits of Solar Photovoltaics in Traditional Electric
Power Systems’, Energy Policy, Vol 35, pp 2852 - 2861
• Denholm, P and R. M. Margolis, 2007, ‘Evaluating the
limits of Solar Photovoltaics in Electric Power
Systems Utilizing Energy Storage and other Enabling
Technologies’, Energy Policy, Vol 35, pp 4424 – 4433
• Lamont, Alan, 2008, ‘Assessing the Long Term System
Value of Intermittent Electric Generation
Technologies’, Energy Economics, , Vol 39, pp 1208 –
1231

Comparison of PV and Diesel-generator power
• Kolhe, Mohanlal, Sunitha Kolhe and J.C. Joshi, 2002,
“ Economic viability of stand alone photovoltaic
system in comparison with diesel powered system for
India”, Energy Economics, vol24, pp 155 – 165.
• Stand alone PV systems in remote areas of India are
compared with the diesel-powered systems through
sensitivity analysis. PV systems are found to be the
lowest cost option for the daily energy demand of 15
kWh/day under unfavourable economic conditions
and upto 68 kWh / day under favourable conditions.

Textbooks of Solar energy Engineering
1. Principles of Solar Engineering, D. Yogi Goswamy,
Frank Kreith, Jan. F. Kreider, 2nd Edition, Taylor &
Francis, 2000, Indian Reprint, 2003, Ch. 9,
Photovoltaics, pp 411-446
2. Fundamentals for Solar Energy Conversion, Edward.
E. Anderson, Addison Wesley Publ. Co., 1983.
3.Fundamentals of Renewable Energy Sources, G. N.
Tiwari and M. K. Ghosal, Narosa Publ. House, New
Delhi, 2007, Ch. 2, Solar Energy, Ch. 3 Photovoltaic
systems pp 52 - 165

Textbooks of Solar energy Engineering
4. Wind and Solar Power systems, Mukund R Patel,
2nd Edition, Taylor & Francis, 2001
5. Roger Messenger and Jerry Ventre, Photovoltaic
Systems engineering, 2nd edition, CRC Press. 2003.
6.Solar Energy, 3rd edition, S.P. Sukhatme and J. K.
Nayak, Tata McGraw-Hill Publ. Co., N. Delhi., 2008,
Ch. 9, Section 1, pp 313 - 331

An important reference book for PV
Systems
• Practical Handbook of Photovoltaics:
Fundamentals and Applications
Edited by: Tom Markvart and Luis Castaner
[2003]

Handbook of photovoltaic science and engineering
• Antonio Luque, Steven Hegedus
John Wiley and Sons, 2003 - 1138
pages
Handbook of Photovoltaic Science
and Engineering incorporates the
most recent technological
advances and research
developments in Photovoltaics. All
topics relating to the photovoltaic
(PV) industry are discussed and
each chapter has been written by
an internationally-known expert in
the field.

Photovoltaic solar energy generation
Adolf Goetzberger, Volker U. Hoffmann
• Springer, 2005 - Technology
& Engineering - 232 pages
• This comprehensive description
and discussion of photovoltaics
(PV) is presented at a level that
makes it accessible to the
interested academic. Starting
with an historical overview, the
text outlines the relevance of
photovoltaics today and in the
future. Then follows an
introduction to the physical
background of solar cells and
the most important materials
and technologies, with
particular emphasis …..