20250611Staff Comments.pdf

RECEIVED
June 11, 2025
ADAM TRIPLETT IDAHO PUBLIC
DEPUTY ATTORNEY GENERAL UTILITIES COMMISSION
IDAHO PUBLIC UTILITIES COMMISSION
PO BOX 83720
BOISE, IDAHO 83720-0074
[phone]
IDAHO BAR NO. 10221
Street Address for Express Mail:
11331 W CHINDEN BLVD, BLDG 8, SUITE 201-A
BOISE, ID 83714
Attorney for the Commission Staff
BEFORE THE IDAHO PUBLIC UTILITIES COMMISSION
IN THE MATTER OF IDAHO POWER )
COMPANY'S APPLICATION FOR A ) CASE NO. IPC-E-24-45
CERTIFICATE OF PUBLIC CONVENIENCE )
AND NECESSITY FOR TWO BATTERY )
STORAGE FACILITIES ) REDACTED COMMENTS OF
THE COMMISSION STAFF
COMMISSION STAFF ("STAFF") OF the Idaho Public Utilities Commission
("Commission"), by and through its Attorney of record, Adam Triplett, Deputy Attorney
General, submits the following comments.
BACKGROUND
In June 2023, the Company issued a Request for Proposal ("RFP") for 2026 resources for
its identified capacity deficit in 2026, following the Oregon Procurement rules.
In 2024, the Company filed two cases for approval of resources with the Commission to
help meet its projected capacity deficit of 236 megawatts ("MW") in 2026.
In its comments filed in Case No. IPC-E-24-12, Staff believed the Market Purchase
Agreement was one of the least-cost least-risk resources selected in the RFP process and
STAFF COMMENTS 1 June 11, 2025

recommended approval.' In Final Order No. 36309, the Commission approved the Market
Purchase Agreement with capacity up to 200 MW.
In its comments in Case No. IPC-E-24-16, Staff was not confident that the selected 150
MW Boise Bench BESS project was least-cost. The Company's least-cost portfolio analysis was
a combination of three resources to fill the 2026 capacity deficit; however, the identified third
resource was no longer feasible. Therefore, Staff recommended approval of the Certificate of
Public Convenience and Necessity("CPCN") due to the capacity need and cost caps on the
project due to the uncertainty of the project being least-cost. 2 In Final Order No. 36389, the
Commission approved the request for a CPCN for the 150 MW Boise Bench BESS; however, the
Commission did not order cost caps for the project. The Company's two approved resources did
not fulfill the total identified 2026 capacity deficit of 236 MW.
The Company anticipated filing a third case for Commission approval for the Savion
Solar plus BESS project as identified in the 2026 Final Short List("FSL"). However, due to
permitting issues, the resource was no longer feasible and would not be online by June 1, 2026.
Application at 8.
The Company returned to its Initial Short List("ISL") and the FSL from the 2026 RFP
and was not able to secure a resource for the remaining deficit. This led the Company to
negotiate outside the 2026 RFP bids due to the time constraint of the capacity deficit.
On December 27, 2024, Idaho Power Company applied for a CPCN to acquire new
dispatchable energy storage that would provide a total of 100 MW of incremental nameplate
capacity through two battery energy storage system(`BESS")projects: (1) the Hemingway
Incremental 50 MW BESS ("Hemingway Incremental"), and(2)the Boise Bench 50 MW
Expansion BESS ("Bench Expansion") .
On February 3, 2025, the Commission issued a Notice of Application and Notice of
Intervention Deadline, setting a deadline for interested parties to intervene. Order No. 36454.
The Industrial Customers of Idaho Power, Idaho Irrigation Pumpers Association, Inc., and
Micron Technology, Inc. intervened. Order Nos. 36485 & 36492.
'IPC-E-24-12 Staff Comments at 4-5.
2 IPC-E-24-16 Staff Comments at 4-5.
STAFF COMMENTS 2 June 11, 2025

