System Status Update & Demand Response

Transcription

1 System Status Update & Demand Response 13 November 2014 AMEU Technical Committee Meeting Dharmesh Bhana

2 Overview Winter 2014 Summer Outlook NRS048-9 Implementation Changes Demand Response Conclusion 2

3 Overview Eskom load shed for the first time in 6 years for 14 hours on 6 March. This was due to a major coal supply incident in a very tight system, exaggerated by unprecedented rainfall throughout the country. Three more load shedding events during June due to multiple unit trips, as well as a constrained power system in meeting demand. Most recent load reductions were on 30 October 2014 due to unplanned outages /delayed RTS and 2 November 2014 due to the impact of Majuba Silo collapse. The system continued to remain tight and vulnerable over winter. However, there seemed to be some relief over August due to warmer weather, as well as improved reliability from some generation plant. System peak demand was recorded on 9 July 2014 at MW. Note that this would exclude some of the demand-side responses. Daily peak energy recorded at MWh. Positive response to requests for demand reduction through the various demand response products available. Excellent for winter when customers usually take plant out. Significant effort by Generation to improve plant reliability and execute maintenance as planned. NERSA granted Eskom flexibility in the implementation of NRS048-9 to limit impact of load reductions on customers and the economy.

4 Overview Winter 2014 Summer Outlook NRS048-9 Implementation Changes Demand Response Conclusion 4

5 Winter 2014 The period running up to winter was difficult. We are grateful to all industrial, commercial and residential consumers for reducing load during this period. Power system emergencies - whereby key industrial customers and residential load shedding is used to reduce load - were declared on, 11, 12 & 17 June to protect the integrity of the national power system. This pragmatic use of the NRS048-9 Code of Practice in terms of load shedding versus load curtailment limited impact on customers. We incurred very high diesel expenditure and interruptible loads were used to manage the system during this period. All available independent power (wind, gas and solar) and municipal generation available in the country was brought on-line to supplement supply. System was less constrained over August, especially for the morning peaks, e.g. reserves of over 4000MW for morning peak versus 1000MW for evening! 5

6 Maintenance over this period Planned Maintenance % Jan Feb Mar April May June July Aug Sep Oct Nov Dec Year to date average

7 Increased gas turbine usage Although costly, the use of OCGTs created space to do maintenance Lower OCGT usage was expected in winter due to the peak profile 7

8 Impact of Renewable IPPs (REIPPs) 2014/11/13 8

9 Daily Unplanned trend for the Generation Fleet including Partial losses

10 MW 2014 YTD PLL > 7 days trend 20 Oct PLL YTD trend Coal related PLL exc coal Linear (Coal related) Linear (PLL exc coal)

11 Overview Winter 2014 Summer Outlook NRS048-9 Implementation Changes Demand Response Conclusion 11

12 Summer Profile: Peak profile versus summer flat profile If constrained during summer then an entire day challenge Air-conditioning, geysers and pool pumps primarily impact demand Residential and commercial customers can make the biggest difference MW Summer & Winter load profiles Summer flat (Table Mountain profile) Typical Winter Day :00 02:00 05:00 08:00 11:00 14:00 17:00 20:00 23:00 02:00 Winter Peak Profile Winter constraints are short, sharp peaks while summer constraints are throughout the day Help us reduce demand as it reduces high diesel usage 12

13 Coal stock at sufficient levels! Coal stock days are above the expected level of 42 days, with October ending on 49 days. (November 2014 is up to 2 November 2014) There are three stations below minimum level i.e. Majuba at 22.9, Tutuka at 39.5, Kriel OC at 31.9 days and 2 stations dropped below alarm level i.e. Arnot at 33.1 and Duvha at 26.5 Additional Coal is currently being sourced to increase the stock days for these stations. Actual Stock days FY2008, FY2014 and YTD FY /8 2013/ / Apr May Jun Jul Aug Sep Oct Nov Dec Jan Feb Mar Note: Eskom financial year is from April to March 13

14 November 2014 Capacity outlook 13 November

15 December 2014 Capacity outlook 19 August

16 January 2014 Capacity outlook 19 August

17 Summer Risks Variability increases due to the following risks: Increased full- and partial load losses: High vacuum load losses, especially at Matimba:( >1000MW). Deteriorating coal quality impacting on plants ability to reach full load. Wet coal Impact of Majuba Silo failure Below minimum coal stock days at Kriel UG, Majuba, and Tutuka Outage management capability and quality Insufficient diesel levels to run OCGTs and fuel oil levels Continuous heavy rain Unreliable availability of supply from HCB 17

