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FlexibilisationOperation in coal Plants-Indian Scenario

Renewable Integration & Sustainable Energy Initiative

Greening the Grid (GTG) Program

A Partnership between USAID/India and Government of India

18th Feb,2019

• Changing Power Sector Scenario

• Scenario in 2022

• Impact of Variable Renewable power

• Barriers of Flexibilisation

• Benchmarking and Preparation

• Leveraging Digitalization for flexibility

• Cycling Costs

• Operation and Maintenance Strategy

• Initiatives with International cooperation

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Outline

Changing Power Sector Scenario

Installed capacity

Today Target

~349 GW ~ 948 GW by 2032

Per capita consumption ~ 1075 kWh ~ 3026 kWh

…(World average)

Renewable capacity ~72 GW 175 GW (by 2022)

Generation (in BUs) ~1165 BUs ~1552 BUs by FY 19

1. Government’s focus on attaining affordable “24x7 Power for All” by 2019. 2. Energy Sector growing at a CAGR of ~7%-8%. 3. Big push to Renewable Energy- to grow from ~72GW presently to 175GW by 2022.

AT & C Losses ~24.82% 15% by FY 19

Peak Load Demand ~160 GW ~229 GW (by FY 19)

Source: MOP, CEA

Although coal will remain the mainstay of energy security in India, there will be a fundamental change

in the business model of coal based stations.

Preparation and management of Flexible Operation of Fossil based plants will be a critical factor for

survival in the Changed Business Environment and will need Realignment of Strategies .

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Emerging Scenario & Need for Flexibility ..1 As per NREL study on Grid Modeling for India (2016), for a 2022 scenario, technical minimum of 70% for coal-based

plants would result in RE curtailment of about 3.7%. The curtailment reduces to 0.76% for a tech. min. of 40%

Thermal under increased VRE Baseload Cycling Impacts of Plant Cycling on Damage Rates and the ultimate Costs of providing power

Critical risks of process safety, increased costs, higher probability of equipment failure and reduction in unit life associated with cycling will need effective management

Building a Business Case for Flexibilisation

Flexibilisation: Why Bother? Or Why should I get ready? …What to do?

Source: CEA committee Report on Roadmap for flexible operation

Key Facts of Cycling

Almost any unit can be cycled.

This can be done with minimal capital investment.

However, we have to account for:

Long term penalty of increased wear & tear damage and reduced

reliability.

Short term penalty of higher heat rate, increased O&M, training

requirements, and equipment efficiency.

Component Damage can be determined

Understand amount of damage present

Rate of accumulation

Total damage before failure

Cycling a power plant is more difficult operating mode than

baseload operation.

Barriers to Flexiblisation

Operating Expertise to be created

Simulators for flexible operation

New Analytical Tools required

Increased Digitilisation

One time investment for making units flex ready.

Country-wide cost estimated at 14,000 crores for

82 GW capacity.

Most of the state Utilities yet to reduce

minimum load levels

Geographical Concentration of Renewable

Transmission constraints

Curtailment of RE

In India ,Market participation is

limited. (Net Traded Energy is <

5%)

Largely under Long Term Contract

arrangements(PPA),which have

limited flexibility.

Incentivization through regulation or market needed.

Grid codes..

AGC,Anciliary services

Flexibilisation for

Integration of

175 GW RE

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Flexibilization: Benchmarking and Preparation

• Defining from different perspectives

Defining

• Metrics

• Quantifying Measuring

• Sources, options

• Preparedness for Coal based plants

Operational

-isation

• Regulatory framework

• Market structure and mechanisms

Compensation/

Incentivisation

Merit order based on?

•Variable Cost

•Heat Rate

•Emissions

Mechanisms for

operationalization

Ancillary service,

DSM, AGC

Choosing which units to flex?

• Units on base load-Energy supply

sources stacking to meet the total

state energy need are classified as

sources that will always have

demand and hence shall run on

max. allocated share i.e. base load

operation.

• Flexible Units on low load &

evening peak- Daily in the evening

generation from Solar would

come to zero and this energy

need would be satisfied by units on

merit, who would run on min. load

and support his evening need +

portion of the demand peak.

• Flexible Units-Daily start &

peaking- If the peak is not met by

the low load and peaking units up

in the merit order, then new

sources shall be started daily till

the balance peak need is met.

Maintenance schedule …

Retrofits/R&M..

