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TITLE

DISTRIBUTED RENEWABLE ENERGY

GENERATION IN INDIA

Author VIKAS VERNEKAR

Date

Sep-2008

MSc Sustainable Energy & Environment

Cardiff School of Engineering

Cardiff University

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Table of Contents Pages

1. Abstract 3

2. Introduction to Distributed Generation (DG) 4

3. Available Options for distributed generation 4

4. Present Energy scenario of Indian power sector. 6

5. Sources of renewable energy generation 8

6. Distributed Generation Using Renewable 10

6.1 Wind Energy 10

6.2 Small Hydro power 11

6.3 Solar energy 13

6.4 Geothermal energy 13

6.5 Biomass(Solids,landfillgas and biogas) 14

6.6 Tidal energy 16

7. Advantages and Disadvantages 18

8. Conclusion 19

9. References 20

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1. ABSTRACT:

On a global scale, power supply is the most capital incentive sector of all. Every industry

and every aspect of social progress is heavily dependent on energy. Energy access, energy

security, poverty alleviation, and environmental Considerations, combined with increasing

fossil fuel prices, are key drivers for accelerating the adoption of affordable Distributed

generation (DG). Distributed Generation (DG) is considered to be important in improving

the security of energy supplies by decreasing the dependency on imported fossil fuels and

in reducing the emissions of greenhouse gases. Distributed Renewable energy

technologies, such as hydro (small), solar, geothermal, biomass, and wind, can deliver

power with virtually zero emissions. Distributed generation (smaller generators that

produce power locally apart from centralized grid) also has the potential to significantly

reduce emissions and promote greater cost and network efficiencies.

In India most of the people live in rural areas and still 20 % of villages are not electrified

and people in many of the electrified villages are very much dissatisfied with the quality of

grid power due to the remote places. As India is a developing country its energy demand is

also increasing day by day, there is a huge demand supply gap of 9% of average load and

15.2 % of peak demand (As on Jan-2008). India is mainly dependent on fissile fuels which

are producing greenhouse gasses and polluting the environment. If we consider all these

things the Distributed renewable energy technology is the best option for India to come out

of these problems. India is blessed with a variety of renewable energy sources such as

Wind energy, solar energy, small hydro plants, biomass, geothermal energy, wave and tidal

energy. In this case study I’m going to discuss what is distributed generation, what is the

present energy scenario of India, what are the options available for energy generation using

distributed renewable energy and how much potential is there in DREG in India and some

of the Distributed renewable sources which can be used for generating energy in a small

scale (local demand and for the future demand) for the sustainable future.

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2. INTRODUCTION DISTRIBUTED GENERATION:

Distributed generation (DG) can be defined as the installation and operation of electric

power generation units connected directly to the distribution network or connected to the

network on the customer site of the meter. DG is also referred to as dispersed generation or

embedded generation or variety of small, modular power-generating technologies that can

be combined with energy management and storage systems and used to improve the

operation of the electricity delivery system, whether or not those technologies are

connected to an electricity grid. Implementing DG can be as simple as installing a small

electricity generator to provide backup power at an electricity consumer's site. Or it can be

a more complex system, highly integrated with the electricity grid and consisting of

electricity generation, energy storage, and power management systems. DG systems range

in size and capacity from a few kilowatts up to 10 MW. They comprise a portfolio of

technologies, both supply-side and demand-side, that can be located at or near the location

where the energy is used. Distributed generation can provide standby generation, peak

shaving capability, base load generation or cogeneration.

Distributed Generation (DG) has an essential role to play in reducing emissions and

improving security of supply because it can use relatively small, localized, sources of fuel

(often renewable) to generate electricity, with or without heat.

DG options can be classified based on the prime movers used—engines, turbines, fuel cells

or based on the fuel source as renewable or non-renewable. There are a large number of

possible system configurations.

3. Available Options for distributed generation

Distributed generation systems can be divided in two segments

1. Combined heat and power

2. Renewable Energy Sources

DISTRIBUTED ENERGY GENERATION

Combined Heat and Power Renewable Energy Sources

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The available DG options in these segments are.

