PC04 & PC05 Hydro Study Case Results

Anna Beus

October 3, 2016

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

PC04 & PC05 Hydro Modeling Logic

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Assumptions

• High Hydro Year• Low Hydro Year

Production Cost Model

Scope

• Scope• Key Questions

Results

• Generation Dispatch

• Path Flows• Cost• Dump Energy

High and Low Hydro Studies

• Study Requestor: PG&E

• Changes from 2026CC:

– PC04: 2011 hydro data substituted for median hydro data (2005) for high hydro case

– PC05: 2001 hydro data substituted for median hydro data (2005) for low hydro case

• Key Question:

– How does production cost, generation dispatch, and transmission utilization change under high and low hydro conditions?

*No changes were made to transmission or load

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Generation Results

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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

0 50,000 100,000 150,000 200,000 250,000 300,000 350,000

Conventional Hydro

Energy Storage

Steam - Coal

Steam - Other

Nuclear

Combined Cycle

Combustion Turbine

IC

Other

DG/DR/EE - Incremental

Biomass RPS

Geothermal

Small Hydro RPS

Solar

Wind

Annual Generation by Category (GWh)

2026 PC1 V1.3 2026 PC4 High Hydro 2026 PC5 Low Hydro

Production Cost and CO2

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Annual Generation by Category (GWh)

Category 2026 PC1 V1.32026 PC4 High

Hydro2026 PC5 Low

Hydro % Difference High

vs. V1.3% Difference Low

vs. V1.3

Conventional Hydro 234,570 282,538 189,678 20% -19%

Energy Storage 2,962 2,642 2,973 -11% 0%

Steam - Coal 194,852 185,099 201,391 -5% 3%

Steam - Other 1,873 1,633 2,155 -13% 15%

Nuclear 39,192 38,972 39,493 -1% 1%

Combined Cycle 265,714 233,284 294,961 -12% 11%

Combustion Turbine 35,356 32,959 40,650 -7% 15%

IC 977 501 1,849 -49% 89%

DG/DR/EE - Incremental 33,550 33,550 33,550 0% 0%

Biomass RPS 21,328 20,467 24,024 -4% 13%

Geothermal 41,156 40,905 41,172 -1% 0%

Small Hydro RPS 3,738 3,989 2,702 7% -28%

Solar 45,659 45,101 45,636 -1% 0%

Wind 73,989 73,793 73,986 0% 0%

== Total == 994,915 995,433 994,220 0% 0%

Other Results

Var. Prod. Cost (M$) 17,795 15,985 19,709 -10% 11%

CO2 Cost (M$) 3,613 3,411 3,874 -6% 7%

CO2 Amount (MMetrTn) 317 294 340 -7% 7%

Dump Energy (GWh) 601 1,355 629 126% 5%

Pumping (PL+PS) (GWh) 11,875 11,395 11,860 -4% 0%

Exports (MWh) 0 0 0 0 0

Changes in Total Annual Generation (PC04)

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(40,000) (20,000) 0 20,000 40,000 60,000

Conventional Hydro

Energy Storage

Steam - Coal

Steam - Other

Nuclear

Combined Cycle

Combustion Turbine

IC

Other

DG/DR/EE - Incremental

Biomass RPS

Geothermal

Small Hydro RPS

Solar

Wind

Annual Energy Difference (GWh): 2026 WECC V1.3 vs 2026 PC4 V1.3

Changes in Total Annual Generation (PC05)

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(50,000) (40,000) (30,000) (20,000) (10,000) 0 10,000 20,000 30,000 40,000

Conventional Hydro

Energy Storage

Steam - Coal

Steam - Other

Nuclear

Combined Cycle

Combustion Turbine

IC

Other

DG/DR/EE - Incremental

Biomass RPS

Geothermal

Small Hydro RPS

Solar

Wind

Annual Energy Difference (GWh): 2026 WECC V1.3 vs 2026 PC5 V1.3

Generation Change by State (PC04)

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-10,000

-5,000

0

5,000

10,000

15,000

20,000

25,000

AB AZ BC CA CO ID MT MX NE NM NV OR SD TX UT WA WY

Annual Gen Change (GWh) 2026 WECC V1.3 vs 2026 PC4 V1.3

Conventional Hydro

Energy Storage

Steam - Coal

Steam - Other

Nuclear

Combined Cycle

Combustion Turbine

IC

Other

Biomass RPS

DG/DR/EE - Incremental

Geothermal

Small Hydro RPS

Solar

Wind

Generation Change by State (PC05)

