SOLAR ENERGY: POSSIBILITIES AND
27 February, 2008
Jagat S Jawa
Solar Energy Society of India
Solar Energy - Introduction
Available in abundance throughout the
Renewable energy source
Locally available thereby making it
possible to supply energy earlier than in a
Grid connected could improve quality of
supply at the ends of the grid where
otherwise supply would have been laxe.
Estimated potential of Solar Photovoltaic
(as per CEA, National Electricity Plan) is
50,000 MW out of a total of 1,80,000 MW
for renewables and only 3 MW has been
tapped so far
Eleventh plan target is 14,000 MW grid
interactive Renewable Power which does
not have share of solar power generation.
Direct solar insolation for over 10 months
in a year are available in the thar desert
stretching over vast areas of Rajasthan &
Gujarat. Even if 1% of it is used, it can
generate about 6000 MW of electric
Solar Energy-Converting to
1.Solar Thermal Power Generation
Solar thermal power generating systems use
solar thermal collectors that collect solar heat
and provide thermal energy for generation of
These systems are similar to the conventional
power plants that use fossil fuels to get
required thermal energy
Various types of solar collectors used for
power generation include parabolic
trough collectors, dish collectors,
Since higher temperature is required,
collectors are concentrating type that
have ability to concentrate available solar
radiation many times.
A.Parabolic Trough Collector System.
In this system, parabolic trough-shaped mirrors
are used to focus sunlight on thermally efficient
receiver tubes through which a heat collection
fluid is used.
The fluid can be heated to as high as 400ºC
and is transferred to water through heat
exchangers to produce super heated steam that
can be used for electricity generation.
Most quoted station is nine trough
systems, built in Mojave desert of
California which have been feeding 354
MW peak load electricity into California
grid since 1991. These systems sized
between 14 and 80 MW, are hybridized
with upto 25 % natural gas in order to
provide dispatchable power when solar
energy not available.
B. Dish Collector System
This system uses an array of parabolic
dish shaped mirrors to reflect solar
energy to focus of dish where it is
absorbed by receiver. Receiver can attain
temperatures around 800ºC and steam
produced can be used to generate
electricity through an engine (Kilowatt
Such power generating units installed and
operated in several places of the world
have given hopes of decentralized energy
generation from solar energy. There still
are problems regarding long term
trouble-free operation of system and its
(C) Power Tower System
In this system, solar collectors known as
heliostats are used to collect solar heat.
Heliostats are nearly flat mirrors with
high reflectivity and collected solar
radiation is concentrated on a receiver
placed at focal point mounted on top of a
Concentrated solar radiation heats
working fluid passing through receiver to
temperatures as high as 550°C .
First Power Tower, Solar one, was built
in Southern California and operated in
Mid-1980’s to generate 10 MW of power
Some Recent Solar Thermal Power Plants
1. 25 MW Solar Plant Parabolic trough collectors Under construction.
in Algeria Expected to be completed
2. 64 MW in Nevada Parabolic trough collectors Electricity supply
Sol 1 Power Plant agreement signed with
3. 50 MW Andasol-I Parabolic trough collectors 5,10,000 sq.m. solar field
and upto 7 hours of
Plant in Spain.
thermal storage. Expected
4. 50 MW Andasol-II Parabolic trough collectors 6,20,000 sq.m solar field
in Setille, Spain and upto 12 hours of
thermal storage to be
completed in 2008
5. PS1O Abengoa 10 MW Tower plant with Storage is for an hour for
Plant in Setille, low temperature water half load. Under
Spain storage commissioning.
6. 850 MW Solar Dish System. Construction started for
1MW. 850 MW to be
Power plants Distributed
completed by 2010
Cost versus value for Solar
Through use of thermal storage and
hybridization, solar thermal electric
technologies can provide a source of
Solar thermal technologies can be
hybridized with fossil fuels and also with
existing power plants.
Installed cost is around Rs.12 to 15
Cost of electricity generated may vary
from Rs.10 to Rs.15 Per kWh.
The figures can vary depending on a
number of factors such as site of
installation, hybridization scheme, fiscal
and financial incentives offered by
2. Solar Photovoltaics
Solar Photovoltaic (SPV) technology
enables direct conversion of sunlight into
Photovoltaic cells, commonly known as
solar cells, are used to convert light into
A number of solar cells joined together
make a solar photovoltaic module.
A combination of solar modules in
series/parallel combination, storage
battery, interface electronics, mechanical
support structure, cable, switches, etc.
constitute a solar photovoltaic
(A) SPV Power Plants
Stand alone PV power plants of 1 kW–200 kW
capacities have been installed in different parts
of India for initial electrification of villages.
The locations include Andaman & Nicobar
Islands, Lakshadweep Islands, Assam,
Meghalaya, Tripura, Uttrakhand, Uttar Pradesh
and West Bengal.
West Bengal leading state in stand alone PV
23 Power Plants of about 1.2 MWp
installed in Sunderbans area of West
40 kWp power plant in Nyoma Town in
Leh in Ladakh for community use.
100 kWp installed in Durbuk block in
200 kWp stand alone SPV power plant set
up by Brahma Kumaris Education
Society in Gurgaon district
B. Grid Interactive PV Power Plants
First 100 kWp plant near Aligarh.
Solar diesel local grid in several islands
of Lakshadweep and Andaman &
(C) PV MARKET GROWTH.
During last 5 years, market significantly
expanded to achieve a cummulative PV
deployment of more than 335 MWp
including exports (225 MWp).
By 31/3/2007 more than 14,00,000 PV
systems mostly for small decentralized
applications, aggregating to about 110
MWp delployed in India.
Sector wise details are.
