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Mandate To optimally operate and maintain Eskom’s electricity generating assets for the duration of their economic life. The Generation division operates 27 power stations with a total nominal capacity of 41 995MW, comprising 35 726MW of coal-fired stations, 1 860MW of nuclear, 2 409MW of gas-fired and 2 000MW hydro- and pumped-storage stations, as well as the 3MW wind farm at Klipheuwel. Operating highlights
Operating challenges
Future focus areas
Coal-fired stations Generation benchmarks the performance of its coal-fired power stations against those of the members of VGB (Vereinigung der Großkesselbesitzer e.V), a European-based technical association for electricity and heat generation industries. VGB’s objective is to provide support to and facilitate the improvement of operating safety, environmental compatibility and the availability and efficiency of power plants used for power and heat generation, either in operation or under construction. When interpreting the results of the benchmark, it should be noted that the operating regimes of the other utilities contributing to the VGB database may not be the same as those of Eskom. The graphs that follow illustrate the results of the benchmarking for the 2000 to 2012 calendar years (the VGB results for 2013 are not yet available). The VGB data for 2012 reflects information gathered from 123 VGB member generating units, but does not include data from Eskom’s units. The Eskom data on the graphs has been plotted to the end of the 2013 calendar year to show the trend. The trend in Eskom’s performance continues to be worse than the VGB benchmark. The availability indicator of the top performing stations in the VGB benchmark has historically been consistent, with a slight decline in 2012. The availability of the stations in the median and worst quartiles has been declining. The benchmarking information indicates that Eskom units are on a par with the VGB benchmark with respect to planned maintenance in the median and low quartiles. The PCLF of Eskom’s best performing units was significantly better than that of VGB benchmark units. However, the UCLF trend is not at the same level. In the 2012 calendar year Eskom’s units’ performance was worse than the VGB benchmark on all quartiles, with the trend for 2013 indicating that Eskom units will perform even worse than the benchmark. With the very tight demand versus supply situation and the need to keep the lights on, Eskom has focused on risk-based and statutory maintenance rather than the reliability and design-based maintenance needed to improve the UCLF performance. With respect to the use of available plant (energy utilisation factor (EUF)), all Eskom coal-fired units are performing at a level close to, and in many cases above the VGB best quartile. This indicates that Eskom is operating its power station units at much higher load factors than the VGB benchmark units, negatively impacting on plant performance. Eskom’s use of available plant (EUF) is on the VGB best quartile, although the mix in the loading has changed with the European utilities no longer operating on coal base load. The trend is indicating that Eskom’s units have consistently maintained a high EUF. This said, Eskom units are trending significantly higher than VGB compared to the previous years, due to the need to load available plant more to meet demand.
Koeberg nuclear power station Eskom is affiliated to the World Association of Nuclear Operators (WANO) and the Institute of Nuclear Power Operations (INPO), and South Africa is a member of the International Atomic Energy Agency (IAEA). These affiliations enable Eskom to benchmark performance, conduct periodic safety reviews, define standards, disseminate best practice and train personnel. The last IAEA safety review was conducted during August 2011 with a follow-up review in April 2013. The last WANO peer review was conducted in November 2011, with a follow-up midcycle review conducted in April 2013, in preparation for the next WANO peer review scheduled for July 2014. Through the INPO, Eskom has obtained accreditation from the National Nuclear Training Academy in the United States for its systematic approach to training of licensed and non-licensed nuclear operators at Koeberg. Eskom is the only utility outside the United States of America to receive such accreditation. The WANO performance indicators provide a quantitative indication of plant performance in the areas of nuclear plant safety and reliability and personnel safety. There are currently 14 WANO performance indicators in use worldwide, as well as a performance indicator index that uses 10 of these 14 performance indicators. A selection of WANO performance indicator graphs are shown below. Benchmark data is for 10 calendar years, with a Koeberg mean (the average of two units) to 31 March 2014. Benchmark trends have remained fairly consistent, with the exception of collective radiation exposure, which has shown a gradual improvement for all quartiles over the period shown:
Koeberg 12-month unit capability factor (UCF) vs the median, best and worst quartile for all pressurised water reactor (PWR) units worldwide
Koeberg 12-month unplanned capability loss factor (UCLF) vs the median, best and worst quartile for all pressurised water reactor (PWR) units worldwide