STAFF ANALYSIS
Staff has reviewed the Company's Application, responses to Production Requests and
supporting documentation. First, Staff believes the 50 MW Hemingway Incremental project is
cost effective and will help meet the 2026 capacity deficit. Therefore, Staff recommends the
Commission grant a CPCN for this project.
Second, Staff believes the Company will be resource sufficient in 2026 without the need
for the 50 MW Bench Expansion project given implementation of the 50 MW Hemingway
Incremental project, the previously approved 150 MW Boise Bench BESS resource, and the
initial overbuild planned for both projects. In addition, due to currently known import tariff
increases, Staff believes the 50 MW Bench Expansion project may not be cost-effective and
could put ratepayers at financial risk without significant effort to mitigate the cost. Therefore,
Staff does not recommend a CPCN for the Bench Expansion project.
Third, Staff recommends that the Company explore ways to mitigate the increased cost of
the 150 MW Boise Bench BESS project given the import tariffs.
Finally, Staff recommends that the Company keep the Commission appraised of the tariff
situation and the delivery status of the batteries for the overall Boise Bench BESS project.
Need for Capacity
After receiving Commission approval of the Market Purchase Agreement and the 150
MW Boise Bench BESS, and the fall through of the Savion project, the Company updated its
capacity position resulting in a 41 MW capacity deficit, which the Company is now seeking to
fill with two proposed BESS projects. Ellsworth Direct at 10-11. The update also included (1)
an updated load forecast, (2) inclusion of a wildfire risk factor, (3) an updated generation unit
outage schedule, and(4) the acceleration of the commercial operation date of the PVS 2, LLC,
solar facility.
Staff reviewed the new wildfire risk factor that was utilized in the calculation of the
updated capacity deficit. The Company stated, "Incorporating these wildfire risk inputs into the
RCAT model impacts the outage generation table used to calculate the Loss of Load
Expectation, thus impacting the annual capacity position calculation." See Company's response
to Production Request No. 1. Staff reviewed the Company's workpapers provided in its response
to Production Request Nos. 1 and 20 and believes that the wildfire risk factor is a reasonable
STAFF COMMENTS 3 June 11, 2025

input into the Company's assessment of its capacity position. Additionally, Staff reviewed and
re-validated the Company's capacity deficit with its supporting workpapers.3 Staff concludes
that the update to assumptions and inputs are reasonable and that a 41 MW capacity deficit in
2026 is valid.
Below is a summary table of previous cases which identified a 2026 capacity deficit and
how each resource selected has contributed to reducing the deficit. The last row of the table
displays the capacity deficit calculated in December 2024, and how the two proposed BESS
projects will reduce the capacity deficit.
Table 1: Summary of Capacity Position Changes
2026 Capacity Capacity
Document Load& Resource Position Position After
Changed Assumptions Before the Project the Project
2023 IRP(Sep'23) B2H online Jun '26 (22) MW N/A
2023 IRP B2H online Nov'26 (356) MW N/A
IPC-E-24-12 B2H online Nov'26 (236) MW (186) MW
2026 20OMW Powerex Updated load forecast
Market Purchase CBM =0 MW year-round
Valmy 261 MW online in '26
IPC-E-24-16 No change. Concurrent (186) MW (120) MW
2026 15OMW Boise BESS analysis as IPC-E-24-12.
IPC-E-24-45 B2H online Nov'27 (41) MW +7 MW
2026 2 x 50MW BESS Updated load forecast
extensions Wildfire risk factor
Delay hydro shutdown
Accelerate PVS2 to May 2026
50MW Summer Firm Energy
The Selected BESS Projects
Staff evaluated the selection of the 50 MW Hemingway Incremental and 50 MW Bench
Expansion projects based on the information contained in the initial filing. The Company had to
negotiate outside of the RFP to fmd additional resources to fill its anticipated 2026 capacity
deficit. After reviewing the remaining available alternatives of projects that were included in the
Company's RFP shortlists and with the 41 MW capacity deficit, Staff believed the two selected
3 Company's response to IIPA's Production Request No.25—Attaclunent.
STAFF COMMENTS 4 June 11, 2025