EHS

EFOR, EOH

Reliability

Knowing the component-wise cycling costs is necessary for deciding maintenance

schedules

Plant Categorization

ECR<< State M.O. GCV < 2800,VM<15%

Supercritical (except 14 Units)

Base Load 140GW, 299Units

ECR=> State MO (>Rs.2.5/kWh) GCV >2800,VM > 15%

ECR>> State M.O. (unlikely to get schedule in 2022)

HR>2500, GCV>3400

Flexible Daily Start 13 GW, 83 units

Units>25 Years Unit size-200 and above

HR> 2500

>25Year HR>2600 Unit sizes<200 MW

Retire/replace

Flex with Efficiency Retrofit 21 GW, 80 units

Flexible-Low Load (48.4 GW, 139 units

Metrics Category

9

Regulatory Context

10

Economics of Cycling

Start Up Cost Impacts • Cycling start costs have

a very large spread or variation & unique to every start-up type (Cold, Warm and hot)

• Certain procedures such

as coal drying can reduce pulverizer startup costs

O & M Cost

• Increased life consumption

• Increased Maintenance

is required

• More frequent component replacements

• Heat rate impacts

Reliability Impacts-Equivalent Forced Outage Rate (EFOR)

• Load following & ramping

costs due to accelerated life consumption

• Increased maintenance requirement

Environmental Impacts

• Specific (Kg/MWh) NOx, SOx & CO emissions will be somewhat higher at a unit level while flexing. Overall emissions would reduce for flexible units due to reduced coal usage.

• Significant adverse impacts are very unlikely as most of the plants have well performing ESPs/Dust Hoppers for addressing any increased emissions

• CERC vide issuance of 4th Amendment to IEGC Regulations 2010, notified the Technical Minimum in respect of a unit (s) for CGS or ISGS as 55% of MCR loading or Installed Capacity of such unit(s). Amended regulations also provide for compensation for the following;

– Heat rate degradation

– Increased auxiliary consumption

– Increased Oil consumption

• Coal based plants operating on flexible modes i.e. Pmin < 55% and subject to cycling, load following and two-shifting require additional compensation mechanisms/ allowances for increased capex and opex costs

• Regulatory provisions for frequent start-ups & high ramping needs to be evolved

• Ancillary Services need to recognize costs of flexibility (in regulated approaches) or provide a market mechanism which allows for recovery of additional costs.

Regulatory Context

A Supply Offer in CAISO would have the following cost components (considered in the SCED co-optimsation of energy and ancillary markets)

• Startup costs associated with bringing a resource online from being shut down:

– Broken down into Cold, Intermediate and Hot Startup Costs

• Operational Ramp Rate expressed in megawatts per minute (MW/min) as a function of the operating level - must be a staircase function with up to four segments.

• Transition costs associated with moving from one configuration to another for multi-stage suppliers (MSG),

• Minimum load costs associated with operating the resource at the minimum operating level (Pmin) where a resource cannot drop below without compromising the resource’s operation

• Incremental energy costs associated with producing energy above Pmin at each operating level

India International Example of cost components

Flexibilization Costs

CAPEX

OPEX

Increased Forced Outages.

Life consumption costs

Load Following Costs

(significant load follows)

Increased Ramp Rates

Start-up Cost (Aux. Power + Chemicals + Water + life consumption)

Start-up Oil

Heat Rate effects due to Power Plant Cycling

O&M costs

One-time cost required for preparing units for Flexing

ECR costs Under-

utilization /Oppor. loss

500 MW UNIT

Oil cons. in Kl

200/210 MW

Oil cons.in Kl

COLD 90 50

WARM 50 30

HOT 30 20

Approx. Rs. 20-50 Cr Capex / 200 MW unit as per OEDs’ (Siemens & GE at Dadri & Simhadri) estimate

-10

0

10

20

30

40

50

90% 80% 70% 60% 50% 40% 30%

Addl. Paisa/ Kwh(Eff. Loss)

200/210MW 500 MW 660MW

Sub C units 200-MW Units are economically better suited for Flexible operation

Flex

Co

sts

0255075

100125150175200225250275300325 200MW unit- Typical Tariff Impact

(Paisa/Kwh)

Due to HR Add. O&M* Start up oil

0

50

100

150

200

250

300

350

500MW unit- Typical Tariff Impact (Paisa/Kwh)

