energy conservation - case study power_6thnov_09_ai… · 6th november 2009, mumbai 5 energy...

6th November 2009, Mumbai

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EnergyConservation- Case study

EnergyConservation- Case study

Sachin S Gurao

Tata Power Company


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Energy Conservation Initiatives – Press ReleasesTata Power flagship Energy Conservation

campaign “Energy Club” attains a critical milestone

Tata Power takes the next big leap in Energy Conservation; Empowers It’s harbingers (Energy Champions) for a greater role

Tata Power Organizes ‘Energy Champions Meet’

Tata Power takes its energy conservation to the youth

Aug 24 2009

May 25 2009

Jan 2009

Sept 17, 2008


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Energy Conservation in Power Utility

• A power plant produces electrical energy and also consumes a substantial amount of energy in the form of auxiliary consumption required for various plant equipments and services

• Management attitude -The top management of the company is committed to, and has the right attitude towards energy conservation. This is passed on to the the plant staff for ensuring success by Quality Management Systems such as Tata Business Excellence Model and ISO


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Trombay Generating Station

• Installed Capacity - 1600 MW

• ISO 9001:2000 Certified

Perception has changed to strike a balance between reliability and energy

conservation


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Energy Conservation in Power UtilityEnergy conservation in Power Utility is achieved mainly by-1) Operating the equipments at maximum efficiency.2) Reduction of Auxiliary Power Consumption

Energy Conservation Measures adopted at Tata Power have taken both these factors into consideration


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Factors affecting Auxiliary Consumption

• Unit Generation and Load Pattern• Operation of Plant Auxiliaries

• Service auxiliary such as Illumination, Air Conditioning etc

• Unit startups / shutdowns


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Energy Saving Techniques

Energy saving Techniques adopted are classified in the following categories -

– Design and Conceptual Stage– Techniques developed through O&M

experience– Energy auditing by external agencies


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Design and Conceptual Stage



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• Use of Steam Turbine driven Boiler Feed Pumps. ( 2 X 9 MW)

• Pioneered concept of using Variable Speed Drives for Large Motors by using LCI drives for 4 X 2 MW ID Fan Motor of 500MW Unit

• Use of Fluid Coupling for Motor Driven Boiler Feed Pump


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Techniques developed through O&M Experience



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In addition to techniques adopted at design stage various initiatives have been taken over the years to optimise the Auxiliary Power Consumption. These are

– Modification in Operation Strategy to achieve Optimisation

– Installing energy efficient devices– Monitoring of Aux Power Consumption –

continuously improving the levels and accuracy – Knowledge sharing and benchmarking with

other power utilities


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Modification in Operation Strategy to achieve Optimisation

Modification in Operation Strategy to achieve Optimisation


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Efficiency enhancement of ACW pumps by coating of casing and impeller

Totally 6 pumps have been coated

Power saving 262800 KWh ( Rs 6,57,000) annually

Flat belt drive for ventilation fans ( reduces transmission losses)

Implemented for 2 fans

Saving achieved : 61320 KWh (Rs 1,53,300) annually

Optimisation By Modifying Operations


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Previous system System modification Saving achieved O&S building AC(110 TR) - 3 compressors running in the day and 2 in the night

Timer based running of 1 compressor from 17:15 Hrs to 08:00 hrs

Rs 13.5 Lacs annually (540000 KWH)

All 26 AHU in 13 locations in service for 24 Hrs.

Timer based switching OFF 1 AHU in each location from 19:00 Hrs to 08:00 Hrs

Rs 11.5 Lacs annually (424787KWH)

Air washer system Unit-6 East side- X3 air washer pumps (55KW): 2 pumps running to cater for system requirement

Running 1 pump is adequate during monsoon and winter seasons ( 6 months)

Rs 5.9 Lacs Annually(237600 KWH)



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Previous system System modification Saving achieved

Air washer system Unit-6 west side- 2X3 air washer pumps(37.5KW): 2 pumps running to cater system requirement


Rs 8.1 Lacs(321408 KWH) Annually

Air washer system east and west side - 2X3 air washer pumps running to cater system requirement


Rs 8.1 Lacs (321408 KWH) annually



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Installing Energy Efficient Equipments

Installing Energy Efficient Equipments


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VFD for Heater Drip Pump OF 2 UnitsIdea Description

Earlier case :

– Heater drip pump was loaded up to only 40 % of its capacity & header pressure is 20 % higher than the design value with control valve throttled at 69 %.

Present case :

– VFD installed to operate the pump at lower RPM with control valve fully open to meet the flow requirement.

KPI Impact Savings

Rs. 40 Lacs

Investments

Rs. 80 LacsSpecific Power Consumption

Risk Factors

• Required header pressure & control cannot be controlled at lower loads

Risk Mitigation

• Operate control valve at lower loads


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VFD FOR HEATER DRIP PUMP : Earlier

LPH-2

Drain receiver

0.5 Bar 26.7 Bar

69% Open

LIC

Condensate system

Case with 500 MW– Flow: 20 Kg per Sec– RPM: 1450– AMP: 25-26– KW: 220-230


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VFD FOR HEATER DRIP PUMP : Present

Drain receiver

0.5 Bar 14 Bar

100% Open

LIC

Vary RPM

Case with 500 MW

Flow: 20 Kg per SecRPM: 1060KW: 80-85

LPH-2Condensate system


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VFD for CRP & BFP

CRP - Condensate Recirculation Pump : CRP is provided for recirculation condensate water of feed water tank through CPH (Condensate pre-heater). Its main function is to maintain cold end temperature of CPH. Normally when it operates its control valve is throttled up to 65% indicating power loss in form of throttling losses. Reduction in speed results in increase in control valve opening & thereby energy saving.

