20170925Utah_DPU Set 2 (1-17).pdf

1407 W.North Temple
ROCKY MOUNTAIN Salt Lake City,UT 84116
POWER
A DIVISION OF PACIFICORP
August 11,2017
Erika Tedder
Division of Public Utilities
160 E 300 S,41 Floor
Salt Lake City,UT 84114
etedder@utahgov (C)
RE:UT Docket No.17-035-39
DPU 2nd Set Data Request (1-17)
Please find enclosed Rocky MountainPower's Responses to DPU 2nd Set Data Requests 2.1-
2.17.Also provided is Attachment DPU 2.11 -2.Provided on the enclosed Confidential CD are
Confidential Attachments DPU 2.4,2.6 -1,2.8,and 2.11 -1 and Confidential Response 2.6.
Confidential information is provided subject to Public Service Commission of Utah (UPSC)
Rules 746-1-602 and 746-1-603.
If you have any questions,please call Tarie Hansen at [phone].
Sincerely,
Bob Lively
Manager,Regulation
Enclosures
C.c.:Dan Kohler/DPU (C)
Dan Peac/DPU dpeaco daymarkea.com (C)(W)
Aliea Afnan/DPU [e-mail] (W)
[e-mail] (W)
Béla Vastag/OCS [e-mail](C)
Philip Hayet/OCS [e-mail]_m (C)
Gary A.Dodge/UAE gdodge hidlaw.com (C)
Kevin Higgins/UAE (C)
Neal Townsend/UAE (C)(W)
17-035-39 /Rocky Mountain Power
August 11,2017
DPU Data Request 2.1
DPU Data Request 2.1
In reference to Mr.Hemstreet's testimony,lines 318-325,how many turbines does the
Company expect will experience component failures that render them unable to provide
service before they can be repowered?Please provide this information by wind fleet site
for each of the followingwind farms:
(a)Glenrock I
(b)Glenrock II
(c)RollingHills
(d)Seven Mile I
(e)Seven Mile II
(f)High Plains
(g)McFadden Ridge
(h)Dunlap
(i)Marengo I
(j)Marengo II
(k)GoodnoeHills
(1)Leaning Juniper
Response to DPU Data Request 2.1
The Company objects to this response to the extent it requests information not maintained
in the ordinary course of business or developmentof a special study.Without waiving
these objections,the Company responds as follows:
The Company's economic analysis assumes that approximately 45 turbines will
experience failures that render them unable to be returned to service before repowering.
This number reflects an estimate across the entire wind fleet proposed to be repowered,
and the Company does not have an analysis of estimated failures that will be unable to be
returned to service at the individual wind plants.
17-035-39 /Rocky Mountain Power
August 11,2017
DPU Data Request 2.2
DPU Data Request 2.2
What is the estimated economic impact relating to these turbine failures as factored into
the economic analysis?
Response to DPU Data Request 2.2
The Company has not prepared a sensitivity to isolate the economic impact relating to
these turbine failures,although their impacts are factored into the financial analysis.
Nonetheless,the Company offers the followingresponse:
The Company's economic analysis assumes that approximately 45 turbines will
experience failures that render them unable to be economically returned to service before
repowering.As a result,the Company's analysis assumes that generationwill be reduced
from the projects by 2.5 percent 2 years before repowering,5 percent in the year before
repowering,and 7.5 percent in the year of repowering (generally 2019,except for
Dunlap).Althoughgeneration will be reduced,the Company will avoid the cost of
replacing these failed components.These estimated impacts are shown in the table below
and are derived from the work papers provided with the Direct Testimony of Company
witness,Rick T.Link and the work papers provided with the Company's response to
DPU Data Request 1.9;specifically Confidential Attachment DPU 1.9,the spreadsheet
entitled "Wind Repower CAPEX (May 10 2017)CONF."