projects would be the most feasible solutions to resolve the 2026 capacity deficit, for the reasons
below:
1. Several of the projects that were included in the Company's ISL and FSL of the 2026
RFP were no longer feasible due to a range of issues preventing the projects from
meeting the required commercial operation date ("COD");
2. The inability to find additional short-term market purchases that would allow later
implementation of projects on the shortlist that could not meet the COD; and
3. The Company's ability to develop a solution to meet the 2026 deficit through a
combination of purchasing power from the market and cost-effectively expanding the
capacity of BESS projects that are already in operation and/or currently being
implemented with Commission authorization.
As mentioned in the Background section of these comments, the Savion Project, one of
the most promising FSL projects, was no longer feasible due to a denied permit. Staff then
discovered that other projects on both the ISL and the FSL were no longer viable because of the
inability for them to meet the desired COD in time to satisfy the 2026 capacity deficit or lack of
ability to interconnect to the system. Application at 8 and response to Production Request No. 9.
Because of the lack of options, Staff also investigated whether the Company could
acquire short-term market purchases, bridging the time gap allowing projects that could not meet
the required COD to be implemented later. As mentioned earlier, to meet the 2026 capacity
deficit, a 200 MW market purchase was selected through the RFP process and the Commission
approved it through Order No. 36309. The Company did find an additional 50 MW market
purchase opportunity for the summer months of 2026 to be delivered to the Company's border.
Ellsworth Direct Testimony at 14. However, the Company was not able to find any additional
market purchases that could satisfy the remaining 2026 capacity deficit. See response to
Production Request No. 11.
Through the RFP, the Company received a bid for a 100 MW Hemingway BESS project,
which was one of the top 10 most cost-effective resources to meet the 2026 deficit. This bid was
an additional amount of BESS capacity to be added to the existing 116 MW BESS at the
Hemingway substation. However, the Company initially screened out the bid because the
existing generator interconnection agreement only allowed an additional 50 MW of available
capacity. But due to the lack of feasible options, the Company was able to negotiate with a
STAFF COMMENTS 5 June 11, 2025

battery supplier for a 50 MW project instead of the 100 MW project in the original bid. Hackett
Direct Testimony at 26.
The capacity deficit of 41 MW was not completely remedied by the addition of the 50
MW Hemingway Incremental. To acquire the remaining capacity needed, the Company
negotiated additional equipment necessary to expand the Commission-approved 150 MW Boise
Bench BESS by another 50 MW, for a total of 200 MW.
50 MW Hemingway Incremental Project
The Company proposes to increase its Hemingway BESS capacity by building an
additional 50 MW segment. The 50 MW Hemingway Incremental project will not be directly
integrated with the existing 116 MW of Hemingway BESS; however, it will share the same point
of interconnection. The Company plans to operate the Hemingway Incremental project and the
existing BESS as a single asset.4
In the Company's response to Production Request No. 4, the estimated construction cost
is-. Additionally, the Company estimates O&M cost for the Incremental 50 MW to
be $1.5 million in the first year, increasing to $2 million over the remaining life of the project.
The O&M costs evaluated considered long-term service agreements, warranties, and
augmentation, as well as property taxes and property insurance.5 The Company executed a
Long-Term Service Agreement("LTSA") for the 50 MW Hemingway Incremental project in
December 2024.
Hemingway Incremental Project Overbuild
While the Company's modeling suggests that 50 MW of incremental Hemingway BESS
capacity is sufficient to offset a portion of the Company's capacity deficit, the actual beginning-
of-life capacity of the resource is slightly higher. In response to Production Request No. 8, the
Company explains that to satisfy a contractual performance guarantee of 50 MW or 200 MWh
for three years, the Hemingway Incremental project needs a beginning-of-life capacity of about
58 MW. This capacity can supply a total of 233 MWh across four hours. In the same response,
the Company provided a table showing the expected energy of the resources over 20 years. Staff
a See Company's response to Production Request No.2.
5 See Company's response to Production Request No.2.
STAFF COMMENTS 6 June 11, 2025

believes that it is reasonable to include some amount of excess capacity to account for initial
degradation. A reasonable amount of excess capacity allows for the measurement of actual
degradation in the first years of operation and lead time to acquire additional capacity. Staff
believes that the negotiated three-year capacity guarantee and associated beginning-of-life
capacity satisfies these needs. Staff has verified the degradation assumptions and believes that 8
MW of additional capacity aligns with the three-year guarantee.
Evaluation of Hemingway Incremental Project
Staff determined the levelized cost of the 50 MW BESS project is less than the levelized
cost of the original 150 MW Boise Bench BESS project that was approved through Order No.
36386. Furthermore, the levelized cost is lower than all the BESS projects that were selected for
the initial and final RFP short-lists. It is for these reasons that Staff believes the project should
provide incremental capacity at a cost comparable to the lowest cost BESS projects submitted for
bid through the RFP. Staff believes that the 50 MW Hemingway Incremental project is cost
effective and will help meet the 2026 capacity deficit.
CPCNfor Hemingway Incremental Project
Staff evaluated the Company's Application with Idaho Code § 61-526 and Rule 112.
Staff believes the Company has met the requirements of Idaho Code § 61-526 showing (1)
financial ability, (2) good faith of the Applicant, and(3)public need. Additionally, the Company
provided documents through its Application and through discovery that Staff believes satisfies
Rule 112. As Staff believes the project is cost effective and will contribute to the capacity
position, Staff recommends the Commission grant a CPCN for 50 MW of BESS capacity
through the Hemingway Incremental project.
50 MW Bench Expansion Project
The Company proposes a 50 MW expansion to the already approved 150 MW Boise
Bench BESS. The 50 MW Bench Expansion project is planned to be directly incorporated into
the approved 150 MW Boise Bench BESS project to be a single 200 MW BESS project at the
Boise Bench Substation and will share the same point of interconnection.6
6 See Company's response to Production Request No.2.
STAFF COMMENTS 7 June 11, 2025

