20230213Quarterly Report.pdf

LISA O’HARA
Corporate Counsel
lo’[e-mail]
February 13, 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 fourth quarter of 2022. The Report presents CAISO’s quantification of benefits
associated with participation in the Western EIM. For the fourth quarter of 2022, CAISO estimated
Western EIM gross benefits of $17.18 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
LJO:sg
Enclosure
RECEIVED
Monday, February 13, 2023 10:06:21 AM
IDAHO PUBLIC
UTILITIES COMMISSION

Western Energy Imbalance Market Benefits
Fourth Quarter 2022

January 31, 2023
WEIM BENEFITS REPORT FOURTH QUARTER 2022

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CONTENTS

EXECUTIVE SUMMARY ........................................................................................................ 3
BACKGROUND .................................................................................................................... 4
WEIM ECONOMIC BENEFITS IN Q4 2022 ............................................................................ 4
CUMULATIVE ECONOMIC BENEFITS SINCE INCEPTION ................................................................. 5
INTER-REGIONAL TRANSFERS ........................................................................................................ 6
WHEEL-THROUGH TRANSFERS ..................................................................................................... 22
REDUCED RENEWABLE CURTAILMENT AND GHG REDUCTIONS .................................. 29
FLEXIBLE RAMPING PROCUREMENT DIVERSITY SAVINGS ........................................... 31
CONCLUSION..................................................................................................................... 36
APPENDIX 1: GLOSSARY OF ABBREVIATIONS ............................................................... 37
WEIM BENEFITS REPORT FOURTH QUARTER 2022

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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.

Q4 2022 Gross Benefits by Participant
(millions $)
Arizona Public Service $34.87
Avista $9.73
BANC $83.44
BPA $12.96
California ISO $88.53
Idaho Power $17.18
LADWP $25.17
NV Energy $42.33
NorthWestern Energy $12.95
PacifiCorp $53.87
Portland General Electric $21.11
PNM $11.55
Puget Sound Energy $14.81
Powerex $3.45
Seattle City Light $4.71
Salt River Project $31.04
Tacoma Power $4.07
TEP $11.21
TID $2.31
Total $485.29
Gross benefits from WEIM since November 2014
$3.40 billion
ECONOMICAL
$485.29 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
10,960
Metric tons of CO2** avoided
curtailments

OPERATIONAL
58%
Average reduction in flexibility
reserves across the footprint
2022
Q4 BENEFITS
WEIM BENEFITS REPORT FOURTH QUARTER 2022

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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 Western EIM 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 Western EIM, 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 Q4 2022
Table 1 shows the estimated WEIM gross benefits by each region per month1. The monthly
savings presented show $99.25 million for October, $129.34 million for November, and $256.70
million for December with a total estimated benefit of $485.29 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 FOURTH QUARTER 2022

MPP/MA&F Copyright 2022 California ISO Page 5 of 37
Region October November December Total
APS $4.68 $3.32 $26.87 $34.87
AVA $1.60 $2.43 $5.70 $9.73
BANC $13.91 $24.57 $44.96 $83.44
BPA $2.15 $2.24 $8.57 $12.96
CISO $26.39 $40.63 $21.51 $88.53
IPCO $3.92 $4.00 $9.26 $17.18
LADWP $3.72 $6.74 $14.71 $25.17
NVE $7.38 $9.69 $25.26 $42.33
NWMT $2.83 $1.68 $8.44 $12.95
PAC $12.40 $10.85 $30.62 $53.87
PGE $3.73 $4.67 $12.71 $21.11
PNM $2.19 $2.50 $6.86 $11.55
PSE $2.11 $2.60 $10.10 $14.81
PWRX $0.52 $0.18 $2.75 $3.45
SCL $0.97 $1.07 $2.67 $4.71
SRP $6.63 $8.51 $15.90 $31.04
TPWR $0.59 $0.95 $2.53 $4.07
TEP $3.01 $1.90 $6.30 $11.21
TID $0.52 $0.81 $0.98 $2.31
Total $99.25 $129.34 $256.70 $485.29
TABLE 1: Q4 2022 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 $3.40 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 FOURTH QUARTER 2022

