ENERGY CONSERVATION IN THERMAL POWER STATION Engineering Staff College, Hyderabad 10th December,...

ENERGY CONSERVATION IN THERMAL POWER STATION

Engineering Staff College, Hyderabad

10th December, 2002

Key Note Address by

K. SREERAMA MURTHY, Member, APERC, HYD.


Government of India established a dedicated group within

the National Productivity Council (NPC) to address

energy efficiency issues in various sectors. NPC achieved

considerable success towards developing awareness of

energy conservation and its improvement.

One of the key initiatives taken by GOI include (Energy

Conservation Act, 2001).

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ENERGY CONSERVATION ACT, 2001 Energy Conservation Act passed in the Parliament in August

2001 and Gazetted in October 2001. Mandatory energy audit for the energy intensive industries by an

accredited energy auditor. Development of norms and benchmarks for energy in energy

intensive industries. Bureau of energy efficiency (BEE) was created to be the primary

implementing agency. Energy Management Centre, Ministry of Power merged with

BEE.


2

THERMAL POWER STATIONS ARE THE MOST ENERGY INTENSIVE INDUSTRY

Cost of fuel (input energy) is 85% of the total operating costs.

8 to 10% of final output (electrical energy) is consumed for its own auxiliaries.

Due to the above, energy efficiency issues are of the highest priority in Thermal Power Station.

Energy Audit becomes mandatory under Energy Conservation Act, 2001.


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Functions of the newly constituted BEE as per the EC Act 2001 are: Recommend to the Central Government the norms for processes

ad energy consumption standards. Promote use of energy efficient processes, equipment, devices

and systems Promote innovative financing of energy efficiency projects. Maintain a list of accredited energy auditors as may be specified

by regulations. Specify, by regulations, qualifications for the accredited energy

auditors. Specify, by regulations, the manner and intervals of time in

which the energy audit shall be conducted. Specify, by regulations, certification procedures for energy

managers to be designated or appointed by designatedconsumers.


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ENERGY AUDIT (EC ACT, 2001)

Energy audit means the verification, monitoring and

analysis of use of energy including submission of

technical report containing recommendations for

improving energy efficiency with cost benefit analysis

and an action plan to reduce energy consumption.


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Energy Service Company (ESCO)

An ESCO, or Energy Service Company, is a business thatdevelops, installs, and finances projects designed to improve theenergy efficiency and maintenance costs for facilities over a sevento 10 years time period. ESCOs generally act as project developersfor a wide range of tasks and assume the technical and performancerisk associated with the project. Develop, design, and finance energy efficiency projects; Install and maintain the energy efficient equipment involved; Measure, monitor, and verify the project's energy savings; and Assume the risk that the project will save the amount of energy

guaranteed.These services are bundled into the project's cost and are repaidthrough the money savings generated.


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Customer

Total potential - 60%

HT Transmission

Lt Distribution

Generation Improvement potential 10%

I 2 R Losses 10%

Need for End-use Energy Efficiency:Maximising system-wide benefits

Non Technical losses 20%

Inefficient end use 20%

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WHY ENERGY EFFICIENCY (EE)?“Negawatts” win over “Megawatts”

Economic Perspective (National and/or supplier) EE (or Negawatts) are cheaper than Megawatts. EE provides maximum system wide benefits. EE reduces need for imports & scarce resources. EE mitigates risk from supply vulnerabilities.Customer Perspective: Utilities come closer to customers, better control. Supply quality and reliability improvements. Lowers impact of tariff rationalization / increase. Societal Perspective: Environmental benefits (emissions and wastes)

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Performance Typical IndiaStation use 6% - 8% 6% - 12%Frequency fluctuations 0.2 Hz 2 HzVoltage fluctuations 5% - 7% 10% - 40%Statistical no-availability 0.1 hours per year About 200 - 800 hours/yearThermal efficiency 43% 37% (because of bad coal)

