20171218PAC to Staff Attachment Utah_DPU Set 10 (1-24).pdf

1407 W.North Temple
ROCKY MOUNTAIN Salt Lake City,UT 84116
POWER
A DIVISION OF PAC1FICORP
December 1,2017
Erika Tedder
Division of Public Utilities
160 E 300 S,4 6 Floor
Salt Lake City,UT 84114
etedder@utahgov (C)
RE:UT Docket No.17-035-40
DPU 10th Set Data Request (1-24)
Please find enclosed Rocky Mountain Power's Responses to DPU 10th Set Data Requests 10.1-
10.24.Also provided are Attachments 10.4,10.5,10.11,and 10.24.
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 [e-mail](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/[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]_m (C)(W)
17-035-40 /Rocky Mountain Power
December 1,2017
DPU Data Request 10.1
DPU Data Request 10.1
Reference the Attachment to OCS 8.1,Preliminary Aeolus West Transmission Path
Transfer Capability Assessment,p.5.
a.Why was the study performed using the 2021-2022 heavy winter WECC approved
case?
b.Did the Company perform any analysis using alternative WECC cases?If so,please
provide the results of the analysis.If not,please explain why not?
c.Provide a complete list of all available WECC approved cases,along with
documentation of the details of each case (loads,generation,interchange,etc.).
Response to DPU Data Request 10.1
a.The 2021-2022 heavy winter base case was selected for the studies because it was the
most recent Western Electricity Coordinating Council (WECC)base case near the
2020-2021 time period that also included dynamic stability data.
b.While other base cases were used for the analysis of the full Energy Gateway project,
which was completed in 2011,only the 2021-2022 heavy winter base case was used
for the D.2 (Bridger/Anticline-Aeolus)technical studies.
c.The Company objects to this request as undulyburdensome and not reasonably
calculated to lead to the discovery of admissible information.Without waiving the
objection,since the inception of WSCC/WECC in 1967,approximately 500 power
flow base cases have been developed and approved.
17-035-40 /Rocky Mountain Power
December 1,2017
DPU Data Request 10.2
DPU Data Request 10.2
Reference the Attachment to OCS 8.1,Preliminary Aeolus West Transmission Path
Transfer Capability Assessment,p.5.
a.Why did the Company choose to model summer line ratings with this analysis?
b.Did the Company do any sensitivities to assess transfer capability using alternative
line ratings?If so,please provide the results of the analysis.If not,please explain
why not?
Response to DPU Data Request 10.2
a.While the Western Electricity Coordinating Council (WECC)2021-2022 heavy
winter base case was used for the analysis,summer line ratings were applied to
provide more conservative study results.
b.As the Company uses only summer and winter line ratings,performing an analysis
using alternative line ratings is beyond the scope of the technical analysis.
17-035-40 /Rocky Mountain Power
December 1,2017
DPU Data Request 10.3
DPU Data Request 10.3
Reference the Attachment to OCS 8.1,Preliminary Aeolus West Transmission Path
Transfer Capability Assessment,Table 1,p.5.Please explain how the repowered wind
projects were "added to the system model"but the output was limited to existing LGI
levels"?How did this change impact flows or model results?
Response to DPU Data Request 10.3
Updating the system models to reflect the most up-to-date technology provided improved
performance for the system model.The newer models have better performance during
outage and fault conditions.The output at each facility was limited to the existing large-
generationinterconnection agreement (LGIA)amount,therefore the new technology
would have little impact on flow levels.
17-035-40 /Rocky Mountain Power
December 1,2017
DPU Data Request 10.4
DPU Data Request 10.4
Reference the Attachment to OCS 8.1,Preliminary Aeolus West Transmission Path
Transfer Capability Assessment,p.I1,noting that the "[t]ransmission line impedances
between Dave Johnston and Standpipe were verified and updated."Please provide the
impedances before and after the update,and provide a basis for the update,including any
supporting documentation.
Response to DPU Data Request 10.4
The transmission line impedance in the base case was updated to match the line data
book that is maintained by PacifiCorp and updated periodically.
Before D.2 After D.2
Line R X B R X B
Section/Parameter
Dave Johnston -0.00120 0.01077 0.02228 0.00119 0.01074 0.02246
Amasa 230 kV
Amasa -Difficulty 0.00590 0.05293 0.10952 0.00587 0 .05311 0 .10991
230 kV
Difficulty -0.00237 0.021510 0.04456 0.00193 0.01805 0.04094
Shirley Basin 230
kV
Shirley Basin -0.00190 0.01721 0.03565 0.002438 0.022095 0.049570
Aeolus #1 230 kV
Aeolus -0.00048 0.00430 0.00891 0.000276 0.003661 0.014030Freezeout]230 kV
Freezeout -0.00142 0.012915 0.02673 0.000930 0.012321 0.047220Standpipe2230kV
Please refer to Attachment DPU 10.4 for supporting documentation.
I Aeolus -Freezeout 230 kV after impedance is updated because the existing line is being
reconstructed as a part of D.2 project.
2 Freezeout -Standpipe 230 kV line after impedance is updated because the existing line is being
reconstructed as a part of D.2 project.