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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
from_BAA ISO to_BAA NEVP, and 0 MWh from_BAA NEVP to_BAA ISO in the opposite
WEIM BENEFITS REPORT FOURTH QUARTER 2022

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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
15min WEIM transfer
(15m – base)
5min WEIM transfer
(5m – base)
AVA BPAT 15,158 12,587
October AVA CISO 0 0
AVA IPCO 26,459 30,539
AVA NWMT 1,270 1,446
AVA PACW 1,320 1,715
AVA PGE 0 0
AVA PSEI 48 0
AVA SCL 3 0
AVA TPWR 0 0
AZPS CISO 192,466 157,183
AZPS LADWP 21,821 24,761
AZPS NEVP 4,788 7,232
AZPS PACE 18,644 12,065
AZPS PNM 7,838 11,773
AZPS SRP 6,054 4,026
AZPS TEPC 14,440 16,207
BANC BPAT 0 0
BANC CISO 975 2,168
BANC TIDC 32 0
BPAT AVA 7,866 9,835
BPAT BANC 0 0
BPAT CISO 22,265 28,438
BPAT IPCO 1,871 0
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October BPAT LADWP 0 0
BPAT NEVP 0 0
BPAT NWMT 5,158 3,882
BPAT PACW 1,618 2,544
BPAT PGE 18,376 19,890
BPAT PSEI 15,371 13,882
BPAT PWRX 3,154 116
BPAT SCL 2,308 2,148
BPAT TPWR 7,834 8,742
CISO AVA 0 0
CISO AZPS 10,968 10,765
CISO BANC 176,979 181,497
CISO BPAT 29,414 37,685
CISO LADWP 32,588 41,322
CISO NEVP 7,163 9,378
CISO PACW 3,856 23,974
CISO PGE 19,121 32,229
CISO PWRX 182,958 202,784
CISO SRP 39,021 47,568
CISO TEPC 0 50
CISO TIDC 2,904 3,495
IPCO AVA 18,149 15,602
IPCO BPAT 1,447 24
IPCO NEVP 17,199 15,814
IPCO NWMT 129 329
IPCO PACE 3,919 2,623
IPCO PACW 19,330 16,217
October IPCO PSEI 0 0
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IPCO SCL 3,050 2,414
October LADWP AZPS 1,020 783
LADWP BPAT 0 0
LADWP CISO 72,253 60,516
LADWP NEVP 13,252 14,137
LADWP PACE 36,626 40,015
LADWP TEPC 0 0
NEVP AZPS 2,331 2,585
NEVP BPAT 0 0
NEVP CISO 151,640 113,102
NEVP IPCO 80,489 71,536
NEVP LADWP 51,010 56,748
NEVP PACE 9,150 5,830
NWMT AVA 17,794 16,950
NWMT BPAT 16,143 11,477
NWMT IPCO 26,879 29,525
NWMT PACE 10,900 6,778
NWMT PACW 46 0
NWMT PGE 2 0
NWMT PSEI 0 0
NWMT TPWR 1,668 1,410
PACE AZPS 60,262 64,728
PACE IPCO 116,013 124,712
PACE LADWP 38,487 33,775
PACE NEVP 58,737 55,391
PACE NWMT 12,863 10,755
PACE PACW 29,618 25,279
October PACE SRP 0 0
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PACE TEPC 702 2,084
October PACW AVA 2,440 2,992
PACW BPAT 6,910 6,058
PACW CISO 41,606 59,413
PACW IPCO 15,321 19,077
PACW NWMT 0 0
PACW PGE 38,473 33,653
PACW PSEI 23,217 20,909
PACW SCL 1,460 1,189
PGE AVA 0 0
PGE BPAT 40,539 38,923
PGE CISO 18,375 16,560
PGE NWMT 0 0
PGE PACW 19,409 31,612
PGE PSEI 0 0
PGE SCL 1,402 1,059
PGE TPWR 1,834 1,837
PNM AZPS 50,316 42,351
PNM SRP 1,609 1,431
PNM TEPC 24,024 22,571
PSEI AVA 0 0
PSEI BPAT 14,148 19,217
PSEI IPCO 0 0
PSEI NWMT 2 0
PSEI PACW 0 0
PSEI PGE 0 0
PSEI PWRX 18,178 18,857
October PSEI SCL 8,355 7,596
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PSEI TPWR 6,452 11,381
October PWRX BPAT 3,299 218
PWRX CISO 0 0
PWRX PSEI 8,918 10,556
SCL AVA 0 0
SCL BPAT 1,138 2,710
SCL IPCO 1,775 2,887
SCL PACW 669 1,147
SCL PGE 831 1,382
SCL PSEI 5,400 10,023
SRP AZPS 7,000 8,635
SRP CISO 169,609 159,863
