In the August 30, 2023, meeting of the Planning Advisory Committee (PAC), MISO shared initial thoughts on this issue for feedback. In your feedback, respondents are asked to consider the questions on slide 5 of the presentation and to weigh in on the following:
Feedback is due by September 15.
Clean Grid Alliance Comments on MISO’s Presentation to the Planning Advisory Committee on Storage Transmission Service Requirements
Sept 15, 2023
Clean Grid Alliance appreciates the opportunity to provide input to MISO and the Planning Advisory Committee on MISO’s questions to stakeholders, offered at the August 30th, 2023 Planning Advisory Committee meeting regarding Transmission Service Requirements for Energy Storage.
-Should storage resources be allowed to utilize NITS to charge?
Response: Storage resources should be allowed to utilize both NITS and short term, non-firm point to point transmission service for charging. Without both options, utility storage will be significantly financially advantaged in the market as NITS service essentially costs nothing at all, and is not available for independent power producers. A balance can be achieved by allowing for both short term non-firm point to point and NITS to be utilized.
•Should a storage resource be allowed to utilize non-firm transmission service to charge?
Response: Absolutely, yes. This is the service MISO had indicated to stakeholders would be available for use including in its 841 filing and informational responses, up to May 2, 2023, when this concept was first introduced to stakeholders. Not requiring long term firm point to point transmission service was the justification MISO offered for needing to add language to BPM 15 to require charging in the GIP DPP shoulder studies as MISO a “study gap” existed between the two types of service.
Additionally, we would like to add that that projects directed to charge by MISO for energy or ancillary services should not pay any transmission services charges. As it pertains to charging directed by MISO for energy arbitrage, this would recognize that charging during periods of high supply and low demand is a critical reliability service that mitigates system ramping challenges and helps avoid negative pricing and curtailment during oversupply. This is a practice already employed in CAISO and SPP.
In general, owners of ESRs should not be required to pay for transmission service that they do not use, as it will restrict ESRs from coming online in MISO’s footprint where they can reduce congestion and provide other benefits and significant cost savings to load.
Storage has a wide range of uses, and a 2 hour battery and long-duration storage serve different functions and may require different services. Hence, all types of TSR requests should remain available as the function and needs for storage can vary significantly and may change over time.
A requirement for Firm, Long-Term point-to-point transmission service violates the directive of FERC Order 841 that “require[s] each RTO and ISO to revise its tariff to establish a participation model consisting of market rules that, recognizing the physical and operational characteristics of electric storage resources, facilitates their participation in the RTO/ISO markets”[1] (emphasis added). Onerous and unreasonable requirements need not violate a specific provision of the Order to violate its overarching goal. Facilitation of ESRs, in this case, means they should have access to the form of Transmission Service that best fits the intended use of a given project, including short-term non-firm and NITS, when applicable.
•What is the appropriate transmission service duration requirement for a charging storage resource (e.g. hourly, daily, monthly, yearly, five year with roll over rights)?
Response: Storage should be able to choose which duration suits it best. This will ultimately allow MISO load to be served in the most cost efficient manner.
As mentioned above, projects directed to charge by MISO for energy or ancillary services should not pay any transmission services charges. As it pertains to charging directed by MISO for energy, this would recognize that charging during periods of high supply and low demand is a critical reliability service that mitigates system ramping challenges and helps avoid negative pricing and curtailment during oversupply. This is a practice already employed in CAISO and SPP.
•For queued storage projects not yet online, how soon may transmission service be requested and/or procured (e.g. while in the queue, once a GIA a signed)?-Response: While in the queue.
•What is the applicability of transmission service requirements for storage relative to behind-the-meter or distribution-connected resources?
Response: Energy Storage connected to either the transmission system or distribution system, when directed by MISO to charge for energy or ancillary services, should not pay transmission service.
•Do storage resources that only charge from a co-located resource require transmission service to charge?
