20230531Quarterly Report.pdf

LISA O’HARA
Corporate Counsel
lo’[e-mail]

May 31, 2023

Ms. Jan Noriyuki
Secretary
Idaho Public Utilities Commission
PO Box 83720
Boise, ID 83720-0074

Re: Case No. IPC-E-16-19
Deferral and Recovery of Costs Associated with Participation in Energy Imbalance
Market – California Independent System Operator (“CAISO”) Quarterly Energy
Imbalance Market (“EIM”) Benefits Assessment Report

Dear Ms. Noriyuki:

Pursuant to Order No. 33706 issued in Case No. IPC-E-16-19, Idaho Power Company
(“Idaho Power” or “Company”) hereby submits the quarterly CAISO Western EIM Benefits Report
(“Report”) for the first quarter of 2023. The Report presents CAISO’s quantification of benefits
associated with participation in the Western EIM. For the first quarter of 2023, CAISO estimated
Western EIM gross benefits of $13.31 million for Idaho Power.

The EIM has provided financial benefits to the Company, and ultimately its customers.
However, as discussed in Idaho Power’s prior quarterly compliance filings as well as the
Company’s May 24, 2019, Report of EIM Benefits and Costs of Participation, CAISO’s calculation
of benefits for Idaho Power is overstated due to several of the modeling assumptions used in its
benefit calculation. The Company developed a more precise methodology, that uses inputs
specific to Idaho Power, for determining actual EIM benefits, the details of which are discussed in
the Company’s May 24, 2019, Report of EIM Benefits and Costs of Participation.

If you have any questions regarding this report, please contact Matt Larkin, Revenue
Requirement Senior Manager, at [phone] or [e-mail].

Sincerely,
Lisa J. O’ Hara

Enclosure
RECEIVED
2023 May 31, 4:35PM
IDAHO PUBLIC
UTILITIES COMMISSION

WESTERN ENERGY IMBALANCE MARKET
BENEFITS REPORT
First Quarter 2023

Prepared by: Market Analysis and Forecasting
May 26, 2023
WEIM BENEFITS REPORT FIRST QUARTER 2023

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CONTENTS

EXECUTIVE SUMMARY ........................................................................................................ 3
BACKGROUND .................................................................................................................... 4
WEIM ECONOMIC BENEFITS IN Q1 2023 ............................................................................ 4
CUMULATIVE ECONOMIC BENEFITS SINCE INCEPTION ................................................................. 5
INTER-REGIONAL TRANSFERS ........................................................................................................ 6
WHEEL-THROUGH TRANSFERS ..................................................................................................... 23
REDUCED RENEWABLE CURTAILMENT AND GHG REDUCTIONS .................................. 30
FLEXIBLE RAMPING PROCUREMENT DIVERSITY SAVINGS ........................................... 31
CONCLUSION..................................................................................................................... 36
APPENDIX 1: GLOSSARY OF ABBREVIATIONS ............................................................... 37
WEIM BENEFITS REPORT FIRST QUARTER 2023

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EXECUTIVE SUMMARY
This report presents the benefits associated with
participation in the Western Energy Imbalance
Market (WEIM).
The measured benefits of participation in the WEIM
include cost savings, increased integration of
renewable energy, and improved operational
efficiencies including the reduction of
the need for real-time flexible reserves.
This analysis demonstrates the benefit of economic
dispatch in the real time market across a larger
WEIM footprint with diverse resources and geography.

Q1 2023 Gross Benefits by Participant
(millions $)
Arizona Public Service $26.43
Avista
BANC $44.63

Gross benefits from WEIM since November 2014 $3.82 billion
ECONOMICAL $418.82 M
Gross benefits realized due to more efficient inter-and intra-regional dispatch in the Fifteen-Minute
Market (FMM) and Real-Time Dispatch (RTD)* ENVIRONMENTAL 22,685
Metric tons of CO2** avoided curtailments OPERATIONAL 50%
Average reduction in flexibility
reserves across the footprint
2023
Q1 BENEFITS
WEIM BENEFITS REPORT FIRST QUARTER 2023