SRP PACE 0 0
SRP PNM 92 189
SRP TEPC 31,310 38,448
TEPC AZPS 649 0
TEPC CISO 46,986 42,114
TEPC LADWP 0 0
TEPC PACE 7 27
TEPC PNM 5,722 5,558
TEPC SRP 2,796 2,212
TIDC BANC 36 0
TIDC CISO 19,733 18,321
TPWR AVA 0 0
TPWR BPAT 8,764 12,810
TPWR NWMT 670 1,113
TPWR PGE 607 1,156
TPWR PSEI 10,490 9,840
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November AVA BPAT 9,872 9,792
AVA CISO 0 0
AVA IPCO 27,850 24,185
AVA NWMT 5,106 5,780
AVA PACW 2,175 2,744
AVA PGE 48 0
AVA PSEI 0 0
AVA SCL 0 0
AVA TPWR 0 0
AZPS CISO 169,811 123,910
AZPS LADWP 17,593 13,016
AZPS NEVP 9,297 11,454
AZPS PACE 25,509 23,635
AZPS PNM 18,378 24,773
AZPS SRP 5,415 4,088
AZPS TEPC 3,491 3,962
BANC BPAT 0 0
BANC CISO 405 233
BANC TIDC 25 0
BPAT AVA 8,159 6,366
BPAT BANC 0 0
BPAT CISO 9,885 16,776
BPAT IPCO 2,127 0
BPAT LADWP 0 0
BPAT NEVP 0 0
BPAT NWMT 9,659 4,329
BPAT PACW 4,465 5,948
November BPAT PGE 22,607 20,730
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BPAT PSEI 13,237 13,088
November BPAT PWRX 4,764 0
BPAT SCL 2,841 2,101
BPAT TPWR 11,212 12,518
CISO AVA 0 0
CISO AZPS 17,159 20,078
CISO BANC 234,883 238,370
CISO BPAT 18,391 24,670
CISO LADWP 22,495 26,855
CISO NEVP 17,012 20,969
CISO PACW 18,738 38,561
CISO PGE 22,570 37,719
CISO PWRX 116,263 128,587
CISO SRP 26,378 33,224
CISO TEPC 0 0
CISO TIDC 3,407 3,462
IPCO AVA 14,643 14,186
IPCO BPAT 1,816 0
IPCO NEVP 38,862 22,356
IPCO NWMT 534 1,004
IPCO PACE 3,679 2,057
IPCO PACW 11,779 17,466
IPCO PSEI 0 0
IPCO SCL 5,841 5,584
LADWP AZPS 1,470 1,894
LADWP BPAT 0 0
LADWP CISO 101,230 92,703
November LADWP NEVP 15,365 19,462
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LADWP PACE 20,870 23,045
November LADWP TEPC 0 0
NEVP AZPS 1,685 3,980
NEVP BPAT 0 0
NEVP CISO 172,364 121,695
NEVP IPCO 39,730 38,318
NEVP LADWP 20,804 26,069
NEVP PACE 18,659 16,759
NWMT AVA 13,472 13,343
NWMT BPAT 10,242 6,741
NWMT IPCO 13,944 13,045
NWMT PACE 12,126 6,640
NWMT PACW 5 0
NWMT PGE 12 0
NWMT PSEI 28 0
NWMT TPWR 0 0
PACE AZPS 62,929 66,771
PACE IPCO 75,414 73,707
PACE LADWP 23,204 21,709
PACE NEVP 86,307 75,628
PACE NWMT 12,517 15,086
PACE PACW 24,706 25,635
PACE SRP 0 0
PACE TEPC 267 770
PACW AVA 6,109 6,452
PACW BPAT 9,244 6,035
PACW CISO 64,046 92,137
November PACW IPCO 19,534 23,428
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PACW NWMT 7 0
November PACW PGE 33,945 31,961
PACW PSEI 19,253 18,488
PACW SCL 1,479 1,248
PGE AVA 0 0
PGE BPAT 36,874 37,663
PGE CISO 44,156 41,706
PGE NWMT 22 0
PGE PACW 19,603 31,002
PGE PSEI 0 0
PGE SCL 1,420 1,244
PGE TPWR 0 0
PNM AZPS 51,866 39,582
PNM SRP 1,545 1,342
PNM TEPC 15,852 16,442
PSEI AVA 7 0
PSEI BPAT 15,156 17,988
PSEI IPCO 0 0
PSEI NWMT 40 0
PSEI PACW 13,153 16,071
PSEI PGE 0 0
November PSEI PWRX 11,824 11,395
PSEI SCL 12,130 10,341
PSEI TPWR 8,472 11,446
PWRX BPAT 5,169 0
PWRX CISO 0 0
PWRX PSEI 15,870 16,888
SCL AVA 0 0
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SCL BPAT 1,904 2,695
November SCL IPCO 4,640 4,581
SCL PACW 666 980
SCL PGE 805 1,158
SCL PSEI 5,586 8,341
SRP AZPS 24,218 24,520
SRP CISO 178,030 154,174
SRP PACE 0 0