Due to HR Add. O&M* Start up oil

Typical Cost Impact for 200/210 MW unit ECR 200.0

200/210MW Unit

Additional Impact--> Due to HR Add. O&M Start up oil Addl. total

charges

Sr. No. Unit loading % Increase in

NHR (%) Addl. Paisa/ Kwh

1

Minimum load with

significant load following

90% NIL 0 0.00 0 0 2 80% 0% 0 0.00 0 0

3 70% 1.1% 2.1 3.31 0.0 5.4 4 60% 3.8% 7.5 3.31 0.0 10.8

5 50% 7.5% 15.0 3.31 0.0 18.3 6 40% 11.6% 23.2 3.31 0.0 26.5

7 30% 17.3% 34.6 3.31 0.0 38.0 Weekly start 11.6% 23.2 60.22 14.8 98.2 Daily start 3.8% 7.5 257.39 65.2 330.1 • Costs based on study conducted under USAID GTG-RISE program with technical support from M/s

Intertek AIM, USA at Ramagundam & Jhajjar TPS of NTPC

Two significant load following for units with PLF <=70% Average PLF for load following=63% For daily starts(1 cold start/week,4 warm start/week,2 hot start/week) PLF of daily start units=43% PLF of weekly start units=45% No oil consumption for v.low load operations has been considered

Assumptions

Typical Cost Impact for 500 MW unit ECR 200.0

500 MW Unit

Additional Impact--> Due to HR Add. O&M

Start up oil

Addl. total

charges

Sr. No. Unit loading % Increase in

NHR (%) Addl. Paisa/ Kwh

1

Minimum load with significant

load following

90% 1% 1.1 0.0 0.0 1.1

2 80% 1.7% 3.4 0.0 0.0 3.4 3 70% 3.3% 6.7 7.15 0.0 13.8 4 60% 6.3% 12.6 7.15 0.0 19.7

5 50% 10.0% 20.0 7.15 0.0 27.2

6 40% 13.8% 27.6 7.15 0.0 34.8

7 30% 19.0% 38.0 7.15 0.0 45.2

Weekly start 13.8% 27.6 69.18 10.7 107.5

Daily start 6.3% 12.6 307.74 43.5 363.8 • Flexible operation leads to a higher rate of deterioration of components; estimate of increase

in O&M Cost is a representation of damage costs (deterioration in life)

• Costs based on study conducted under USAID GTG-RISE program with technical support from M/s Intertek AIM, USA at Ramagundam & Jhajjar TPS of NTPC

THE NEXT STEPS….. Inside the plant

Strategies to unlock flexibility in coal generation plants in India

1. Changes to Operational Practices for Existing Plants

• Significant new capital

investments are not mandated • Changes to certain plant

operational practices – improved data collection & real-time monitoring; can unlock latent flexibility

2. Operation of HP/LP bypass Periodically for Fast Load Reduction

• Power plants in Europe

regularly operate HP/LP bypass for fast load

• This is not prevalent in India

due to economic reasons - higher fuel consumption & significant loss in efficiency

3. Flexibility retrofit investments for existing plants

• Range of retrofit options are

available to improve various flexibility parameters of power plants

• A detailed study is required to

select units to implement retrofits

4. Efficiency Retrofits for Very Old & Inefficient Plant

• Old plants can be run for a very limited duration & can be an effective low-cost solution

• In Germany, 40 year old plants are upgraded for start and stop operations twice a day along with load following

5. Incentivizing Additional Power Plant Flexibility Investments

• Regulated & market-based power

systems can ensure fair compensation for coal plant’s flex services

• Policy support for reviewing inflexible

contract terms & creating new revenue streams for flexibility services can encourage plant owners to operate more flexibly.

Operational practices for minimising cycling damages

• Modifying start-up/shutdown ,ramping procedures to lower the component fatigue stresses

• Plant lay-up procedure

• Operations like forced cooling of boiler must be based on economics rather than maintenance requirement

• Modified chemistry chemistry monitoring

• Use of nitrogen blanketing

• Ensure deaerater heating and SCAPH during start-up

• Modifying inspection plans around cycling plants

• Tuning of auto control loops

• Judicious use of HP/LP bypass

• Sliding pressure operation

• Taking oil guns for short run may be worthwhile instead of jeopardising the integrity of assets

• Ensure operation of dampers, dranis and vents

• Modifying start-up/shutdown ,ramping procedures to lower the component fatigue stresses

• Plant lay-up procedure

• Operations like forced cooling of boiler must be based on economics rather than maintenance requirement

• Modified chemistry chemistry monitoring

• Use of nitrogen blanketing

• Ensure deaerater heating and SCAPH during start-up

• Modifying inspection plans around cycling plants

• Tuning of auto control loops

• Judicious use of HP/LP bypass

• Sliding pressure operation

• Taking oil guns for short run may be worthwhile instead of jeopardising the integrity of assets

• Ensure operation of dampers, dranis and vents

Cycling Damages in boiler components-Global Benchmark

In the Indian condition,we have limited data. Benchmarking for other units will be done.

