20180105PAC to Staff UT_DPU Set 11 (1-21) Redacted.pdf

1407 W.North Temple
ROCKY MOUNTAIN Salt Lake City,UT 84116
POWER
A DMSION OF PACIFICORP
January 2,2018
Erika Tedder
Division of Public Utilities
160 E 300 S,4th Floor
Salt Lake City,UT 84114
drydatareguestágahm
eted_der@_u_ta_h.gov (C)
RE:UT Docket No.17-035-40
DPU l lth Set Data Request (1-21)
Please find enclosed Rocky Mountain Power's Responses to DPU l lth Set Data Requests l 1.1-
11.21,excluding 11.6 and 11.16.These responses will be provided separately.Also provided
are Attachments DPU l1.4,l1.11,and 11.18.Provided on the enclosed Confidential CD are
Confidential Responses DPU l1.1 and I1.3 and Confidential Attachment DPU 11.1.
Confidential information is provided subject to Public Service Commission of Utah Rule 746-1-
602 and 746-1-603.
If you have any questions,please call me at [phone].
Sincerely,
Jana Saba
Manager,Regulation
Enclosures
C.c.:Dan Kohler/DPU [e-mail](C)
Aliea Afnan/DPU [e-mail] (W)
[e-mail](W)
Dan Peaco/DPU [e-mail] (C)(W)
Kevin Higgins/UAE [e-mail] (C)
Neal Townsend/UAE [e-mail](C)(W)
Gary A.Dodge/UAE [e-mail](C)
Phillip Russell/UAE [e-mail] (C)
Philip Hayet/OCS [e-mail](C)
Béla Vastag/OCS [e-mail](C)
Sophie Hays/UCE sop_hm (C)
Kate Bowman/UCE [e-mail](C)(W)
Emma Rieves/UCE [e-mail](C)(W)
Lisa Tormoen Hickey/[e-mail] (C)
Mitch Longson/Interwest [e-mail] (C)
Nancy Kelly/WRA [e-mail](C)
Jennifer Gardner/WRA [e-mail](C)
Penny Anderson/WRA [e-mail] (W)
Peter J.Mattheis/Nucor [e-mail] (C)
Eric J.Lacey/Nucor [e-mail] (C)(W)
William J.Evans/UIEC [e-mail]
Vicki M.Baldwin/UIEC [e-mail](W)
Chad C.Baker/UIEC [e-mail] (W)
17-035-40 /Rocky Mountain Power
January 2,2018
DPU Data Request 11.1
DPU Data Request 11.1
CONFIDENTIAL REQUEST-Refer to Mr.Rick Link's confidential work papers
.The formulas included in this row refer to
specific sheets in the "Gateway IRP Data"work paper,but the values do not match in the
work paper provided.
(a)Please explain the discrepancy in values.
(b)Please provide work papers with corrected values/formulas,if needed.
(c)If corrected work papers are provided,please identify all changed values between the
work papers originally provided with the filing,and the new work papers.
Response to DPU Data Request 11.1
(a)The Company is unable to confirm a discrepancy in values.Please refer to
Confidential Attachment DPU l1.1,which validates the "Gateway Results Direct
Testimony"work paper,"Price-Policy-Annual PaR"sheet,row 89 against the source
work paper "Gateway IRP Data.xlsx".
(b)Please refer to the Company's response to subpart (a)above.
(c)Please refer to the Company's response subpart (a)above.
Confidential information is provided subject to Public Service Commission of Utah Rule
746-1-602 and 746-1-603.
17-035-40 /Rocky Mountain Power
January 2,2018
DPU Data Request 11.2
DPU Data Request 11.2
Refer to the Company's Response to Data Request OCS 8.9.
(a)How does the Company define "excessive generator tripping/curtailment"?
(b)Please provide any documentation or support for the level of generator
tripping/curtailmentthat would reflect imprudent transmission planning.
Response to DPU Data Request 11.2
(a)The Company's intention is to maintain generator tripping near that of its largest
single generator contingency,currentlyabout 645 megawatts (MW).System
conditions as well as required regulating reserves are considered in the level of
generator tripping.While there is no formal definition of excessive in this context,for
explanatory purposes only,an amount nearly double this,e.g.,1,200 MW,would be
considered excessive.