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*WEIM Quarterly Benefit Report Methodology: https://www.westerneim.com/Documents/EIM-BenefitMethodology.pdf.
**The GHG emission reduction reported is associated with the avoided curtailment only. The current market process and
counterfactual methodology cannot differentiate the GHG emissions resulting from serving ISO load via the EIM versus dispatch that
would have occurred external to the ISO without the WEIM. For more details, see
http://www.caiso.com/Documents/GreenhouseGasEmissionsTrackingReport-FrequentlyAskedQuestions.pdf
BACKGROUND
The WEIM began financially binding operation on November 1, 2014 by optimizing resources
across the ISO and PacifiCorp Balancing Authority Areas (BAAs). NV Energy began
participating in December 2015, Arizona Public Service and Puget Sound Energy began
participating in October 2016, and Portland General Electric began participating in October
2017. Idaho Power and Powerex began participating in April 2018, and the Balancing Authority
of Northern California (BANC) began participating in April 2019. Seattle City Light and Salt River
Project began participating in April 2020.
In 2021, new balancing authorities began participating in the WEIM, with the Turlock Irrigation
District (TID) in March 2021, the second phase of BANC in March 2021, and the Los Angeles
Department of Water and Power (LADWP) and Public Service Company of New Mexico (PNM)
in April 2021, followed by NorthWestern Energy (NWMT) starting in June 2021.
Avista Utilities (AVA) and Tacoma Power (TPWR), two utilities serving a combined 600,000
electric customers in the Pacific Northwest, became the newest members of the WEIM, with
both beginning their participation on March 2, 2022. On May 3, 2022, the Bonneville Power
Administration (BPA) and Tucson Electric Power (TEP) both joined the WEIM.
The Western EIM footprint now includes portions of Arizona, California, Idaho, Montana,
Nevada, New Mexico, Oregon, Utah, Washington, Wyoming, and extends to the border with
Canada.
WEIM ECONOMIC BENEFITS IN Q1 2023
Table 1 shows the estimated WEIM gross benefits by each region per month1. The monthly
savings presented show $173.57 million for January, $115.44 million for February, and $129.81
million for March with a total estimated benefit of $418.82 million for this quarter2. This level of
WEIM benefits accrued from having additional WEIM areas participating in the market and
economical transfers displacing more expensive generation.

1 The WEIM benefits reported here are calculated based on available data. Intervals without complete data are excluded in the calculation. The intervals excluded due to unavailable data are normally within a few percent points of the total intervals. 2 For several quarterly estimates, CAISO benefits were calculated on a variation of the counterfactual
methodology. For CAISO only the logic had considered offline resources as part of the bid stack in the
counterfactual. In Q4 2021, CAISO identified some questionable results that drove persistent negative benefits
for CAISO when considering offline resources. Since Q4 2021, the benefit calculation for CAISO area follows
the same methodology applicable to all WEIM entities in which only online resources are used.
WEIM BENEFITS REPORT FIRST QUARTER 2023

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Region January February March Total
APS $11.52 $7.21 $7.70 $26.43
AVA $2.84
BANC $18.37 $20.87 $5.39 $44.63
BPA $4.57 $4.20 $3.06 $11.83
CISO $22.41 $17.64 $27.81 $67.86
IPCO $6.31 $3.33 $3.67 $13.31
LADWP $10.65 $9.48 $7.86 $27.99
NVE $17.93 $8.34 $20.92 $47.19
NWMT $8.07 $2.60 $1.93 $12.60
PAC $19.32
PGE $9.27 $6.46 $5.94 $21.67
PNM $10.25
PSE $7.33 $3.39 $4.56 $15.28
PWRX $2.15
SCL $1.74 $1.04 $1.42 $4.20
SRP $12.39
TPWR $3.25 $1.23 $2.07 $6.55
TEP $4.17 $1.67 $4.53 $10.37
TID $1.03 $0.75 $1.23 $3.01
Total $173.57 $115.44 $129.81 $418.82
TABLE 1: Q1 2023 benefits in millions USD
CUMULATIVE ECONOMIC BENEFITS SINCE INCEPTION
Since the start of the WEIM in November 2014, the cumulative economic benefits of the market
have totaled $3.82 billion. The quarterly benefits have grown over time as a result of the
participation of new BAAs, which results in benefits for both the individual BAA but also
compounds the benefits to adjacent BAAs through additional transfers. The ISO began
publishing quarterly WEIM benefit reports in April 2015.3
Graph 1 illustrates the gross economic benefits of the WEIM by quarter for each participating
BAA.

