Life Cycle Management through Cost Effective Refurbishment, Rehabilitation and Maintenance in Eskom Power Stations.

Transcription

1 Life Cycle Management through Cost Effective Refurbishment, Rehabilitation and Maintenance in Eskom Power Stations. 24 th February 2010 Compiled by: Nigel Volk (Senior Manager: Asset Management)

2 Eskom power stations 2

3 Eskom Generation plant mix Type of plant Number of stations Number of units Net maximum capacity Coal-fired 13 ** 77 ** MW Coal-fired (return to service) MW Hydroelectric MW Pumped storage MW Nuclear MW Wind MW Gas MW Total MW ** These numbers include the two remaining RTS stations (Grootvlei and Komati) and the five units from these stations that have already been returned to service. The remaining 10 units are reflected under coal-fired (return to service) Note: Koeberg Power Station is operated and maintained by the Nuclear Division The net maximum capacity reflects the MW that the station can supply to the grid after taking out the capacity used for auxiliaries (plant) 3

4 Presentation Structure 1. Performance & Availability Threats 2. Effective Rehabilitation 3. Effective Refurbishment 4. Effective Maintenance 5. Life Cycle Costs 6. Conclusion 4

5 1. Performance & Availability Threats Eskom currently supplies 95% of the electricity in South Africa. Essentially the grid is isolated with no strong in feeds which can supply in cases of crisis. Hence if the power stations do not perform well under current circumstances of limited excess capacity this will ultimately lead to load shedding. This is a scenario which Eskom vigorously expects to avoid and hence plant condition and life are critical. Currently prudent planning availability percentage for Eskom is 86%, which is a function of: 8% Planned outages 5% Unplanned outages Plants have an aspiration to achieve availability of: 7% Planned outages 3% Unplanned outages Availability is currently slightly below aspiration due to the following external drivers: 5

6 1. Performance & Availability Threats: Load Factor and Wear Related Failures. Unplanned Outage % UCLF Load Factor Av Unplanned Unavail. (UCLF) A major influencing factor which has led to significantly higher plant deterioration and hence costs has been the much higher load factors over the last 8 years. When load factors increased from 2002 it was necessary to ensure stable availabilities which led to higher costs to sustain the performance Av Load Factor (EUF) Load Factor 6

7 1. Performance & Availability Threats: Age Related Failures. Certain items of plant fail as a natural consequence of age. Most of Eskom s installed plant is in mid life and mid life failures are occurring. Turbine Boiler & Civils Generator Gen Transformer Refurbishment Activities Valves & Boiler Tubes Maintenance Activities 60 Years 7

8 1. Performance & Availability Threats: Coal Quality and Wear/ Availability Related Failures. Coal Quality (CV) Coal Quality of Station A Coal Quality is having a major influence on plant unavailability. Deterioration over the last few years has been significant. This has been a result of difficult mining conditions as well as export competition. This leads to higher wear in the boilers and also limitations being reached in milling, ashing and other auxiliary plant 8

9 1. Performance & Availability Threats: Effects on Planned Unavailability MAJOR FACTORS INFLUENCING PLANNED UNAVAILABILITY DRIVER: AGE DRIVER: COAL QUALITY, LOAD FACTOR Outage Philosophy Modification/ Refurbishment Opportunity Maint. An overriding influence in South Africa is also a lack of highly skilled persons both in Eskom and in our major contractors necessary to manage the processes. DRIVER: AGE, COAL QUALITY, LOAD FACTOR 9

10 1. Performance & Availability Threats: Effects on Unplanned Unavailability Age & Skills Related Affected by: Load Factor, Coal Quality, Skills, Age Age Related Age Related 10

11 2. Effective Rehabilitation: Return to Service of Camden, Grootvlei and Komati. Because of the limited capital cost of refurbishing the Mothballed Stations they were very cost effective compared to new capacity. Hence Eskom returned them to service first before considering new capacity Distribution for CAMDEN / R/MWh/H5 H5: Mean= H6: Mean= H7: Mean= H8: Mean= CAMDEN Other New Plant Options such as New Coal Fired Station X Axis: R/MWh The choice to return the plant to service or decommission was made on the basis of the condition of the plant after 15 years of mothballing and given the fact that only limited refurbishments were necessary. Camden s performance today is in line with the rest of Eskom s fleet. 11