18 Overview Winter 2014 Summer Outlook NRS048-9 Implementation Changes Demand Response Conclusion 18

19 Feedback: NERSA engagement Flexibility in the application of NRS048-9 (Winter) Shedding vs. curtailment : At evening winter peak shedding first. Schedule changes: 5am-9pm to 6am-10pm to accommodate 5.30pm to 6.30pm peak (avoiding rotation on the day) Stage granularity: Shedding only what is required within a stage rotation of control rooms. Record keeping and submission to NERSA to demonstrate equitable use. Declaration of an emergency: Operational declaration (Control rooms and curtailment customers). Compliance: Once prepared for possible shedding, municipal demand reduction with 15min. Process for managing changes going forward. Integration into NRS Ed.2

20 Background cont d Summer Profile 00:00 01:00 02:00 03:00 04:00 05:00 06:00 07:00 08:00 09:00 10:00 11:00 12:00 13:00 14:00 15:00 16:00 17:00 18:00 19:00 20:00 21:00 22:00 23: Stage 1 Stage 2 Constrained all day Summer points to note Table Mountain profile Constrained all day incl. from 5-9pm Air-conditioning, geysers & pool pumps primarily impact demand Commercial, agricultural & residential customers can make the biggest difference 22000

21 Approach to summer (discussion) Issue Winter Summer Motivation Period expected 5-9pm (5.30pm 6.30pm) 6am 10pm (as required) Summer profile Curtailment vs. shedding Curtailment not deployed until after Stage 2 shedding* Curtailment deployed as per NRS If at peak, load shedding only*. Equity in relation to smaller industry / customers. 2hr time to implement curtailment. Curtailment 10% under Stage 1&2 after Stage 2 shedding. 20% under Stage 3 Only used if needed Development of KIC schedules based on unique requirements to achieve % s (EIUG) Minimise impact in particular when more than 2 days Load shedding schedules Implemented 5am-9pm to have single 5-7pm slot Revert to 6am-10pm to have single slot at 6-10pm Peak is 6-8pm Schedule rotation Self-rotation from one day to another Self-rotation from one day to another Ensure same areas are not impacted the same time every day for long-duration shedding Granularity Call full stage of shedding, rotate control rooms Call full stage, rotate control rooms. Shed as little as is necessary. Declaration of an emergency Internal control room and key customers only Internal control room and key customers only Clear operational protocols KIC s require formal instruction Planned vs. Emergency Emergency only Emergency only, unless system conditions require a longer term Increased predictability

22 Learning from system emergency incidents Cause (NB context of a constrained system) Emergencies declared Voluntary demand reduction Forced demand reduction Stakeholders: large customers Stakeholders: Smaller customers Metro s and municipalities Schedules November 2013 February 2014 March 2014 Disruption in the supply of OCGT fuel 19 Nov (17H00-29 Nov) Revised (21H00 21 Nov) Large customers Metros, munics Small customers Curtailment i.t.o. NRS048-9 HVDC line failure 20 Feb (11H40-21H00) 21 Feb (15H50-21H00) Large customers Metros, munics Small customers Curtailment i.t.o NRS048-9 Kendal coal and Duvha conveyer fire 6 Mar (06H00-22H00) Large customers Metros, munics Small customers Curtailment & shedding i.t.o. NRS % reduction 10% reduction Initially 10% and then 20% reduction No load shedding No load shedding Stage 3 shedding (20%) Stage 2 shedding (10%) No load shedding No load shedding Implemented load shedding Eskom and several Metro/munic schedules published as a precaution Schedules remained published Several Metro/munic schedules not available until later in the day/week.

23 Learning from system emergency incidents Cause (NB context of a constrained system) Emergencies declared Voluntary demand reduction Forced demand reduction Stakeholders: large customers Stakeholders: Smaller customers Metro s and municipalities Schedules June 2014 June 2014 June 2014 Kendal MUT causing depletion of reserves. 11 Jun (peak) 12 Jun (peak) Large customers Metros, munics Small customers Shedding only (11 th ) Shed & curtail (12 th ) System demand System demand 17 Jun (18H00-19H00) 18, 19 Jun (18H00-20H00) Large customers Metros, munics Small customers Shedding only i.t.o NRS048-9 Large customers Metros, munics Small customers None 10% reduction 10% reduction N/A Stage 1 shedding Stage 1 shedding N/A Implemented load shedding Schedules remained published Eskom website available schedules Implemented load shedding Schedules remained published Eskom website available schedules N/A Schedules remained published Eskom website available schedules

24 Overview Winter 2014 Summer Outlook NRS048-9 Implementation Changes Demand Response Conclusion 24

25 Demand Response Programmes DEMAND RESPONSE PRODUCTS Instantaneous DR Supplemental DR Self Generation DR Normal DR Emergency DR Fixed Time DR