17-035-40 /Rocky Mountain Power
December 1,2017
DPU Data Request 10.5
DPU Data Request 10.5
Reference the Attachment to OCS 8.1,Preliminary Aeolus West Transmission Path
Transfer Capability Assessment,p.11,noting that the "Platte -Standpipe 230 kV
dynamic line rating of 608/666/680 MVA was assumed during the analysis."Refer also
to pp.13-14,stating that "anytime the emergency dynamic line rating on the Platte -
Standpipe is lower than 651 MVA the nomogram in Figure 2 will be shifted to the left."
a.Please provide the thermal rating of the line without dynamic capability.
b.What is the bandwidth of dynamic line ratings?i.e.what is the range of potential
ratings and what conditions impact those ratings?
c.What is the range of shift impact from the change in emergency dynamic line
rating?Please provide details on this range,includingthe effect of maximum and
minimum conditions on the nomogram.
d.Why was 608/666/680 MVA selected for this study?Please provide all analysis
and documentation supporting this response.
e.Did the Company conduct any analysis using different line ratings?If so,please
provide the results of the analysis.If not,please explain why not?
f.Did the Company use dynamic line ratings for any other lines in the system for
this analysis?If so,please identify the lines,ratings,and justification.
g.Is it common practice for the Company to use dynamic line ratings for
transmission planning studies?If so,please provide documentation supporting
this response.If not,please explain that decision was made for this study?
Response to DPU Data Request 10.5
a.The thermal rating of the line without the dynamic line rating is 428 mega volt
amp (MVA)(continuous)/498 MVA (4-hour)/519 MVA (30 minutes)based on
engineering analysis with 85/100/105 degrees Celsius transmission line conductor
temperature,35 degrees Celsius summer and 7,165-foot elevation.
b.The line with dynamic line rating can go up to 608 MVA (continuous)/666 MVA
(4-hour)/680 MVA (30 minutes)based on engineering analysis with 85/100/105
degrees Celsius transmission line conductor temperature,35 degrees Celsius
summer and 7,165-foot elevation.
c.The study was not conducted to identifythe impact due to change in emergency
dynamic line rating.
17-035-40 /Rocky Mountain Power
December 1,2017
DPU Data Request 10.5
d.The 608/666/680 MVA rating was selected based on engineering analysis for
wmter season.
e.The study utilized only the dynamic line rating for Platte -Standpipe 230 kilovolt
(kV)line.
f.For this study purpose and geographic location of the area of interest,the only
dynamic line rating system is installed on Platte -Standpipe 230 kV line.
g.For system operating limit (SOL)studies involvingthe Platte -Standpipe 230 kV
line it is common practice for the Company to use the dynamic line ratings.See
the spring and summer 2017 TOT 4A-4B SOL study provided as Attachment
DPU 10.5g-l.An excerpt from PacifiCorp's Weak Link database indicating the
Platte-Standpipedynamic line ratings is included as Attachment DPU 10.5 for
TOT 4A included as Attachment DPU 10.5g-2.It is noted,however,that there
are limited dynamic line ratings in use in the PacifiCorp system.
17-035-40 /Rocky Mountain Power
December 1,2017
DPU Data Request 10.6
DPU Data Request 10.6
Reference the Attachment to OCS 8.1,Preliminary Aeolus West Transmission Path
Transfer Capability Assessment,p.14,noting that the "case was modified to
simultaneously stress the Aeolus West and the TOT 4B path flows.
a.Please explain why the TOT 4B path was selected for simultaneous evaluation with
Aeolus West
b.In the nomogram points where the TOT 4B path is limited below 857 MW,are there
operational consequences to the system north of the TOT 4B path?
c.In the nomogram points where the TOT 4B path is limited below 857,please identify
the generators that are curtailed in each point and the MW of curtailment.
d.Do generationentities to the North of the TOT 4B path have financial or contractual
rights to move energy across that interface that would be violated if the limit is
reduced?If so,please provide details and documentation regarding these rights and
the consequences of operating the system with a reduced TOT 4B limit.
Response to DPU Data Request 10.6
a.There is a known interaction and established operating nomogram between the
existing TOT 4B and TOT 4A paths.Since Aeolus West adds one new line in
parallel with the existing TOT 4A path,it was anticipated that the interaction between
paths would likelypersist.
b.The study did not identify operational consequences to the system north of the TOT
4B path due to Gateway D.2 project.
c.There are no generators curtailed for TOT 4B nomogram points below 857 megawatts
(MW).The nomogram indicates that as less power flows north across TOT 4B,more
power can flow east across Aeolus West.
d.TOT 4B transmission obligations are well below 857 MW,and therefore no financial
or contractual commitments are in jeopardy.
17-035-40 /Rocky Mountain Power
December 1,2017
DPU Data Request 10.7
DPU Data Request 10.7
Reference the Attachment to OCS 8.1,Preliminary Aeolus West Transmission Path Transfer
Capability Assessment.
a.Please provide a path definition for Yellowtail South.
b.Please explain the interaction between the Yellowtail South,Montana South and TOT
4B paths and identify reasons for reversal of flows between the three paths.
