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Power Association of Northern California
Maintaining Grid Reliability In An Uncertain EraMay 16, 2011PG&E Conference Center
Jim Mcintosh
Director, Executive Operations Advisor
California ISO
Slide 2
The Challenges & How We Plan To Address Them
• Forecasting• Generation fleet characteristics• Ramping requirements• Ambitious environmental goals• Reliability with fewer gas powered plants• Cost containment
• We need to strike a balance between reliability, renewables, and reasonable cost.
Slide 3
Policy Drivers
• State law AB32 – reduction of greenhouse gas emissions to 1990 levels by 2020– Western Climate Initiative
• 20% Renewable Portfolio Standard (RPS) by 2012-2013
• 33% RES by 2020 (Executive Order)
• Repowering or replacement of once-through cooling power plants (~34% of in-state gas and nuclear capacity)
Slide 4
Additional Supply Side Policies
• Small-scale renewable feed-in tariff program– Resources must be smaller than 1.5 MW and the cap is 480-500 MW
• Storage bill AB2514 (Sept. 2010)– Requires the CPUC to consider and adopt procurement targets for
viable and coast-effective energy storage systems.
Slide 5
Location of OTC plants in local capacity requirement (LCR) areas within CAISO
*Retired out 2010
-
1,000
2,000
3,000
4,000
5,000
6,000
7,000
Biomass/Biogas Solar Geothermal Small Hydro Wind2006 701 420 1,101 614 2,648
2012 (expected) 701 2,246 2,341 614 6,688
Slide 6
MW
The 2-3 year look-ahead: renewable resource portfolios in 2006 and 2012 (20% RPS), by capacity (MW)
Slide 7
The ISO grid control room faces significant short- and long-term challenges
• Uncertainty of grid infrastructure development
• Ramping requirements significantly increased
• Continued development of control room tools
• Load and wind forecasting accuracy
• Rapid changes in grid generation fleet, especially wind and solar technologies
1. Wind and solar variability will be a significant issue by 2012-2013.
2. Synchrophasors are the most significant advancement in control center technology in the last 30 years.
Slide 8
These challenges can be addressed through improved control room tools (Synchrophasors) and training
• Wind and solar modeling & production forecasting
• State estimator solution & accuracy
• Grid reliability & engineering studies
• Network and market modeling
• Awareness of regional disturbances (e.g. 1996 event)
• Dynamically assess the grid (EMS not sufficient)
• 30 samples per second compared to once every four seconds
• Can increase COI transfer by 1500 MW
• Estimated reduction in congestions costs $250 million
• Better real time visualization
Challenges of Fossil Fuel and Wind Generation
Slide 9
Predictability
No surprises
Dependable energy schedules
Accurate forecasts
Contingency reserves available
Generators that follow dispatch commands
Excellent tools for visibility of system status
High quality data
De-rate information on units is timely and accurate
GRID OPERATORS
Hard to predict
Shows up unscheduled
Maximum generation at night when loads are low and there is no place for the energy
Large ramp changes both up and down
Lack of good data from wind generation facilities
Lack of visibility on what wind generations are doing
Don’t follow dispatch commands ---treated as “Must Take” generation
WIND GENERATORS
Slide 10
Difficulty of Predicting Wind Energy
Average
Total Wind Generation
0
200
400
600
800
1000
1200
1400
1600
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24
MW
Wind activity across a 24 hour period.
Slide 11
RAMPING!
Wind generation tends to be inversely correlated to daily load curve, creating ramping impacts
CAISO Load vs. Total WindSummer 2006
22,000
24,000
26,000
28,000
30,000
32,000
34,000
36,000
38,000
40,000
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24
Hours
Lo
ad
MW
0
100
200
300
400
500
600
700
800
900
1,000
1,100
1,200
Win
d/S
ola
rM
W
Load Total Wind Solar
Slide 12
Photovoltaic Plant Output on a Partly-Cloudy Day
10 Second Sample – March 25, 2008
13
Requirements for Integration of Renewables
GenerationPortfolio Storage
DemandResponse
Resources Required for Renewables Integration
Quick Start Units
Fast Ramping
Wider Operating
Range (lower Pmin)
Regulation capability
Shift Energy from off-peak to on-peak
Mitigate Over Generation
Voltage Support
Regulation capability
Price sensitive load
Responsive to ISO dispatches
Frequency Responsive
Responsive to Wind Generation Production
“Partners in Success”
Wind Generation
Solar Generation
Hydro Generation
Geo-thermal
Generation
Slide 14
New record Wind production
About 40 mws
Each cell is 2 hours
Day ahead schedule
Green is actual production