R&M of Thermal Power Stations

“Emerging Scenario”C Subramaniam &

AGMJoydeep NagSr. Manager

(OS-R&M)NTPC Ltd. EOC, Noida-24

*Views expressed in the presentation are not necessarily those of the management

15 - 20 years (PLF 50 - 70%)

19%

Less than 15 years (PLF >

60%)55%

20 - 30 years (PLF 40 - 55%)

16%

30 - 40 years (PLF 30 -40%)

8%

40 years & above (PLF <

40%)2%

Age & Performance (PLF) of Utility Industries

Present Drivers of R&M in India

Low PLF: R&M is resorted to when PLF deteriorates to unviable level

De-rated Capacity: Utilities take up R&M to recover lost capacity

Life Extension: To extend life of critical components

Obsolescence: Sometimes utilities are forced to take up R&M due to obsolescence & non-availability of spares

Environment / Safety: To meet the new norms

Incentives needed for projects targeting:

•Efficiency / Capacity improvement – e.g. by uprating process parameters, redesign of boiler, improved design of turbine blades.•Fuel switch-over / substitution – e.g. retrofitting for Naptha firing, bio-mass co-firing•Earning of CER (CDM) – e.g. green house gas reduction

Incentivisation of R&M

Some Emerging Facts

1. India is the 4th largest Greenhouse Gas emitter in the world and will soon become 3rd largest

2. As per the experts, India is going to be worst hit due to global warming as it has vast tracts of glaciers, a number of glacier-fed rivers and a very long coastline.

3. Heat rate of 56 stations aggregating 38611 MW has revealed an average heat rate of 2861 Kcal / Kwhr as against a design of 2398 Kcal / Kwhr (% deterioration 19.3%). The % deterioration per year is 3.35% over previous year. (Source CEA Report for 2006-07)

Emerging Business Challenges

1. Competition from the new generation of plants (with low Cost Of Generation and project completion time as low as 25-30 months for 500 MW units)

2. Impending pollution / emission tax in line with Kyoto protocol

3. Volatility in fuel cost

4. Fuel security issues

The bottom line is that the older fleet have to remain fighting fit to sustain their economic viability

Global

reduced fuel consumption

operation free of restrictions

POWER PLANT R&M OBJECTIVES

environmental control updating

availability improvement

RESULTS

increased power output

reduced power generation cost

efficiency upgrading

increased electrical output

emissions within new norms

life extension

improved reliability

plusCDM BENEFITS

Focus of R&M in Developed World

Increase in generation with improved performance

Increase in safety, reliability, availability and operational flexibility

Recapturing and/ or enhancing of unit capacity

Extension of economic useful life by 15-20 years at comparatively lower capital cost

Benefit by way of additional life

Possibility of reducing cost of generation

R&M with Efficiency Increase

Fuel consumptionper kWh

0 20 40 years

Rehabilitation Rehabilitationw/o efficiency improvement

Rehabilitationwith efficiency improvement

Increased power output resulting from efficiency increase isfree of fuel cost, free of operational cost and free of emissions.

Internationally Utilities are adopting total R&M Solutions

• ComponentsBoiler + ESP

Turbines &Generators

Electrical

Instrumentation & Control

Cooling WaterSystems

Ash HandlingCoal Handling

Design Audit

Updating

Modernization

Replacement

EfficiencyImprovementReliabilityIncreaseReduction ofStart up TimesSparesAvailabilityCompliance toenvironmentalstandardsCyclic loadoperationExtended life time

• Benefits

Source ALSTOM

Performance Improvement after R&M

Parameter Unit Pre-R&M Post-R&MBoiler Load T/hr 815 815Life steam temperature oC 517 535Reheat temperature oC 526 540Flue gas temperature oC 215 166Boiler efficiency % 83 90NOx mg/Nm3 400 190CO mg/Nm3 75 175SO2 mg/Nm3 4,300 170Particulate matter mg/Nm3 150 3Turbine capacity MW 514.3 536.5Spec. TG heat rate kJ/kWh 8,735.0 8,510.0Efficiency LP Turbine % 76.9 85.8Net unit efficiency % 31.5 35.8

Boxberg Power Station500 MW units

Case Study of a German Power Plant

Improvement of efficiency and environmental conditions by retrofitting the units

This was mainly achieved due to using low NOx burners in boiler, redesigning of LP turbine and cooling tower modernisation

The emission levels of the units was reduced drastically due to use of low NOx burners, installing Flue Gas Desulfurification plant and optimisation of operation of ESP

Flue gas discharge through cooling towers, automatic concrete cutter for existing chimneys

Source ALSTOM

Reactive vs. Proactive Approach

R&M decisions in India are overwhelmingly Reactive in nature. Utilities wait for the performance parameters to go down, then R&M is conceived.