In the Company's response to Production Request No. 3, the initial total estimated
construction cost of the 200 MW BESS was . The total 200 MW BESS cost
estimate was approximately more than the cost estimate provided in IPC-E-24-16
for the 150 MW Boise Bench BESS. The cost of the 50 MW Bench Expansion alone was
estimated to be-. However, as discussed below, the cost estimate for the 200 MW of
BESS has been updated to include a higher import tariff, significantly increasing the project cost
estimate. Staff discusses this cost change further in sections below.
Additionally, the Company estimates O&M for the 50 MW Bench Expansion to be $l.4
million in the first year, increasing to $1.9 million over the remaining life of the project. The
O&M costs consider long-term service agreements, warranties, and augmentation, as well as
property taxes and property insurance. The Company is pursuing negotiations for an LTSA for
the total 200 MW BESS at the Boise Bench substation.
Tariff Risks
On May 1, 2025, the Company reached out to Staff to discuss the financial impact of
increased U.S. Government import tariffs on goods from China. The Company alerted Staff that
the Boise Bench battery supplier,_, is a Chinese company and thus the product would be
subject to the new 145% import tariff and estimated this would increase the total project price by
approximately . See Company's response to Production Request No. 26. The
Company did not explicitly state this concern with the Hemingway Incremental Project;
therefore, Staff's analysis of tariff risks focused on the Boise Bench BESS 200 MW project.
In addition to alerting Staff about tariff risks, the Company discussed five alternatives it
was considering due to the increased project costs:
See Company's response to Production Request No.2.
STAFF COMMENTS 8 June 11, 2025

, which would leave the Company still needing additional
resources to meet its capacity deficit. As discussed above, the Company has no alternative
resources through the 2026 RFP and would need to look outside of it to secure additional
resources.
This would not be able to meet the
identified capacity deficit in 2026.
The Company concluded that alternative No. 4 was
The Company indicated it
favored alternative No. 5,
Since May 5, 2025, there have been trade negotiations which have resulted in the import
tariff being reduced to 30% for 90 days, effective May 14 through August 12, 2025.8 The
Company has since decided to request
- The Company estimated under
the reduced tariff. See Company's response to Production Request No. 27.
As this is an evolving situation, there is substantial financial risk to ratepayers due to the
uncertainty of the resource cost.
Cost Evaluation of the Boise Bench BESS
The import tariff rates could affect the cost effectiveness of the Boise Bench BESS
project. The Chinese supplier can deliver approximately. of the product during the 90-day
period. However, there is a risk that the. of batteries that cannot be delivered in this
timeframe may have a tariff rate much greater than the 30%rate, which could affect the
economics of the project. Staff believes the uncertainty of higher import tariffs may keep this
project from being cost-effective. Table 2 displays cost-estimate comparisons of the following:
the original 150 MW Boise Bench BESS project filed in Case No. IPC-E-24-16, the cost of the
150 MW Boise Bench BESS with the 50 MW Bench Expansion project using the initial cost
8 Company's response to Production Request No.27.;see also Nick Edser,"Markets rise as US an dchina agree to
slash tariffs,"BBC(May 12,2025),hitps://www.bbc.com/news/articles/czxOry7kdk5o.
STAFF COMMENTS 9 June 11, 2025