26 Illustration of typical RESERVE deployment order Increasing Tightness of Supply Emergency reduction NRS Emergency RESERVE MARKET Operating Stage 4 Load shedding and curtailment ( Stage 3 ) Load shedding and curtailment ( Stages 1& 2 ) Curtailment ( Stage 0 ) Self Generation DR (Hi Rate) Interruptible Load Agreements Supplemental DR Open Cycle Gas Turbines Max cont. rating/emergency Level 1 Self Generation DR (Low to Medium Rate) Automatic Gen Control (AGC) Instantaneous DR Instantaneous 26 ENERGY MARKET

27 Demand Response Products Supplemental DR Supplemental Reserves > 1 MW load ( Minimum 10% of average MW demand between 5h00-22h00 during weekdays) Minimum 30 minute notification Pre-recorded phone call 30 minute integration metering (MV 90 or pre-approved Meter on Line) 1 x 2 hour event per day 150 on target events per year Reduction measured against average of previous 3 similar days (CBL) Performance linked Capacity Payment for Standby R26.70/11.21 MW / hr Performance linked Energy Payment for load reduction at R1250/ MWh

28 Load Reduction and Rates CBL is a daily profile representing the amount of electricity the CUSTOMER would have consumed in each Integration Period for Week Days and Weekend Days Minimum 30 minute notification (LR)= sum [(CBL (n) Actual Load (n)).cbl (m) Actual Load (m))] n = first Integration Period of the Load Reduction request m = last Integration Period of the Load Reduction request Capacity payment Peak R26,70/MW (May-Aug between 6h00-09h00 & 17h00-20h00) (Sept-April between 9h00-12h00 & 18h00-21h00) Off-peak R11,21/MW (Including Week-ends, public holidays) Energy Payment R1250/MWh

29 Demand Response Products (continue) Self Generation DR Emergency Reserves 30 minute notification Pre-recorded phone call 30 minute integration metering 1 x 2 hour Event per day (may contract up to 4 or 6 or 16 hours per day) 100 Events per year Generation measured against Ref. point 60 minutes before notification Performance measurement over 30 min Performance linked Capacity Payment for standby at: Capacity payment = R18, 75 per MW per hour scheduled Energy Payment for self-generation up to R3000 / MWh

30 Additional DR Products Pilot Option Load Shift 2 Week Dispatch Take or Pay Agreement Objectives To shift load from standard periods to off peak periods during the summer months To provide customer with ample time to reduce load when required by the System Operator. reduced rate. Description of Option A higher rate in the standard period (between 10am and 6pm or 10am to 8pm) to discourage the customer. An extremely low rate in the off peak period (10pm to 6am) to incentivise customers to consume/shift their load. Customers will be expected to participate from Mondays to Fridays. Customers will be notified 10 days in advance (Friday for the following week Monday) as to whether they are required to reduce load for that week. Eskom will indicate the days and times that the load should be reduced. Customers load reduction will be measured against a CBL. There is no standby payment applicable in this programme. To provide the customer with a guarantee of dispatch over a period of time at a Enter into a "take-or-pay" agreement with a customer where we guarantee 100 hours of usage per month for a period of 4 months. Unused hours will be rolled over -March Customer will be used for a minimum of 2 hours and a maximum of 8 hours per event. Any usage over the 400 hours current supplemental DR rate of R1250/MWh. Market Energy Market Reserve Market Reserve Market Proposed Energy R800-R900/MWh (80-90c/kWh) Rate (effective rate) R800/MWh (80c/kWh) R1000/MWh (R1/kWh) Proposed Standby Rate R 0 R 0 0 Notice Period to Customer fixed period 2 weeks advanced notice On the day Typical No. of hours per event 8 hours 2-8 hours 2-8 hours Typical No. of events per week 5 events 3-5 events 3-5 events Min MW 250MW 250MW 30MW Pilot Duration 2 months (ending March 2015) 2 months (ending March 2015) 5 months (ending March 2015) 30

31 Overview Winter 2014 Summer Outlook NRS048-9 Implementation Changes Demand Response Conclusion 31

32 Conclusion Managed to get through winter with limited impact on customers with 3 load reduction events The winter plan has yielded the desired results thus far. We had a better handle on the system, while on the other hand managed to deal with some opportunity maintenance. Managed to reduce Partial Load Losses from an excess of 3500MW to 1500MW. Predictable generation fleet performance still a challenge, UCLF cannot change quickly and can only be reduced by removing/repairing each and every damaged component in a power station. With the maintenance that needs to be done, the system will remain tight during summer. The tight system means that the probability of load reduction and load shedding remains high in the event of significant incidents on the power system. Impact of Majuba needs to be factored into capacity plans. Pragmatic implementation of NRS048-9 will limit impact on customers. We thank all electricity users who continue to assist by reducing consumption. 32

33 Thank you