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POWER GENERATION CONSTITUENTS:

INSTALLED CAPACITY OF COUNTRY AS ON 31 AUG 2008

Power sector in India constitutes four sectors, out of which thermal power accounts for much of the

power produced in India followed by hydro and then others. Due to growing power requirement and

availability of vast coal reserves will keep thermal power dominance in future also.

Pollution due to gases emitted is biggest drawback of thermal power

GREEN HOUSE EFFECT :

S

C

IE

N

T

IF

I

C

P

R

ED

I

C

TI

V

E

Air interaction

Greenhouse Gases Earth Interactions

Global

Warming Climate Change Impacts -AdaptationMitigation Strategy

Crop Productivity

Frequent Disasters

Water Scarcity

Vector borne diseases

Renewable sources

Energy Efficiency

Clean Coal Technology

CCS

EFFECTCAUSE

R. . .,

12195

8.4%

NUCLEAR

41202.8%

THERMAL

93115

64%

HYDRO,

36198,

24.8%

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The greenhouse effect is the heating of the surface of a planet or moon due to the presence of an atmospherecontaining gases that

absorb and emitinfrared radiation. The Earth receives energy from the Sun mostly in the form of visible light and nearby wavelengths.

About 50% of the sun's energy is absorbed at the Earth's surface. Like all bodies with a temperature aboveabsolute zerothe Earth's

surface radiates energy in the infrared range. Greenhouse gases in the atmosphere absorb most of the infrared radiation emitted by

the surface and pass the absorbed heat to other atmospheric gases through molecular collisions. The greenhouse gases also radiate

in the infrared range. Radiation is emitted both upward, with part escaping to space, and downward toward Earth's surface. The

surface and lower atmosphere are warmed by the part of the energy that is radiated downward, making our life on earth

possible.Earth's most abundant greenhouse gases are: water vapour,carbon dioxide,methane,nitrous oxide,ozone and cfcs.In context

to thermal power plants, emissions of the resulting CO2 depends fundamentally on fuel consumption and on

some particularities concerning its use. In the long term most of the emitted carbon compounds

degrade into CO2.Coal is considered a heavily polluting fuel in terms of black carbon, sulphates andother gaseous pollutants primarily due to incomplete and inefficient combustion.coal based TPP are

responsible for almost 21 per cent of the greenhouse gas emissions.Coal is the most carbon intensiveof all fossil fuels, emits massive amounts of carbon dioxide or CO2 leading to global warming and

climate change.

Quick coal facts:

Indian Coals Properties

Range

Ash 25 - 50%

SiO2+ Al2 03 in Ash 80 - 92%

Moisture 8 - 20%

Volatile Matter 18 - 30%

Sulphur 0.2 1.0%

Heating Value (HHV) 2500 - 5000 Kcal/Kg

Typical characteristics of flue gas:

L o s t t o O u t e r S p a c e

S o l a r

R a d i a t i o n

E a r t h s

R a d i a t i o n

R e f l e c t e dr a d i a t i o n b y t r a c e g a s e si n t h e a t m o s p h e r e

L o s t t o O u t e r S p a c e

S o l a r

R a d i a t i o n

E a r t h s

R a d i a t i o n

R e f l e c t e dr a d i a t i o n b y t r a ci n t h e a t m o s p h e

Radiation Balance With Greenhouse Gases

http://en.wikipedia.org/wiki/Atmospherehttp://en.wikipedia.org/wiki/Atmospherehttp://en.wikipedia.org/wiki/Infraredhttp://en.wikipedia.org/wiki/Infraredhttp://en.wikipedia.org/wiki/Infraredhttp://en.wikipedia.org/wiki/Absolute_zerohttp://en.wikipedia.org/wiki/Absolute_zerohttp://en.wikipedia.org/wiki/Absolute_zerohttp://en.wikipedia.org/wiki/Atmospherehttp://en.wikipedia.org/wiki/Infraredhttp://en.wikipedia.org/wiki/Absolute_zero

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Pollutant Coal fired % Gas %

CO2 8-14 4

Nitrogen 81 81

Sox 300-3000(ppm) 1 ppm

NOx 100-1000(ppm) 100-500 ppm

Particulates 1000-10,000 10(mg/m3)

Clean coal technology:

Clean coal technology is a term used to describe technologies being developed to reduce the environmental impact of coal energy

generation. These include chemically washingminerals and impurities from the coal, gasification ( Integrated Gasification

Combined Cycle), treating thefluegases withsteamto removesulfur dioxide,carbon captureand storage technologies to capture

the carbon dioxide from the flue gas and dewatering lower rank coals (brown coals) to improve the calorific quality, and thus theefficiency of the conversion into electricity.