3 Prior reports are available at https://www.westerneim.com/Pages/About/QuarterlyBenefits.aspx
WEIM BENEFITS REPORT FIRST QUARTER 2023

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GRAPH 1: Cumulative economic benefits for each quarter by BAA
INTER-REGIONAL TRANSFERS
A significant contributor to EIM benefits is transfers across balancing areas, providing access to
lower cost supply, while factoring in the cost of compliance with greenhouse gas (GHG)
emissions regulations when energy is transferred into the ISO. As such, the transfer volumes
are a good indicator of a portion of the benefits attributed to the WEIM. Transfers can take place
in both the 15-Minute Market and Real-Time Dispatch (RTD).
Generally, transfer limits are based on transmission and interchange rights that participating
balancing authority areas make available to the WEIM, with the exception of the PacifiCorp
West (PACW) -ISO transfer limit and the Portland General Electric (PGE) -ISO transfer limit in
RTD. These RTD transfer capacities between PACW/PGE and the ISO are determined based
on the allocated dynamic transfer capability driven by system operating conditions. This report
does not quantify a BAA’s opportunity cost that the utility considered when using its transfer
rights for the EIM.
Table 2 provides the 15-minute and 5-minute WEIM transfer volumes with base schedule
transfers excluded. The WEIM entities submit inter-BAA transfers in their base schedules. The
benefits quantified in this report are only attributable to the transfers that occurred through the
WEIM. The benefits do not include any transfers attributed to transfers submitted in the base
schedules that are scheduled prior to the start of the EIM.
The transfer from BAA_x to BAA_y and the transfer from BAA_y to BAA_x are separately
reported. For example, if there is a 100 Megawatt-Hour (MWh) transfer during a 5-minute
interval, in addition to a base transfer from ISO to NVE, it will be reported as 100 MWh
WEIM BENEFITS REPORT FIRST QUARTER 2023

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from_BAA ISO to_BAA NEVP, and 0 MWh from_BAA NEVP to_BAA ISO in the opposite
direction. The 15-minute transfer volume is the result of optimization in the 15-minute market
using all bids and base schedules submitted into the WEIM. The 5-minute transfer volume is the
result of optimization using all bids and base schedules submitted into WEIM, based on unit
commitments determined in the 15-minute market optimization. The maximum transfer
capacities between WEIM entities are shown in Graph 2 below.

Month From BAA To BAA (15m – base) (5m – base) AVA BPAT 14,447
January AVA CISO
AVA IPCO
AVA NWMT
AVA PACW 8,338 9,885
AVA PGE 0 0
AVA PSEI 0 0
AVA SCL 0 0
AVA TPWR 0 0
AZPS CISO 239,844 188,035
AZPS LADWP 54,635 54,691
AZPS NEVP 14,963 15,504
AZPS PACE 35,647 38,963
AZPS PNM 5,920 2,973
AZPS SRP 2,800 2,312
AZPS TEPC 5,524 1,721
BANC BPAT 0 0
BANC CISO 5,730 5,948
BANC TIDC 29 0
BPAT AVA
BPAT BANC
BPAT CISO
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BPAT IPCO
January BPAT LADWP BPAT NEVP
BPAT NWMT BPAT PACW
BPAT PGE BPAT PSEI BPAT PWRX BPAT SCL 3,419 3,355 BPAT TPWR 7,335 8,831 CISO AVA 0 0 CISO AZPS 13,475 17,544 CISO BANC 101,677 105,617
CISO BPAT 23,062 26,574 CISO LADWP 49,505 56,542
CISO NEVP 18,639 20,381
CISO PACW 15,177 34,803
CISO PGE 35,840 53,953
CISO PWRX 154,650 171,000
CISO SRP 2,381 4,371
CISO TEPC 0 0
CISO TIDC 4,468 4,804
IPCO AVA 18,399 19,962
IPCO BPAT IPCO NEVP IPCO NWMT IPCO PACE 39,298 18,343 IPCO PACW 30,297 31,398
WEIM BENEFITS REPORT FIRST QUARTER 2023

