Power Generation In India

Industry Information Insights 2014

Rewave Infra Solutions EnergySector.in

Table of Contents

Introduction

Thermal Power Plants

Hydel Power Plants

Nuclear Power Plants

Generation Capacity in India

Year-wise Trends in Generation Capacity

Power Generation

Introduction

Level of voltage could be changed virtually to any otherdesired level with transformers which was hitherto impossiblewith D.C system.

A.C Generators

A.C power can be generated as a single phase or as a balanced poly-phase system. However, it was found that 3-phase power generation at 50 Hz will be economical and most suitable.

Present day three phase generators, used to generate 3-phasepower are called alternators (synchronous generators). Analternator has a balanced three phase winding on the statorand called the armature. The three coils are so placed in spacethat there axes are mutually 120° apart.

From the terminals of the armature, 3-phase power isobtained. Rotor houses a field coil and excited by D.C. Thefield coil produces flux and electromagnetic poles on the rotorsurface.

One of the many ways to measure the advancement of acountry is the index per capita consumption of electricity -more it is more advanced the country is.

History of Power Generation

Historically, electrical power was available from batteries with limited voltage and current levels.

D.C generators were developed first to generate power inbulk. However, due to limitation of the D.C machine togenerate voltage beyond few hundred volts, it was noteconomical to transmit large amount of power over a longdistance.

In later half of eighties in nineteenth century, it was proposedto have a power system with 3-phase, 50 Hz A.C generation,transmission and distribution networks. Once A.C system wasadopted, transmission of large power (MW) at highertransmission voltage become a reality by using transformers.

Interconnected Power Systems

A power station has more than one generator and thesegenerators are connected in parallel. Also there exist a largenumber of power stations spread over a region or a country. Aregional power grid is created by interconnecting thesestations through transmission lines.

Suppose due to technical problem the generation of a plantbecomes nil or less, then a portion of the demand of power inthat area still can be made from the other power stationsconnected to the grid. Thus, complete shut down of powercan be avoided in an area in case of technical problem in aparticular station.

In an interconnected system, with more number of generatorsconnected in parallel, the system voltage and frequency tendto fixed values irrespective of degree of loading present in thesystem.

Frequency and Voltage

The frequency of the generated emf for a p polar generator isgiven by

• F = np/2; where n is speed of the generator in rps

• F = np/120; when n is in rpm (revolutions per minute)

Frequency of the generated voltage is standardized to 50 Hz inIndia and several European countries. In USA and Canada it is60 Hz.

For a 2 pole generator, 3000 rpm is required for 50 Hz powergeneration.

All electrical appliances (fans, refrigerator, TV, etc.) are to beconnected to A.C supply are therefore designed for a supplyfrequency of 50 Hz.

Frequency is one of the parameters which decides the qualityof the power supply.

Thermal Power Plants

In India, coal is available in abundance and so thermal powerplants are most popular. However, these plants pollute theatmosphere because of burning of coal.

Stringent conditions (such as use of more chimney heightsalong with the compulsory use of electrostatic precipitator)are put by regulatory authorities to see that the effects ofpollution is minimized. A large amount of ash is producedevery day in a thermal plant and effective handling of the ashadds to the running cost of the plant.

The speed of alternator used in thermal plants is 3000 rpmwhich means 2-pole alternators are used in such plants.

The generator is run at some fixed rpm by some externalagency to generate voltage at 50 Hz. A turbine is used torotate the generator. Turbine are of two types - steam turbineand water turbine.

In a thermal power station, coal is burnt to produce steamwhich in turn, drives the steam turbine and hence thegenerator (turbo set).

In a thermal power plant coal is burnt to produce hightemperature and high pressure steam in a boiler. The steam ispassed through a steam turbine to produce rotational motion.The generator, mechanically coupled to the turbine, thusrotates producing electricity.

Chemical energy stored in coal after a couple oftransformations produces electrical energy at the generatorterminals.

Proximity of a generating station nearer to a coal reserve andwater sources will be most economical as the cost oftransporting coal gets reduced.

Hydel Power Plants

Water turbines generally operate at low rpm, so number ofpoles of the alternator are high.

In a hydel power station, water head is used to drive waterturbine coupled to the generator. Water head may beavailable in hilly region naturally in the form of water reservoir(lakes etc.) at the hill tops.

