System Status. Date May 2015

Transcription

1 System Status Date May 2015

2 Contents Demand Overview Renewable Generation Summer and Winter profile Emergency Reserves Usage System Status 5 month outlook

3 Actual System Weekly Peak Demand (Including IOS) 2014 Actual Demand data Peak demand for 2014 was MW. With supply from non Eskom generators (sold to Eskom) the peak demand was MW 2015 Actual Demand data The Year-To-Date peak demand for 2015 is MW (considering only Eskom generation and firm imports). 3 Year-To-Date peak of 2015 is MW (include non Eskom generators).

4 Demand Overview Renewable Generation Summer and Winter profile Emergency Reserves Usage System Status 4 month outlook

5 Impact of renewable generation Average MW contribution about 1000MW MW per technology Wind about 400 MW (more in winter) PV about 800 MW 2015/05/18 CSP about 100 MW (two hour storage) 5

6 Example of hourly renewable generation Output varies due to local and seasonal changes Contribute during middle of the day 2015/05/18 6 Potential to off set OCGT use

7 Demand Overview Renewable Generation Summer and Winter profile Emergency Reserves Usage System Status 5 month outlook

8 Summer and Winter Profile Demand Changes Summer: air conditioning Winter: 1 degree cold increase up to 800 MW 8 Loadshedding Impact Summer: hours Winter: 2-4 hours

9 How do we meet demand Day Ahead Demand Forecast Hourly demand forecast include operating reserves Generation Capacity Hourly generation capacity Operating reserves Changes in generation capacity and demand Emergency Reserves Used if insufficient operating reserves.

10 Operating Reserves Operating Reserves 2000MW Changes in Demand Temperature Industry Supply Demand Changes in Supply Generator Trips Other Capacity losses 10

11 Demand Overview Renewable Generation Summer and Winter profile Emergency Reserves Usage System Status 5 month outlook

12 Usage of Emergency reserves Use in 2015 Higher use of OCGTs Use in 2015 Similar use of ILS 12 LFI in 2015 High in January

13 Typical IL usage Manage High Demand January - 3 February -10 March - 8 Disturbance Recovery January - 3 February - 2 March - 0 Manage high demand: To reduce demand on the grid To prevent a frequency decline Disturbance recovery: 13 To recover frequency following a major disturbance

14 Demand Overview Renewable Generation Summer and Winter profile Emergency Reserves Usage System Status 5 month outlook

15 Weekly System Status (Shortfall on Expected Demand including Operating Reserves) Draft Winter Plan: Busy finalising 15

16 Load Reduction (Load shedding and Load curtailment Types of Load Reduction Rotational DX customers and municipal (opening breakers) Key Industrial Curtailment Key industrial customers to reduce demand Stages for rotational loadshedding 1 is about 800MW 2 is about 1600MW 3 is about 3200MW

17 Manual load shedding to manage system frequency Response to sudden incident Operator will take action To prevent a frequency decline UFLS activated

18 Security of the system Use of ILS up to 2000 MW Use of ILS up to 2000 MW Load shedding Stage 1 4 (4000MW about 10% of demand ) Unscheduled Load shedding (shed up to 65%) UFLS Stage 1-5 Slow decline UFLS (Total of 7 stages) (starts at 49.2 Hz) (total of 50%) Rapid decline UFLS Stage 7 Generators start tripping UFLS 47.9 Generators start tripping 2015/05/18 18

19 Thank you

20 Additional Slides 20

21 Current load shedding schedules (Ed 1) Stage Type Reduction obtained by interrupting supply - load shedding Reduction obtained by instructing reduction - curtailment (pre-agreed) Stage MW Scheduled / Notified Shed 5% of national noncurtailment load at peak Curtail 10% of normal demand within 2h of notification Stage MW Scheduled / Notified Shed 10% of national noncurtailment load at peak Stage MW Scheduled / Notified Shed 20% of national noncurtailment load at peak Curtail 20% of normal demand within 2hrs of notification Stage 4 Unscheduled (instructed) Shed >20% of national noncurtailment load at peak As instructed by the National System Operator at the time.

22 Explanation of risk associated with colors Color GREEN YELLOW Shortfall excl. OCGT s Adequate capacity to meet demand and operating reserves Shortfall of up to 1000 MW. ORANGE Shortfall of MW. RED Shortfall of MW (3 days) PURPLE Shortfall of MW (3 day3) BROWN Shortfall of more than 4000 MW. (2 days Implications for use of resources during the week Normal generation required Sufficient operating reserves Some OCGTs may be required but not extensively. Water utilization not an issue ILS only required to respond to low frequencies Operating reserves will be met with limited emergency resources Combination of water and OCGT s will be used to meet demand (neither used to full capacity on a given day). ILS only required to respond to low frequencies Some operating reserves but not full 2000MW Combination of water and OCGT s will be used to meet demand. Low risk of reaching minimum gen hours at hydro stations ILS only required to respond to low frequencies Very limited operating reserves. All OCGTs required most of the day throughout the week and will be utilized over the weekend to replenish dam levels Water utilized extensively during the day, risk that by Thursday or Friday minimum gen hours will be reached ILS will be required on Thursday to meet evening peak No operating reserves, short on demand All available resources required (incl OCGTs, GT s) required most of the day throughout the week and will be utilized over the weekend to replenish dam levels. Water used extensively and minimum gen hours will be reached before the end of the week. 22 ILS will be required during peak periods, high risk that their contract time will be reached.