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January IPCO PSEI
IPCO SCL
January LADWP AZPS
LADWP BPAT
LADWP CISO LADWP NEVP LADWP PACE
LADWP TEPC
NEVP AZPS 250 844
NEVP BPAT 0 0
NEVP CISO 175,550 131,046
NEVP IPCO 49,907 49,266
NEVP LADWP 36,279 37,424
NEVP PACE 14,755 12,031
NWMT AVA 30,886 31,569
NWMT BPAT 9,417 8,840
NWMT IPCO 22,211 22,310
NWMT PACE 22,893 13,364
NWMT PACW 0 0
NWMT PGE 71 0
NWMT PSEI 285 0
NWMT TPWR 0 0
PACE AZPS 57,485 51,918
PACE IPCO
PACE LADWP
PACE NEVP
PACE NWMT 10,358 13,373
PACE PACW 40,489 39,802
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January PACE SRP
PACE TEPC
January PACW AVA
PACW BPAT
PACW CISO
PACW IPCO
PACW NWMT
PACW PGE
PACW PSEI 20,751 19,480
PACW SCL 1,402 1,248
PGE AVA 0 0
PGE BPAT 28,931 31,304
PGE CISO 29,499 28,293
PGE NWMT 165 0
PGE PACW 14,299 18,163
PGE PSEI 0 0
PGE SCL 1,241 1,141
PGE TPWR 0 0
PNM AZPS 113,667 119,571
PNM SRP 498 465
PNM TEPC 15,512 17,130
PSEI AVA 0 0
PSEI BPAT 25,093 31,195
PSEI IPCO
PSEI NWMT
PSEI PACW
PSEI PGE 0 0
PSEI PWRX 13,662 15,620
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January PSEI SCL
PSEI TPWR
January PWRX BPAT
PWRX CISO
PWRX PSEI
SCL AVA
SCL BPAT
SCL IPCO
SCL PACW 516 774
SCL PGE 789 1,094
SCL PSEI 5,235 8,650
SRP AZPS 49,716 50,770
SRP CISO 117,888 110,109
SRP PACE 0 0
SRP PNM 0 0
SRP TEPC 5,623 7,555
TEPC AZPS 812 40
TEPC CISO 62,756 61,758
TEPC LADWP 137 162
TEPC PACE 840 876
TEPC PNM 14,631 15,096
TEPC SRP 10,235 9,133
TIDC BANC 184 190
TIDC CISO
TPWR AVA
TPWR BPAT
TPWR NWMT 0 0
TPWR PGE 0 0
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TPWR PSEI
February AVA BPAT AVA CISO
AVA IPCO
AVA NWMT
AVA PACW
AVA PGE 0 0
AVA PSEI 0 0
AVA SCL 0 0
AVA TPWR 0 0
AZPS CISO 121,604 89,140
AZPS LADWP 29,838 26,510
AZPS NEVP 27,657 25,294
AZPS PACE 128,447 130,889
AZPS PNM 9,649 9,443
AZPS SRP 1,545 1,483
AZPS TEPC 2,310 2,350
BANC BPAT 0 0
BANC CISO 1,189 682
BANC TIDC 77 0
BPAT AVA 10,013 8,934
BPAT BANC
BPAT CISO
BPAT IPCO
BPAT LADWP
BPAT NEVP
BPAT NWMT
BPAT PACW
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February BPAT PGE
BPAT PSEI
February BPAT PWRX
BPAT SCL
BPAT TPWR
CISO AVA
CISO AZPS
CISO BANC
CISO BPAT 26,038 28,530
CISO LADWP 45,705 50,036
CISO NEVP 68,821 56,244
CISO PACW 22,574 55,675
CISO PGE 62,842 89,377
CISO PWRX 304,096 326,115
CISO SRP 31,532 30,711
CISO TEPC 0 0
CISO TIDC 6,530 7,114
IPCO AVA 22,331 26,192
IPCO BPAT 1,540 779
IPCO NEVP 23,409 14,186
IPCO NWMT 191 738
IPCO PACE 15,762 8,421
IPCO PACW 28,915 21,610
IPCO PSEI
IPCO SCL
LADWP AZPS
LADWP BPAT 0 0
LADWP CISO 18,190 14,640
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February LADWP NEVP
LADWP PACE
February LADWP TEPC
NEVP AZPS
NEVP BPAT
NEVP CISO
NEVP IPCO NEVP LADWP
NEVP PACE 100,091 87,196 NWMT AVA 12,646 12,559
NWMT BPAT 2,857 775 NWMT IPCO 19,350 18,526 NWMT PACE 29,657 25,144 NWMT PACW 0 0 NWMT PGE 0 0
NWMT PSEI 195 0
NWMT TPWR 0 0
PACE AZPS 32,910 27,943
PACE IPCO 39,841 33,920
PACE LADWP 10,562 10,073
PACE NEVP 16,583 14,061
PACE NWMT 7,867 6,093
PACE PACW 26,877 17,452
PACE SRP PACE TEPC PACW AVA PACW BPAT 2,345 1,680 PACW CISO 33,658 46,692
WEIM BENEFITS REPORT FIRST QUARTER 2023