Whereas, the need of the hour is Proactive Approach, that is, R&M is to be planned beforehand to sustain and improve performance

The Need of the Hour

Cost effective technology upgrades

In-kind replacement

Financial Risk based R&M optimization

From Time based R&M

Pro-active R&MReactive R&M

Improve upon design efficiency

Attain design efficiency

Uprating of capacityRestoration of lost capacity

Using the technological leverage, the focus of R&M should change from:

One : One replacements

Technology Upgrades

Availability vs. Maintenance

R&M Success Stories In NTPC

Parameter Pre-R&M Post-R&M

Design load of unit (MW) 110 120

PLF (%) 52.76 85.28

Boiler Efficiency (%) 84.0 86.5

Turbine Heat Rate (Kcal/KWHr) 2175 1993

Sp Coal Consumption (Kg/KWHr) 1.00 0.65

Exit Gas Temperature (ºC) 200 145

Ash Emission (mg/Nm3 ) 250 75

Auxiliary Power Consumption (%) 2 % Reduction

R&M –Technology Upgrades Kothagudam TPS (4 X 110 MW)

Source BHEL / PPIL

Performance Targetsunit as per operation post

PG Test (as informed) retrofit(Aug’81)

Rated output [MW] 110,0 110,0 120,0

Main steam flow [t/h] 367,4 > 375 365,79

TG heat rate [kcal/kWh] 2173.3 2477,3 < 2008

Addressed Areas for R&M• HP-, IP-, LP-Turbine • Generator• Boiler Re-heater• Control & Instrumentation (Option)• HP / LP Bypass (Option)

R&M –Technology Upgrades AECO Sabarmati (1 X 110 MW)

Source NASL

Advanced Technological Solutions

Advanced Supercritical Retrofit: Vertical Tube Supercritical boiler technology is ideal for retrofitting to existing sub-critical boilers. Such a retrofit, combined with modification of the steam turbine, steam pipe-work and some of the balance-of-plant can raise the plant cycle efficiency up to 43-46% with commensurate carbon dioxide reductions. Biomass Co-firing .

Source Doosan Babcock

Retrofitting of Sub-critical Units to

Supercritical ParametersSource Doosan Babcock

Source ALSTOM

EPC Model for R&M

Challenges in R&M

••Limited Agencies for R&M implementation Limited Agencies for R&M implementation in the country.in the country.••Prohibitive cost of New Technologies Prohibitive cost of New Technologies impediment for introduction on wider scale.impediment for introduction on wider scale.••Formulation of risk sharing formula so that Formulation of risk sharing formula so that R&M is a WinR&M is a Win--Win proposition both for the Win proposition both for the utility and the vendorutility and the vendor••Unfavorable cost Unfavorable cost -- benefit analysis.benefit analysis.••R&M activity to be linked with planned shut R&M activity to be linked with planned shut down.down.

Summary

There is huge potential in India for R&M activities There is huge potential in India for R&M activities because of large number of old plants which are because of large number of old plants which are inefficient and running below design capacityinefficient and running below design capacity

Implementation of the R&M Schemes has benefited Implementation of the R&M Schemes has benefited the stations by way ofthe stations by way of

••Overcoming Technological obsolescence.Overcoming Technological obsolescence.••Low cost capacity additionLow cost capacity addition••Extending the life of equipment / components.Extending the life of equipment / components.••Complying with Statutory and Environmental NormsComplying with Statutory and Environmental Norms••Sustaining availability and improved performance Sustaining availability and improved performance

R&M should focus on ‘costR&M should focus on ‘cost--effective technology effective technology upgrades’ instead of inupgrades’ instead of in--kind replacements.kind replacements.

Summary (contd)

R&M to be planned in advance before major R&M to be planned in advance before major deterioration or breakdown of unitdeterioration or breakdown of unit

Target Objectives of R&M to be clearly identified Target Objectives of R&M to be clearly identified upfrontupfront

R&M should be taken up on a ‘Project Mode’ with R&M should be taken up on a ‘Project Mode’ with clearly identified dates akin to ‘New Builds’.clearly identified dates akin to ‘New Builds’.

Tariff after R&M and potential CDM benefits to be Tariff after R&M and potential CDM benefits to be factored in while evaluating Optionsfactored in while evaluating Options

Urgent need to enhance manufacturing capacity to Urgent need to enhance manufacturing capacity to handle load of R&M / Creation of new manufacturing handle load of R&M / Creation of new manufacturing basebase