12 3. Effective Refurbishment: Age Effects The failure probabilities of plant is carefully analysed and plant is replaced or refurbished when no longer reliable. Eskom s Annual Technical Planning Process is used to manage the risk, cost, benefit balance in this regard. Generator Turbine Boiler & Civils Gen Transformer Refurbishment Activities Valves & Boiler Tubes Maintenance Activities 60 Years 12

13 3. Effective Refurbishment: Historical Perspective: Refurbishment Cost Increased age of plant means increased failure probabilities and hence more refurbishment. Capital Costs Most Eskom plant in this age group R/kW Note significant increase in costs at this stage in station life Years 13

14 3. Effective Refurbishment: Portfolio Analysis and Prioritisation Projects are ranked in terms of their impact on risks to ensure that the critical projects get done. Refurbishments with limited risk return which have the least return are prioritised last. Refurbishment Project funding is cut off at the threshold of risk which can be accepted. Mandatory Projects 14

15 4. Effective Maintenance: Age Effects Maintenance Activities generally focus on plant failures with relatively short failure periodicities. This includes boiler tube wear etc. It requires constant and disciplined attention to the plant. Generator Turbine Boiler & Civils Gen Transformer Refurbishment Activities Valves & Boiler Tubes Maintenance Activities 60 Years 15

16 4. Effective Maintenance: Historical Perspective Maintenance Costs (Coal Fired) R/kW Historical Trend of maintenance cost averaged across the fleet has been increasing almost linearly. The wear on the plants is of course a progressive effect. AVERAGE Maintenance Profile Years 16

17 4. Effective Maintenance: The Need for Structured Asset Management improvement (AMi) Maintenance Improving Plant Programs Reliability Doing things right Doing the right things Ready and effective outages To ensure effective maintenance Eskom Generation started a structured maintenance improvement process in This process is intended to bring power stations up to worlds best practice where appropriate. Measure what s happening Analyse, advise, respond Key components available 17

18 Asset Management improvement (AMi) Improving Plant Reliability 4. Effective Maintenance: The need for Structured Maintenance Programs Doing things right Doing the right things Ready and effective outages Measure what s happening The need to improve maintenance processes led to a decision to do the following: Analyse, advise, respond Key components available 1. Asset Management Framework: Decision taken to establish an Asset Management Framework in Eskom Generation in line with British Standard BSI PAS Works Management: Roll out principles of EPRI s Work Management Guidelines. 3. Reliability Basis Optimisation: Utilise EPRI PM Templates as the basis to develop Eskom wide standard templates. Currently 180 templates complete and still identifying new needs. Much quicker and effective than normal RCM process. 4. Outage Optimisation: Implementing Modular Spares, Outage Readiness Indicator, Outage Effectiveness Measures as well as apply Theory of Constraints (TOC) to Outage planning. 5. Metrics: Brought in line with worlds best practice and developed an overall maintenance index. 6. Fleet wide Monitoring: Operational monitoring of data using sophisticated algorithms originally developed for the space shuttle program. 7. Spares: Strategic Spares programs to ensure spares availability. 8. Efficiency: Improve Efficiency through targeted interventions. 18

19 4. Effective Maintenance: Maintenance Processes need to be Entrenched. The most difficult part of improving maintenance effectiveness is entrenching the processes through change management. 19

20 4. Effective Maintenance: Measurement of the Effects through Maintenance Index OUTAGE/ PROJECT Corrective/ Proactive Maint. MONITORING Predictive Maint. MAINTENANCE Preventive/ Corrective Maint. DDP SL OPS MAINTENANCE DEVIATION Defects Prioritisation ENG/ OUTAGE/ PROJECT ANALYSIS Occurrence Investigation RCA Corr. Action Risk Analysis Classification Configuration EMERGENT WORK EW RI OUTAGE PLANNING SC BL PLANNING & RESOURCING ES Plan & Schedule Spares sourcing TECH PLAN/ MODIFICATION Tech Plan,CRA, DRA, ERA PC MAINTENANCE STRATEGIES Compile Strategies Review Strategies LCM LOPP HUMAN PERFORMANCE SU 20

