CAISO Market Inner Working - EMS Users Conference

2012 EMS Users Conference 

California ISO Market Inner Working 

Dr. Khaled Abdul-Rahman, Director 

Power Systems Technology Development (PSTD) 

California ISO 

September 17, 2012 – Rancho Cordova, CA 

ISO PUBLIC © 2012 CAISO

Topics 

� CAISO Grid and Market Processes 

� Full Network Model and CAISO’s Use of CIM Standards 

� Balancing Supply and Demand 

� Flexible Fleet Capabilities 

� Non-Generation Resources (LESR, DDR) 

� Need for More Effective Operational Tools 

� On-Going Enhancements 

� Future Key Enhancement 

ISO PUBLIC © 2012 CAISO 

Slide 2

California ISO LMP Market 

� On April 1, 2009, CAISO started its new LMP market 

� The objective of the co-optimization is to balance net 

expected demand with net expected supply at minimum 

cost while observing physical characteristics of 

resources and grid reliability constraints. 

� The optimized unit commitment and dispatch levels may 

be sufficient to satisfy the expected system condition. 

� To the extent imbalance conditions vary from the 

expected condition, sufficient flexibility must be 

committed to respond to such variations. 


Slide 3

California ISO by the numbers 


� 57,963 MW of power plant 

capacity 

� 50,270 MW record peak demand 

(July 24, 2006) 

� 30,000 market transactions 

per day 

� 25,865 circuit-miles of 

transmission lines 

� 30 million people served 

� 286 million megawatt-hours of 

electricity delivered annually 

Slide 4

California ISO in WECC 

� Largest of 37 Balancing Authorities in the West 

� 38 intertie points with neighboring systems 

� Managing 80% of California load 

� Represent 30% of the Western Interconnection load 


Slide 5

ISO Resource Mix 

14.6% - hydro, geothermal, 

biomass, wind, solar 

* In addition to 29% Net Imports 

1.7% - coal 

14.6% - large hydro 

15.7% - nuclear 

53.4% - natural gas 


Source: California Energy Commission 

Slide 6


Source: www.caiso.com 

Slide 7

Variable Generation Locations 


Slide 8

Balancing Supply and Demand 


Slide 9

CAISO Market Processes 

Real 

Time 

Real Time 5- 

Min Dispatch 

Market 

Hour Ahead 

Process and 

Real Time 

Unit 

Commitment 


Day Ahead 


Pre-Day 

Ahead 

Activities 

Process 

Begins 

Slide 10

Real Time 

� Process generation and transmission outages 

� RA replacement 

Real Time 5- 

Min Dispatch 


� Model transmission constraints 

� Forecast next day’s hourly load 

� Commit long-start units 

Hour Ahead 

Process and 

Real Time 

Unit 

Commitment 

� Medium to Long Term: CRR auctions, RMR, Transmission 

Planning, economic transmission projects assessment 


Day Ahead 


Pre-Day 

Ahead 

Activities 

Slide 11

Real Time 

Real Time 5- 

Min Dispatch 


� Receive and process bids 

Hour Ahead 

Process and 

Real Time 

Unit 

Commitment 

� Mitigate market power (MPM) 


Day Ahead 


Pre-Day 

Ahead 

Activities 

� Clear energy supply & demand including virtual bids and 

procure ancillary services (IFM) 

� Commit additional capacity to meet load forecast (RUC) 

� Issue hourly operating schedules and day ahead prices 

Slide 12

Real Time 

Real Time 5- 

Min Dispatch 


Hour Ahead 

and Real 

Time Unit 

Commitment 

� Receive and process bids 

� Mitigate market power (MPM) 


Day Ahead 


Pre-Day 

Ahead 

Activities 

� Schedule interchange with adjacent areas (HASP) 

� Procure additional ancillary services (RTUC) 

� Commit short start resources (RTUC) 

Slide 13

Real Time 

Real Time 5- 

Min 

Dispatch 


Hour Ahead 

Process and 

Real Time 

Unit 

Commitment 

� Issue 5-min dispatch instructions for generators and 

participating load 

� Set and publish 5-minute prices 

� Issue exceptional dispatches, if needed 

� Issue 10-min contingency dispatch instructions (RTCD) 