Response to DPU Data Request 10.7
a.The Yellowtail South path,which is not an approved Western Electricity
Coordinating Council (WECC)path,includes the followinglines:Yellowtail*(PACE)to Frannie 230 kilovolt (kV)Yellowtail*(PACE)to Sheridan 230 kVYellowtail*(WAPA)to Lovell #1 115 kVYellowtail*(WAPA)to Lovell #2 115 kV
*Measured point
b.Detailed analysis of the interaction between the Yellowtail South,Montana South,
and TOT 4B paths will be completed as part of the FAC-013-2 Transfer Capability
assessment study,which is currentlyscheduled to be performed in the September
2017 thru October 2019 time period.
17-035-40 /Rocky Mountain Power
December 1,2017
DPU Data Request 10.8
DPU Data Request 10.8
Reference the Attachment to OCS 8.1,Preliminary Aeolus West Transmission Path
Transfer Capability Assessment,p.11,noting that "[t]he Jim Bridger generation output
was maintained such that Jim Bridger West path flows were held at 2400 MW."Please
explain why this path flow was maintained at 2400 MW and explain any consequences
(operation,contractual,financial)for a reduction in this flow.Provide all documentation
and analysis supporting this response.
Response to DPU Data Request 10.8
The intent of the technical studies was to maintain the 2400 megawatt (MW)rating of the
Bridger West transmission path,while supporting higher wind generationlevels in
southeast Wyoming.During high transfer conditions on the D.2 Project
(Bridger/Anticline-Aeolus),Jim Bridger plant generationwill be redispatched to
maintain flows up to 2400 MW on the Bridger West transmission path.Flow on the
Bridger West transmission path can drop below 2400 MW,depending on southeast
Wyoming wind generation dispatch and dispatch of the Jim Bridger power plant.
17-035-40 /Rocky Mountain Power
December 1,2017
DPU Data Request 10.9
DPU Data Request 10.9
Reference the Attachment to OCS 8.1,Preliminary Aeolus West Transmission Path
Transfer Capability Assessment,p.14,noting that "the load at Platte substation can cause
a shift in the nomogram."
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 any 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 10.9
a.With the addition of the D.2 Project (Bridger/Anticline-Aeolus)facilities and the
subsequent identification of the Aeolus West transmission path,load at Platte was
moved "upstream"of the Aeolus West cutplane so that resources do not need to cross
the Aeolus West metering point to serve the Platte load.In the model,82.5 megawatts
(MW)of load was represented in the Platte area.If the Platte loads had been
"downstream"of the Aeolus West cutplane,Aeolus West transfer levels on the
Aeolus West vs.TOT 4B nomogram would have increased by approximately
82.5 MW.
b.No specific sensitivity studies were performed that evaluateddifferent load levels in
the Platte area.However,with the Platte area load being moved "upstream"of the
Aeolus West transmission path cutplane,different load levels in the Platte area should
have little or no impacts on the Aeolus West path transfer capability.
17-035-40 /Rocky Mountain Power
December 1,2017
DPU Data Request 10.10
DPU Data Request 10.10
Reference the Attachment to OCS 8.1,Preliminary Aeolus West Transmission Path
Transfer Capability Assessment,p.12,noting that "east to west transfers have
effectivelyincreased by 817.5 MW due to shifting the Platte area load (82.5 MW)east
of the Aeolus West cut plane.
a.Please explain why the Platte area load was shifted for the Aeolus West path
definition.Provide all supporting documentation and analysis relatedto this decision.
b.Did the Company conduct any sensitivity analysis for this study keeping the Platte
load on the southwest side of the path by keeping the Standpipe-Platte230 kV line
and removing the Platte-Latham 230 kV line from the new Aeolus West definition?
If so,please provide those results.If not,why not?
Response to DPU Data Request 10.10
a.With the addition of the D.2 Project (Bridger/Anticline-Aeolus)facilities and the
subsequent identification of the Aeolus West transmission path,load at Platte was
moved "upstream"of the Aeolus West cutplane so that resources do not need to cross
the Aeolus West metering point to serve the Platte load.
b.No specific sensitivity studies were performed that evaluated shifting the Aeolus
West path metering point from the Platte-Lathan 230 kilovolt (kV)line to the
Standpipe-Platte 230 kV line.The intent of the change was to move the Platte load
"upstream"of the Aeolus West cutplane so that resources do not need to cross the
Aeolus West metering point to serve the Platte load.In the model,82.5 megawatts
(MW)of load was represented in the Platte area.If the Platte loads had been
"downstream"of the Aeolus West cutplane,Aeolus West transfer levels on the
Aeolus West vs.TOT 4B nomogram would have increased by approximately
82.5 MW.
17-035-40 /Rocky Mountain Power
December 1,2017
DPU Data Request 10.11
DPU Data Request 10.11
Reference the Attachment to OCS 8.1,Preliminary Aeolus West Transmission Path Transfer
Capability Assessment.
a.Please provide all currentlyapprovedremedial action schemes across PacifiCorp's
system.
b.Please provide documentation of the approval process for a new RAS.
c.Does WECC allow remedial action schemes be implemented as a solution to N-1
contingencies for planning purposes?Please provide documentation or policies
supporting this response.
d.Has PacifiCorp ever relied on implementing a RAS for N-1 contingencies when planning
prior transmission projects?If so,please identify those projects and provide
documentation supporting this response.