(b)There is no formal documentation in response to this request.The Company reserves
the right to change the amount of generator tripping used in the future.If and when
this were to occur,all appropriateplanning studies,followingNorth American
Electric Reliability Corporation (NERC)and Western Electricity Coordinating
Council (WECC)reliability criteria will be performed.
17-035-40 /Rocky Mountain Power
January 2,2018
DPU Data Request 11.3
DPU Data Request 11.3
CONFIDENTIAL REQUEST-Please provide the Company's annual return on each of
the benchmark wind projects individually,in a format similar to that provided for the
transmission projects.See confidential work papers provided in support of the Direct
Testimony of Mr.Rick Link,
Response to DPU Data Request 11.3
Please refer to the followingconfidential work papers supporting the Direct Testimony of
Company witness,Rick T.Link,specifically tab "Generic (Purchase)"of the following
work papers:
Folder:"Wind Projects"
File:"Ekola 250 RFPBM Vl3G EPC 03312017-30YR-GW4 FINAL.xlsx"
Folder:"Wind Projects"
File "McFadden 110 RFPBM Vl3G EPC 03312017 30YR-GW4 FINAL.xlsx"
Folder:"Wind Projects"
File "TB Flats I 250 RFPBM Vl3G EPC 03312017-30YR-GW4 FINAL.xlsx"
Folder:"Wind Projects"
File "TB Flats II 250 RFPBM Vl3G_EPC 03312017-30YR-GW4_FINAL.xlsx"
Confidential information is provided subject to Public Service Commission of Utah Rule
746-1-602 and 746-1-603.
17-035-40 /Rocky Mountain Power
January 2,2018
DPU Data Request 11.4
DPU Data Request 11.4
Refer to the Direct Testimony of Mr.Rick Link,lines 642-684.
(a)Please provide a narrative explanation for why 62 years was selected as an economic
life of the asset.Provide all documentation and analysis supporting the 62-year value.
(b)Has the Commission previously approved transmission projects assuming a 62-year
life?If so,please provide reference to the specific projects and documentation of the
Commission's approval.
Response to DPU Data Request 11.4
(a)The Company used a transmission plant economic life of 62 years consistent with the
most recently approved depreciation study in the Public Service Commission of Utah
(PSCU)order in Docket No.13-035-02 dated November 7,2013.Please refer to
Attachment DPU l1.4,which provides the detailed calculation of the transmission
average service life of 62 years,the weighted average service life of the applicable
Federal Energy Regulatory Commission (FERC)transmission accounts.
(b)The Company's recovery of transmission investmentthrough its group depreciation
methodology is consistent with FERC accounting guidelines and has been approved
by the PSCU.Explicitwithin this methodology is the determination of applicable
service lives by FERC Account.Althoughthe Company is not aware of the PSCU
approving transmission projects based specifically on a 62-year life,the Company
believes that the transmission composite life of 62 years,as approved by the PSCU in
the most recent depreciation study,Docket No.13-035-02,is representative of the
expected life of the Company's transmission system investment and is an appropriate
period to evaluate the economics of the Transmission Projects.
17-035-40 /Rocky Mountain Power
January 2,2018
DPU Data Request 11.5
DPU Data Request 11.5
Refer to the Company's Response to Data Request OCS 5.1,stating that "PacifiCorp has
not included the costs of the transmission that will remain in rate base beyond 2050,but
has also not included any incremental benefits associated with this transmission asset
beyond 2050,when additional generation,including new wind facilities,could be added
to the system to meet system load".
(a)Please provide all documentation and analysis supporting the potential incremental
benefits of the transmission asset beyond 2050.
(b)Please provide a calculation of the costs of the transmission project between 2050 and
2082,including the impact on net benefits of the projects.
Response to DPU Data Request 11.5
(a)The Company has not prepared documentationor performed analysis attempting to
quantifylong-term benefits of the transmission assets beyond 2050.However,this
does not mean that transmission assets will not provide system benefits throughout
their useful life.
(b)Please refer to the confidential work papers that accompanied the Direct Testimony of
Company witness,Rick T.Link,specifically:
Folder:"Other Summary Reports"
File:"Gateway IRP Data.xlsx",tab "Gateway",cells F37:G84.Column F reports
Gross Revenue Requirement by year through 2082.Column G reports Wholesale
Transmission Revenue through year 2082.