Clean coal technology usually addresses atmospheric problems resulting from burning coal. Historically, the primary focus was on

sulfur dioxide and particulates, since it is the most important gas in the causation ofacid rain. More recent focus has been on carbon

dioxide (due to its impact on global warming) as well as other pollutants.Concerns exist regarding the economic viability of these

technologies and the timeframe of delivery, potentially high hidden economic costs in terms of social and environmental damage,and

the costs and viability of disposing of removed carbon and other toxic matter.

How CCT can be implemented:

1. Beneficiating coal (pre-combustion) coal de-watering, washing. coal washing lowers thelevel of sulphur and minerals in the coal.

2. Pollution Controls for Existing Power Plants :

a)Particulate emissions can be reduced by Electrostatic Precipitators (ESPs) and fabric filters.

ESPs are most widely used. Flue gases are passed between collecting plates.

These attract particles using an electrical charge.

b)NOX emissions can be reduced by Low-NOX Burners (LNB). These reduce the formation of

NOX by controlling the flame temperature and the chemical environment in which the coal

combusts.

c)SO2 emissions - can be reduced by Flue Gas Desulpurisation (FGD). Wet FGD, or wet

scrubbing, is most common and absorbs SO2 using a sulphur absorbing chemical (sorbent),

such as lime

3. Efficient Combustion Technologies

a)Supercritical Pulverised Coal Combustion (PCC) - uses high pressures and temperatures.This

can increase the thermal efficiency of the plant from 35% to 45%. This reduces emissions as

less coal is used.

http://en.wikipedia.org/wiki/Coalhttp://en.wikipedia.org/wiki/Mineralshttp://en.wikipedia.org/wiki/Mineralshttp://en.wikipedia.org/wiki/Gasificationhttp://en.wikipedia.org/wiki/Fluehttp://en.wikipedia.org/wiki/Fluehttp://en.wikipedia.org/wiki/Steamhttp://en.wikipedia.org/wiki/Steamhttp://en.wikipedia.org/wiki/Steamhttp://en.wikipedia.org/wiki/Sulfur_dioxidehttp://en.wikipedia.org/wiki/Sulfur_dioxidehttp://en.wikipedia.org/wiki/Carbon_capturehttp://en.wikipedia.org/wiki/Carbon_capturehttp://en.wikipedia.org/wiki/Carbon_capturehttp://en.wikipedia.org/wiki/Acid_rainhttp://en.wikipedia.org/wiki/Acid_rainhttp://en.wikipedia.org/wiki/Global_warminghttp://en.wikipedia.org/wiki/Coalhttp://en.wikipedia.org/wiki/Mineralshttp://en.wikipedia.org/wiki/Gasificationhttp://en.wikipedia.org/wiki/Fluehttp://en.wikipedia.org/wiki/Steamhttp://en.wikipedia.org/wiki/Sulfur_dioxidehttp://en.wikipedia.org/wiki/Carbon_capturehttp://en.wikipedia.org/wiki/Acid_rainhttp://en.wikipedia.org/wiki/Global_warming

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b)Fluidised Bed Coal Combustion (FBC) - allows coal combustion at relatively low

temperatures, which reduces NOX formation. A sorbent is used to absorb sulphur.

c)Coal gasification - coal is reacted with steam and air or oxygen under high temperatures and

pressures to form syngas (mostly carbon monoxide and hydrogen). Syngas can be burnt to

produce electricity or processed to produce fuels such as diesel oil.

Integrated Coal Gasification Combined Cycle (IGCC) is the technology behind some

experimental zero emission projects. It is considered the most suitable technology for

possible carbon capture and storage but less reliable than other options.In IGCC a gas turbine

burns syngas to produce electricity. Exhaust heat from the turbine is used to produce steam to

power a steam turbine.

Integrated Gasification Fuel Cells (IGFC) - a zero emission technology under development

that does away with the steam cycle. It uses hydrogen from coal gasification in a solid fuel cell

to produce electricity.

4. Super-Advanced Technologies Carbon sequestration or elimination.

>>>>>>>or v write this.>>>

CARBON DIOXIDE CAPTURE

The three main CO2 capture technologies are as follows.

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(a) Post-combustion solvent absorption (for supercritical andgasification). The flue gases are

washed with a solvent thatseparates the CO2 from the nitrogen. In a de-absorber, thesolvent is

reheated and the CO2 driven off. It is cooled and compressed ready to be piped away.

(b) Oxyfuel firing (for supercritical only). The air is separated into nitrogen and oxygen in a

cryogenic air separation unit and the fuel is then burned in oxygen diluted by recycled CO2.

The flue gas is predominantly CO2, which is then cleaned, cooled and compressed ready to be

piped away .

(c) Pre-combustion capture (for gasification only). Coal is gasified to give a mixture of

hydrogen and carbon monoxide.