The potential energy of water can be used to drive the turbogenerator set installed at the base of the hills through pipingcalled pen stock.

Water head may also be created artificially by constructingdams on a suitable river. In contrast to a thermal plant, hydelpower plants are eco-friendly, neat and clean as no fuel is tobe burnt to produce electricity.

While running cost of such plants are low, the initialinstallation cost is rather high compared to a thermal plantsdue to massive civil construction necessary.

Also sites to be selected for such plants depend upon naturalavailability of water reservoirs at hill tops or availability ofsuitable.

Nuclear Power Plants

To ensure sustainable chain reaction, moderator and controlrods are used. Moderators such as heavy water (deuterium)or very pure carbon 12C are used to reduce the speed ofneutrons.

To control the number neutrons, control rods made ofcadmium or boron steel are inserted inside the reactor. Thecontrol rods can absorb neutrons. If we want to decrease thenumber neutrons, the control rods are lowered down furtherand vice versa.

The heat generated inside the reactor is taken out of thechamber with the help of a coolant such as liquid sodium orsome gaseous fluids. The coolant gives up the heat to water inheat exchanger to convert it to steam.

Nuclear Power Plants

The present day atomic power plants work on the principle ofnuclear fission of 235U. In the natural uranium, 235U constitutesonly 0.72% and remaining part is constituted by 99.27% of238U and only about 0.05% of 234U.

The concentration of 235U may be increased to 90% by gasdiffusion process to obtain enriched 235U.

When 235U is bombarded by neutrons a lot of heat energyalong with additional neutrons are produced. These newneutrons further bombard 235U producing more heat andmore neutrons. Thus a chain reaction sets up.

However this reaction is allowed to take place in a controlledmanner inside a closed chamber called nuclear reactor.

The initial investment required to install a nuclear powerstation is quite high but running cost is low. Although, nuclearplants produce electricity without causing air pollution, itremains a dormant source of radiation hazards due to leakagein the reactor. Also the used fuel rods are to be carefullyhandled and disposed off as they still remain radioactive.

The steam then drives the turbo set and the exhaust steamfrom the turbine is cooled and fed back to the heat exchangerwith the help of water feed pump.

Generation Capacity In India

Mode Capacity (MW) Share (%) of Total

Thermal 168254.99 69.2

Nuclear 4780.00 2.0

Hydro 40531.41 16.7

RES 29462.55 12.1

Total 243028.95 100.0

Total generation capacity as on 31 March, 2014 andcontribution by thermal, hydro, nuclear and renewablesources in India are given below.

Thermal69%

Nuclear2%

Hydro17%

RES12%

Source-wise Installed Power Generation Capacity

Sector-wise Capacity

Sector Capacity (MW) Share (%)

State 92,187.70 37.93%

Private 82,715.30 34.04%

Central 68,125.95 28.03%

Total 243,028.95 100.00%

State38%

Private34%

Central28%

Sector-wise Share of Power Generation Capacity

State

Private

Central

Year-wise Trends

In 2013-14, the annual power generation capacity additiongrowth rate stood at 8.81%.

The capacity increased from 223.34 GW in March 2013 to243.03 GW in March 2014.

112.68 118.43 124.29132.33

143.06 147.97159.40

173.63

199.88

223.34243.03

0

50

100

150

200

250

300

2003-04 2004-05 2005-06 2006-07 2007-08 2008-09 2009-10 2010-11 2011-12 2012-13 2013-14

GW

Trends in Power Generation Capacity

Power Generation

Source Million Units

Thermal 792477.11

Hydro 134847.52

Nuclear 34227.79

Bhutan Import 5597.9

Total 967150.32

Gross annual power generation in India during 2013-14 was967.2 billion units as against the target of 975 billion units.This figure excludes electricity generation from plants lessthan 25 MW.

Source-wise Power Generation

Thermal82%

Hydro14%

Nuclear3%

Bhutan Import

1%

Source-wise Power Generation

558.3 587.4 617.5 662.4 704.5 723.8 771.6 811.1876.8 912.1 967.2

0

200

400

600

800

1000

1200

2003-04 2004-05 2005-06 2006-07 2007-08 2008-09 2009-10 2010-11 2011-12 2012-13 2013-14

BillionUnits

Annual Gross Generation Trends

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