Technical Transmission & Distribution losses

7% - 9% from 440 Kv to 220 V (entire national

grid)

Estimated 30% from 220 KV to 220 V

Commercial losses <1% >20%Financial standing Profitable Technically Bankrupt

Comparison between a Typical and most Indian Power Utilities


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Efficiency Improvement OpportunitiesAverage 1.5% increase in effeciency of Thermal Power Plants inIndia could result in: CO2 reduction: 4.5% per annum (over 10 Millon Ton/ annum) Coal savings: 9 Million tons per annum Coal savings worth Rs. 630 Crore Higher productivity from same resources; equvalent to

capacity addition. Lower generation cost per KWh.


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% MWHeat input to boiler 100 1428Boiler losses 9.5 137Steam & feed range radiation losses 0.5 7Condenser loss 52.5 750TG set Elec. & Mech. Losses 1.5 20Works Auxiliaries 1 14Generator output 35 500

ENERGY BALANCE OF 500 MW PLANT UNIT


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Basic Rankine Cycle 41.40%Cycle with superheat 45.80%Cycle with reheat 47.50%Cycle with superheat and feedheating 52.00%Cycle with reheating and feedbeating 53.20%Carnot Cycle 52.10%

EFFICIENCY OF VARIOUS IDEAL CYCLES


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Loss GCV v% NCVp %Dry flue gas 4.00 4.30Wet flue gas 5.25 -Sensible heat in water vapour - 0.75Combustible in ash 0.25 0.25Radiation and unaccounted 0.45 0.46Total loss 9.95 5.76Boiler efficiency = (100% - losses) 90.05 94.24

Typical values of the normally calculated boiler losses for a PF-fired boiler


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GCV v NCVpHydrogen 143 050 121 840Carbon to CO 10 200 -Carbon to CO2 33 820 -

Heat values of carbon and hydrogen in kJ/kg


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Efficiency Improvement - Boiler & Auxiliaries

Boiler Performance Testing & Optimization: Balancing of coal and air flow in coal pipes of each mill. Air heater performance testing. Combustion regime evaluation to ascertain level of combustion

completion and uniformity of heat release. Evolving an optimum boiler operating regime by testing boiler under

different conditions. Assessment of reasons for loss of draft margins. Confirming accuracy of online oxygen monitor.

Feedback from these tests is used to cross-check the 'on line' stationinstruments and to plan the work to be undertaken during next overhaul.

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ENERGY EFFICIENT MEASURES IN T.P.S.

Factors during the design stage:(1) Highest steam parameters particulars the

temperature.(2) Reducing exhaust pressure.(3) Regenerative feed heating.(4) Improvements in combustion.(5) Improvements in turbine blade design.(6) Improvements in alternator performance

including the improved cooling systems.23


ENERGY EFFICIENT MEASURESDURING OPERATION

Factors during operation - Boiler:

(1) Control of excess air.

(2) Control of fireness of pulverised fuel.

(3) Keeping heat transfer areas clean - soot blowing.

(4) Keeping the tramp air (air leakage) to minimum.

(5) Control of flue gas temperature leaving the stack.

(6) Optimising the auxiliaries consumption.

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ENERGY EFFICIENT MEASURESDURING OPERATION

Factors during operation - Turbo-Generator:

(1) Controlling the throttle losses.

(2) Optimising condenser performance.

(3) Optimising feed heaters performance.

(4) Optimising auxiliaries consumption.

(5) Reduction in make-up water consumption.

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Boiler Feed Pumps 30.8%I.D. Fans 17.8%Circulating water pumps 16.4%Mills 10.5%Primary air fans 7.0%Forced draft fans 6.9%Other motors 10.6%

The energy consumption in the driving equipment of the auxiliaries is as follows:

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ENERGY CONSERVATION IN THERMAL POWER STATION Engineering Staff College, Hyderabad 10th December,...

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