Combined heat and power:

� Internal combustion engine fuelled by diesel

� Internal combustion engine fuelled by natural gas

� Micro-turbine fuelled by natural gas

� Proton exchange membrane (PEM) fuel cell with reformer fuelled by

natural gas

Renewable Energy Sources:

� Hydro power ( small)

� Wind turbine

� Biomass ( befouls, landfill gas, sewage treatment plant gas and biogas)

� Solar photovoltaic (PV) , Solar thermal energy

� Biogases cogeneration in sugar factories

� Geothermal

� Wave and tidal energy

Renewable energy technologies, such as hydro (small), solar, geothermal, biomass, and

wind, can deliver power with virtually zero emissions. Distributed generation (smaller

generators that produce power locally apart from centralized grid) also has the potential to

significantly reduce emissions and promote greater cost and network efficiencies. Both

renewable energy and distributed generation lend well to promoting energy security.

This case study reviews the different technological options available for Distributed

Renewable energy Generation, their current status and future potential. The relevance of

these options for a developing country context is examined using data for India,

In order to place DG in the context of the Indian power sector, a brief background of the

Indian power sector is provided before comparing the DG options.

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4. PRESENT SCENERIO OF INDIAN POWER SECTOR:

India ranks sixth in the world in total energy consumption .India had an installed capacity of

145819 MW (As per Ministry of Power,Govt of India) as on 31st Jan 2008. Of this

92,893 MW is accounted for by thermal power plants, 36,348 MW of large hydro plants,

4120 MW of nuclear and 12458 MW of Renewable plants. However the capacity addition

has not been able to keep pace with the increasing demand for electricity. This is reflected

by the persistent energy and peak shortages in the country. The total installed capacity fuel

wise as on jan-2008 is given below.

TOTAL INSTALLED CAPACITY

FUEL MW %

COAL 76989 52.9

GAS 14704 10.1

OIL 1200 0.8

HYDAL 36348 25.0

NUCLEAR 4120 2.8

RENEWABLE 12458 8.4

TOTAL 145819 MW

From the above we can say that India had been traditionally depending on thermal power

as a major source of power generation, which constitutes about 65% of current capacity.

Balance is contributed by Hydro power (25%), Nuclear (3 %) and remaining Renewable

energy (7%).

As India is a developing country its energy demand is increasing over the years and

growth in demand for power has outstripped supply. There is a huge demand supply gap of

9% between energy requirement and energy availability. And there is peak demand

shortage of 15.2 %.

Due to this in many parts of the country, electricity is available only for few hours in a day

and is of poor quality, making it unusable for industrial purposes.

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Present Energy Availability, Demand and Shortage:

YEAR ENERGY

REQUIRMENT

(MU)

ENERGY

AVAILIBILITY

(MU)

ENERGY

SHORTAGE(

MU)

ENERGY

SHORTAGE

(%)

2004-05 591373 548115 43258 7.3

2005-06 631554 578819 52735 8.4

2006-07 690587 624495 66092 9.6

2007-08(UP

TO JAN-08

608804 554248 54556 9

Peak demand and Shortage

YEAR PEAK DEMAND

(MU)

PEAK MET

(MU)

PEAK

SHORTAGE(

MU)

PEAK SHORTAGE

(%)

2004-05 87906 77652 10254 11.7

2005-06 93255 81792 11463 12.3

2006-07 100715 86818 13897 13.8

2007-08(UP

TO JAN-08

107010 90793 16217 15.2

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From the chart we can see that country faces an average energy shortage of about 9 percent

and a peak shortage of about 15.2 percent -- reflected in power cuts nationwide.

In India most of the people live in rural areas, out off 59372 No of villages only 475117

No of villages are electrified and still 20 % of villages are yet to be electrified .And people

in many of the electrified villages are very much dissatisfied with the quality of grid power

due to they are situated at remote places.