Response to DPU Data Request 10.11
a.PacifiCorp's approvedremedial actions schemes (RAS)are listed below:
Jim Bridger RAS
Goshen RAS
Naughton RAS
Dave Johnston Transformer Tripping Scheme
Lake Side I RAS
Lake Side II RAS
Path 18 Overload Tripping Scheme
Standpipe RAS
Pintura RAS
Amasa RAS
Grace RAS
Yale Runback Scheme
Meridian Area Load Tripping Scheme
North Umpqua RAS
b.Please refer to Attachment DPU 10.lla,PacifiCorp's Remedial Action Scheme
Protection &Control Procedure No.304 and Attachment DPU 10.1lb Western
ElectricityCoordinating Council's (WECC)Procedure andInformationRequiredfor
RAS Assessment.
c.Yes.Please refer to Attachment DPU 10.1lb.See also the North America Electric
Reliability Corporation (NERC)Glossary of Terms which defines Special Protection
Systems (also called Remedial Action Schemes)as "An automatic protection system
17-035-40 /Rocky Mountain Power
December 1,2017
DPU Data Request 10.11
designed to detect abnormal or predetermined system conditions,and take corrective
actions other than and/or in addition to the isolation of faulted components to maintain
system reliability.Such action may include changes in demand,generation(MW and
Mvar),or system configuration to include (a)under-frequency or under-voltage load
shedding,(b)fault conditions that must be isolated,or (c)out-of-step relaying (not
designed as an integral part of an SPS)."The phrase "abnormal system condition"refers
to any contingencies includingN-1.
d.Yes.Before the completion of the Sigurd-Red Butte 345 kilovolt (kV)#2 line on
May 28,2015,PacifiCorp used RAS to trip Huntingtongenerationfor loss of the Sigurd-
Three Peaks 345 kV or Three Peaks--Red Butte 345 kV lines.Summaries for the
HuntingtonRAS and Three Peaks RAS are included in Attachments DPU 10.lle and
DPU 10.lld.After completion of the Sigurd-Red Butte 345 kV #2 line,both RAS were
removed.Please refer to Attachments DPU 10.1le and DPU 10.1lf.
17-035-40 /Rocky Mountain Power
December 1,2017
DPU Data Request 10.12
DPU Data Request 10.12
Reference the Attachment to OCS 8.1,Preliminary Aeolus West Transmission Path
Transfer Capability Assessment,Table 5.
a.Please provide detailed description of the RAS used for each of the five cases
analyzed for this study.
b.Please provide the transmission line ratings for all the limitingelements identified in
the study,including,but not limited to,Platte-Latham and Yellowtail-Sheridan 230
kV lines.
Response to DPU Data Request 10.12
a.There were three different remedial action schemes (RAS)for N-1 outages identified
in the study:
1.Aeolus RAS to trip up to 640 megawatts (MW)of wind generationdepending on
pre-outage flow conditions for any of the new transmission element outages
between Aeolus-Anticline/JimBridger.Further detail is as follows:Three phase
fault (4 cycles)between Aeolus 230 kilovolt (kV)and Jim Bridger 345 kV bus
followed by outage of Aeolus 500/230 kV transformer,Anticline-Aeolus 500 kV
line,Anticline 345/500 kV transformer,Anticline-Bridger 345 kV line and
Aeolus RAS to trip generationup to 640 MW in 10 cycles from fault inception.
2.Freezeout RAS to trip up to 140 MW of generationin the Freezeout area for the
Aeolus-Freezeout 230 kV line outage,dependingon pre-outage flow conditions.
Further detail is as follows:Three phase fault (5 cycles)at Aeolus or Freezeout
230 kV bus followed by loss of the Aeolus-Freezeout 230 kV line and RAS to
trip generationin the Freezeout area (up to 140 MW)in 10 cycles from fault
inception.
3.Shirley Basin RAS to trip up to 60 MW of generation in the Shirley Basin area for
the Aeolus-ShirleyBasin 230 kV #2 line outage,depending on pre-outage flow
conditions.Further detail is as follows:Three phase fault (5 cycles)at Aeolus or
Shirley Basin 230 kV bus followed by loss of the Aeolus-ShirleyBasin 230 kV
line #2 and RAS to trip generationin the Shirley Basin area (up to 60 MW)in
10 cycles from fault inception.
b.The identified limitingelements for various nomogram points from the preliminary
study were Platte-Latham and Yellowtail-Sheridan 230 kV lines.The ratings for the
Platte-Latham line are 428/478/557 mega var amp (MVA)and for the Yellowtail-
Sheridan 230 kV line are 339/376/376 MVA,continuous,four-hour emergency and
30 minute emergency,respectively.
17-035-40 /Rocky Mountain Power
December 1,2017
DPU Data Request 10.13
DPU Data Request 10.13
Reference the Attachment to OCS 8.1,Preliminary Aeolus West Transmission Path
Transfer Capability Assessment,p.17,Section 5.B.
a.At which node was the wind injected in the Bighorn region?
b.Please explain why the sensitivity reduced generationin the Shirley Basin region for
this sensitivity.
c.Did the Company conduct any other sensitivities keeping the full amount of wind
capacity proposed for the Shirley Basin region,plus additional wind to meet the 1,270
MW level?If so,please provide the results of this analysis.If not,why not?