In a shift reactor the carbon monoxide is converted to CO2 and hydrogen, which are then

separated. The hydrogen is then diluted with nitrogen and burned in a gas turbine. Future gas

turbines aim to reduce the necessary dilution and increase efficiency .

CCT in india:

India's state-controlled Bharat Heavy Electricals and Andhra Pradesh Power Generation, alsogovernment-owned, have signed an agreement to set up a 125 megawatt clean coal power plant.

The power plant will be sited in Vijaywada, the third largest city in the southern state of AndhraPradesh, and use integrated gasification combined cycle, or IGCC, technology.

The government said Bharat Heavy Electricals has been running a 6 MW pilot IGCC plant in Tamil Nadusince 1983, which is now being scaled up to commercial size.

IGCC produces significantly less greenhouse gases than traditional coal-fired plants, according to thegovernment, and has an operating efficiency of around 40 percent.

The government said IGCC also reduces water consumption by about 40 percent and has lower solidwaste production.

Efforts:

Integrated Gasification Combined Cycle

Integrated Gasification Combined Cycle (IGCC) is emerging as a best available technologyto utilize low quality or contaminated energy resources, coal or oil.

It can meet emission limits not achievable by other conventional or advanced competing technologies.

In particular IGCC offers refiners the possibility of reducing to zero the production of residual fuel oil,an increasingly undesired product, while at the same time, co-producing electricity, hydrogen and

steam.

It also drastically cuts SO2 emissions.

Critical Factors for Selection of IGC:

IGCC is a capital-intensive technology.

Therefore, to exploit with maximum profit all the advantages of this technology, it is important tooptimize the design to improve performance and reduce capital cost.

One important design aspect is the degree of integration between the gas turbine and the airseparation unit.

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The choice of the optimum degree of integration can bring substantial benefits in performanceefficiency and capital outlay.

How does IGCC work:

>IGCC is a combination of two leading technologies.

>The first technology is called coal gasification, which uses coal to create a clean-burning gas(syngas).

>The second technology is called combined-cycle, which is the most efficient method of producingelectricity commercially available today.

Coal Gasification:

>The gasification portion of the IGCC plant produces a clean coal gas (syngas) which fuels thecombustion turbine.

>Coal is combined with oxygen in the gasifier to produce the gaseous fuel, mainly hydrogen andcarbon monoxide.

>The gas is then cleaned by a gas cleanup process.

>After cleaning, the coal gas is used in the combustion turbine to produce electricity.

NTPC EFFORTS:

1. NTPC has set aside 1% of profit for R&D including greener power.

2. Separate setup for clean coal technology development.

3. Development of IGCC as suited to Indian coal.

4. Development of micro marine algae(consumes 30 times more co2 than plants like jathropa) apilot project taken up in simhadri.

5. studies awarded for assessment for technology for co2 capture, co2 storege

6. solar thermal based air conditioning project.

7. studies under USAID study of feasibility of 100 mw project in dadri

8. studies with BHEL study of IGCC , 100 mw demonstration plant at auria.

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Chairmans statement

TECHNOLOGY FOR HIGHER EFFICIENCY AND ENVIRONMENTAL GAINS

Environmentally alert and sensitive people should actually be pleased to know that NTPC is among the

cleanest fossil fuel based large power generators in the world as its CO 2 intensity is comparable with

the best. As the largest and most efficient power utility in India, we are committed to play our role in

dealing with the climate change related issues and we are playing an active role in finding solutions.

We are driven by our Vision on Climate Change, which is, "Going Higher on Generation reducing

GHG emissions".

Clean Coal Technologies

Adoption of Super-critical and Ultra Super-critical Technology

Your company is also considering to further increase the steam parameters and is presently

conducting a study to introduce ultra super-critical technology in the unit sizes of 660/800 MW

units for future power plants. This has the potential to achieve efficiency levels of over 41%

CO 2 Reduction through Super-critical Units: An approximate estimation shows that by adoption

of super-critical technology with unit configuration of 6X660 MW or 5X800 MW, the coal consumption

over the 25 years'life time of the power plant reduces by 26 to 30 million tons as compared to coal

consumption by a typical sub-critical 4,000 MW power plant with unit configuration of 8X500 MW. The

consequent CO 2 emission reduction is also expected to be about 33 million tons.

Considering that your Company is going to undertake super-critical units in a large number of projects,

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and even ultra super-critical units in the longer term will save substantial amount of coal and thereby

substantially reduce CO 2 emissions

Going forward, your Company intends to stop setting up sub-critical units in its new green-field

projects.

Induction of IGCC technology for Indian Coal: Your Company is making efforts for induction of

Integrated Gasification Combined Cycle (IGCC) technology which has potential to achieve higher

efficiencies and reduction of CO 2 emissions. With this objective, your Company has decided to appoint

a reputed consultant to assist in preparation of technical specifications and providing services as

owners engineers