SRP PNM 1,109 1,248
SRP TEPC 22,138 28,468
TEPC AZPS 269 0
TEPC CISO 24,735 19,095
TEPC LADWP 0 0
TEPC PACE 54 385
TEPC PNM 10,725 10,931
TEPC SRP 28,475 22,127
TIDC BANC 17 0
TIDC CISO 18,516 17,906
TPWR AVA 0 0
TPWR BPAT 9,018 11,092
TPWR NWMT 0 0
TPWR PGE 0 0
TPWR PSEI 10,053 10,147
December AVA BPAT 16,513 16,892
AVA CISO 354 361
AVA IPCO 20,615 15,885
AVA NWMT 8,675 3,211
AVA PACW 2,182 1,879
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AVA PGE 0 0
AVA PSEI 50 0
AVA SCL 0 0
AVA TPWR 0 0
AZPS CISO 217,909 187,535
AZPS LADWP 40,012 42,673
AZPS NEVP 21,042 22,865
AZPS PACE 73,138 72,884
AZPS PNM 57,843 37,746
AZPS SRP 5,860 3,921
December AZPS TEPC 7,254 6,300
BANC BPAT 0 0
BANC CISO 360 295
BANC TIDC 33 0
BPAT AVA 21,382 14,912
BPAT BANC 0 0
BPAT CISO 18,784 23,780
BPAT IPCO 3,299 297
BPAT LADWP 0 0
BPAT NEVP 0 0
BPAT NWMT 14,272 3,753
BPAT PACW 3,807 4,382
BPAT PGE 16,120 16,001
BPAT PSEI 17,181 15,102
BPAT PWRX 6,119 0
BPAT SCL 6,427 6,174
BPAT TPWR 11,931 12,834
CISO AVA 50 49
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CISO AZPS 10,910 13,784
December CISO BANC 243,805 245,309
CISO BPAT 31,124 38,622
CISO LADWP 18,592 22,935
CISO NEVP 47,868 49,634
CISO PACW 24,801 54,705
CISO PGE 35,322 55,003
CISO PWRX 67,544 76,385
CISO SRP 6,169 10,517
CISO TEPC 0 16
December CISO TIDC 7,962 7,231
IPCO AVA 30,665 30,978
IPCO BPAT 713 0
IPCO NEVP 34,077 23,009
IPCO NWMT 395 1,472
IPCO PACE 16,019 6,920
IPCO PACW 41,591 27,917
IPCO PSEI 0 0
IPCO SCL 10,017 9,044
LADWP AZPS 6,205 6,437
LADWP BPAT 0 0
LADWP CISO 86,038 76,740
LADWP NEVP 28,959 34,065
LADWP PACE 27,482 24,068
LADWP TEPC 0 0
NEVP AZPS 5,931 7,783
NEVP BPAT 0 0
December NEVP CISO 126,215 92,655
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NEVP IPCO 74,249 63,113
December NEVP LADWP 16,409 16,169
NEVP PACE 32,771 23,723
NWMT AVA 29,257 32,584
NWMT BPAT 9,227 7,194
NWMT IPCO 16,759 16,697
NWMT PACE 26,611 9,625
NWMT PACW 44 0
NWMT PGE 45 0
NWMT PSEI 355 0
NWMT TPWR 0 0
PACE AZPS 34,112 23,767
PACE IPCO 60,699 60,112
PACE LADWP 21,211 24,983
PACE NEVP 86,163 75,891
PACE NWMT 12,889 19,264
PACE PACW 24,651 24,279
PACE SRP 0 0
PACE TEPC 573 306
PACW AVA 5,636 4,509
PACW BPAT 14,823 12,052
PACW CISO 46,461 66,361
PACW IPCO 20,463 21,587
PACW NWMT 3 0
PACW PGE 40,592 37,467
PACW PSEI 23,009 21,643
PACW SCL 1,597 1,456
December PGE AVA 0 0
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PGE BPAT 42,026 42,746
December PGE CISO 43,528 41,651
PGE NWMT 298 0
PGE PACW 12,010 20,839
PGE PSEI 0 0
PGE SCL 1,605 1,450
PGE TPWR 0 0
PNM AZPS 63,186 78,499
PNM SRP 2,494 2,653
PNM TEPC 18,123 20,165
PSEI AVA 2 0
PSEI BPAT 17,207 17,624
PSEI IPCO 0 0
PSEI NWMT 132 0
PSEI PACW 12,207 14,049
PSEI PGE 0 0
PSEI PWRX 6,210 6,361
PSEI SCL 16,491 16,172
PSEI TPWR 5,473 6,745
PWRX BPAT 9,262 0
PWRX CISO 0 0
PWRX PSEI 19,063 19,179
SCL AVA 0 0
SCL BPAT 2,506 2,789
SCL IPCO 4,734 5,644
SCL PACW 603 806
SCL PGE 792 988
December SCL PSEI 6,638 8,276
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TABLE 2: Energy transfers (MWh) in the FMM and RTD markets for Q4 2022

