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 dbeckstead@wecc.biz 801-819-7656