The transmission and distribution losses are extremely high which accounts more than

25% and in some states its 35 to 40 %, this includes theft. As India is mainly dependent on

fossil fuels for energy generation it is increasing the emission of greenhouse gases in the

environment. And now India counts for world’s 3rd largest CO2 emitter from power

generation. In order to meet the increasing demand , to reduce the demand supply gap, to

electrify villages and especially to reduce CO2 emissions ,distributed renewable energy

generation is the best option .Let us see what are the options available in distributed

renewable energy generation

5. Sources of Renewable Energy Generation: India is blessed with a variety of renewable energy sources, the main ones being biomass,

biogas, the sun, wind, and small hydro power.

Solar Thermal Solar Photovoltaic

Tidal Solar

Geo thermal energy

Small hydro

Wave energy

Wind Biomass

Renewable Energy Generation

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Installed capacity of Renewable energy in India:

INSTALLED CAPACITY OF RENEWABLE ENERGY IN INDIA

RESOURCES INSTALLED CAPACITY (MW)

Wind power 657

Biomass power 9522

Small hydro power 2221

waste to energy 56

solar power 2.12

TOTAL 12458

The installed capacity of renewable energy is only 12458 MW which is 8.4 % of total

energy generation. In which Biomass is contributing 76%, small hydro 18%, wind 5%,

waste to energy 1% and solar is contributing very less portion.

Villages where grid extension is not feasible are electrified through locally available

renewable energy sources to meet universal electrification. Renewal based distributed

electricity generation systems are especially relevant for electrification of remote villages.

Grid extension may not be feasible or cost effective in many of these villages and hence

local solutions through distributed generation will have to be identified. Since renewable

are widely available and Grid connectivity is either not feasible or not cost effective.

Now we will discuss the different Renewable sources available for distributed generation.

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6. Distributed Generation Using Renewable

6.1 Wind energy :

A wind energy system transforms the kinetic energy of the wind into mechanical or

electrical energy that can be harnessed for practical use. Mechanical energy is most

commonly used for pumping water in rural or remote locations. Wind turbines generate

electricity for homes and businesses and for sale to utilities. The most economical

application of electric wind turbines is in groups of large machines (700 kW and up),

called "wind power plants" or "wind farms." Wind plants can range in size from a few

megawatts to hundreds of megawatts in capacity.

The Indian wind energy sector has an installed capacity of 1870 MW (as on March 31,

2008). In terms of wind power installed capacity, India is ranked 4th in the World. Today.

The estimated power generation capacity in India through wind is about 47,000 MW. The

installed capacity is about 1,870 MW, which is about 4% of the total estimated potential.

Wind turbines used to generate electricity come in a wide variety of sizes. Large wind

turbines, which are usually installed in clusters called wind farms, can generate large

amounts of electricity. Large wind turbines may even produce hundreds of megawatts

(MW) of electricity - enough to power hundreds of homes. Small wind turbines, which are

generally defined as producing no more than 100 kW of electricity, are designed to be

installed at homes, farms and small businesses either as a source of backup electricity, or to

offset use of utility power and reduce electricity bills.

Wind energy offers many advantages over conventional power production, including

minimal environmental impact, reduced dependence on fossil fuels, and potential long-

term income for property owners who lease land for wind farms.

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The state wise wind energy potential is as follows

states Gross potential (MW)

Andhra Pradesh 9063

Gujarat 7362

Karnataka 7161

Kerala 1026

Madhya Pradesh 4978

Maharashtra 4519

Orissa 1520

Rajasthan 6672

Tamil Nadu 4159

West Bengal 32

others 508

TOTAL 47,000

6.26.26.26.2 SmallSmallSmallSmall Hydro power: Hydro power: Hydro power: Hydro power:

Hydro power is obtained from the potential and kinetic energy of water flowing from a

height. The energy contained in the water is converted into electricity by using a turbine

coupled to a generator.