Koeberg 12-month unplanned automatic scrams per 7 000 hours (UA7) vs the median, best and worst quartile for all pressurised water reactor (PWR) units worldwide The worldwide best and worldwide mean graph lines are both close to zero on the graph below
Koeberg 12-month collective radiation exposure (CRE) vs the median, best and worst quartile for all pressurised water reactor (PWR) units worldwide
Koeberg 36-month collective radiation exposure (CRE) vs the median, best and worst quartile for all pressurised water reactor (PWR) units worldwide The smoothing over a longer period than used in the benchmarks above takes into account the frequency of refuelling outages, of which three occur per two-year moving window
Koeberg INPO index vs the median, best and worst quartile for the units that are members of WANO Atlanta Centre. This sample includes various reactor types
Performance Key financial statistics for the year ended 31 March 2014
Operating maintenance costs The year-on-year maintenance cost has grown incrementally as a result of extensive planned and unplanned maintenance. The UCLF figure of 12.61% and the PCLF figure of 10.50% are indicative of the level of maintenance that was executed. Capital expenditure (excluding capitalised borrowing costs) There has been extensive capital expenditure on general overhauls. This is in support of the Generation sustainability strategy. Total property, plant and equipment The two factors that have contributed significantly to the growth in property, plant and equipment is the commissioning of Komati Unit 3 (transferred from Group Capital) and extensive capital expenditure on general overhauls. Technical performance for the year ended 31 March 2014
Generation capacity Despite the constrained system, more planned maintenance was done in 2013/14, including significantly more maintenance that was scheduled in the winter months. The power plant availability (EAF) of 75.1% for the year to 31 March 2014 (2012/13: 77.6%), against a target of 80%, reflects the increase in both unplanned unavailability, as well as the increased planned maintenance. Generation aspires to reach the 80% EAF target over five years as it increases its efforts and focus in driving sustainability of Generation’s assets. A total of nine maintenance outages were scheduled and completed – a good achievement to meet winter demand and do more maintenance than before. Refer to the maintenance backlog on page 32. As generating units are taken off-load for maintenance during periods of constrained capacity,
this necessitates increased usage of the open-cycle gas turbine (OCGT) stations when Eskom is
unable to meet demand. The total production by the OCGT stations reached The board approved an increase in the original 2013/14 budget for the diesel usage at the OCGT
stations from R3.6 billion to The following mechanisms, over and above the use of OCGTs, assisted Eskom to meet the daily peak demand during the year:
Significant events during the year Coal conveyor fire – disruption of normal coal supply to Duvha power station On 20 December 2013 a fire broke out at the overland coal conveyor transfer house outside the Duvha power station security fence, caused by a conveyor rubbing against the structure. Although the belt had tripped out, a fire had started. This incident negatively impacted coal stock days and coal cost for the power station. The recovery of the one conveyor stream was completed at the end of March 2014. There are still some defects that need to be addressed but coal is being delivered via this conveyor. The recovery of the second stream is still in progress and is targeted for completion in the first quarter of the new financial year. Rotational load shedding on 6 March 2014 Rotational load shedding took place for 14 hours on 6 March 2014 from 08:00 to 22:00. Refer to the “Leading and partnering to keep the lights on” section (page 103) in the integrated report for more information. Duvha Unit 3 over-pressurisation incident On 30 March 2014, Eskom experienced an over-pressurisation incident in the boiler of Unit 3 at Duvha power station, taking the 575 MW unit out of service. As the incident happened right at the end of the year, it has no material impact on the UCLF for the current year. However, as Unit 3 will be out of service for a prolonged period, it will have a material impact on UCLF going forward, until such time as the repairs have been completed. One person was treated for dust inhalation but no other injuries were reported. The incident is still under investigation. Plant performance EAF The generating plant availability has decreased during the year to March 2014, compared to the same period in the previous year, as a result of an increase in unplanned unavailability as well as the increased planned maintenance. The overall availability (EAF) is below target. UCLF The unplanned capability loss factor (UCLF) for the year to March 2014 is slightly higher than previous years, indicative of ageing plant and related deteriorating plant health conditions as well as the impact of the increased utilisation of the plant. The UCLF for 2013/14 was 12.61% compared to 12.12% in 2012/13 and 7.97% in 2011/12. Breakdown of system UCLF (%)1
The main contributors to UCLF were: Partial load losses The partial load losses continue to contribute significantly to the system total unplanned losses, and continue to increase. The unplanned capability loss factor attributable to these losses was 5.24%, contributing 42% of the system UCLF. The main power stations that contributed to these energy losses to date were:
The main reasons for the partial load losses were problems at the draught plant (23%), mills (16%), turbine (14%), gas cleaning (10%) and feed water (10%). Boiler tube failures Boiler tube failures are typically the result of welding repair damage, corrosion, fly ash erosion, etc. In the year to March 2014, there were 210 boiler tube failures, with a UCLF of 2.18%, contributing 17% to the system UCLF. This is higher in both number and UCLF contribution when compared to the previous year, when a total number of 191 failures and a UCLF contribution of 1.95% were recorded. The main power stations that contributed in the current year were, in order of energy loss:
Major/significant load losses The unplanned capability loss factor against major/significant events was 1.58%. The table that follows lists the events that occurred:
Monthly UCLF % over the last three years
EUF The utilisation of available plant capacity (EUF) was significantly higher than target and higher than the previous four years due to the increased loading of available plant to meet the demand. The overall fleet EUF was at 83.55% (2012/13: 81.87%). The utilisation of the coal-fired units for the year to 31 March 2014 was 92.73%, nuclear at 99.52% and peaking stations (including the OCGT stations) achieved 20.72%. UAGS/7 000 Unplanned automatic grid separations (UAGS) per 7 000 operating hours is a reliability indicator. For the year to 31 March 2014, the UAGS/7 000 ratio is 5.24, with 527 UAGS trips (2012/13: UAGS/7 000 ratio of 4.09 and 409 UAGS trips). OCLF The unplanned unavailability percentage due to factors outside of management control (OCLF) for the year to 31 March 2014 was 3.11% (including constrained UCLF) and 1.75% (excluding constrained UCLF). This is mainly the result of coal-related load losses experienced mainly at Tutuka and Arnot power stations, due to coal supply and coal quality challenges. PCLF As of March 2014, PCLF (reflecting the energy loss during the year because of planned shutdowns) was 10.77% (including constrained UCLF) and 10.50% (excluding constrained UCLF) against a target of 10.00%. On average, more planned maintenance has been done this year than in the previous six years, resulting in a higher PCLF. Although the PCLF has increased, the bulk of the planned maintenance that was executed was risk-based unscheduled maintenance rather than design-based preventative maintenance. As seen below, during the 2013/14 year the monthly PCLF has increased over the winter months when traditionally minimal planned maintenance was performed. Monthly PCLF % over the last three years
Maintenance backlog reduction strategies Eskom’s coal-fired generating units require routine maintenance to ensure that they meet technical performance requirements, are safe to operate and do not violate environmental laws. Refer to the “Leading and partnering to keep the lights on – decreasing the maintenance backlog” section (page 114) in the integrated report for more information. The power station enhancement project The power station enhancement project quick-win actions have almost been completed:
Medium- and long-term actions are outage dependent and are therefore impacted by the deferment of outages. While this project operated as a standalone project in 2012/13, it has now been incorporated with the Generation sustainability strategy and implementation is continuing. Energy-efficiency improvement programme The energy-efficiency improvement programme aims to improve the heat rate of the units at Eskom’s coal-fired stations. Heat rate measures the conversion rate of heat from the energy source (coal) to electricity generated. Improvements would indicate an improvement in plant performance and will help reduce Eskom’s environmental footprint, including its carbon emissions. The heat rate gap analysis at each station has been converted into an equivalent MW electricity for units sent out (MWe USO) into the grid. Measurement and verification studies were conducted using the services of independent accredited SANS 50010 institutions by comparing MWe USO to a known baseline of performance. Average annual station heat rate (MJ/kWh)
While some stations have attained and sustained heat rate performance improvement gains, the overall heat rate (plant performance) improvements in 2012/13 have not been sustained, with a 2.1% deterioration in 2013/14 compared to 2012/13. This deterioration is attributed to the deferment of outages that have impacted the execution of technical projects as well as coal qualities at certain power stations. Koeberg performance Unit 1
Unit 2
On 23 October 2013 Koeberg Units 1 and 2 achieved a new record of 184 days with both units operating simultaneously. Koeberg’s units sustained zero UAGS trips during the year. Safety Regrettably, two contract employees lost their lives. Of these, one related to a fall from height and one related to an electrical contact incident. Notwithstanding the fatalities, the safety performance for Generation has improved compared to the previous year. Generation experienced 28 lost-time injuries (LTIs) during the 2013/14 financial year compared to 55 for 2012/13. The 28 LTIs include eight noise-induced hearing losses. The 12-month moving average LTIR was 0.21 (target: 0.36), compared to 0.37 for the same period in 2012/13. The number of days to recuperate from injuries is also showing a decrease. The 2012/13 LTIR for Generation is now reflected as 0.37 because of the late reporting of a noise-induced hearing loss incident. The performance of Generation contractors is also showing an improvement. During the year, 34 LTIs (LTIR 0.26) were reported compared to 54 LTIs (LTIR of 0.41) in the 2012/13 financial year. The LTIs in 2013/14 include the two fatalities as well as a noise-induced hearing loss incident. Public exposure to radiation Public exposure to radiation arising from Koeberg operations remains well within the limits set