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-20,000

-15,000

-10,000

-5,000

0

5,000

10,000

AB AZ BC CA CO ID MT MX NE NM NV OR SD TX UT WA WY

Annual Gen Change (GWh) 2026 WECC V1.3 vs 2026 PC5 V1.3

Conventional Hydro

Energy Storage

Steam - Coal

Steam - Other

Nuclear

Combined Cycle

Combustion Turbine

IC

Other

Biomass RPS

DG/DR/EE - Incremental

Geothermal

Small Hydro RPS

Solar

Wind

Results – Most Heavily Utilized Paths

• Congestion vs Utilization– Some lines are designed to be congested

• “Most Heavily Utilized” = A path that meets any one of the following criterion (10-year plan utilization screening):– U75 > 50%

– U90 > 20%

– U99 > 5%

• Uxx = % of year that flow is greater than xx% of the path limit

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Results – Changes in Transmission Utilization (PC04)

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P45 SDG&E-CFE

Most Heavily Utilized Paths

Path Name 75% 90% 99%

P83 Montana Alberta Tie Line 41.40% 30.70% 0.00%

-P52 Silver Peak-Control 55 kV 36.94% 22.12% 0.00%

-P60 Inyo – Control 115 kV Tie 51.30% 21.96% 0.00%

P01 Alberta – British Columbia 27.08% 15.72% 7.32%

P45 SDG&E – CFE 17.18% 13.52% 11.37%

P29 Intermountain-Gonder

P26 Northern-Southern California

P03 Northwest-British Columbia

P47 Southern New Mexico

P08 Montana to Northwest

P60 Inyo-Control

P27 IPP DC Line

P10 West of Colstrip

P01 Alberta-British Columbia

P65 PDCIP66 COI

P16 Idaho-Sierra

P83 Montana Alberta Tie Line

P52 Silver Peak-Control

P80 Montana Southeast

P45 SDG&E-CFE

Results – Changes in Transmission Utilization (PC05)

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P45 SDG&E-CFE

Most Heavily Utilized Paths

Path Name 75% 90% 99%

-P60 Inyo – Control 115 kV Tie 57.07% 31.30% 0.00%

-P52 Silver Peak-Control 55 kV 45.18% 31.05% 0.00%

-P80 Montana Southeast 51.55% 15.57% 1.45%

P83 Montana Alberta Tie Line 20.48% 12.65% 0.18%

P45 SDG&E – CFE 13.26% 9.63% 7.79%

P29 Intermountain-Gonder

P26 Northern-Southern California

P03 Northwest-British Columbia

P47 Southern New Mexico

P08 Montana to Northwest

P60 Inyo-Control

P27 IPP DC Line

P10 West of Colstrip

P01 Alberta-British Columbia

P65 PDCIP66 COI

P16 Idaho-Sierra

P83 Montana Alberta Tie Line

P52 Silver Peak-Control

P80 Montana Southeast

P45 SDG&E-CFE

Results – PC04 High Hydro

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0%

10%

20%

30%

40%

50%

60%

Pe

rce

nt

of

Ho

urs

Most Heavily Utilized Paths - 2026_PC4 High Hydro

U75 U90 U99

Results – PC05 Low Hydro

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0%

10%

20%

30%

40%

50%

60%

Pe

rce

nt

of

Ho

urs

Most Heavily Utilized Paths - 2026_PC5 Low Hydro

U75 U90 U99

Path 65 Flows

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Path 66 Flows

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Path 83 Flows

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Path 01 Flows

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Findings

• Generation and Energy Changes:– Increased hydro availability Reduction of combined cycle,

coal (steam), and combustion turbine generation– Decreased hydro availability Increased combined cycle, coal

(steam), combustion turbine generation

• Transmission Changes:– Transmission impacts are minimal and the interconnection

seems to be able to operate reliably under both hydro conditions.

• Production Cost Changes:– Increased hydro availability Lower production cost and

carbon emissions– Decreased hydro availability Increased production cost and

carbon emissions

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Questions

Anna Beus

abeus@wecc.biz

(801) 819-7666

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