Response to DPU Data Request 10.13
a.At the Frannie 230 kilovolt (kV)bus.
b.A sensitivity analysis was performed to evaluate the transmission system impacts of
increasing the magnitude and changing the location of generationresources.As part
of this analysis,assumed wind generationwas increased from 1169 megawatts (MW)
to 1270 MW,by increasing the repowered generation by 137.5 MW and adding
240 MW of new generationin the Bighorn area of northern Wyoming,and reducing
the new wind generationat Shirley Basin from 500 MW to 250 MW.
c.The company did not conduct the sensitivities keeping the full amount of wind
capacity proposed for the Shirley Basin region,plus additional wind to meet the
1,270 MW level.Refer to the response in DPU 10.13b indicating that the purpose of
the sensitivity analysis was to evaluate changes in the location and magnitude of
resources.
17-035-40 /Rocky Mountain Power
December 1,2017
DPU Data Request 10.14
DPU Data Request 10.14
Reference the Attachment to OCS 8.1,Preliminary Aeolus West Transmission Path
Transfer Capability Assessment.Why did the Company model a 99 MW project at the
Foote Creek area (Table 4,p.10)rather than 110 MW,as referenced in the Direct
Testimony of Rick Link,line 501?
Response to DPU Data Request 10.14
At the time the technical studies were performed,the modeling data received for the
Foote Creek area project supported a 99 megawatt (MW)wind farm.Data supporting a
110 MW interconnection has subsequently been provided.
17-035-40 /Rocky Mountain Power
December 1,2017
DPU Data Request 10.15
DPU Data Request 10.15
Reference the Attachment to OCS 8.1,Preliminary Aeolus West Transmission Path Transfer
Capability Assessment,page 17,regarding the sensitivity analysis modeling 1,270 MW.
a.The accounting of MW included in this sensitivity appears to be incorrect;1,169 MW
+137.5 MW +240 MW -250 MW =1,296.5 MW (not 1,270 MW).Please clarify
what level of generationwas modeled in this sensitivity and at which node the
generation was modeled.
b.Has the Company evaluatedwhether there would be additional transmission upgrades
needed to interconnect 240 MW of generationin the Bighorn area?If so,please
provide all supporting analysis and documentation.
Response to DPU Data Request 10.15
a.To assist in better defining the resources that were included in the base case and the
sensitivity case,the followingtables are provided:
Base Case:
Base Case Resources (MW)
Wind Farrn Repower (137.5 MW)Existing Repower Total
High Plains/McFadden Ridge I (30 MW)127.5 0.0 127.5
Glenrock/Rolling Hills (54 MW)239.0 0.0 239.0
Dunlap (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
The interconnection substations (nodes)are listed above.
17-035-40 /Rocky Mountain Power
December 1,2017
DPU Data Request 10.15
Sensitivity Case:
Sensitivity Case Resources (MW)
Wind Farm Repower (20%)Existing Repower Total
High Plains/McFadden Ridge I 127.5 MW 25.2 152.7
Glenrock/Rolling Hills 239.0 47 3 286 3
Dunlap 111.0 22.0 133.0
Seven Mile 1&II 118.5 23.5 142.0
Total 118.0
Location New
Bighorn Basin Area 240.0
Aeolus Area
Freezeout 320.0
Aeolus 250.0
Shirley Basin 250.0
Foote Creek Area 92.0
Total 1152.0
Grand Total 1270.0
The interconnection substations (nodes)are listed above.The Bighorn Basin
generationwas integrated on a new substation located on the Yellowtail-Frannie
230 kilovolt (kV)line.
b.In the context of this study,redispatch of the Wyodak resource was assumed.
17-035-40 /Rocky Mountain Power
December 1,2017
DPU Data Request 10.16
DPU Data Request 10.16
Reference the Attachment to OCS 8.1,Preliminary Aeolus West Transmission Path
Transfer Capability Assessment,regarding the remedial action schemes.What is the
maximum level of wind generationthat could be added in the Freezout/Aeolus/Shirley
Basin area without requiring remedial action schemes for N-1 contingencies?
Response to DPU Data Request 10.16
The preliminaryAeolus West Transmission Path Transfer Capability Assessment study
did not evaluate the maximum level of wind generationthat could be added without
requiring remedial action schemes for N-1 contingencies.
17-035-40 /Rocky Mountain Power
December 1,2017
DPU Data Request 10.17
DPU Data Request 10.17
Link Direct.In reference to Mr.Link's testimony,lines 479-487,stating that the
Company's economic analysis modeled 1,180 MW of new wind.
(a)Did the Company conduct any analysis modeling alternative levels of new wind?If
so,please provide the results of these analysis,includingSO and PaR model outputs
and calculations of costs and net benefits to customers.
(b)Please provide a full analysis of the economic benefits for the 1,270 MW of new wind
generation,the full amount for which the Company is requesting pre-approval.