Pre-Repowering Generation Reduction (MWh)-61,999 -136,854 -211,710
Avoided Capital Gearbox Replacements--Idled WTGs ($m)5.67 6.21 6.57
Please refer to Mr.Link's Direct Testimony,specifically Exhibit RMP_(RTL-3),which
shows the net (benefit)/cost for each of the nine scenarios referred to in Mr.Link's
testimony.The "Change in NPC"shows an increase in net power costs (NPC)in the first
three years as a result of reduced generation.The impact of lost production tax credits
(PTC)is included in the "Cost of Project"line.The impact of avoiding the cost of
repairing components is also included in the "Cost of Project"line.
An economic analysis will be performed to evaluate each component failure to determine
whether the turbine can economically be returned to service before repowering.The
Company has not made a blanket determination that component failures will not be
addressed before repowering.Therefore,the assumption that a certain number of turbine
component failures will not be repaired before repowering is conservative.
17-035-39 /Rocky Mountain Power
August l1,2017
DPU Data Request 2.3
DPU Data Request 2.3
In reference to Mr.Hemstreet's testimony,lines 269-272,in consideration of the
locations of the WTGs to be repowered throughoutthe system,what is the average
available excess carrying capacity for each of the constrained transmission lines serving
those areas?
Response to DPU Data Request 2.3
The Company objects to this request as vague and ambiguous.Without waiving these
objections,the Company responds as follows:
For the Wyoming wind projects,the available transfer capability across the currently
constrained TOT 4A path is zero.However,since the wind projects are network
resources,opportunities for re-dispatch of generatingresources to take advantage of the
low-cost generationprovided by the facilities will be available.The definition of the path
is provided below.
The TOT 4A path is defmed as the sum of flows on the following230 kilovolt (kV)lines:
Riverton -Wyopo
Platte -Standpipe
Spence -Mustang
For the Marengo wind project in Washington,the available transfer capability across the
230 kV transmission system connected to the resource is zero.As above,since the wind
projects are network resources,opportunities for re-dispatch of generating resources to
take advantage of the low-cost generationprovided by the facilities will be available.
The Leaning Juniper and GoodnoeHills wind projects in Oregon and Washington do not
connect to PacifiCorp transmission.These projects connect to another transmission
service provider's transmission system and available capacity is not known.
17-035-39 /Rocky Mountain Power
August 11,2017
DPU Data Request 2.4
DPU Data Request 2.4
In reference to Mr.Hemstreet's testimony,lines 350-358,Mr.Hemstreet claims that the
32 turbines that won't be repowered will need new gear boxes.What is the average cost
per turbine (all in cost to replace the gear boxes)?What is the location by wind plant of
each of the 32 turbines?
Response to DPU Data Request 2.4
To clarify,the Direct Testimony of Company witness,TimothyJ.Hemstreet indicates
that of the 32 turbines that will not be repowered,10 of those turbines have gearboxes
that are estimated to require replacement during their remaining service life.As stated in
Mr.Hemstreet's Direct Testimony (page 340 through 344),the average all-in cost to
replace the gearboxes is $400,000.This cost figure also applies to the 10 gearboxes
among the 32 turbines that will not be repowered.Please refer to Confidential
Attachment DPU 2.4,which provides the all-in cost of recent gearbox replacements of
the scope described in Mr.Hemstreet's Direct Testimony.
The number of turbines not repowered by project location are as follows:
Numberof
Turbines Not
Project Repowered
Glenrock 1 8
Glenrock 3 6
Rolling Hills 18
TOTAL 32
Confidential informationis provided subject to Public Service Commission of Utah
(UPSC)Rules 746-1-602 and 746-1-603.
17-035-39 /Rocky Mountain Power
August l1,2017
DPU Data Request 2.5
DPU Data Request 2.5
But for the wind repowering,would the gearboxes need to be replaced?
Response to DPU Data Request 2.5
Yes.If this data request is related to DPU Data Request 2.4,the wind repowering project
does not affect whether or not the 10 gearboxes among the 32 turbines at the Glenrock /
RollingHills site that will not be repowered will need to be replaced.If the question is
intended to more broadly address the impact of repowering on the Company's estimates
of the number of gearboxes requiring replacement,the answer is also that the wind
repowering project does not affect the Company's estimates of the number of gearboxes
that will need to be replaced.