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February PACW IPCO PACW NWMT
February PACW PGE PACW PSEI PACW SCL
PGE AVA PGE BPAT
PGE CISO
PGE NWMT 0 0
PGE PACW 25,456 28,718
PGE PSEI 0 0
PGE SCL 1,341 1,289
PGE TPWR 0 0
PNM AZPS 90,489 91,889
PNM SRP 1,128 1,556
PNM TEPC 14,685 16,367
PSEI AVA 0 0
PSEI BPAT 24,244 26,069
PSEI IPCO 0 0
PSEI NWMT 314 0
PSEI PACW 19 0
PSEI PGE 0 0
PSEI PWRX 22,045 22,782
PSEI SCL
PSEI TPWR
PWRX BPAT
PWRX CISO 0 0
PWRX PSEI 7,676 7,094
WEIM BENEFITS REPORT FIRST QUARTER 2023

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February SCL AVA
SCL BPAT
February SCL IPCO
SCL PACW
SCL PGE
SCL PSEI
SRP AZPS
SRP CISO
SRP PACE 0 0
SRP PNM 23 5
SRP TEPC 24,646 24,850
TEPC AZPS 1,800 683
TEPC CISO 29,966 26,352
TEPC LADWP 152 272
TEPC PACE 371 121
TEPC PNM 10,702 7,802
TEPC SRP 31,790 30,468
TIDC BANC 12 0
TIDC CISO 17,975 16,672
TPWR AVA 0 0
TPWR BPAT 5,585 6,249
TPWR NWMT 0 0
TPWR PGE 0 0
TPWR PSEI
March AVA BPAT AVA CISO
AVA IPCO
AVA NWMT
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AVA PACW
AVA PGE
March AVA PSEI
AVA SCL
AVA TPWR
AZPS CISO
AZPS LADWP
AZPS NEVP
AZPS PACE 157,262 161,848
AZPS PNM 15,947 17,827
AZPS SRP 4,154 3,967
AZPS TEPC 3,646 4,856
BANC BPAT 0 0
BANC CISO 44,574 36,068
BANC TIDC 3,432 2,735
BPAT AVA 11,325 10,021
BPAT BANC 0 0
BPAT CISO 17,197 22,876
BPAT IPCO 14,535 4,749
BPAT LADWP 0 0
BPAT NEVP 0 0
BPAT NWMT 17,054 12,962
BPAT PACW 4,837 3,257
BPAT PGE
BPAT PSEI
BPAT PWRX
BPAT SCL 4,745 4,992
BPAT TPWR 10,188 13,112
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March CISO AVA
CISO AZPS
March CISO BANC
CISO BPAT
CISO LADWP
CISO NEVP
CISO PACW
CISO PGE
CISO PWRX 320,642 338,692
CISO SRP 57,800 54,009
CISO TEPC 0 0
CISO TIDC 13,747 14,714 IPCO AVA 30,978 32,600
IPCO BPAT 6,070 6,616 IPCO NEVP 27,095 16,084
IPCO NWMT 1,024 1,548
IPCO PACE 56,934 50,980
IPCO PACW 40,885 30,879
IPCO PSEI 5,331 4,233
IPCO SCL 9,549 8,271
LADWP AZPS 2,818 4,747
LADWP BPAT 0 0
LADWP CISO 37,042 26,249
LADWP NEVP LADWP PACE LADWP TEPC NEVP AZPS 3,215 5,454 NEVP BPAT 0 0
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March NEVP CISO NEVP IPCO
March NEVP LADWP NEVP PACE NWMT AVA NWMT BPAT NWMT IPCO NWMT PACE NWMT PACW 0 0 NWMT PGE 1 0
NWMT PSEI 110 0 NWMT TPWR 0 0
PACE AZPS 18,149 12,804
PACE IPCO 31,322 32,991
PACE LADWP 7,604 4,718
PACE NEVP 5,031 3,178
PACE NWMT 6,576 4,985
PACE PACW 31,300 24,028
PACE SRP 0 0
PACE TEPC 0 0
PACW AVA 6,192 6,250
PACW BPAT 6,379 4,744
PACW CISO 17,710 37,856
PACW IPCO
PACW NWMT
PACW PGE
PACW PSEI 40,077 37,812
PACW SCL 1,724 1,375
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March PGE AVA
PGE BPAT
March PGE CISO
PGE NWMT
PGE PACW
PGE PSEI
PGE SCL
PGE TPWR
PNM AZPS 114,933 125,827
PNM SRP 803 852
PNM TEPC 13,343 12,707
PSEI AVA 0 0
PSEI BPAT 33,095 26,767
PSEI IPCO 2,931 2,478
PSEI NWMT 97 0
PSEI PACW 5,289 6,876
PSEI PGE 1,040 1,124
PSEI PWRX 23,355 26,297
PSEI SCL 23,516 21,716
PSEI TPWR 7,682 7,104
PWRX BPAT 16,390 0
PWRX CISO 0 0
PWRX PSEI 7,650 6,979
SCL AVA
SCL BPAT
SCL IPCO
SCL PACW 359 522
SCL PGE 721 814
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TABLE 2: Energy transfers (MWh) in the FMM and RTD markets for Q1 2023