21 4. Effective Maintenance: Measurement of the Effects through Maintenance Index Plant load factors, skills and age play a role here. Plans in place to address. Adherence to maintenance targets is strictly monitored and controlled. Where performance is outside target levels comprehensive corrective actions are developed and implemented to ensure adequate maintenance 08/03/10 Nigel Volk 21

22 5. Life Cycle Costs: Overall Station Cost Pyramid Maintenance Cost over the 60 year life less than 50% of initial capital cost to build. Major Refurbishment over 60 year life only 20% of initial capital cost to build. Lifecycle Maintenance costs R Bn Refurbishment Capex R16 Bn Total Maintenance & Refurb costs average out at 1% of capital cost per year. In line with industry norms Station Construction Cost much higher than Maintenance and Refurbishment cost. Station Construction Cost R90 Bn 22

23 5. Life Cycle Costs: Why availability so important Eskom Stations Intensive analysis has been carried out to ascertain the optimal operational performance to ensure the most cost effective station life. For South Africa with its isolated grid system performance of 90% availability appears most cost effective. 23

24 5. Life Cycle Costs: Comparison of New Plant to Installed Plant R/MWh COAL O&M CAPEX The capital investment involved in New Plant is huge compared to the maintenance and fuel costs. Replacement of capacity due to poor maintenance is therefore not an option. COAL 2010 O&M 24

25 5. Life Cycle Costs: Comparison of New Plant to Installed Plant COAL O&M Even by 2035 the cost of maintaining the installed plant is much more cost effective than installing new. R/MWh CAPEX COAL 2035 ENV O&M 25

26 5. Life Cycle Costs: Eskom plant generally in mid life Capex Maintenance 400 R/kW Note significant increase in costs at this stage in station life. Most Eskom plant in this age group Hence it is clear that the overall cost drivers of Eskom s fleet over the last few years have been to much higher maintenance and refurbishment costs overall. 26

27 R/MWh 5. Life Cycle Costs: Relationship of current fleet costs to new plant. Relative R/MWh of all options NEW PLANT Analysis shows that the installed plant will remain cost effective relative to new plant at least for the next 25 years. There is even a good case to extend the life of older installed plant on the basis of techno economics. It is critical this cost balance is analysed and maintained. Hence good maintenance, refurbishment etc. is critical

28 6. Conclusion: Plant Life Cycle Management is a function of plant, people and process Plant performance is a function of all three aspects shown to the right. Addressing processes without cognizance of plant operating factors and skills will not deliver adequate results in a South African context Plant (age, load factor, coal quality) OUTAGE PLANNING OUTAGE/ PROJECT Corrective/ Proactive Maint. MONITORING Predictive Maint. MAINTENANCE Preventive/ Corrective Maint. People (skills) TECH PLAN/ MODIFICATION Tech Plan,CRA, DRA, ERA OPS MAINTENANCE DEVIATION Defects Prioritisation Process (world best practice) EMERGENT WORK (world PLANNING best & practice) RESOURCING ES Plan & Schedule Spares sourcing MAINTENANCE STRATEGIES Compile Strategies Review Strategies LCM LOPP HUMAN PERFORMANCE ENG/ OUTAGE/ PROJECT ANALYSIS Occurrence Investigation RCA Corr. Action Risk Analysis Classification Configuration 28

29 6. Conclusion The Life Cycle of Eskom s Plant can be assured through effective Rehabilitation, Refurbishment and Maintenance but it needs to be managed consciously with a focus on the most cost effective solution for the prevailing circumstances. The current high load factors due to increasing demand and limited installed plant together with steadily reducing coal qualities has been and will continue to challenge plant performance. Effective strategies are being developed and implemented to mitigate these effects such as elevated boiler tube leak repair programs. Given the high capital cost of base load power plant it is critical to ensure the ongoing refurbishment and maintenance is adequately funded to ensure long term cost effective sustainability of supply. Skills development will continue to be a high priority for Eskom to ensure adequate skills to carry out the necessary work highlighted above. 29

30 Thank You 30