Provide all supporting work papers,including SO and PaR model outputs and
calculations of costs and net benefits to customers.
(c)Please provide a full analysis of the economic benefits of adding 1,080 MW of new
wind.Provide all supporting work papers,including SO and PaR model outputs and
calculations of costs and net benefits to customers.
(d)Please provide a full analysis of the economic benefits of adding 980 MW of new
wind.Provide all supporting work papers,includingSO and PaR model outputs and
calculations of costs and net benefits to customers.
Response to DPU Data Request 10.17
(a)Yes.In the 2017 Integrated Resource Plan (IRP),PacifiCorp assumed 1,100
megawatts (MW)of new Wyoming wind would be placed in service at the end of
2020.Please refer to work papers and analysis provided in the confidential data disks
that accompanied the 2017 IRP,specifically:
Data Disk 2_CONF\System Optimizer Output\Preferred Portfolio\
Data Disk 3 CONF\PaR Summary Reports\PaR Summary Report Final Screening.zip
(b)The Company has not performed the requested analysis.As specified in the 2017 IRP
action plan,the Company is seeking at least 1,100 MW of new Wyoming wind
resources.The Company will analyze Wyoming wind resource bids submitted into
the 2017 Renewable Request for Proposals (2017R RFP)when establishing a final
shortlist with aggregate capacity up to 1,270 MW.Consistent with the procedural
schedule adopted for this proceeding,this analysis will be provided in the Company's
supplemental filing in mid-January 2018.
(c)The Company has not performed the requested analysis.Please refer to the
Company's response to subpart (b)above.
17-035-40 /Rocky Mountain Power
December 1,2017
DPU Data Request 10.17
(d)The Company has not performed the requested analysis.Please refer to the
Company's response to subpart (b)above.
17-035-40 /Rocky Mountain Power
December 1,2017
DPU Data Request 10.18
DPU Data Request 10.18
Link Work Papers.Refer to the Link Direct Testimony Work Paper "Wind Summary
Data.xlsx".Please explain why the energy values for projects differ between the PaR
and SO tables.
Response to DPU Data Request 10.18
Please refer to the "New Wind Data for Cales"worksheet of the referenced file "Wind
Summary Data"provided with the confidential work papers supporting the Direct
Testimony of Company witness,Rick T.Link.Specifically,columns B through I reflect
output from the Planning and Risk (PaR)model,which performs a stochastic analysis of
the Company's system over the forecast horizon by sampling a representative week for
each month.The resulting annual generationdata for the proposed projects reflects the
extension of the sampled weeks for any given year,and necessarily varies from a fixed
annual assumption.
In contrast,the System Optimizer model (SO model)does not perform its simulation
using stochastic variations or sample weeks.The referenced SO model data in columns
K through Q is therefore less variant and more closely aligns with a fixed annual
assumption.
17-035-40 /Rocky Mountain Power
December 1,2017
DPU Data Request 10.19
DPU Data Request 10.19
Refer to the Company's response to 4.2(b).
(a)Please provide the minimum operating levels for the Dave Johnson,Jim Bridger,and
Wyodak facilities used in the redispatch analysis.
Response to DPU Data Request 10.19
The Dave Johnston and Jim Bridger generatingfacilities'outputs were adjusted to limit
the Aeolus West and Jim Bridger West transmission path within or at its path transfer
capability of 1696 megawatts (MW)and 2400 MW.In the preliminaryAeolus West
transmission path transfer capability assessment study,the present and assumed future
Wyoming wind output was increased to its maximum output.The repowered units output
was limited to the existing large generationinterconnection agreement (LGIA)generation
levels.
As per MOD-32 (Data for Power System Modeling and Analysis)data which is based on
engineering assessment followingare the minimum output level for Jim Bridger,Dave
Johnston plants and Wyodak:
Facility Minimum operating level
Jim Bridger Unit 1 135.4 MW
Jim Bridger Unit 2 133.8 MW
Jim Bridger Unit 3 200.0 MW
Jim Bridger Unit 4 200.0 MW
Dave Johnston Unit 1 59.0 MW
Dave Johnston Unit 2 49.0 MW
Dave Johnston Unit 3 131.0 MW
Dave Johnston Unit 4 203.0 MW
Wyodak 207.0 MW
17-035-40 /Rocky Mountain Power
December 1,2017
DPU Data Request 10.20
DPU Data Request 10.20
Refer to the Company's response to DPU 4.12.
(a)Please provide the "current system master plan"referenced in part (b)of the response.
(b)Please identify the "rigorous review by transmission entities within the Western
Interconnection"referenced in part (b)of the response.Provide any documentation
or analysis supporting this review.
(c)Did the Company analyze the amount of wind that could be interconnectedwith a 345
kV solution?If so,please provide all documentation and work papers supporting this
analysis,includingany evaluation of economic benefits.
Response to DPU Data Request 10.20
(a)The current transmission system master plan for Wyoming calls for the construction
of the 500 kilovolt (kV)transmission facilities associated with Energy Gateway
illustrated on the figure below:
Energy Gateway
WASHINGTON
MONTANA
>O
PaciflCorp retail service area
Newtransmissionlines:
-500kV minimumvokage
-345 kV minunum vokage
230 kV minimum vokqp
Existing substation
New substation
AREZONA NEW MEXICO
This map is forgeneral reference only and renects current plans.
k may not renect the final routes,construction sequence or exact line cordiguration.