Day Ahead 


Pre-Day 

Ahead 

Activities 

Slide 14

Real Time 

Real Time 5- 

Min Dispatch 


Hour Ahead 

Process and 

Real Time 

Unit 

Commitment 


Day Ahead 


� Resources respond to dispatch instructions 

� Monitor minute-to-minute conditions 

Pre-Day 

Ahead 

Activities 

� Deviations within the 5-min time intervals are balanced 

through dispatch of regulation capacity reserve via AGC 

� Operators intervene only when needed 

Slide 15

CAISO Market Temporal Hierarchy 


Slide 16

Full Network Model 

� CAISO maintains two separate network models using CIM 

Standards: 

o Grid reliability network model used by EMS 

o Market Network model used by IFM/RTM and CRR 

o Same detailed representation inside California ISO 

Control Area 

� Various vendor systems and many legacy systems were 

integrated leveraging SOA technology and adopting IEC 

CIM standard as communication platform 

� CAISO needed to extend the IEC CIM standards 61970, 

61968 and CME to define various market related data and 

messages 


Slide 17

Examples of CIM and its Extension at CAISO 

� Modeling of Reference Data 

Standard CIM classes have been extended for the modeling of quasi-static 

data to support the CAISO markets 

� Example: Registered Resources 

o Three major resource types in CAISO: generator, load and inter-tie 

o CME classes re-used to create an extension representing the inter-tie 

resource 

� Example: Multi-Stage Generator (MSG) 

o MSG concept models resources with more than two operating states 

o Represents an extensions of the two-state (on/off) model for generating 

units 

� Example: Pricing Node 

o A Pnode is directly associated with a ConnectivityNode 

o CAISO extended CIM to define a new class AggregatedPnode – to 

represent pricing hub, zones or aggregated resource 


Slide 18

Balancing Supply and Demand 

Many factors influence balancing supply and demand. 


Reserve 

Supply 

Demand 

Slide 19

CAISO Needs for Flexible Fleet Capability 

� CAISO needs more flexible measures to balance the increasingly 

weather-dependent (variable) generation and other uncertainties 

associated with load as well as changing operational system 

conditions. 

� CAISO has observed that the unit commitment and position of 

resources in the 15-min RTUC may lack sufficient ramping capability 

and flexibility to meet system conditions for the 5-min RTD during 

which conditions may have changed from the assumptions made 

during the prior 15-min pre-dispatch. 

� Shortage of ramping following capability may result in: 

o Leaning on the interconnection 

o RTD energy price is not priced by economic bids, but by 

administrative penalty prices, which may impact market 

efficiency in the long run 


Slide 20

Non-Generation Resources - Limited Energy Storage 

Resource (LESR) 

� Based on simulation results, the addition of faster 

regulation resources can improve the average CPS1 

scores when compared to the base case results while 

keeping the same regulation requirements. 

� Simulation results also suggest that CPS1 performance 

can be maintained near base case levels while 

reducing the regulation requirements with the addition 

of fast resources. 

� The results also indicate diminishing returns for levels 

of fast resources beyond certain percentages that are 

power system dependent. 


Slide 21

Load Leveling using Storage 

Natural Load (MW) 

Load with Battery (MW) 

Battery Operating Profile 

Charge Charge 

Discharge Discharge 


Slide 22

Renewable Stabilization 

Solar variability 

Storage charge/discharge by AGC 


Smooth Solar output 

Slide 23

ACE shaping 

MW 

5.000 

4.000 

3.000 

2.000 

1.000 

0.000 

-1.000 

-2.000 

-3.000 

-4.000 

-5.000 

=/- 4 MW Regulation Scaled to 250 MW ACE Signal 

299 

309 

319 

329 

339 

349 

359 

369 

379 

389 

399 

409 

419 

429 

439 

449 

459 

469 

479 

Time (Minutes) 


489 

499 

509 

519 

529 

539 

549 

559 

569 

579 

589 

599 

Charge 

Discharge 

Slide 24

Non-Generation Resources – Dispatchable Demand 

Response (DDR) 

� For many people, curtailing load a few times a year in reaction to 

peak demands on the power system is “demand response” – Not 

enough! 

� Demand Response refers to all methods in which demand side 

assets can react to the needs of the power system 

� Demand response are already participating in operating reserves! 