by the National Nuclear Regulator. Exposure to radiation is measured in units of milliSievert
(mSv). The limit recommended by the International Atomic Energy Agency for public exposure to
radiation is 1.0 mSv per year. However, the National Nuclear Regulator has set a stricter limit of
0.25 mSv per year for The following graph indicates that the average public exposure to radiation arising from Koeberg’s
operations has been less than
Environmental performance Particulate emissions Eskom’s particulate emissions performance for 2013/14 was 0.35 kg/MWh sent out, which was better than the target of 0.36 kg/MWhSO, and the same as the performance for 2012/13. Power stations with fabric filter plants continue to sustain low emission levels. However, challenges are experienced with emissions at many of the stations with electrostatic precipitators. This is due to a range of factors, including capacity constraints and lack of access to plant for maintenance and repairs, as well as maintenance execution. At some stations, a combination of a decline in coal quality and the high load factors result in the dust-handling plant being over-burdened. Compliance with National Emission Standards Refer to the “Reducing Eskom’s environmental footprint and pursuing low-carbon growth” section (page 127) in the integrated report for more information regarding Eskom’s retrofit programme to reduce emissions as well as the impact of the new atmospheric emission licences on Eskom. Emission offsets There is support from both the Department of Public Enterprises and the Department of Environmental Affairs for the implementation of household emission offset projects (for example, through insulating houses and subsidising liquid petroleum gas to replace the use of coal or wood for heating and cooking in houses). Though these offsets will not reduce Eskom’s emissions, it will improve ambient air quality and reduce human exposure to high levels of pollution at a fraction of the cost of emission abatement retrofits at power stations. Eskom is investigating options, and is currently initiating a household emission offsets pilot project to test the effectiveness of this approach. Water performance Water usage for all commissioned power stations for the year to 31 March 2014 was at 1.35 litres per kilowatt hour sent out (L/kWhSO), better than the target of 1.39 L/kWhSO (2012/13: 1.42 L/kWhSO). The improved performance is due to an increase in the proportion of energy generated by dry-cooled stations, as well as increased opportunities for maintenance, implementation of initiatives identified by the water management task teams, good rains and the increased recovery of water compared to previous year. Water management task teams at the power stations are addressing the reduction of water usage and legal contraventions, compiling comprehensive action plans to address all aspects of water management and water-use performance. Significant progress has been achieved in terms of Eskom’s drive to obtain Blue and Green drop certification status for its water treatment and sewerage works management at power stations. Environmental compliance There were 24 environmental legal contraventions in the year to 31 March 2014 compared to 33 for the year to 31 March 2013. The nature of contraventions this year is summarised below and is broadly similar to previous years:
One environmental legal contravention was declared against Generation, in terms of the operational health dashboard, during the financial year. The contravention is associated with the failure of Hendrina power station to effectively and timeously manage water-related environmental legal contraventions that took place between October 2012 and October 2013. Generation has already implemented measures to address the deficiencies identified. A pre-compliance notice issued to Lethabo power station in 2012 was successfully closed by the Department of Environmental Affairs. The department indicated that no further enforcement action will be taken against Lethabo power station. The enforcement actions initiated by the Department of Environmental Affairs against Camden and Matimba power stations in 2012 (for alleged non-compliance with environmental requirements) and to which Eskom responded in 2012, remain unresolved. Feedback from the authorities is still outstanding. Eskom continues to implement the commitments made to the authorities to resolve the issues raised in these enforcement actions. All Generation power stations have successfully maintained their ISO 14001 environmental management system certification status. There has been an overall increase in environmental skills within the division with the appointment of additional staff, as well as staff participation in focused interventions aimed at addressing increasing environmental legislative requirements and operational challenges. Environmental performance indicators for Generation
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