17-035-40 /Rocky Mountain Power
December 1,2017
DPU Data Request 10.20
(b)Gateway West and South were evaluatedthoroughlyby entities in the Western
Interconnection by followingthe guidelines outlined in "Project Coordination,Path
Rating and Progress Report Processes"whose latest version is provided in
Attachment-3 DPU 10.24.This process spanned over 24 months and included
representatives from affected utilities.
(c)As the D.2 Project (Bridger/Anticline-Aeolus)is a sub-segment of the Energy
Gateway masterplan,which calls for 500 kV transmission to be constructed west and
south of Aeolus substation,no 345 kV alternativeswere considered.
17-035-40 /Rocky Mountain Power
December 1,2017
DPU Data Request 10.21
DPU Data Request 10.21
Provide an accounting of the Company's return on investment for the transmission
project and Company-owned wind projects.Where applicable,provide the location of
values in Company witness work papers already provided.
Response to DPU Data Request 10.21
The estimated annual pretax return on the transmission project and Company-owned
wind net rate base for years 2020 through 2023 is shown on line 6 of the Direct
Testimony of Company witness,Jeffery K.Larsen,Exhibit RMP_(JKL-2)page 2.The
pretax return rate calculation detail is provided in Exhibit RMP_(JKL-4),lines 1
through 4.
For the Company's projection of the portion of return on investment for the transmission
project and Company-owned wind projects split out separately,please refer to the
Company's response to OCS Data Request 2.12.
17-035-40 /Rocky Mountain Power
December 1,2017
DPU Data Request 10.22
DPU Data Request 10.22
Refer to the Company's response to DPU 5.1.
(a)Provide any update regarding risk assessments conducted by the Company regarding
PTC qualification.
(b)Draft federal legislation currently under consideration by the U.S.Congress (H.R.1,
the Tax Cuts and Jobs Act)includes provisions impacting both the value of wind
PTCs and the continuity of construction provisions.Has the Company conducted a
review of the likelihood of PTC qualification if this legislationpasses?If so,please
provide all documentation,analysis,memorandum,etc.
Response to DPU Data Request 10.22
(a)The Company believes that the current proposed federal legislation regarding income
tax reform will not impact the current five percent safe harbor and continuity of
construction requirements as enacted by the Protecting Americans from Tax Hikes
(PATH)Act of2015 as they relate to the Company's proposed new wind projects.
Therefore there has been no Company update to any risk assessments regarding
production tax credit (PTC)qualification.
(b)On November 16,2017,the United States (U.S.)House of Representatives passed
House of Representatives Bill (HR)1,Tax Cuts and Jobs Act which amended Internal
Revenue Code (IRC)Section 45 and added a statutory requirement requiring "the
construction of any facility,modification,improvement,addition,or other property
shall not be treated as beginningbefore any date unless there is a continuous program
of construction which begins before such date and ends on the date that such property
is placed in service."This provision is effective for "taxableyears beginning before,
on,or after the date of enactment of this Act."
After the passage of HR 1,the Report of the Committee on Ways and Means (House
Report 115-409)(Committee Report)was issued and states that "the Committee
believes that codifying existing guidance regarding when the construction of a
renewable power facility begins will provide increased certainty to taxpayers
engaging in renewable power projects."The Committee Report also states that the
provision "is intended to codify Treasuryguidance for determining when
construction of a facility has begun,includingthe physical work test,the five
percent safe harbor,and the continuity requirement"(emphasis added).
Accordingly,it appearsthat the four-year safe harbor to meet the continuity-of-
construction requirement as set out in the various Internal Revenue Service (IRS)
Notices will remain available to taxpayers under the HR l and the Company wind
projects will continue to qualify for the 100 percent PTC.The Senate mark-up of
HR l as passed by the Senate Finance Committee has no amendments relatingto the
PTC.
17-035-40 /Rocky Mountain Power
December 1,2017
DPU Data Request 10.23
DPU Data Request 10.23
In reference to the Company's response to DPU 6.5(c):
(a)Do the QFs reference in this section have preferential positions on the transmission
interconnection queue relative to the Company's benchmark projects?
(b)If these projects are able to complete the interconnection process,will they prevent
the interconnection of the Company's benchmark projects or other projects selected
in the wind RFP?
(c)If these projects are completed,which node would be the point of interconnection?
(d)Has the Company conducted any analysis comparable to the Preliminary Aeolus West
Transmission Path Transfer Capability Assessment (Attachment to OCS 8.1)
including these QFs?If so,pleaseprovide that analysis and supporting
documentation.
Response to DPU Data Request 10.23
(a)The QFs referenced in the Company's responseto DPU 6.5(c),known as "Boswell
Springs I-IV,"have preferential positions on the transmission interconnection queue
relative to the Company's benchmark projects.