� New and more intelligent technologies enable loads to participate in 

many more forms: 

o Regulation Services 

o Flexible Ramp 

o Localized DR 

o T & D upgrade deferral 


Slide 25

What Do We Need From DDR? 

� One of the key promises of “the smart grid” is much 

tighter integration of loads with the needs of the 

power system 

� As DRs participate in ways more integral to the grid 

needs, they must respond: 

o Faster (seconds and minutes not hours and days) 

o More frequent (constant adjustment) 

o Bi-directional (grid balance) 

� Technology must exist to limit the impact to the end 

customer (inherent flexibility and operational constraints) 


Slide 26

Need for More Effective Operational Tools 

Voltage instability - progressive and uncontrollable decline in voltage 

after disturbance, increase in load demand, or change in other system 

conditions, often results in system disintegration or blackout. 

� Increased power transfers across interfaces 

� Increased intermittent renewable resources in the grid 

� Need effective control tools due to minute by minute 

decisions 

� Limits calculated in planning studies are not accurate 

enough due to unplanned outages and de-ratings 

� Sudden fluctuations of supply and net load due to 

intermittent renewable generators, DER, load forecast 

uncertainty, uninstructed dispatch deviations 

� System Operator needs new tools 


Slide 27

Situational Awareness Tools 

� PI Displays (along with EMS displays) 

� Real-Time VSA 

� Real-Time DSA (in the plan) 

� RTDMS (PMU measurements – Real-Time Dynamics 

Monitoring System) 

� Renewables watch (Weather, wind speeds, renewable 

generation) 

� Monitor Fires in the area (Google Earth Maps) 


Slide 28

On-Line Voltage Stability Analysis (VSA) Tool 

� EMS System and On-Line VSA Integration 

o SE solutions as base case 

o Fully automatic with High Availability (HA) 

o Operational since 6/09 

� Importance of Market System and Look-Ahead VSA Integration 

o Integrated VSA with market system may verify the system 

conditions as set out in the DAM or RTM to provide better 

situational awareness of the security of the system and the 

operating limits 

o VSA can potentially allow the transmission limits found in offline 

studies to be updated based on the current network model 

conditions, thus allowing the ISO to operate the grid at lower cost 

and the consumers to reap the benefit of lower market pricing. 


Slide 29

Integrated Market System and VSA-LA Design Features 

� Seamless Integration with Market and EMS systems 

� Fast Contingency screening and Ranking 

� Renewable Resources Volatility Simulation 

� Control Actions Recommendations 

� Real Time Market Look Ahead Market Verification 

� Day Ahead Market (DAM) Verification 

� Study Mode for “What-If” Analysis 


Slide 30

VSA-RT Geographical Interface Margin Display 


Slide 31

Sample VSA-DA Results: Area X Load Margin 

for Two Different Trading Days 

3400 

3200 

3000 

2800 

2600 

2400 

2200 

2000 

Area X Load Margin from VSA-DA 

0 4 8 12 16 20 24 


Slide 32

Sample VSA-DA study Results - Load Margin Trend Curve for DAM 


Slide 33

Some Ongoing Enhancements 

� Market Operator Training Simulator (MOTS) 

� Enhanced Contingency Analysis in Market Apps 

� Optimal Scheduling of Small Size Resources 

� Integrated IFM and RUC 

� Transmission and Generation Outage Coordination Tool 

� Forecasting Enhancements (load, gen, DER, ramping, reg, spin, ns) 

� Visualization Tools 


Slide 34

Future Network Applications Key Enhancements 

� Expanded Market Network Model 

� DC Lines Modeling 

� Dynamic Line Ratings 

� Voltage Schedules & Reactive Power Controls 

� Topology Error Estimation 

� Islanding Operation Support 


Slide 35

Future Market Applications Key Enhancements 

� Transmission Reservation to Support Dynamic Transfer 

� Flexible Ramp Product 

� Mileage Requirement Model to support Pay-For- 

Performance 

� Expand NGR Model to Include DR, EV, Micro-grid, 

Virtual Plant Model 

� Price Sensitive Demand Response 

� Model Impact of Gas Network Constraints in the Market 


Slide 36

Q & A 

For more follow up questions, please contact: 

Dr. Khaled Abdul-Rahman 

kabdul@caiso.com 

Thank You 


Slide 37

CAISO Market Inner Working - EMS Users Conference

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