Please also refer to the Company's response to subpart (a)above.
17-035-40 /Rocky Mountain Power
January 2,2018
DPU Data Request l1.7
DPU Data Request 11.7
Refer to the Company's Response to Data Request DPU 10.14.
(a)Please explain the timeline,given that the Company's filing was made in June and the
transmission capability assessment was completed in October.
(b)Please provide a narrative description of how the study results would change if the
l10 MW value was used for Foote Creek.
Response to DPU Data Request 11.7
(a)For power flow and dynamic stability modeling purposes,detailed models are
necessary to properly represent and study a generatingfacility using transmission
planning software tools.While the size of the proposed Foote Creek facility was
intendedto be l10 megawatts (MW),the detailed model information received by
PacifiCorp transmission planning,and used in the preliminary Aeolus West
transmission path transfer capability assessment,was initially 99 MW.These studies
take a considerable amount of time to perform;hence,the difference in the dates.
(b)The power flow from the Foote Creek area into Standpipe would be marginally
higher using a l10 MW project;however,this study has not been performed.
17-035-40 /Rocky Mountain Power
January 2,2018
DPU Data Request 11.8
DPU Data Request 11.8
Refer to the Company's Response to Data Request DPU 10.15.
(a)According to the tables provided in response to part (a),the incremental repowered
capacity assumed in the analysis was 118 MW,rather than 137.5 MW,as noted in the
study on page 17.Please confirm that this conclusion is correct and explain why the
report contains the 137.5 MW value.
(b)Please explain why the Foote Creek capacity is 99 MW in the base case and 92 MW
in the sensitivity case.
Response to DPU Data Request 11.8
(a)The 118 megawatt (MW)refers to existing generation located at Seven Mile Hill 1
and Seven Mile Hill 2.The table below shows that the repower total is 137.5 MW:
Base Case Resources (MW)
Wind Farm Repower (137.5 MW)Existing Re power Total
High Plains/McFadden Ridge I (30 MW)127.5 0.0 127.5
Glenrock/Ro\\\ng Hills (54 MW)239.0 0.0 239.0
Dun lap (26 MW)111.0 0.0 111.0
Seven Mile 1&II (27.5 MW)118.5 0.0 118.5
Total 0.0
Note:Repowered wind turbines included new technology;however output was
limited to LGIA capacity levels
Location New
Aeolus Area
Freezeout 320.0
Aeolus 250.0
Shirley Basin 500.0
Foote Creek Area 99.0
Total 1169.0
Grand Total 1169.0
(b)The 92 MW is a typographical error;the number should be 99 MW.
17-035-40 /Rocky Mountain Power
January 2,2018
DPU Data Request 11.9
DPU Data Request 11.9
Refer to the Company's Response to Data Request DPU 10.9.The data request did not
address the impact of moving the Platte loads to either side of the cutplane.Rather,the
question addressed the Company's statement on page 14 of the transfer capability
assessment that "the load at Platte substation can cause a shift in the nomogram;higher
load at Platte can shift the curve towards the right and lower load at Platte can shift the
curve towards the left,making it more conservative."Given this statement:
(a)What is the range of shift effect from changing loads?Please provide details on the
minimum and maximum effects on the nomogram.
(b)Did the Company conduct and sensitivity analysis for this study using different load
levels at the Platte substation?If so,please provide those results.If not,why not?
Response to DPU Data Request 11.9
(a)Based on 2016 load at Platte substation,for the maximum load of 110 megawatts
(MW)the nomogram shift is anticipatedto be approximately +28 MW.For the
minimum load at Platte of 37 MW the nomogram shift is anticipated to be
approximately -45 MW.Hence,the range of shift in nomogram points could be +28
MW to -45 MW due to changing load.These calculated numbers are approximations
only and no power flow analysis was performed to verify the numbers.
(b)No.
17-035-40 /Rocky Mountain Power
January 2,2018
DPU Data Request 11.10
DPU Data Request 11.10
Refer to the Company's Response to Data Request DPU 10.10(b).
(a)If the Aeolus West transfer levels were increased by 82.5 MW on the nomogram,
would the TOT 4B flows need to be reduced?Please provide a revised nomogram
reflecting this change.