The rural energy scenario in India is characterized by inadequate, poor and unreliable

supply of energy services. Realizing the fact that mini hydropower projects can provide a

solution for the energy problem in rural, remote and hilly areas where extension of grid

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system is comparatively uneconomical, promoting mini hydro projects is one of the

objectives of the small hydro Power program in India.

Small-scale hydropower systems capture the energy in flowing water and convert it to

usable energy. Although the potential for small hydro-electric systems depends on the

availability of suitable water flow, where the resource exists it can provide cheap clean

reliable electricity.

Depending upon the energy generation capacity these hydro plants can be classified as

• Micro hydro electric schemes - Up to 101 KW

• Mini hydro electric schemes - 101 to 2000 KW

• Small hydro electric schemes - 2000 to 15000 KW

BENEFITS OF SMALL HYDRO:

Hydroelectric systems provide the following general benefits

� Hydroelectric energy is a continuously renewable electrical energy source

� ‘Fuel-free’ source of power

� Renewable energy source therefore helping to reduce greenhouse gas emissions and having

a net positive impact on the environment.

� Constant generation over long periods unlike wind and solar power

� Long lifetime of systems, typically 25 years or more Low maintenance

requirements and running costs

� Reasonable payback for grid -connected systems, often 10 years or less

� Hydropower offers a means of responding within seconds to changes in load

demand.

In India large potential of energy remains untapped in low flow high head falls in hilly

areas, river slopes, canal falls, irrigation and water supply dams which can be exploited by

installing small hydro plants. Most of this potential exists in rural and remote areas.

The estimated potential of small hydro is 15000 MW in India which can be cheaply

harnessed as a very attractive source of renewable energy.

SMALL HYDRO POWER POTENTIAL

POTENTIAL 15000 MW

INSTALLED CAPACITY 2221 MW

Thus a small hydro power can be used as a cost efficient option for distributed generation.

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6.3 Solar Energy:

Solar radiation represents the earth’s most abundant energy source. Apart from its direct

form, solar energy is responsible for creation of other renewable energy sources such as

wind, flowing streams and rivers, photosynthetic production of biomass, and thermal

gradients in the ocean. Solar energy is being used by humankind from time immemorial for

various purposes. More recent applications of solar energy, like its direct conversion to

electricity and transformation to thermal energy at various temperatures, have expanded its

potential use enormously.

Solar energy, experienced by us as heat and light, can be used through two routes

� The Thermal route uses the heat for water heating, cooking, drying, water

purification, power generation, and other applications.

� The Photovoltaic route converts the light in solar energy into electricity, which

can then be used for a number of purposes such as lighting, pumping,

communications, and power supply in unelectrified areas.

Potential of solar energy:

The geographical location of India provides long days of sunny weather for the majority of

the year. Most parts of India receive 4–7 kWh (kilowatt-hour) of solar radiation per square

meter per day with 250–300 sunny days in a year. This allows solar energy in India to be

a viable option for a means of generating electricity for a large proportion of the

population. The highest annual radiation energy is received in western Rajasthan while the

north-eastern region of the country receives the lowest annual radiation.

6.4 Geothermal Energy:

Geothermal energy is the natural heat of the earth. From the surface down through the

crust, the normal temperature gradient - the increase of temperature with the increase of

depth - in the Earth's crust is 17 °C -- 30 °C per kilometer of depth (50 °F -- 87 °F per

mile). Geothermal reserves up to depths of 10 km are estimated at 403X106 Quads.

Hot rocks underground heat water to produce steam. We drill holes down to the hot region;

steam comes up, is purified and used to drive turbines, which drive electric generators.

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There may be natural "groundwater" in the hot rocks anyway, or we may need to drill more

holes and pump water down to them.

Advantages:

� Geothermal energy does not produce any pollution, and does not contribute to the

greenhouse effect.

� The power stations do not take up much room, so there is not much impact on the

environment.

� No fuel is needed.

� Once you've built a geothermal power station, the energy is almost free.