March SCL PSEI
SRP AZPS
March SRP CISO
SRP PACE
SRP PNM
SRP TEPC
TEPC AZPS
TEPC CISO
TEPC LADWP 0 0
TEPC PACE 5,869 4,703
TEPC PNM 21,855 16,460
TEPC SRP 24,516 21,236
TIDC BANC 4,589 5,538
TIDC CISO 19,037 15,510
TPWR AVA 0 0
TPWR BPAT 6,029 4,742
TPWR NWMT 0 0
TPWR PGE 0 0
TPWR PSEI 6,198 7,767
WEIM BENEFITS REPORT FIRST QUARTER 2023

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GRAPH 2: WEIM transfer
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WHEEL-THROUGH TRANSFERS
As the footprint of the WEIM grows, wheel-through transfers may become more common. In order to derive the wheel-through transfers for each WEIM BAA, the ISO uses the following calculation for every real-time interval dispatch:
• Total import: summation of transfers above base transfers coming into the WEIM BAA under analysis
• Total export: summation of all transfers above base transfers going out of the WEIM BAA under analysis
• Net import: the maximum of zero or the difference between total imports and total exports
• Net export: the maximum of zero or the difference between total exports and total imports
• Wheel-through: the minimum of the WEIM transfers into (total import) or WEIM transfer out (total export) of a BAA for a given interval
All wheel-through transfers are summed over both the month and the quarter.

Currently, a WEIM entity facilitating a wheel through receives no direct financial benefit for facilitating the wheel; only the sink and source directly benefit. As part of the WEIM Consolidated Initiatives stakeholder process, the ISO committed to monitoring the wheel through volumes to assess whether, after the addition of new WEIM entities, there is a potential future need to pursue a market solution to address the equitable sharing of wheeling benefits. The ISO will continue to track the volume of wheel-through transfers in the WEIM market in the
quarterly reports.

This volume reflects the total wheel-through transfers for each WEIM BAA, regardless of the
potential paths used to wheel through. The net imports and exports estimated in this section
reflect the overall volume of net imports and exports; in contrast, the imports and exports
provided in Table 2 reflect the gross transfers between two WEIM BAAs.

The metric is measured as energy in MWh for each month and the corresponding calendar
quarter, as shown in Tables 3 through 6 and Graphs 3 through 6.

BAA Net Export Net Import Wheel Through
AVA

89,033

139,575

41,711
AZPS

335,627

97,806

587,198
BANC

45,406

344,159

27
BPAT

163,219

151,860

188,705
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TABLE 3: Estimated wheel-through transfers in Q1 2023
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GRAPH 3: Estimated wheel-through transfers in Q1 2023

BAA Net Export Net Import Wheel Through
AVA

31,563

51,280

15,559
AZPS

104,474

41,250

199,725
BANC

5,948

105,806

-
BPAT

44,031

66,013

64,078
CISO

250,023

450,123

245,565
IPCO

54,962

115,578

66,641
LADWP

28,738

139,583

32,273
NEVP

136,668

54,724

93,943
NWMT

63,081

5,166

13,003
PACE

208,253

59,238

43,474
PACW

81,578

31,385

122,731
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TABLE 4: Estimated wheel-through transfers in January 2023

GRAPH 4: Estimated wheel-through transfers in January 2023

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BAA Net Export Net Import Wheel Through
TABLE 5: Estimated wheel-through transfers in February 2023

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GRAPH 5: Estimated wheel-through transfers in February 2023