estimate in this case, and the updated cost estimate with the new tariffs. As can be seen in the
table, if 70% of the batteries are subject to a 145% tariff rate, the total cost of the full 200 MW of
BESS capacity will increase from
Table 2: Cost Estimate Comparisons
PC-E-24-45 I PC-E-24-45
150 MW Boise Bench 150 MW Boise Bench
Scenario IPC-E-24-16 BESS w/50 MW BESS w/50 MW
Expansion Expansion
(Tariff Assumed at Filing) (Current Tariff)
Capacity 150 MW 200 MW 200 MW
Percentage of Deliveries at Tariff o 0 0
100/ 100/ 30/ 70/
Rate
Tariff Rate 0% 7.50% 30% 145%
Manufacturer Supplied BESS
Equipment
Other Construction Costs
Total Project Cost
Project Cost: $/ MW
Capacity Evaluation of the Boise Bench BESS
As discussed earlier, Staff analyzed the Company's capacity position. Following the May
1, 2025, meeting with the Company, Staff inquired what the capacity position would be with and
without the 200 MW Boise Bench BESS. In the Company's response to Production Request No.
24, the Company updated its capacity position again. Without the 200 MW Boise Bench BESS
and the 50 MW Hemingway Incremental project included, the system has a 29 MW capacity
deficit. With the 200 MW Boise Bench BESS and the 50 MW Hemingway Incremental project,
the system has a surplus capacity of 46 MW.
Although the Company has merged the two Boise Bench BESS capacities together in this
case, the Commission has only provided a CPCN for 150 MW of BESS capacity. By linearly
interpolating between these two points, Staff concludes that the 150 MW BESS would enable a
surplus system capacity of about 27 MW. In other words, Staff believes the Company is likely
able to maintain reliable service through 2026 with the already approved 150 MW Boise Bench
STAFF COMMENTS 10 June 11, 2025

BESS without the 50 MW Bench Expansion. The table below depicts the capacity position in
each scenario.
Table 3: Updated Capacity Positions
Load&Resource Capacity Position
Document Changed Assumptions After the Project
IPC-E-24-45 Resource Stack without (29)MW
Production Request No. 200 MW Boise Bench BESS
24:
All other resource Resource Stack with 200 +46 MW
assumptions remained MW Boise Bench BESS
the same as described in
the Application Resource Stack with 150 +27 MW
MW Boise Bench BESS
The Company signed the supply agreement in July 2024 for 200 MW prior to
Commission approval. The Commission only approved a Company CPCN for 150 MW BESS
capacity at that point. At the time of Commission approval in Order No. 36389, the tariff
circumstances were not known. However, m this case, tariff impacts to ratepayers are known
and ratepayers would bear all the risk of additional cost increases. Staff is opposed to ratepayers
paying for extra capacity length and bearing all the risk of increased tariffs. Therefore, Staff
believes that the already approved 150 MW of Boise Bench BESS puts the Company into a
capacity sufficient position for 2026 without the need for the additional 50 MW Bench
Expansion. However, the Bench Expansion could be needed to fill deficits in 2027 and beyond,
which can provide the Company with additional time to explore ways to minimize the cost,
including some of the five alternatives that the Company presented to Staff on May 1, 2025.
Furthe more, because the tariffs also have a significant effect on the cost of the 150 MW
Boise Bench BESS project, Staff recommends that the Company explore ways to mitigate the
cost of the tariffs. For example, because the infrastiuchue of a BESS is scalable and can be
implemented in an incremental way, Staff recommends the Company explore ways to
incrementally delay taking delivery of batteries to take advantage of potential more favorable
trade conditions. This would include exploring the renegotiation of delivery delays with its
battery supplier coupled with efforts to find other sources of capacity including, but not limited
to, short-term market purchases, incremental demand response,potential short-term curtailment
STAFF COMMENTS 11 June 11, 2025