17-035-39 /Rocky Mountain Power
August l1,2017
DPU Data Request 2.6
DPU Data Request 2.6
Please state by wind farm how many gearboxes have been replaced to date at each
respective wind plant?
(a)Please provide the costs of each of the gearbox replacements at each wind plant with
supporting documentation.
(b)Please state when the Company was first made aware of the gearbox failure issues.
(c)Please state the name of the manufacturer and model of the defective gearboxes.
(d)Were any of the defective gearboxes under warranty or any type of service
agreement?If so,how long was the warranty coverage period for?
(e)Did the manufacturer or WTG supplier assume any cost and liabilityfor replacements
of the gear boxes?
Confidential Response to DPU Data Request 2.6
Please refer to the Company's response to DPU Data Request 1.3 subpart (5),specifically
Confidential Attachment DPU l.3 -2.
(a)Please refer to the Company's response to DPU Data Request 2.4;specifically
Confidential Attachment DPU 2.4.In addition,please refer to Confidential
Attachment DPU 2.6 -1,which provides costs for gearbox replacement projects for
models of the type described in the Direct Testimony of Company witness,Timothy
J.Hemstreet.
(b)The Company became aware that certain gearbox models were failing at a higher rate
than other models in the wind fleet in 2014.
(c)The manufacturers and model numbers of the impacted gearboxes are indicated in the
table below:
[CONFIDENTIALBEGINS)
[CONFIDENTIALENDS)
17-035-39 /Rocky Mountain Power
August 11,2017
DPU Data Request 2.6
(d)Yes.Please refer to Confidential Attachment DPU 2.6 -2,which provides the original
warranty terms for each project.
(e)Yes,when covered under warranty,the wind turbine generator (WTG)manufacturer
supplied the gearboxes,and in some cases parts exchange labor.Outside of the
warranty period,the WTG manufacturer did not assume any cost or liability.
Confidential information is provided subject to Public Service Commission of Utah
(UPSC)Rules 746-1-602 and 746-1-603.
17-035-39 /Rocky Mountain Power
August 11,2017
DPU Data Request 2.7
DPU Data Request 2.7
For each of the Company's wind plants,please provide the O&M costs by plant,
includingany repairs,for the past ten years.Please identify what the repair was,the cost,
why it was needed,when it was done,if the repair was covered under any type of
warranty or service agreement,and who was responsible for the repair costs.
Response to DPU Data Request 2.7
The Company objects to this request as requiring information not maintained in the
ordinary course of business or developmentof a special study.Without waivingthese
objections,the Company responds as follows:
The Company contracts the service and maintenance of its wind projects under
agreements that do not provide for the tracking of itemized costs associated with routine
service,maintenance and repairs performed within the defined contract scope.When
repairs performed under the service and maintenance contracts cannot address the
identified reliability or failure issues,these components are typically replaced under a
capital project if the components are no longer covered under the warranty terms of the
turbine supply contract.The Company therefore does not have the requested information
for each repair.For operations and maintenance (O&M)costs by wind project,please
refer to the Company's response to OCS Data Request 1.40 and Attachment OCS 1.40.
Please also refer to the Company's response to DPU Data Request 2.6.
17-035-39 /Rocky Mountain Power
August 11,2017
DPU Data Request 2.8
DPU Data Request 2.8
With respect to Mr.Hemstreet's testimony,lines 345-347,please identify the location of
the 230 gearbox models remaining in the Company's wind fleet that the Company
anticipates will need to be replaced.Please include the wind farm,the expected date of
failure,and the forecast costs to repair or replace.
Response to DPU Data Request 2.8
Please refer to the Company's response to DPU Data Request 1.3;specifically subpart (5)
and Confidential Attachment DPU 1.3 -2,which provides the locations of the 230
gearboxes the Company anticipates will need to be replaced.As indicated in the
Company's responses to DPU Data Request 2.4 and DPU Data Request 2.6,the average
all-in cost to repair each gearbox is $400,000 in 2016 dollars,which represents the
forecast costs for ongoing gearbox replacements.