SRP AZPS 31,010 27,353
December SRP CISO 112,006 103,851
SRP PACE 0 0
SRP PNM 3 3
SRP TEPC 26,398 26,296
TEPC AZPS 416 188
TEPC CISO 72,158 68,914
TEPC LADWP 547 640
TEPC PACE 1,332 887
TEPC PNM 18,980 12,548
TEPC SRP 8,538 9,468
TIDC BANC 122 0
TIDC CISO 8,770 8,897
TPWR AVA 0 0
TPWR BPAT 12,015 13,298
TPWR NWMT 0 0
TPWR PGE 0 0
TPWR PSEI 17,779 17,616
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GRAPH 2: Estimated maximum transfer capacity
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
WEIM BENEFITS REPORT FOURTH QUARTER 2022

MPP/MA&F Copyright 2022 California ISO Page 23 of 37
 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

76,406

118,148

50,611
AZPS

450,985

83,461

361,025
BANC

2,697

665,176

-
BPAT

106,572

247,609

161,995
CISO

834,232

1,105,856

903,198
IPCO

61,352

485,208

153,667
LADWP

260,650

218,438

133,216
NEVP

368,747

165,967

291,319
NWMT

127,090

26,505

44,920
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PACE

677,683

131,016

146,951
PACW

195,076

96,713

293,040
PGE

183,493

164,535

124,801
PNM

200,941

80,674

24,095
PSEI

115,928

144,662

69,316
PWRX

23,028

420,672

23,813
SCL

31,497

46,312

22,908
SRP

505,405

74,935

67,643
TEPC

183,825

170,815

11,269
TIDC

45,124

14,187

-
TPWR

31,920

21,761

45,153

TABLE 3: Estimated wheel-through transfers in Q4 2022

GRAPH 3: Estimated wheel-through transfers in Q4 2022

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MPP/MA&F Copyright 2022 California ISO Page 25 of 37
BAA Net Export Net Import Wheel Through
AVA

