WECC Update
Dan Beckstead Staff Engineer
System Adequacy Department
W E S T E R N E L E C T R I C I T Y C O O R D I N A T I N G C O U N C I L
Overview
• WECC Functions • Planning Models and Data
– Powerflow Models – Loads and Resource Data – Production Cost Models and LTPT – State of the Interconnection Data
• GADS Data • Questions & Answers
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WECC Functions
• What we do: – Compliance Monitoring and Enforcement – Standards Development – Reliability Planning and Performance
Analysis
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WECC’s mission is to promote and foster a reliable and efficient bulk electric system
Analysis in WECC Reliability Planning
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What Reliability Challenges Might WECC Face?
Near Term
Resource Adequacy Stability Cascading
Outages
Long Term
Congestion Transmission Expansion Flexibility
Power Flow Model
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Power Flow • Mathematical model of the
power system used to evaluate steady state and dynamic representations of the power grid.
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WECC Base Case
• NERC Compliance • Service to Stake Holders
– TPL Studies – Interconnections agreements – Planned Projects – Topology for economic studies – Path Rating Process
• WECC Annual Study Report
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Contingency Analysis 8
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0
500
1000
1500
2000
2500
3000
3500
4000
4500
0 5 10 15 20 25 30 35 40 45
MW
Time (s)
Actual Simulated
59.6
59.65
59.7
59.75
59.8
59.85
59.9
59.95
60
0 5 10 15 20 25 30 35 40
Freq
uenc
y
Time (s)
Actual Simulated
Loads and Resource Data
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L&R Data Request
• NERC assessment report • Basis for resource adequacy evaluation at
WECC – Submitted by BAs in the western interconnection – Data format outlined by L&R Data Manual
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Resource Adequacy • Power Supply Assessment • Probabilistic approach to RA modeling
Actual year hourly demand data; Existing generation; Planned generation; Projected and actual demand reduction data; Projected peak demand; Projected energy forecasts; Scheduled peak hour outages; Actual year peak hour outages; Other data collected in support of the annual WECC PSA and Seasonal Assessments, and the NERC Long Term Reliability Assessment (LTRA).
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Long Term Planning Tool
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Long Term Planning Tool
• Year 20 Model (latest 2034) • Zonal Capital Cost Optimization
– Generator Resources – Transmission Utilization
• Focus is to understand potential energy futures and evaluate decisions and measures to achieve those futures
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Path Focus 14
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Geospatial Considerations 15
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Year-20 Water Availability 16
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Production Cost Model
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Production Cost Model
• Year 10 Model (latest 2026) • Full Nodal Hourly Optimization
– Generator Resources – Transmission Utilization
• Used as a possible future to evaluate: – Transmission Utilization – Changes in resource dispatch
• CO2 emission • Dump energy
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2026 TEPPC Common Case – Major Assumptions
2026 Common
Case
Loads
Resources
Transmission
Dataset Building Activities
Resource Portfolio
SWG
Loads DWG
Transmission Network
SWG
TEPPC Dataset
WECC Staff
Debugging/Validation DWG/MWG/SWG/Staff
Modeling Enhancements
MWG
Scenario Runs/Analysis/Reporting
LRS Submittals
Utility IRPs Resource Planners
Work Group Participants WREZ Tool
NREL Meso-scale Data
Data Improvements
DWG
WECC Staff
LRS Submittals
SCG Common Case Transmission Assumptions
WECC Powerflow Case
2026 Common Case Transmission Assumptions
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Study Results and Recommendations
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Case
Expected Impacts relative to Common Case
Heaviest Path
Utilization
Total Variable
Production Cost
CO2 Emissions
Dump Energy1
Proportion of
Renewable Energy
PC2 Low Loads
PC3 High Loads
PC4 High Hydro Unknown Unknown
PC5 Low Hydro Unknown
PC6 High NG price Unknown
PC7 Low NG price Unknown
PC 10 High CO2 $ Unknown
PC 11 Low CO2 $ Unknown Unknown
Study Results and Recommendations
• Recommendations – Uncertainties in Planning – Expected Future Grid – Need for Greater Collaboration and Improved
Base Case Review – Continue Investigation of Variable Resource
Integration
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State of the Interconnection
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State of the Interconnection (SOTI)
• Purpose – High-level snapshot of
the Interconnection across 5 topics
– Foundational information that feeds other work
– Reference tool for a broad audience
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Events & Outages
Load
Generation
Transmission
Entity Oversight
Changes In 2017
• Moved to online platform – Will be released in early June
• User can interact with data – Drill down, select specific
information, etc. – Interactive maps
• Expanded subject coverage
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GADS Data
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Generation Outages
• SOTI report illustrates outage trends
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0
2
4
6
8
10
Coal Gas Hydro
Out
ages
Median Number of Outages Per Unit
2013 2014 2015 • There were 9,363 outages of conventional generation units in 2015, up 11% from 2014
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Forced Outage Rates
• WECC planning models use forced outage rates to extrapolate a likely outage rate used in 10 and 20 year futures
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0%
1%
2%
3%
4%
Coal Gas Hydro
Perc
ent o
f Yea
r
Median Unavailability Per Unit From Unplanned Outages
2013 2014 2015
Questions
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Dan Beckstead Staff Engineer Western Electricity Coordinating Council [email protected] 801-819-7656