IEEE Electrification - December 2021 - 44

would be about US$5 million more
per year than a 25-MW CT, the ROM
analysis found that the higher operational
value of the battery reduced
the differential to about US$2 million
per year. Though the CT
remained the lower-cost option, the
net cost study indicated the price
point at which energy storage assets
would be cost competitive in future
planning. (PGE's 2016 IRP is available
at https://downloads.ctfassets.net/41
6ywc1laqmd/1y737MdERELNLNyWA
W8bw2/3f150507210f0fba46276de38c
0afdfa/2016-irp.pdf.)
The primary benefit of the net cost
When energy storage
is used as a capacity
resource for
reducing peak
needs, as peaks
become flatter,
incremental storage
investments must
have longer
approach is that it can be implemented
with minimal disruption. By identifying
the subhourly benefits of a
resource that other IRP models do not
capture, those costs can be levelized
and deducted from the resource's assumed costs or
applied as an added value to its modeled output. In this
way, the net cost approach complements, rather than displaces,
a utility's existing IRP models.
A secondary benefit of the net cost approach is that it
can be implemented at minimal cost. PGE's in-house
development of the ROM tool was relatively complex
and costly, but multiple entities have since developed
free energy storage modeling tools for use by utilities
and other parties. The Pacific Northwest National Laboratory's
Energy Storage Evaluation Tool (https://eset
.pnnl.gov) and the Electric Power Research Institute's
Storage Value Estimation Tool (www.storagevet.com) are
two such examples.
durations to reduce
the remaining peak.
growing number of states, municipalities
and customers adopt clean
energy goals.
Whereas PGE used the ROM as an
external model for one-off analyses to
inform other IRP models in the 2016
IRP, the 2019 plan fully integrated the
ROM into the process, using it to calculate
a flexibility value-a more
detailed version of the operational
value used in the 2016 IRP-for all
resource options. The ROM calculated
the flexibility value by modeling the
system a week at a time with three
levels of temporal resolution: hourly
unit commitment on a day-ahead
basis, followed by 15-min unit commitment
on an hour-ahead basis, and
concluding with 15-min real-time dispatch.
By stepping through different
levels of granularity, with unit commitments
made in each period preserved in subsequent
periods, PGE was able to drill down into its real-time ancillary
service needs with high resolution and select the optimal
resources to meet them.
But PGE also looked at its flexibility needs at the hourly
PGE's 2019 IRP: Valuing Flexibility
PGE's 2019 IRP established what is an apparent first for a
modern IRP by selecting a preferred portfolio that included
both new PSH and long-duration battery storage. This
IRP was also among the first in the United States to
select dispatchable, behind-the-meter (BTM) energy storage
in its preferred portfolio. These landmark selections
were the result of three significant changes that impacted
the way energy storage was analyzed: preventing the
model from selecting new GHG-emitting generators,
enhancing and integrating the ROM model into the core
planning process, and including BTM energy storage as a
resource option.
The no-GHG constraint was a policy decision that
PGE made based on state policies and customer preferences.
But the model's selection of 200 MW of PSH is
indicative of future investments in long-duration energy
storage that will be necessary to achieve decarbonization
goals, and similar scenarios may be useful for
other utilities to analyze long-term system needs as a
44
IEEE Electrification Magazine / DECEMBER 2021
level and found high-demand periods on winter mornings
in which its resources would be stretched thin over several
hours and the lack of flexibility could create reliability challenges.
This finding created a higher flexibility value for longer-duration
batteries, which drove PGE's selection of
37 MW of 6-h batteries in the preferred portfolio.
The final change in PGE's 2019 IRP was the inclusion of
utility-controlled BTM storage as a resource option. The
change was prompted by an external study that the utility
commissioned to forecast customer adoption of various
distributed energy resources. The study concluded
that customer uptake of energy storage technologies
would be limited by economics and technological familiarity,
but that if the utility were to offer incentives in
exchange for operational control of customer-sited storage,
then customers would be more likely to invest in the
technology (Navigant 2019). The study also quantified the
benefit streams of the devices to the utility and the customer,
allowing PGE to calculate an incentive level to customers
based on the value to the utility and then model
that incentive as an asset cost in the IRP. With a full
accounting of both the costs and benefits of this resource,
the system expansion model identified a cost-effective
level of 4 MW of dispatchable BTM energy storage by
2025. (PGE's 2019 IRP is available at https://downloads.
ctfassets.net/416ywc1laqmd/6KTPcOKFlLvXpf18xKNseh/
271b9b966c913703a5126b2e7bbbc37a/2019-Integrated
-Resource-Plan.pdf.)
Because it utilizes a fully integrated, granular model
for determining the flexibility value of all resource

https://downloads.ctfassets.net/416ywc1laqmd/1y737MdERELNLNyWAW8bw2/3f150507210f0fba46276de38c0afdfa/2016-irp.pdf https://downloads.ctfassets.net/416ywc1laqmd/1y737MdERELNLNyWAW8bw2/3f150507210f0fba46276de38c0afdfa/2016-irp.pdf https://downloads.ctfassets.net/416ywc1laqmd/1y737MdERELNLNyWAW8bw2/3f150507210f0fba46276de38c0afdfa/2016-irp.pdf https://downloads.ctfassets.net/416ywc1laqmd/1y737MdERELNLNyWAW8bw2/3f150507210f0fba46276de38c0afdfa/2016-irp.pdf https://eset.pnnl.gov https://eset.pnnl.gov http://www.storagevet.com https://downloads.ctfassets.net/416ywc1laqmd/6KTPcOKFlLvXpf18xKNseh/271b9b966c913703a5126b2e7bbbc37a/2019-Integrated-Resource-Plan.pdf https://downloads.ctfassets.net/416ywc1laqmd/6KTPcOKFlLvXpf18xKNseh/271b9b966c913703a5126b2e7bbbc37a/2019-Integrated-Resource-Plan.pdf https://downloads.ctfassets.net/416ywc1laqmd/6KTPcOKFlLvXpf18xKNseh/271b9b966c913703a5126b2e7bbbc37a/2019-Integrated-Resource-Plan.pdf https://downloads.ctfassets.net/416ywc1laqmd/6KTPcOKFlLvXpf18xKNseh/271b9b966c913703a5126b2e7bbbc37a/2019-Integrated-Resource-Plan.pdf

IEEE Electrification - December 2021

Table of Contents for the Digital Edition of IEEE Electrification - December 2021