(b)Absent the transmission upgrade,would the movement of the Platte load to the other
side of the cutplane of the existing TOT 4A path allow addition of incremental wind
in the Shirley Basin region?If so,please provide analysis quantifyingthe additional
capacity.If not,why not?
Response to DPU Data Request 11.10
(a)The Aeolus West Transmission Path Transfer Capability Assessment report has
identified the nomogram curve as seen below:
Wyoming SystemOperating Curve
2022 Heavy Winter Loads
Normal OpenPoint:Plattell 5 kVsoo
soo
700
600
500
400
300
200
O 100
0 200 400 600 800 1000 1200 1400 1600 1800
Aeolus West Flow (MW)
The system can be operated reliably anywhere inside the blue curve,with varying
transfer levels on TOT 4B and Aeolus West.It can be seen from the nomogram plot
that the increase in Aeolus West transfers beyond 1,575 megawatts (MW)reduces the
flow on TOT 4B.
In the preliminarypower flow analysis it was identified that the most limitingelement
is the Platte-Latham 230 kilovolt (kV)line for the outage of the Anticline/Bridger-
Aeolus segment.An increase in Platte load will lower the flow on the Platte -Latham
230 kV line and increases Aeolus West transfers.Hence,no revision in the
17-035-40 /Rocky Mountain Power
January 2,2018
DPU Data Request 11.10
nomogram is required to identify the impact on TOT 4B for increased Aeolus West
flow.
(b)The existing system limitation is not impacted by movement of the Platte load to the
other side of the cutplane.Currentlythe low stiffness factor (low short circuit ratio)
prevents interconnection of any additional wind resources in southeastern Wyoming.
17-035-40 /Rocky Mountain Power
January 2,2018
DPU Data Request 11.11
DPU Data Request 11.11
Refer to the Attachment to OCS 8.1,Preliminary Aeolus West Transmission Path
Transfer Capability Assessment,page 13.
(a)If additional components of the Gateway West project are constructed,will the
Company need to continue to rely on the three remedial action schemes?Provide any
analysis conducted by the Company to support this response.
(b)If additional components of the Gateway West project are not constructed,is it
prudent to rely on the remedial action schemes indefinitely?Provide any analysis
conducted by the Company to support this response.
Response to DPU Data Request 11.11
(a)As identified in the Energy Gateway West -TOT 4A path rating studies,the addition
of at least one new 230 kilovolt (kV)transmission line south of Windstar and
rebuilding the existing 230 kV line south of Dave Johnston (Dave Johnston -Heward
[Difficulty]-Shirley Basin -Aeolus)will eliminate the need for a remedial action
scheme (RAS)for loss of a single 230 kV line between Shirley Basin and Aeolus.
Please refer to Attachment DPU l1.11 which provides a copy of the Energy Gateway
Project TOT 4A Transmission Path Rating Report and the submittal letter to Western
Electricity Coordinating Council (WECC)committees.All other RAS schemes will
be required with the addition of other components of Energy Gateway West.
(b)RAS can be a long-term effective planning tool and there are North American
Electric Reliability Corporation (NERC)standards in place to ensure that RAS are
periodically evaluatedand tested to ensure that they still meet desired outcomes and
that they operate as designed.No additional analysis beyond the Aeolus West
Transmission Path Transfer Capability Assessment study has been performed.
17-035-40 /Rocky Mountain Power
January 2,2018
DPU Data Request 11.12
DPU Data Request 11.12
Refer to the Attachment to OCS 8.1,Preliminary Aeolus West Transmission Path
Transfer Capability Assessment,Table 3.Without adding the proposed Transmission
Projects,could the Company integrate incremental wind by dispatching against the Dave
Johnston,Wyodak,and Laramie River plants?If so,please provide analysis quantifying
the maximum amount of incremental wind generation.If not,please explain why not.
Response to DPU Data Request 11.12
At this time,without the addition of the Energy Vision 2020 transmission facilities,
system stiffness factor (short circuit ratio)prevents interconnection of any additional
wind resources (or any type of resources)in southeastern Wyoming.