BAA Net Export Net Import Wheel Through
AVA

25,234

43,115

15,000
AZPS

119,866

21,459

213,651
BANC

38,775

62,872

27
BPAT

50,751

54,143

64,437
CISO

522,398

225,552

239,494
IPCO

54,657

30,694

96,554
LADWP

59,353

78,291

28,681
NEVP

189,617

31,040

118,681
NWMT

32,284

10,909

27,486
PACE

26,422

423,704

56,281
PACW

67,148

36,517

92,207
PGE

31,338

117,388

35,279
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TABLE 6: Estimated wheel-through transfers in March 2023

GRAPH 6: Estimated wheel-through transfers in March 2023

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REDUCED RENEWABLE CURTAILMENT AND GHG REDUCTIONS
The WEIM benefit calculation includes the economic benefits that can be attributed to avoided
renewable curtailment within the ISO footprint. If not for energy transfers facilitated by the
WEIM, some renewable generation located within the ISO would have been curtailed via either
economic or exceptional dispatch. The total avoided renewable curtailment volume in MWh for
Q1 2023 was calculated to be 8,283 MWh (January) + 21,976 MWh (February) + 22,743 MWh
(March) = 53,002 MWh total.
There are environmental benefits of avoided renewable curtailment as well. Under the
assumption that avoided renewable curtailments displace production from other resources at a
default emission rate of 0.428 metric tons CO2/MWh, avoided curtailments displaced an
estimated 22,685 metric tons of CO2 for Q1 2023. Avoided renewable curtailments also may
have contributed to an increased volume of renewable credits that would otherwise have been
unavailable. This report does not quantify the additional value in dollars associated with this
benefit. Total estimated reductions in the curtailment of renewable energy in the ISO footprint,
along with the associated reductions in CO2, are shown in Table 7.
Year Quarter MWh Eq. Tons CO2
1 8,860 3,792
2015 2 3,629 1,553

4 17,765 7,521
1 112,948 48,342
2 158,806 67,969
3 33,094 14,164
4 23,390 10,011

2017
3 23,331 9,986
4 18,060 7,730
1 65,860 28,188
2018 2 129,128 55,267
3 19,032 8,146

2019
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3 33,843 14,485
4 35,254 15,089
1 86,740 37,125
2 147,514 63,136
3 37,548 16,071
4 39,956 17,101
2021

4 38,044 16,283
2022 1 94,168 40,304
2 118,352 50,655
3 42,468 18,176

2023
Total

TABLE 7: Total reduction in curtailment of renewable energy and associated reductions in CO2
FLEXIBLE RAMPING PROCUREMENT DIVERSITY SAVINGS
The WEIM facilitates procurement of flexible ramping capacity in the FMM to address variability
that may occur in the RTD. Because variability across different BAAs may happen in opposite
directions, the flexible ramping requirement for the entire WEIM footprint can be less than the
sum of individual BAA’s requirements. This difference is known as flexible ramping procurement
diversity savings.
Starting in 2016, the ISO replaced the flexible ramping constraint with flexible ramping products
that provide both upward and downward ramping. The minimum and maximum flexible ramping
requirements for each BAA and for each direction are listed in Table 8.
Month BAA Direction Minimum requirement requirement AVA up 22 81
January AZPS up 49 284
BANC up 10 96
BPAT
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CISO up 248 2,337
IPCO up 36 189
LADWP up 30 393
NEVP up 20 446
NWMT up 22 127
PACE up 90 460
PACW
PGE
PNM up 39 155
PSEI up 74 167
PWRX up 78 294
SCL up 7 31
SRP up 17 201
TEPC
TIDC up 2 17
up 3 19
ALL EIM up 315 2,771
AVA down 11 92
AZPS down 23 231
January BANC down 6 152
BPAT
CISO down 187 1,332
down 36 194
LADWP down 38 297
NEVP down 24 414
NWMT down 41 124
PACE down 176 461
PACW
PGE down 28 204
PNM down 41 141
PSEI down 52 153
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PWRX down 69 356
SCL down 4 28
SRP down 20 181
TEPC down 0 165
TIDC down 1 17
TPWR down 2 24
ALL EIM down 279 2,175 AVA
February AZPS up 39 284
BANC up 8 102
BPAT up 87 435
CISO up 259 2,303
IPCO up 44 175
LADWP
NEVP
NWMT up 32 124
PACE up 103 525
PACW up 51 174
PGE up 35 200
February PNM up 39 155
PSEI
PWRX up 79 369
SCL up 6 31
SRP up 27 267
TEPC up 64 200
TIDC up 2 20
TPWR up 23 19
ALL WEIM up 395 2,771
AVA down 14 103
down 31 383
BANC down 9 152
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BPAT down 163 639
CISO down 220 1,332