It may need a little energy to run a pump, but this can be taken from the energy

being generated

Potential of Geothermal energy in India:

In India, there are 350 geothermal energy locations in the country. The most promising of

these is in Puga valley of Ladakh. The estimated potential for geothermal energy in India is

about 10000 MW. There are seven geothermal provinces in India: the Himalayas, Sohana,

West coast, Cambay, Son-Narmada-Tapi (SONATA), Godavari, and Mahanadi.

Potential Applications:

Power generation

Cooking

Space heating

Use in greenhouse cultivation

Crop drying

6.5 BIOMASS ENERGY:

Biogas is a mixture of 55-65 percent methane, 30-40 percent carbon dioxide and the rest is

made up of H2, H2s and N2.it can be produced from the decomposition of animal, plant

and human waste. Cow dung, piggery waste and poultry droppings can be used for

generation of bio-gas. Crop residues, kitchen waste, sea wood, human waste, waste from

sugar cane refinery are also useful for bio-gas generation.

Biomass can be utilized through following different processes for energy conversion:

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Gasification: Gasification is the thermo-chemical process of obtaining energy from solid

matter in a gaseous form. In principle, the process is a thermal decomposition of organic

matter in the presence of limited supply of air or oxygen to produce combustible gases thus

converting calorific value of organic material into a gaseous energy carrier.

Pyrolysis: In contrast to complete combustion of solid carbonaceous material, the process

of pyrolysis refers to combustion in a deficient supply of air / oxygen. The process gives

out carbon-mono-oxide and methane, which are condensed to form tar and aqueous liquor.

The latter is then distilled to give methanol and other organic substances.

Direct Combustion: Thermal decomposition of organic matter is carried out in the

presence of excess air, liberating heat and leaving behind incombustible ash.

Fuel + Air → Heat + Ash + Inert Gases

Direct combustion of Biomass is an important route for generation of grid-quality power

by efficient use of agricultural, agro-industrial and forest residues, which are either being

wasted or are being sub-optimally utilized in the country.

Biomass Potential:

India is a tropical country blessed with abundant sunshine and rains, thus offering an ideal

environment for Biomass production. Further, the vast agricultural produce also makes

available large quantities of agro-residues which can be used to meet energy needs. With

an estimated production of about 350 million tones of agricultural waste every year,

residual biomass is capable of mitigation of GHG emissions to the extent of 300 million

tones / annum.The estimated potential of Biomass based renewable energy options in India

are as follows:

Biomass potential in India

Biomass Energy 16, 000 MW

Biomass Co-Generation 3, 500 MW

Total 19, 500 MW

Installed capacity 303 MW

Economic drivers for use of locally available non-conventional energy sources are

important for distributed generation. Of all the non-conventional energies, biomass is the

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most suited for distributed electricity generation as it offers a number of advantages. Some

of the advantages of biomass energy are: it is renewable, widely and locally available, is

carbon neutral and has the potential to provide significant productive employment in rural

areas.

Additionally, in power generation mode, biomass offers following advantages:

� Ability to produce `firm', dispatchable power;

� Amenability to storage and use as per power demand;

� No need for elaborate pre-firing preparation.

Biomass has been considered one of the ideal energy resources for DG mode of power

Generation in view of these advantages.

APPLICATIONS OF BIOMASS ENERGY:

� Water pumping

� Electricity generation : 3 to 1 MW power plants

� Heat generation : for cooking gas – smokeless environment

� Rural electrification means better healthcare, better education and improved

quality of life.

6.6 TIDAL ENERGY:

Tides are generated through a combination of forces exerted by the gravitational pull of the

sun and the moon and the rotation of the earth. The relative motion of the three bodies

produces different tidal cycles which affect the range of the tides. In addition, the tidal

range is increased substantially by local effects such as shelving, funneling, reflection and

resonance. Energy can be extracted from tides by creating a reservoir or basin behind a

barrage and then passing tidal waters through turbines in the barrage to generate electricity.

Tidal energy is extremely site specific requires mean tidal differences greater than 4 meters

and also favorable topographical conditions, such as estuaries or certain types of bays in

order to bring down costs of dams etc.