17-035-40 /Rocky Mountain Power
January 2,2018
DPU Data Request 11.13
DPU Data Request 11.13
Refer to the Attachment to OCS 8.1,Preliminary Aeolus West Transmission Path
Transfer Capability Assessment.How much of the incremental wind capacity could be
interconnected assuming the Transmission Project is not built,but remedial action
schemes similar to those described in the study are permitted?Provide all analysis and
documentation supporting this response.
Response to DPU Data Request 11.13
At this time,without addition of the Energy Vision 2020 transmission facilities,system
stiffness factor (short circuit ratio)prevents interconnection of any additional resources,
including wind,in southeastern Wyoming.Please refer to the North American Electric
Reliability Corporation (NERC)Reliability Guideline previously provided with the
Company's response to OCS Data Request 1.2.4,specifically Attachment OCS 1.24,
which provides additional information on short circuit ratio and connecting to weak
power systems.
17-035-40 /Rocky Mountain Power
January 2,2018
DPU Data Request 11.14
DPU Data Request 11.14
Refer to the Company's Response to Data Request DPU 10.13.
(a)Please confirm that the incremental wind injected at the Frannie 230 kV bus is on the
northwest side of the TOT 4B interface,opposite the wind added in the Shirley Basin
region.
(b)How much wind could be integrated at the Frannie 230 kV bus without the addition
of the proposed Transmission Projects?Provide all analysis and documentation
supporting this response.
Response to DPU Data Request 11.14
(a)Yes,the incremental wind studied as a sensitivity is north of the TOT 4B cut-plane.
(b)This scenario has not been studied.Please refer to the Preliminary Aeolus West
Transmission Path Transfer Capability Assessment for the analysis that has been
performed,provided in the Company's response to OCS 8.1.
17-035-40 /Rocky Mountain Power
January 2,2018
DPU Data Request 11.15
DPU Data Request 11.15
Refer to the Attachment to OCS 8.1,Preliminary Aeolus West Transmission Path
Transfer Capability Assessment,page 2,stating that with the proposed transmission
project,"the Aeolus West path can transfer up to 1696 MW..."Is it possible that the
WECC path rating study process could come to a different conclusion?
Response to DPU Data Request 11.15
Yes,it is possible that ultimate path rating could be different.
17-035-40 /Rocky Mountain Power
January 2,2018
DPU Data Request 11.17
DPU Data Request 11.17
In the IRP (page 63 -65),the Company indicates it is continuing to permit several other
segments of the Energy Gateway project.
(a)What is the expected in-service date of each Component?
(b)Are any of these segments included in the SO or PaR modeling analysis conducted
for the proposal in this docket?If so,how?If not,why not?
Response to DPU Data Request 11.17
(a)The Company expects the followingin service dates for the remaining segments of
Energy Gateway:
Remainder of Energy Gateway West Segment D (Windstar -Shirley Basin,
Anticline -Populus)-2024.
Energy Gateway West Segment E (Populus -Hemingway)-2024.
Energy Gateway South (Aeolus -Clover)-2024.
Energy Gateway Central (Oquirrh-Terminal)-2021.
(b)No,these additional segments are not included in the System Optimizer model (SO
model)or Planning and Risk (PaR)model analysis conducted for the proposal in this
proceeding.Additional segments were not included in this docket because these
segments were not included in the 2017 Integrated Resource Plan (IRP)preferred
portfolio.Please refer to the Energy Gateway sensitivities reported in PacifiCorp's
2017 IRP,specifically Volume I,Chapter 8 (Modeling Results),pages 206-210 and
219-222.The 2017 IRP is publicly available and can be through the following
website link:
http://www.pacificorp.com/es/iro.html
17-035-40 /Rocky Mountain Power
January 2,2018
DPU Data Request 11.18
DPU Data Request 11.18
Refer to the Company's Response to Data Request WRA 2.2(a).
(a)Please provide the referenced studies evaluating the impacts of the Dave Johnston
Plant retirement as soon as they are complete.
(b)Does the Company's analysis assume the completion of the Transmission Projects
proposed in this docket?
(c)Does the Company's analysis assume the completion of any other components of the
Energy Gateway project?If so,please identify which projects are assumed to be
complete and the assumed date of completion.
Response to DPU Data Request 11.18
(a)Please refer to Attachment DPU 11.18,which provides the preliminaryDave
Johnston retirement assessment.