IPCO down 52 194
LADWP down 68 307
NEVP down 32 414
NWMT down 36 132
PACE
PACW
PGE down 45 204
PNM down 59 146
PSEI down 74 153
PWRX down 66 356
SCL down 7 28
SRP
TEPC down 39 134
down 1 17
TPWR down 2 25
ALL EIM down 438 2,175

March

AVA up 23 81
up 44 300
BANC up 7 102
BPAT up 76 435
CISO up 266 2,323
IPCO up 45 189
LADWP up 51 393
NEVP
NWMT
PACE up 103 525
PACW up 49 174
PGE up 59 200
PNM up 50 155
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March

up 67 167
PWRX up 79 377
SCL up 6 31
SRP up 35 280
TEPC up 62 263
TIDC up 2 20
TPWR
ALL WEIM up 385 2,771
AZPS down 18 383
BANC down 5 152
BPAT down 109 639
CISO down 220 1,332
IPCO
LADWP down 41 307
down 12 414
NWMT down 9 132
PACE down 96 451
PACW down 22 163
PGE down 24 204
PNM
PSEI down 10 153
down 46 356
SCL down 5 28
SRP down 28 400
TEPC down 19 129
TIDC down 0 19
TPWR
ALL WEIM down 1,718 2,175
Table 8: Flexible ramping requirements
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The flexible ramping procurement diversity savings for all the intervals averaged over the month
are shown in Table 9. The percentage savings is the average MW savings divided by the sum of
the individual BAA requirements.
January February March
Direction
Average MW saving
Sum of BAA requirements
Percentage savings
Table 9: Flexible ramping procurement diversity savings in Q1 2023
Flexible ramping capacity may be used in RTD to handle uncertainties in the future interval. The
RTD flexible ramping capacity is prorated to each BAA. Flexible ramping surplus MW is defined
as the awarded flexible ramping capacity in RTD minus its share, and the flexible ramping
surplus cost is defined as the flexible ramping surplus MW multiplied by the flexible ramping
WEIM-wide marginal price. A positive flexible ramping surplus MW is the capacity that a BAA
provided to help other BAAs, and a negative flexible ramping surplus MW is the capacity that a
BAA received from other BAAs.
The EIM dispatch cost for a BAA with positive flexible ramping surplus MW is increased
because some capacities are used to help other BAAs. The flexible ramping surplus cost is
subtracted from the BAA’s WEIM dispatch cost to reflect the true dispatch cost of a BAA. Please
see the Benefit Report Methodology for more details.
CONCLUSION
Using state-of-the-art technology to find and deliver low-cost energy to meet real-time demand,
the WEIM demonstrates that utilities can realize financial and operational benefits through
increased coordination and optimization. In addition to these benefits, the WEIM provides
significant environmental benefits through the reduction of renewable curtailments during
periods of oversupply.
Sharing resources across a larger geographic area reduces greenhouse gas emissions by using
renewable generation that otherwise would have been turned off. The quantified environmental
benefits from avoided curtailments of renewable generation from 2015 to-date reached 814,746
metric tons of CO2, roughly the equivalent of avoiding the emissions from 171,297 passenger
cars driven for one year.

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APPENDIX 1: GLOSSARY OF ABBREVIATIONS

Abbreviation Description
APS Arizona Public Service
AVA Avista Utilities
BAA Balancing Authority Area
BANC Balancing Authority of Northern California
BPA Bonneville Power Administration
CISO, ISO California ISO
EIM Energy Imbalance Market
FMM Fifteen Minute Market
GHG Greenhouse Gas
IPCO Idaho Power
LADWP Los Angeles Department of Water and Power
MW Megawatt
MWh Megawatt-Hour
NVE NV Energy
PAC PacifiCorp
PACE PacifiCorp East
PACW PacifiCorp West
PGE Portland General Electric
PSE Puget Sound Energy
PWRX Powerex
RTD Real Time Dispatch
SCL Seattle City Light
SRP Salt River Project
TEP Tucson Electric Power
TID Turlock Irrigation District
TPWR Tacoma Power
WEIM Western Energy Imbalance Market