28,087

27,179

18,200
AZPS

131,719

28,320

101,527
BANC

2,168

181,497

-
BPAT

35,475

87,708

54,002
CISO

301,772

368,703

288,975
IPCO

9,475

234,727

43,549
LADWP

67,890

109,045

47,561
NEVP

173,265

25,418

76,536
NWMT

52,954

4,340

13,186
PACE

264,269

14,882

52,457
PACW

60,473

19,671

82,818
PGE

54,798

53,116

35,194
PNM

62,616

13,783

3,737
PSEI

32,766

40,925

24,286
PWRX

1,809

212,792

8,965
SCL

13,725

9,984

4,423
SRP

188,884

36,986

18,251
TEPC

48,947

78,396

964
TIDC

18,321

3,495

-
TPWR

8,878

7,329

16,041

TABLE 4: Estimated wheel-through transfers in October 2022

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GRAPH 4: Estimated wheel-through transfers in October 2022

BAA Net Export Net Import Wheel Through
AVA

30,282

28,128

12,218
AZPS

83,298

35,284

121,541
BANC

233

238,370

-
BPAT

34,377

69,198

47,478
CISO

284,906

392,748

287,587
IPCO

19,904

134,514

42,749
LADWP

99,728

50,273

37,376
NEVP

109,099

52,146

97,723
NWMT

26,794

13,225

12,974
PACE

243,821

37,035

35,485
PACW

65,859

24,518

113,890
PGE

65,789

45,741

45,827
PNM

51,010

30,596

6,356
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PSEI

43,754

43,463

23,488
PWRX

8,116

131,210

8,771
SCL

10,059

12,822

7,696
SRP

173,991

26,363

34,419
TEPC

52,114

49,217

425
TIDC

17,906

3,462

-
TPWR

7,478

10,203

13,761
TABLE 5: Estimated wheel-through transfers in November 2022

GRAPH 5: Estimated wheel-through transfers in November 2022

BAA Net Export Net Import Wheel Through
AVA

18,037

62,841

20,192
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AZPS

235,968

19,857

137,956
BANC

295

245,309

-
BPAT

36,720

90,703

60,515
CISO

247,554

344,404

326,636
IPCO

31,972

115,968

67,369
LADWP

93,031

59,120

48,279
NEVP

86,383

88,403

117,061
NWMT

47,342

8,940

18,759
PACE

169,592

79,098

59,009
PACW

68,744

52,524

96,332
PGE

62,906

65,678

43,781
PNM

87,315

36,295

14,001
PSEI

39,409

60,275

21,541
PWRX

13,102

76,669

6,076
SCL

7,713

23,507

10,790
SRP

142,530

11,586

14,973
TEPC

82,764

43,202

9,881
TIDC

8,897

7,231

-
TPWR

15,564

4,229

15,351

TABLE 6: Estimated wheel-through transfers in December 2022

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GRAPH 6: Estimated wheel-through transfers in December 2022
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
Q4 2022 was calculated to be 10,571 MWh (October) + 9,270 MWh (November) + 5,767 MWh
(December) = 25,609 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 10,960 metric tons of CO2 for Q4 2022. 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
3 828 354
4 17,765 7,521
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1 112,948 48,342
2016 2 158,806 67,969
3 33,094 14,164
4 23,390 10,011
1 52,651 22,535
2017 2 67,055 28,700
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
4 23,425 10,026
1 52,254 22,365
2019 2 132,937 56,897
3 33,843 14,485
4 35,254 15,089
1 86,740 37,125
2020 2 147,514 63,136
3 37,548 16,071
4 39,956 17,101
2021 1 76,147 32,591
2 109,059 46,677
3 23,042 9,862
4 38,044 16,283
2022 1 94,168 40,304
2 118,352 50,655
3 42,468 18,176
4 25,609 10,960
Total 1,850,797 792,061