contracts with large customers, and/or finding additional capacity from the Company's existing
resources, to enable the delay. Staff further recommends that the Company be prepared to
demonstrate that it has taken these and other possible steps to mitigate the cost to customers with
documented analysis of the costs and risks of each potential effort.
CPCNfor the Bench Expansion Project
As mentioned above, there are substantial financial risks of the overall Boise Bench
BESS project due to the uncertainty of the import tariffs. Additionally, Staff s analysis shows
there is not a need in 2026 for the additional 50 MW Bench Expansion project. Because of these
reasons, Staff does not recommend the Commission grant a CPCN for the 50 MW Bench
Expansion project at this time.
Staff is aware the Company faces continued load growth and has identified capacity
deficits in 2027 and beyond, although the capacity positions change each time the Company's
models are updated. Staff encourages the Company to evaluate all various options to resolve its
deficits, including this resource if prices stabilize and become cost-effective. Staff also
recognizes that the multi-year RFP process has proven to have significant challenges for the
Company to acquire resources and is discussing this issue in Case No. GNR-E-25-01.
Boise Bench Excess Capacity
As described in further detail above, Staff believes that the entirety of the 50 MW
expansion is not needed for 2026. However, should the Commission reject Staff's
recommendation to deny the CPCN for the 50 MW Bench Expansion, Staff believes a portion of
this project may be excessive beyond the requested capacity.
Similar to the Hemingway Incremental project, the actual beginning-of-life capacity of
the 50 MW Bench Expansion project is also slightly higher. In response to Production Request
No. 7, the Company explains that to satisfy a contractual three-year performance guarantee for
200 MW or 800 MWh, the total Boise Bench BESS needs a beginning-of-life capacity of about
222 MW. Approximately 55 MW of this capacity is associated with the expansion. The total
capacity can supply a total of 887 MWh across four hours. Approximately 221.7 MWh of this
supply is associated with the expansion.
STAFF COMMENTS 12 June 11, 2025

In the same response, the Company provided a table showing the expected energy of the
resources over 20 years. This table shows that the expected energy of the Boise Bench BESS
resource at the end of year three is approximately 829 MWh and does not drop below the
guaranteed energy amount until after year five. Staff believes this indicates that the total Boise
Bench resource may be overbuilt by 29 MWh or about 7 MW. Applying this degradation rate to
the 55 MW of the expansion,beginning-of-life capacity suggests that the expansion may be
excessively overbuilt by approximately 2 MW. Staff believes it is appropriate to include some
amount of excess capacity to account for degradation during the first years of operation;
however, excessive overbuild capacity is not needed to satisfy the capacity deficit identified in
the Company's Application.
Staff applied the $/MW levelized cost of the initial Boise Bench BESS project construction
cost estimate to the 7 MW of expansion overbuild to estimate its value. Staff's calculation
suggests that- of the total project cost is being incurred before needed. - of
this amount is associated with the 50 MW expansion. These estimates are based on the
Company's initial cost estimate; therefore, the impact of import tariffs may increase the value of
the excess capacity.
Future Recovery
In its Application, the Company does not request ratemaking treatment for the two BESS
additions. Generally, this is reasonable because a CPCN only grants the decisional prudence
required to begin the projects and does not guarantee recovery of any project costs. Accordingly,
Staff will review the prudence of all project costs in a future recovery proceeding.
If the Commission grants a CPCN for the Bench Expansion project, the project costs
incurred for any purpose beyond what is supported by the CPCN may not benefit from the
decisional prudence of this filing. Specifically, should the Commission opt to approve the CPCN
for the 50 MW Bench Expansion project, Staff believes that 2 MW of excess capacity for the
expansion project is not needed to maintain capacity of the resource in the near term and that the
associated expense of- should not be included when the Company initially seeks
recovery.
STAFF COMMENTS 13 June 11, 2025

BESS Fire Risk
There are concerns about the fire risks that a BESS may pose. Staff believes that the risk
of a BESS fire occurring is low, but the potential consequences if one does occur are high.
On January 16, 2025, the largest BESS system in the world caught fire, the 750 MW
Vistra system, located in Moss Landing, California.9 The fire caused the evacuation of 1,500
residents, continued burning for several days and 300 MW of BESS capacity was destroyed.'0
On October 2, 2023, the Company's Melba BESS caught fire,burning on and off until
October 5, 2023.11 These are two of over 50 BESS fires that have occurred around the world
since 2021. Over 30 additional large-scale battery fires (not associated with utility BESSs) have
occurred during the same period.12
There are several factors that distinguish BESS fires from typical fires, which pose
additional risks to ratepayers and the public. First, some BESS fires have started
"spontaneously"due to an unknown internal failure allowing thermal runaway to the point of
combustion. Second, once a BESS fire starts, it is extremely difficult to extinguish due to the
intrinsic stored chemical energy. This means the fire may burn a long time and it is more likely
to spread, extending the damage. Third, lithium-ion batteries emit toxic smoke, which is an
immediate hazard to nearby people. Also, the toxic smoke residue presents a longer-term
environmental hazard. Because of these unique hazards, a BESS fire presents meaningful risks
to ratepayers, in the form of investment losses and damage liability.
However, the Company has proposed reasonable steps to mitigate these risks. Staff
agrees with the Company's assessment that codes and standards are rapidly evolving, and the
risk of a battery fire is low and getting lower. Response to Production Request No. 12. Staff
also notes that"[t]he Company has engaged with a nationally recognized consultant, Fire & Risk
Alliance to support safety planning, design, and first responder training." Id. The Company also
asserts that its installation design will include features to isolate battery units from one another to
minimize the risk of fire spread. Id. Finally, the Company states that should a BESS be
destroyed by fire, the Company has recourse to contract warranties and traditional insurance,
which may mitigate the financial impact to ratepayers. Response to Production Request No. 14.
9 hit2s:Hctif.org/news/fire-largest-bess-us-led-evacuation-1500-residents-near-moss-landing-fire-left-burn-out
10 h!Ws:Hstora eg wiki.epri.com/index.php/Failure_Event_-_US,_CA,_Moss_Landing -_16_Jan_2025
"Response to Production Request No.13,Attachment at 3.
12 h!Ws:Hstora eg wiki.epri.com/index.php/BESS_Failure_Incident Database
STAFF COMMENTS 14 June 11, 2025