Exports 225 MWp
Lantern 7.5 MWp
Home Light 16.5 MWp
Street Light 5.5 MWp
Pump 11 MWp
Power Plant 6 MWp
Telecom 22 MWp
Others 40.5 MWp
TOTAL 335 MWp 24
Present installed capacity for solar cells
Present installed capacity for PV Modules
also 155 MWp
Another 40 MWp of solar cell production
capacity and 100 MWp of PV Module
capacity is expected by 3/2008.
Two companies engaged in manufacturing
silicon ingots and wafers in India
9 Manufacturers of crystalline solar cells
and 19 manufactures of PV modules in
During 2006 -2007 about 45 MWp of
solar cells and 80 MWp of modules
produced in India.
(D) Exports of SPV Cells.
In 2006-2007, more than 60 MWp
capacity PV cells & modules were
exported to Germany alone.
By March 2007, more than 225 MWp of
PV products have been exported to USA,
Germany, Australia, several countries in
Africa & Asia.
(E) Policy Support for SPV
At present there is no customs duty on
import of silicon wafers, solar cells and
Most of raw materials can be imported at
5% basic duty. Since mid eighties there is
no excise duty on manufacture of silicon,
solar cells, modules and specified range
of PV systems.
In addition, 100% accelerated
depreciation was allowed in the first year
to a profit making company on
manufacture/installation of certain
specified PV products. However, a few
years back the rate of accelerated
depreciation has been reduced to 80%.
The other benefits include tax holiday for
setting up manufacturing units in
specified backward districts.
With a view to encourage expansions of PV
manufacturing and markets, low interest
bearing loans (5% annual interest rate) are
available to users, intermediaries and
manufactures through IREDA for which
MNRE announced a scheme in 1999.
Recently Government has announced a new
policy to attract investments in semi conductor
technologies including Solar Photovoltaics.
Under this policy if an investment of more
than Rs.1,000 crore were made over a period
of ten years, in that case Government would
provide a subsidy of 20% - 25% under certain
(F) Future Plans in Photovoltaics.
Biggest challenge-Initial cost of PV
Some possible measures in reduction of
(i) Improvement in efficiency of solar
cells and modules
(ii) Reduction in consumption of silicon
material by using thinner wafers.
(iii)Reducing cost of production by volume
production and improved process
(iii)Thin film solar cell modules.
3. Integrated Energy Policy Report of
Renewables important to India’s energy
Solar Power could be an important
Subsidies for renewables justified on
Power Regulators must create alternative
incentive structures such as feed-in-laws
or differential tariff.
Policies for promoting specific
The incentives for solar power generation
should be given for first 5000 MW of
installed capacity each for Solar Thermal
Power Plants and Solar Photovoltaics.
4. Guide Lines issued by
Govt. of India, Ministry of New &
Renewable Energy in January, 2008
for generation based incentives
A. For Grid Interactive Generation
Based incentives Solar Power
MNRE will support Grid Interaction Solar
Power projects as demonstration projects.
Maximum capacity up to 50 MW during
11th Plan period (2007-12).
The Indian Renewable Energy
Development Agency (IREDA) will assist
MNRE in fund handling, monitoring, etc.
I. Eligibility Criteria for
Existing registered companies, central
and state power generation companies,
and public/private PV power project
developers who have set up a registered
company in India.
Individuals, NGOs, financial institutions, societies and
other unorganized investors are not eligible to
II. Projects Eligible for Consideration.
Grid Interactive solar PV Power
Generation plants of a minimum installed
capacity of one MW per plant at a single
Plants with a cumulative capacity upto 10
MW in a state.
A developer with projects upto 5 MW in
the country-either a single project or
Projects to be taken up on Build, Own
and Operate Basis.
Captive Projects not eligible
Project developer desirous of availing
accelerated depreciation benefits for the
project, not eligible.
Projects to be developed & completed by
31 December, 2009.
Projects will be considered on first come
first served basis.
Preference/priority to be given to those
projects which are proposed in the states that
have approved and/or notified tariff for solar
A dedicated electronic meter as specified and
approved by the utility to be installed at point
of power evacuation.
Project developers not allowed to use any
other source of power generation alongwith
solar PV power project.
Third party sale, banking and wheeling of
power not permitted while availing
generation based tariff.
III.Generation Based Incentives.
MNRE may provide through IREDA, a
generation based incentive of a
maximum of Rs.12 per kWh after taking
into account power purchase rate (per
kWh) provided by SERC or utility for
Maximum amount of generation based
incentive applicable for a project will be
determined after deducting power
purchase rate for which PPA has been
signed by the utility with a project
developer, from a notional amount of
Rs.15 per kWh.
IV. Solar Thermal Power Generation
Broad guidelines specified above will
also be applicable for grid connected
solar thermal power generation projects.
However, incentive limited to a
maximum of Rs.10 per kWh.
Future Projections of Solar
Renewable Energy sources will replace fossil fuels to a large
extent in the long term, as these are only limited in
availability and their use is environmentally problematic.
For this reason it is also not surprising that money for the
research of renewable energy sources will be made available
In Great Britain for example, a national team of UK scientists,
involving eight universities and nine industrial partners is
embarking on one of the UK’s largest ever research projects in
photovoltaic (PV) energy. The achievement should make solar
energy more competitive and sustainable.
To cut costs and save material in solar cell
production the research team will work to
reduce the thickness of the cells. The four
year project is scheduled to begin in April,
According to a leading Research Analysis,
the global PV market stood at $12.9 billion
in 2007 and is projected to grow to $ 32.2
billion by 2012. Silicon technology which
accounted for about 89% of market in 2007,
will represent 79% of the market by then.
The research firm said thin films, which
accounted for 10% of PV market in 2007,
will grow at a 45% rate through 2013, driven
by improvements in efficiencies and use of
Thin film will account for 19% of the global
PV market by 2012.