TRANSFORMING AUSTRALIA S ELECTRICITY SYSTEM

Transcription

1 TRANSFORMING AUSTRALIA S ELECTRICITY SYSTEM October 2017 PRESENTED BY JENNY RIESZ SLIDE 1

2 SLIDE 2

3 THE NEM National Electricity Market (NEM) ~85% of electrical load in Australia SLIDE 3

4 AEMO S WORK PROGRAM 45% emissions reduction scenario Distributed Wind & PV Significant retirements SLIDE 4

5 FUTURE POWER SYSTEM SECURITY (FPSS) PROGRAM Adapt AEMO s functions and processes to deliver ongoing power system security and reliability Identify Implementation Prioritise Technical solutions Quantify SLIDE 5

6 IDENTIFYING CHALLENGES Frequency Control Forecasting Variable & uncertain Planning Distributed Low operating cost Non-synchronous SLIDE 6

7 WHAT IS FREQUENCY CONTROL? 50.0 LOAD GENERATION Regulation : Manages minor imbalances Imbalance Frequency changes SLIDE 7

8 VARIABILITY More wind & PV More variability More regulation required Large-scale Photovoltaics SLIDE 8

9 Estimated regulation requirement (MW) QUANTIFYING VARIABILITY Lower 5min generation data Aggregated to different total capacities Quantified 99 th percentile Δ in 5min (estimate of regulation requirement) Can sum σ 2 to find total regulation requirement (with demand) -120 Raise ,000 2,000 3,000 4,000 Installed capacity (MW) Rooftop PV Data Utility PV Data Wind Data Rooftop PV Projection Utility PV projection Wind Projection Findings: Utility-PV is most variable Rooftop PV is least variable Wind is moderately variable SLIDE 9

10 DYNAMIC REGULATION Regulation scheduled by time of day: + 30% Proposed (3.1 GW solar, 8.3 GW wind) Immediate actions: Frequency monitoring Improvements to 5min forecasts + Committed (906 MW solar, 4760 MW wind) Current (274 MW solar, 4070 MW wind) Eventual possibility: Dynamic regulation scheduled hourly based upon PV / wind / demand forecasts? Active management of interconnector flows? SLIDE 10

11 SOLUTIONS Market frameworks Short dispatch intervals (full re-dispatch every 5min) Short time to gate closure (forecasts more accurate) Incentives for participants to self-manage variability (causer pays) Smarter regulation Enable more only when required (eg. in intermittently cloudy periods) Better forecasts New sources of regulation Can be delivered by wind and PV, storage, etc. Trials at present Ela, E.; Gevorgian, V.; Fleming, P.; Zhang, Y.C.; Singh, M.; Muljadi, E.; Schoolbrook, A.; Aho, J.; Buckspan, A.; Pao, L.; Singhvi, V.; Tuohy, A.; Pourbeik, P.; Brooks, D.; Bhatt, N., (2014) Active Power Controls from Wind Power: Bridging the Gaps. Technical Report NREL/TP-5D , National Renewable Energy Laboratory (NREL) SLIDE 11

12 IDENTIFYING CHALLENGES Frequency Control Forecasting Variable & uncertain Planning Distributed Low operating cost Frequency Control Non-synchronous SLIDE 12

13 TYPES OF GENERATORS Coal Gas Hydro Biomass SYNCHRONOUS Geothermal Solar thermal Nuclear NON-SYNCHRONOUS Wind Photovoltaics Batteries Flywheels 3,000 revolutions per minute SLIDE 13

14 INERTIA 50.0 DEMAND GENERATION INERTIA acts as a brake Wind & PV displace synchronous plant Inertia drops Frequency changes faster SLIDE 14

15 RATE OF CHANGE OF FREQUENCY Contingency event RoCoF If RoCoF is too high Trip of generation? Emergency control schemes may not prevent collapse SLIDE 15

16 IRELAND 2017: ~24% wind 2020: 40% renewable Island with no AC interconnectors SLIDE 16

17 VISITING EIRGRID SLIDE 17

18 SOUTH AUSTRALIA 42% energy from wind & PV 1 AC interconnector South Australia SLIDE 18

19 SOLUTIONS Synchronous condensers Keep synchronous generators operating Add inertia Install new synchronous generators New interconnector Fast Frequency Response? Other Reduce contingency size Reduce flows on the interconnector SLIDE 19

20 FAST FREQUENCY RESPONSE Fast power injection (< 1 second) SLIDE 20

21 FAST FREQUENCY RESPONSE Synthetic inertia from a wind power plant - Example of a recorded event in Hydro-Quebec Noel Aubut (2013) Wind Power Status and Experience with Inertial Response from Wind Power Plants, 2 nd Workshop on Active Power Control from Wind Power, Boulder Colorado SLIDE 21

22 IDENTIFYING CHALLENGES Frequency Control Forecasting Variable & uncertain Planning Distributed Low operating cost Frequency Control Non-synchronous System strength SLIDE 22

23 SYSTEM STRENGTH System strength is a measure of power system stability Related to fault current Allows wind & PV to ride through Fault occurs Synchronous generators contribute fault current Triggers protection systems to detect & isolate the fault Maintains voltage stability Synchronous generators (coal, gas, hydro) Contribute fault current Non-synchronous generators (wind, PV) Do not contribute fault current Require a share of fault current to operate SLIDE 23

24 SYSTEM STRENGTH PROJECTION Weighted SCR for possible connections SLIDE 24

25 SYNCHRONOUS CONDENSERS Inertia System Strength SLIDE 25

26 MARKET CHANGES Minimum threshold for inertia AEMO to determine, TNSPs to maintain Market for inertia? Under consideration Price for inertia based upon binding RoCoF constraints? Minimum unit combinations for system strength For South Australia Implemented with Directions Minimum Short Circuit Ratio (SCR) AEMO to determine, TNSPs to maintain New entrant generators must do no harm SLIDE 26

27 IDENTIFYING CHALLENGES Frequency Control Forecasting Variable & uncertain Planning Decentralised system Visibility & control Modelling Distributed Low operating cost Frequency Control Non-synchronous System strength SLIDE 27

28 Minimum demand (MW) ROOFTOP PHOTOVOLTAICS Minimum Operational Demand in South Australia: 1,500 1,250 1, Inertia? System Strength? Frequency Control? Network limits? Ramping? -1,000 Financial year ending Residential and Business Load Rooftop PV Generation Central assumption Sensitivity SLIDE 28

29 TECHNICAL STANDARDS Disturbance ride-through characteristics Distributed resources act in aggregate Must address early for distributed resources < 2min kv voltages during 28 th September 2016 system black event a 5b Heywood interconnector opens SLIDE 29

30 SUMMARY Challenge Implications Possible Solutions More variability More regulation frequency control needed Smarter regulation New providers (wind, PV, storage) Lower inertia Higher RoCoF Fast Frequency Response Synchronous condensers Lower system strength >100% of energy from rooftop PV Voltage control & protection challenges System controllability challenges Synchronous condensers Synchronous condensers Aggregated services from distributed resources Technical standards SLIDE 30