The Company's estimate of the timing of failures for the 230 gearboxes is indicated in
Confidential Attachment DPU 2.8.The Company does not have an estimated date of
failure for each gearbox at each wind project.
Confidential informationis provided subject to Public Service Commission of Utah
(UPSC)Rules 746-1-602 and 746-1-603.
17-035-39 /Rocky Mountain Power
August l1,2017
DPU Data Request 2.9
DPU Data Request 2.9
In reference to Mr.Hemstreet's testimony,lines 381-387,with the warranty and service
agreements aside provided by the turbine manufacturers,has PacifiCorp completed any
reliability analysis or testing of the new equipment?If so,please provide that analysis.
Response to DPU Data Request 2.9
The Company is currentlyin consultation with a professionalthird party to obtain
technological reviews of the turbines proposed for repowering.The Company anticipates
receiving these third-partyreviews during August 2017.The Company will supplement
this response after the reviews are completed.The Company has not performed any
testing of the new equipment because it has not yet been installed.
17-035-39 /Rocky Mountain Power
August l1,2017
DPU Data Request 2.10
DPU Data Request 2.10
In reference to Mr.Hemstreet's testimony,lines 431-435,if the WindFREE and
WindINERTIA technologies don't work,what will the related estimated expenses be if
traditional technologiesare used in their place?
Response to DPU Data Request 2.10
The Company objects to this request as requiring information not maintained in the
ordinary course of business or development of a special study.
The Company has not analyzed the estimated expenses requested.
17-035-39 /Rocky Mountain Power
August 11,2017
DPU Data Request 2.11
DPU Data Request 2.11
In reference to Mr.Hemstreet's testimony,lines 570-581,please complete the attached
table (DPU Attachment 2.11),listing all permits or licensing of any type that the
Company will need to obtain to complete its wind repowering project (including
modifications to current permits or licenses),the status of obtaining each respective
permit,and the date the permit is obtained,etc.Please provide supporting documentation
for this response.Also,please update this response every two weeks with updated
information as it becomes available.
Response to DPU Data Request 2.11
Please refer to Confidential Attachment DPU 2.11 -1 and Attachment DPU 2.11 -2.
Given the limited permit approvalsrequired,and because repowering will be
implemented in 2019 and 2020,the Company does not anticipate that meaningful updates
will be available every two weeks.The Company will,however,provide an updated
response when new information becomes available.
Confidential information is provided subject to Public Service Commission of Utah
(UPSC)Rules 746-1-602 and 746-1-603.
17-035-39 /Rocky Mountain Power
August 11,2017
DPU Data Request 2.12
DPU Data Request 2.12
In reference to Mr.Link's testimony,lines 298-300,what is the cost to modify the LGIA
limits to gain the 20.8 percent output increase capability?Please provide a breakdown of
the costs by wind plant with supporting documentation.
Response to DPU Data Request 2.12
To modify the existing large generator interconnection agreement (LGIA)limits,system
impact and facility studies are required to evaluate the effects of the additional power
output on the transmission system.These studies are currentlyin process and will
determine the final system modification costs once completed.In addition to the
engineering studies,balance of plant (BOP)equipment,includingcollector circuits,
individual step-up transformers and main generator step-up transformers (GSU)at the
collector substations,is being evaluatedfor proper ratings to support the additional
capacity.
The Company has determined that the existing individual step-up transformers are
adequatelysized to support the output of the repowered wind turbine generators (WTG)at
projects where the new turbines do not have step-up transformers within the nacelle.Initial
calculations indicate that most of the collector circuit feeders can carry the additional
capacity,but the final determination of whether or not any segments need replacement
requires additional data gathering and assessment.
The existing 34.5 kilovolt (kV)feeder circuit breakers at all the wind projects are also sized
properly for the additional capacity and do not require replacement.