Future maintenance strategy to address the increasing cycling damages will be based on: • Cycling frequency and age of unit • Boiler Component/Damage ranked on most

affected by cycling • Inspections schedules/Corrective

Actions(anticipated repairs, and Replacements) • Cost benefit analysis

Identification of the damage mechanism by examination and monitoring. The state of knowledge of the underlying mechanism and root cause Self-calibrating incremental damage models that can be used to forecast the effect of frequency and severity of cycling, including failure rates

Maintenance planning-scope & schedule • Systematic records of all components

• Optimise maintenance expenditure

• Overhauling duration, timing and scope-Greater OH frequency in later years of life and cycling

• Failure statistics

• Failure faults-independent of operation

• Due to construction, design, operating errors etc.

• Predictable faults and dependent on service time

• Wear and tear of ageing component

• Corrosion, erosion and distortion

• Creep and fatigue damage

• Cycling

It is necessary to tailor the overhauling and maintenance intervals for the particular unit on the basis of data available.The analysis of component-wise cost data is important

Metrics of equivalent operating hours, EHS is helpful.

Component-wise maintenance decisions can be taken on the importance,redundancy,safety etc.

Predictive Tools: Estimated weekly damages, EFOR,Life management actions

• Process automation/Boiler auto tune • Online Predictive tools for predicting

failures, providing maintenance advisory, tube leakages- by profiling critical parameters

• Combustion stability advanced monitoring system

• Lifetime Monitoring and Control • Lifetime Assessment • Strategic Maintenance • On line coal analyser • Fleet monitoring • Predictive tool for predicting Cycling

costs –Enable least cost Fleet strategy • Digitalization for additional safety • Digitalisation of Training resources

Leveraging Digitalization for supporting flexibility

Fleet wide strategy based on dynamic requirements will require require digitization of the entire commercial operations, maintenance strategy Digitization will be essential for bringing down the levelized system cost of flexible power ,based on forecasting and AGC

Conclusion • Any unit can be flexibilised .However,all units need not be

flexibilised.The flexing needs is to be decided based on the the grid support required from the said unit.

• Moderate amount of flexibilisation can be achieved with modification of operational practices

• Higher level of flexibilisation can be achieved with retrofits and the decision should be taken on case to case basis as in some cases the retrofit cost may be prohibitive.

• The providers of flexibility must be motivated by incentivisation

• The true cost of flexibilisation must be known

• Broader policy and regulatory approaches to improve generation and access to thermal flexibility and ultimately energy security.

• Market and operational rules affect access to thermal flexibility

• The Stakeholders engagement including International cooperation is critical at every step

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Pilot Program Support under GTG-RISE (2017-2020)

Stage 1: Techno Economic Assessment & Roadmap

• Technical due diligence and detailed feasibility assessment

• Designing Cost Benefit Scenarios for considered strategies with capital expend’ requirements

Stage 2: Investment Program & Regulatory Approval

• Finalization of pathway considering budget, overall benefits & scale-up potential

• Finalization of investment budget & regulatory approval

Stage 3: Selection of Implementing Agencies

• Selection of Implementing Agencies

• Leverage private partnerships and contribution in investments

Stage 4: Oversight in Implementation

• Monitoring and evaluation

• Impact assessment

RISE Grants Support for TA

RISE Support

RISE Support + NTPC/ GSECL leverage

RISE Support

GTG-RISE is supporting technical interventions and operational changes at NTPC’s Ramagundam (200 MW unit), Jhajjar (500 MW unit) and GSECL Ukai TPS (200MW & 500 MW unit)

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Anjan Kumar Sinha,

Senior Advisor,Deloitte: RISE

aksinha@gtg-india.com, sinha.anjan@gmail.com

Mob:+91 9650992971

Thank You

• Security Constrained Economic Dispatch (SCED) - SCED is a mathematical model to generate the most economic generation dispatch while considering key system operation constraints, such as power balance constraint, reserve requirement constraints, transmission security constraints, as well as generation limitations, such as ramp rates, minimum and maximum output levels.