Potential:

Since India is surrounded by sea on three sides, its potential to harness tidal energy has

been recognized by the Government of India. Potential sites for tidal power development

have already been located. The most attractive locations are the Gulf of Cambay and the

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Gulf of Kachchh on the west coast where the maximum tidal range is 11 m and 8 m with

average tidal range of 6.77 m and 5.23 m respectively. The Ganges Delta in the Sunder

bans in West Bengal also has good locations for small scale tidal power development. The

maximum tidal range in Sunder bans is approximately 5 m with an average tidal range of

2.97 m. The identified economic tidal power potential in India is of the order of 8000-9000

MW with about 7000 MW in the Gulf of Cambay about 1200 MW in the Gulf of Kachchh

and less than 100 MW in Sundarbans.

Available potential from all the sources:

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7. Advantages and Disadvantages of DREG:

Advantages of Distributed Renewable power generation:

� High peak load shortages: With a deficit of 15.2% in peak demand,

distributed generation systems can be used to reduce the peak demand.

� High transmission and distribution losses: Current losses amount to about

25.0 - 35.0% of the total available energy. Distributed power generation

systems can greatly reduce these losses and improve the reliability of the grid

network.

� Remote and inaccessible areas: In many parts of the country extension of the

grid may not be economically feasible. In such cases distributed generation can

play a major role.

� Rural electrification: Most of the villages are located at remote places where

grid extension is not feasible or not at all possible, in such cases DREG can be

used for electrification of these villages.

� Faster response to new power demands: The modular nature of distributed

generation system coupled with low gestation period enables the easy capacity

additions when required.

� Improved supply reliability and power quality: Disr uptions such as grid

failure, etc., can be prevented as electricity is produced close to the consumer.

The quality of power, voltage and frequency, can also be maintained easily.

� Possibility of better energy and load management: Distributed generation

systems offer the possibility of combining energy storage and management

systems.

� Optimal use of the existing grid assets: Distributed generation facilitates an

optimal use of the grid that improves the reliability of the grid network and

reduces the congestion.

Disadvantages of Distributed Renewable power generation:

� Operational complexity in connecting DG to grid.

� DG finance and access to local capital.

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8. CONCLUSION

Current worldwide electric power production is based on a centralized, grid-dependent

network structure. This system has several disadvantages such as high emissions,

transmission losses, long lead times for plant construction, and large and long term

financing requirements. Distributed renewable power generation is an alternative that is

gathering momentum, and modern technologies, such as hydropower, biomass,

geothermal, wind, solar and ocean energy. Sustainable distributed energy systems include

PV, micro gas turbine, solar thermal, solar hot water, mini hydro-electric, bio-energy, and

small wind energy systems. India has huge renewable potential of 156048 MW, which is

7% more than the present energy demand. Using distributed renewable power generation

the present problems in the energy sector can be solved such as

1. Increasing the security of supply by reducing dependency on imported fissile fuels.

2. Reduction in the emission of greenhouse gases especially CO2.

3. By electrifying the rural villages we can improve the quality of life of villages.

4. Reduction in Transmission and distribution losses.

5. Quality and reliable power

At present India is using only 20.16 % of renewable for energy generation .but India has a

potential of 79.83 %, which can be used in the form of Distributed renewable energy

generation for the sustainable future and for better quality of life.

This can be achieved by making some action planes on renewable energy such as

promotion of renewable energy technologies, Creating an environment conducive to

promote renewable energy technologies, creating an environment conducive for their

commercialization, subsidies from government for installation of small distributed

renewable energy generation units, production of biogas units, solar thermal devices, solar

photovoltaic’s, cook stoves, wind energy and small hydropower units

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9. References’ and Bibliography :

1. Willis, H L and Scott, W G. Distributed Power Generation, Planning and

Evaluation.

2. G.D.Rai, Non-Conventional Energy Sources, Khanna publications.

3. Annual report 2007-08 of Ministry of power government of India.

4. Ministry of New and Renewable energy ,official site, Government of India