Low Pressure Boiler feed Pump : LPBFP is provided for feeding water to LP drum. Normally when it operates at full speed its control valve is 55 % open in full load condition indicating power loss due to throttling. Reduction in speed results in increase in control valve opening & thereby energy saving.


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CRP

C/V

FWT

22 Bar / 3000 RPM

35 % Open

CPHCPH inlet line

CRP discharge to CPH inlet

CPH outlet to Feed water tank

VFD

VFD FOR CRP

BEFORE AFTERFlow: 14 Kg/Sec

RPM: 3000KW: 50

Flow: 14 Kg/SecRPM: 2535

KW: 31

Benefit : Rs. 12 lacs Annually


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FWT

28 Bar / 3000 rpm

55 % Open at full load

VFD

LP Drum

VFD FOR LPBFP

BEFORE AFTERFlow: 12 Kg/Sec

RPM: 3000KW: 50

Flow: 12 Kg/SecRPM: 2279

KW: 31Benefit : Rs. 12 lacs Annually


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BENEFITS

The main benefit is the electrical energy saved which is ~ 2 MUs per annum. Also the project has pay back period of less than 2 years.

This project can qualify for CDM ( Clean development mechanism) for getting Carbon Credits.

Reduction in throttling of control valves increases its life & reduces corresponding maintenance cost.

Due to soft start of the 415 V motor its high inrush current during starting is prevented. This reduces the motor heating & increases its life.


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ENCON ACTIVITY

Optimization of auxiliary power consumed in Lighting and Air Conditioning

Optimizing & Switching OFF unwanted Lighting Optimizing AC temperature set points.

WITH DUE RESPECT TO PLANT OPERATION & SAFETY

Minor modification can lead to large savingEasy to implement

No large investment required


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LIGHTING ENERGY CONSERVATION DONE IN TWO MAIN PARTS

Operation Area-Operation staff – 24 hours

-Light required whenever Operator takes round or when there is an emergency

-Implemented by using Push Button Station at all entrances

Office and Service Area & street

lighting-Staff in General shift and some staff waits back. Not there on Holidays

- Implemented by installation of timers

-Timers give Off command every 1 hour after office timing


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BEFORE AFTER

Battery Room


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BEFORE AFTER

Switchgear Room


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BEFORE AFTER

Locker Room


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TG Deck Entrance From O & S buildingBEFORE AFTER


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Energy Saver for LightingBackground

Large lighting load at Trombay

Features

• Has bypass facility

• Enhances lamp life

Project done

Use of 25 KVA Escosaver

Optimise system impedance to save power

Power Saving

Upto 40%


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Savings before and after operation of Energy Saver

3.501.751.564.414.174.64KVAR

3.913.023.226.545.676.50KVA

2.512.462.754.243.924.51KW

0.610.820.880.640.690.68Cos φ

17.312.212.526.924.925.5Current (A)

B phaseY phaseR phaseB phaseY phaseR phase

Power-Saver ModeDirect ModeParameter

Initial energy consumption / day (Without Power-Saver) = 254 kWh / day

Energy Consumed / day (With Power-Saver) = 147 kWh / day


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Other Modifications• Replace Filament Lamps with LED Lamps• Replace Conventional Ballast of tube lights with Electronic

Ballast• Timers for exhaust fans • Increased Chilled Water Set Temperature in O & S A/c plant• Lighting system based on Timers• All A/C systems and Window A/Cs set at 24 0C• Trombay Housing Colony Lighting

Total Savings due to Energy Conservationat Trombay Plant & Colony

Monthly Saving (KWH) : 12938.4Monthly Saving (Rs) : 32346


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Proposed ActivitiesSr No. Proposed activity

1Timer settings of other external locations viz. Coal yard, Station A switchyard etc are to be modified

2 Energy savers to be shifted from LDB's to major energy guzzlers

3Connecting photo sensitive devices to the lighting panels which are operated manually

4 Conducting awareness programs in residential colony

5 Optimising street lighting in colony

6Reducing operating voltage by adjusting lighting transformer tap( where-ever possible )

7To change the timer setting of O&S building Centralised AC so as to switch it OFF earlier during evening peak

8 Replacement of colony household incandescent bulbs by CFL

9 Utilise solar heater for daily hot water requirement in the housing colony


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Energy auditing by external agencies


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Energy audit of the AC system by Voltas


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Conclusion

• Comparison of auxiliary power consumption of Thermal Power Utilities– India benchmark – 6.33%– International benchmark – 3.99%– Tata Power – 4.33 %

• Tata Power’s Auxiliary Power Consumption has been acknowledged by CEA as one of the best in India


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“Nothing worthwhile is ever achieved without deep thought

and hard work.”

J R D TATA

energy conservation - case study power_6thnov_09_ai… · 6th november 2009, mumbai 5 energy...

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