Given these assurances by the Company, Staff believes that the risk to ratepayers from a
BESS fire should be low; therefore, this type of resource is a reasonable option to meet system
needs. However, Staff recommends that the Company continue to carefully evaluate the fire risk
for this project and future BESS projects.
STAFF RECOMMENDATION
Staff recommends the Commission:
1. Grant a CPCN for the 50 MW Hemingway Incremental project to meet the 2026
capacity deficit;
2. Deny a CPCN for the 50 MW Bench Expansion project;
3. Direct the Company to explore ways to mitigate the cost of tariffs for the 150 MW
Boise Bench BESS as discussed above; and
4. Direct the Company to keep the Commission appraised of the tariff situation and the
delivery status of the batteries for the overall Boise Bench BESS project.
Respectfully submitted this 1 1 th day of June 2025.
Adam riplett
Deputy Attorney General
Technical Staff: Kimberly Loskot
Jason Talford
Matt Suess
Seungjae Lee
L•`Utility`UM ISC\COM M ENTS�I PC-E-24-45 Commcnts-Rodectcd.docx
STAFF COMMENTS 15 June l 1, 2025

CERTIFICATE OF SERVICE
I HEREBY CERTIFY THAT I HAVE THIS 1 1TH DAY OF JUNE 2025, SERVED THE
FOREGOING REDACTED COMMENTS OF THE COMMISSION STAFF, IN CASE NO.
IPC-E-24-45, BY E-MAILING A COPY THEREOF, TO THE FOLLOWING:
DONOVAN E. WALKER TIM TATUM
IDAHO POWER COMPANY IDAHO POWER COMPANY
PO BOX 70 PO BOX 70
BOISE ID 83707-0070 BOISE ID 83707-0070
E-MAIL: dwalker a,idahopower.com E-MAIL: ttatum a idahopower.com
dockets(a,idahopower.com
Industrial Customers of Idaho Power: Industrial Customers of Idaho Power.
Peter J. Richardson Dr. Don Reading
Richardson Adams, PLLC 280 S. Silverwood Way
515 N. 271h St. Eagle, ID 83716
Boise, ID 83702 E-MAIL: dreading(i�mindspring.com
E-MAIL: peter&richardsonadams.com
Micron Technology, Inc.: Idaho Irrigation Pumpers Assn, Inc.:
Austin Rueschhoff Eric L. Olsen
Thorvald A. Nelson Echo Hawk & Olsen, PLLC
Kristine A.K. Roach P.O. Box 6119
Holland & Hart, LLP 505 Pershing Ave., Ste. 100
555 171h St., Ste. 3200 Pocatello,ID 83205
Denver, CO 80202 E-MAIL: elo(w_ echohawk.com
E-MAIL: darueschhoff(ct hollandhart.com
tnelson u.hollandhart.com
karoachQhol landhart.com
aclee c,hollandhart.com
Idaho Irrigation Pumpers Ass 'n, Inc.:
Lance Kaufman, Ph.D.
2623 NW Bluebell Place
Corvallis, OR 97330
E-MAIL: lance(a,aegisinsi hg t.com
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PAT 4MIRDAN, S RETARY
CERTIFICATE OF SERVICE