The existing GSUs,with the exception of High Plains /McFadden Ridge,are rated for the
increased capacity anticipated with the repowered WTGs.At this time,the Company
believes that the cooling system for the existing GSU at High Plains /McFadden Ridge can
be modified to increase its rating.
The Company will supplement this response as the transmission system and BOP studies
are completed.
17-035-39 /Rocky Mountain Power
August 11,2017
DPU Data Request 2.13
DPU Data Request 2.13
In reference to Mr.Link's testimony,lines 471-481,hypothetically,if the Dave Johnston
plant were retired today,would the Aeolus-to-Bridger/Anticlinetransmission segment
still be needed?Please explain and provide supporting documentation.
Response to DPU Data Request 2.13
The Company objects to this request as not reasonably calculated to lead to the discovery
of admissible evidence and as speculative.Without waiving these objections,the
Company responds as follows:
The Aeolus-to-Bridger/Anticlinetransmission segment is not at issue in this proceeding.
17-035-39 /Rocky Mountain Power
August 11,2017
DPU Data Request 2.14
DPU Data Request 2.14
In reference to Mr.Link's testimony,lines 471-481,hypothetically,if the Dave Johnston
plant were retired today,would the 230 kV Network Upgrades be needed?Please
explain and provide supporting documentation.
Response to DPU Data Request 2.14
The Company objects to this request as not reasonably calculated to lead to the discovery
of admissible evidence and as speculative.Without waiving these objections,the
Company responds as follows:
The 230 kilovolt (kV)Network Upgrades are not at issue in this proceeding.
17-035-39 /Rocky Mountain Power
August 11,2017
DPU Data Request 2.15
DPU Data Request 2.15
After the Dave Johnston retirement,years 2028-2050 (presumed useful life of new and
repowered wind generation),and in consideration of the contribution capacities of the
Dave Johnston facilities versus the proposed new and repowered wind generation,is it
assumed that there will be no further need to add generation resources to the transmission
that serves Dave Johnston and the wind facilities to meet load expectations?
Response to DPU Data Request 2.15
The Company objects to this request as not reasonably calculated to lead to the discovery
of admissible evidence and as speculative.
17-035-39 /Rocky Mountain Power
August 11,2017
DPU Data Request 2.16
DPU Data Request 2.16
For the period up to the retirement of the Dave Johnston plant,has the Company
considered other options to mitigate the transmission congestion as the new and
repowered wind comes on line?If so,please provide that analysis with complete
documentation.
Response to DPU Data Request 2.16
The Company objects to this request as not reasonably calculated to lead to the discovery
of admissible evidence and as speculative.Without waiving these objections,the
Company responds as follows:
The existing transmission constraints and the ability of new generationto interconnect to
the company's system in eastern Wyoming is not at issue in this proceeding.
17-035-39 /Rocky Mountain Power
August 11,2017
DPU Data Request 2.17
DPU Data Request 2.17
Please provide any analysis (in Excel format with intact formulae)that has been
performed,other than that already described by Mr.Link in his testimony,showing the
correlation of NPC between intermittent wind resources (NPC to recover intermittency)
and thermal generation.
Response to DPU Data Request 2.17
PacifiCorp's loads and resources must remain balanced,both over its entire system and in
each of its balancing authorityareas (BAA),after accounting for any imports or exports
between BAAs.
To the extent additional wind resources are added to the system,to remain balanced,
either other generationmust be dispatched down,market purchases must be reduced,or
market sales must be increased.If incremental access to markets is limited,thermal
resources are likelyto be dispatched down instead,since their marginal cost is higher
than the marginal cost of wind generation.As a result,a negativecorrelation between
wind generationand thermal generationis expected.
PacifiCorp has not performed any specific analysis on the correlation between
intermittent wind resources and thermal generation,but would note that,to the extent
wind resources are causing thermal resources to be dispatched down (as opposed to
supporting incremental market sales),those same thermal resources would thus have
capacity available to compensate for intermittencyin wind output.