(b)The preliminaryassessment of retiring the Dave Johnston plant early did not include
the Energy Gateway West D.2 segment.
(c)Some of facility requirements identified are similar to those of the Energy Gateway
project and include the following:
New Windstar -Shirley Basin 230 kilovolt (kV)line segment
(Energy Gateway Segment D.1)
Dynamic voltage control device at Latham
(Energy Gateway Segment D.2)
The analysis assumed an operational date of November 2020.
17-035-40 /Rocky Mountain Power
January 2,2018
DPU Data Request 11.19
DPU Data Request 11.19
Refer to the Attachment to OCS 8.1,Preliminary Aeolus West Transmission Path
Transfer Capability Assessment,p.1,noting that the WECC 2021-2022 base case was
utilized.
(a)Provide all analysis conducted by the Company to assess system stability,transfer
capability and the need for remedial action schemes after the Dave Johnston Plant
retires.
(b)If the Company has not conducted any analysis responsive to part (a)above,please
provide an explanation of how the expected unit retirement will impact the
conclusions of the Transfer Capability Assessment.
(c)Provide all analysis conducted by the Company calculating the transfer capability of
the project in all years of the study period.
Response to DPU Data Request 11.19
(a)The Company did not conduct any analysis to assess system stability,transfer
capability and the need for remedial action schemes after the Dave Johnston Plant
retires for the Preliminary Aeolus West Transmission Path Transfer Capability
Assessment.The preliminaryanalysis for the early retirement of Dave Johnston is
provided with the Company's response to DPU Data Request 11.18,specifically
Attachment DPU 11.18.
(b)Please refer to the Company's response to subpart (a)above.
(c)The Company identified the transfer capability limit across the Aeolus West
transmission path,which will be in-service in 2020 and beyond.This analysis
includes all components of the project.The study provided covers the 2021-2022
winter study period,which is the most recent Western Electricity Coordinating
Council (WECC)six-year study base case covering the 2020 project in-service date.
17-035-40 /Rocky Mountain Power
January 2,2018
DPU Data Request 11.20
DPU Data Request 11.20
Refer to the Direct Testimony of Mr.Rick Vail,lines 495-511,describing the WECC
analysis of the Energy Gateway project.
(a)Has WECC performed any analysis on the D.2 projects alone,without the other
components of the Energy Gatewayproject?If so,please provide all such analysis.
(b)What is the currentlyanticipated in-service date for the other components of the
Energy Gatewayproject evaluated in the WECC analysis?
Response to DPU Data Request 11.20
(a)Energy Gatewaypath rating studies for both Energy Gateway West and Energy
Gateway South included all Energy Gateway facilities,includingSegments D,E and
F.At the March 30,2010 project review group meeting,it was agreed that
incremental transmission limitations for transmission segments that are added
between stages,will be addressed via system operating limit (SOL)studies.In
accordance with allowed Western ElectricityCoordinating Council (WECC)
processes,the SOL studies will be conducted for the D.2 segment and will be
completed six months before the new line goes into service in December 2020.
(b)The anticipated in-service date for the Energy Gateway West -Sub-segment D.3
(Anticline-Populus)D.3 and the Energy Gateway South -Segment F (Aeolus to
Clover)is 2024.
17-035-40 /Rocky Mountain Power
January 2,2018
DPU Data Request 11.21
DPU Data Request 11.21
Refer to the Company's response to WRA Data Request 2.2(a)in Docket 17-035-39,
stating that "The more recent 2017 studies,which are underway,will evaluate the Dave
Johnston Plant retirement impacts to new Wyoming wind generationintegration.These
study findings will be available for release upon request to stakeholders and state
commissions by year end".
(a)Please provide the studies evaluating the Dave Johnston Plant retirement impacts to
new Wyoming wind generationintegration mentioned above.
Response to DPU Data Request 11.21
The Company assumes the reference to "WRA Data Request 2.2(a)in Docket 17-035-
39"was intendedto reference the Company's response to WRA Data Request 2.2 subpart
(a)in this proceeding (Docket 17-035-40).Based on this assumption,the Company
responds as follows:
Please refer to the Company's response to DPU Data Request 11.18,specifically
Attachment DPU l1.18.