TABLE 7: Total reduction in curtailment of renewable energy and associated reductions in CO2
WEIM BENEFITS REPORT FOURTH QUARTER 2022

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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
Maximum
requirement
AVA up 0 95
October AZPS up 0 328
BANC up 0 76
BPAT up 0 401
CISO up 0 2,768
IPCO up 0 253
LADWP up 0 361
NEVP up 0 410
NWMT up 0 111
PACE up 0 506
PACW up 0 123
PGE up 0 191
PNM up 0 169
PSEI up 0 166
PWRX up 0 247
SCL up 0 41
SRP up 0 302
TEPC up 0 220
TIDC up 0 19
TPWR up 0 15
ALL EIM up 0 2,583
AVA down 0 113
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AZPS down 0 444
BANC down 0 134
BPAT down 0 581
October CISO down 0 1,145
IPCO down 0 198
LADWP down 0 357
NEVP down 0 471
NWMT down 0 150
PACE down 0 613
PACW down 0 157
PGE down 0 185
PNM down 0 218
PSEI down 0 137
PWRX down 0 307
SCL down 0 26
SRP down 0 519
TEPC down 0 176
TIDC down 0 25
TPWR down 0 18
ALL EIM down 0 1,593
AVA up 15 87
November AZPS up 48 328
BANC up 7 76
BPAT up 47 371 CISO up 321 2,758
IPCO up 29 253
LADWP up 41 361
NEVP up 24 463
NWMT up 4 127
PACE up 100 447
PACW up 36 178
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PGE up 35 190
PNM up 44 141
PSEI up 30 167
PWRX up 70 310
November SCL up 3 30
SRP up 27 302
TEPC up 43 220
TIDC up 2 19
TPWR up 2 19
ALL WEIM up 491 2,684
AVA down 7 103
AZPS down 36 369
BANC down 4 140
BPAT down 72 639
CISO down 192 1,250

IPCO down 46 198
LADWP down 52 285
NEVP down 21 471
NWMT down 30 126
PACE down 176 538
PACW down 27 139
PGE down 31 230
PNM down 38 218
PSEI down 32 137
PWRX down 79 340
SCL down 3 28
SRP down 30 344
TEPC down 22 167
TIDC down 2 25
TPWR down 3 24
ALL EIM down 308 1,989
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December

AVA up 17 81
AZPS up 56 300
BANC up 8 83
BPAT up 54 386
CISO up 313 2,337
IPCO up 34 189
LADWP up 40 393
NEVP up 20 463
NWMT up 25 127
PACE up 115 460
PACW up 48 174
PGE up 48 200
PNM up 44 155
PSEI up 39 167
PWRX up 85 294
SCL up 5 31
SRP up 29 280
TEPC up 60 220
TIDC up 2 19
TPWR up 4 19
ALL WEIM up 455 2,771
AVA down 17 86
AZPS down 26 246
BANC down 6 82
BPAT down 98 639
CISO down 153 1,332
IPCO down 42 194
LADWP down 43 262
NEVP down 22 408
NWMT down 42 124
PACE down 165 501
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December

PACW down 27 143
PGE down 28 204
PNM down 37 141
PSEI down 35 153
PWRX down 56 345
SCL down 5 28
SRP down 22 344
TEPC down 26 165
TIDC down 1 17
TPWR down 3 24
ALL WEIM down 319 2,175
Table 8: Flexible ramping requirements
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.
October November December
Direction Up Down Up Down Up Down
Average MW saving 1,517

1,720 1,551 1,603 1,617 1,606
Sum of BAA requirements 2,908 2,657 2,866 2,622 3,056 2,632
Percentage savings 52% 65% 54% 61% 53% 61%
Table 9: Flexible ramping procurement diversity savings in Q4 2022
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.
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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 792,061
metric tons of CO2, roughly the equivalent of avoiding the emissions from 166,527 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