(b)The four Boswell Springs projects are 80 MW each,for a total nameplate size of 320
MW.The 2017R Request for Proposals (RFP)for renewable resources issued on
September 27,2017 had a limit of up to 1,270 MW of new wind energy
interconnecting in Wyoming.If all four Boswell Springs projects are able to complete
the interconnection process and were counted against the 1,270 MW limit for the
2017R RFP,they would take up only 25.2%of the resources within the limit and
there would be 950 MW available for other projects.PacifiCorp's benchmark wind
projects have a total of 860 MW.The four Boswell Springs projects would not
prevent the interconnection of the Company's benchmark projects or other projects
selected in the wind RFP.
(c)According to the publiclyavailable data in the PacifiCorp Generation Interconnection
Queue as of November 27,2017,the Boswell Springs wind projects proposed Point
of Interconnection is PacifiCorp's Freezeout Substation.
(d)The Q0409 project was used as a proxy for new wind generation in the Preliminary
Aeolus West Transmission Path Transfer Capability Assessment.
17-035-40 /Rocky Mountain Power
December 1,2017
DPU Data Request 10.24
DPU Data Request 10.24
In reference to the Company's response to DPU 8.3:
a.Has the Company conducted any preliminary analysis on the simultaneous
interactions between Aeolus West and Paths 33,30,36,19,20,or 18?If so,
please provide that analysis and all supporting documentation.
b.What is the expected timeline for the FAC-013-2 Transfer Capability
Assessment?Please provide any WECC or NERC policies supporting this
response.
c.What is the expected timeline for the formation and evaluation of the WECC
technical study group?Please provide any WECC policy supporting this response.
d.When does the Company expect System Operating Limit studies to be conducted?
Please provide any WECC policy supporting this response
e.Will the Company know whether or not the Aeolus West path transfer capability,
as determined through the WECC processes,will be sufficient to interconnect up
to 1,270 MW of wind prior to the start of construction of the transmission
facilities?
f.Will the Company know whether or not the Aeolus West path transfer capability,
as determined through the WECC processes,will be sufficient to interconnect up
to 1,270 MW of wind prior to the start of construction of the wind facilities?If
not,and the path rating cannot accommodate the wind,what are the consequences
and what would be the impact on customer costs and benefits?
Response to DPU Data Request 10.24
a.Analysis on the simultaneous interactions between Aeolus West and Paths 33,30,
19,20 and 18 were performed duringthe path rating studies conducted in 2011.
This Path Rating Study Report can be seen in Attachment-l.A simultaneous
evaluation of TOT 4A and Path 36 (TOT 3)were performed as part of the TOT
4A analysis,and no path interactions were identified;however,this analysis will
also be performed as part of the Aeolus West analysis.PacifiCorp will conduct
additional simultaneous interaction analysis for these paths during the FAC-013-2
Transfer Capability Assessment which is planned to be completed in 3Ql9
Preliminary studies evaluatingthe interaction of the Aeolus West and TOT 4B
transmission paths were completed in November 2017.Please refer to Attachment
DPU 10.24 for additional information.A copy of the report is provided as
Attachment-2 within the folder.
17-035-40 /Rocky Mountain Power
December 1,2017
DPU Data Request 10.24
b.While preliminary studies can be performed prior to award of the Energy Vision
2020 Request For Proposal in 1Q18,the assessment of the Aeolus West path
FAC-013-2 Transfer Capability with other utilities cannot be formallyinitiated
until specific new southeast Wyoming wind resources have been identified.
Path rating studies for the Aeolus West transmission path for the full Energy
Gateway project were completed in July 2011;therefore,these studies will not be
needed at this time.The Path Rating Studies performed were based on then
current "Project Coordination,Path Rating and Progress Report Processes"whose
latest version can be seen in Attachment-3.However,for the D.2 Project a
Transfer Capability assessment will be required to meet North American Electric
Reliability Corporation (NERC)Standard FAC-013-2which will be completed by
3Q2019 and System Operating Limit (SOL)studies will be required to meet Peak
Reliability guidelines which will be completed six months prior to energization of
the D.2 Segment.In performingthe FAC-013-2 Transfer Capability assessment
studies,it is anticipated that a technical study group at the commencement of the
studies will be formed and study finding will be shared with the Western
Electricity CoordinatingCouncil (WECC)Study Subcommittee (StS).
c.Please refer to DPU 10.24b,above.
d.PacifiCorp is planningto perform the System Operating Limits (SOLs)study that
are seasonal in nature and will commence on availability of the WECC approved
operating base case (see Appendix "V"of Attachment-5)for the season in which
the path will become active.The SOL studies will be conducted as per the
"System Operating Limits Methodology For The Operations Horizon"and
"Seasonal System Operating Limit CoordinationProcess"developed by the
reliability coordinator for WECC (Peak Reliability)seen in Attachment-4 and
Attachment-5.
e.Technical analysis conducted until now demonstrate that the D.2 Project
(Bridger/Anticline -Aeolus)transmission facilities associated with the Aeolus
West transmission path will be sufficient to interconnect up to 1,270 megawatts
(MW)of wind generation.
f.Please refer to the response to DPU 10.24.e.Based on preliminary technical
studies,PacifiCorp is confident that the proposed D.2 project facilities can
support the interconnection of up to 1,270 MW of wind generation,under the
resource scenarios studied.