Response: Absolutely not. There is no justification for such a requirement.
Key Capture Energy (KCE) thanks MISO and its staff for taking stakeholder feedback on the important topic of transmission service for grid-charging Energy Storage Resources (ESRs). KCE supports providing flexibility to ESRs in procuring transmission service as these facilities will not persistently withdraw from the grid but will alternate between charging, idling, and injection. Additionally, as further described below, such flexibility is necessary because ESRs are not required to secure transmission service in certain circumstances, namely, when the ESR is providing a service.
KCE addresses each question posed by MISO at the August 31, 2023 PAC meeting below. KCE would also like to specifically raise MISO’s current standard of only exempting ESRs from procuring transmission service that are providing Regulating Service or Down Ramp Capability. Order 841 indicated that ESRs “should not be charged transmission charges when they are dispatched by an RTO/ISO to provide a service” (Order 841, paragraph 293). However, the Order provided latitude to individual RTOs to define what such “services” might be. Other RTOs consider ESRs that are charging in response to central dispatch and/or carrying (or qualified for) other ancillary services to be “providing a service”, and hence exempt from assessment of transmission charges. KCE would welcome a conversation through this process to review MISO’s current standard and if any modifications (e.g., expansion of exemptions from transmission charges) should merit consideration.
Clearway Energy, Invenergy, and Pine Gate Renewables (“Joint Commenters”) appreciate the opportunity to provide feedback on the MISO August PAC presentation regarding Transmission Service Requirements for Charging Electric Storage Resources. Joint Commenters recommend that any changes to transmission service requirements for charging storage resources acknowledge and align with the principles outlined below.
I. MISO’s Business Practice Manuals do not Require Long-Term Firm Point-to-Point Transmission Service and MISO should not interpret them that way.
In revisions to the Transmission Settlements Business Practice Manual, BPM-012, that became effective January 1, 2023, MISO specified that pursuant to Order No. 841, Energy Storage Resources become load when charging and that “the owner of the [Electric Storage Resource] must elect to serve the load with Point-to-Point Transmission Service.” Contrary to MISO staff’s subsequent interpretation, no provision of BPM-012 specifies the duration or firmness of point-to-point service required.
II. MISO should clarify that Electric Storage Resources have optionality in meeting obligations for transmission service.
Storage resources are a uniquely diverse class of technologies with a multitude of durations, interconnection configurations, and ownership structures. Any narrow prescription for transmission service risks unduly imposing existential disadvantages on arbitrary groups of storage resources. Unlike conventional load, Electric Storage Resources can curtail their demand for electricity in response to real-time price signals. There is no need to require long-term, firm point-to-point transmission service or to prescribe any specific prohibitions on the type of transmission service that storage resources can elect in MISO.
III. Overly prescriptive Transmission Service Requirements for Electric Storage Resources risk violating Order No. 841, which permitted the RTOs to apply transmission service requirements in a way that was comparable to existing requirements for load. To the extent storage resources are distinguishable from other types of load, Order No. 841 permitted RTOs to exempt electric storage resources from transmission charges altogether and did not permit RTOs to impose more burdensome transmission requirements.
In Order No. 841, the Commission found that it may be appropriate for an RTO to require storage to pay transmission charges. However, the Commission explicitly linked transmission service charges for storage to those that also apply to load (Order No. 841 at P 292). On rehearing, the Commission discussed at length whether storage resources should be assessed transmission service charges at all (Order No. 841-A at PP 108, 120-121). While the Commission found that it may be appropriate to apply “applicable transmission charges” to storage as far as charging may constitute load, it did not state that the RTO could prescribe certain levels of transmission service above and beyond what is already required for comparable load. In this case, MISO would be instituting a blanket requirement for a higher level of transmission service for storage resources than currently applies to comparable load and without regard to varying intended uses for storage resources that may call for other levels of transmission service. Such prescription is not permitted in Order No. 841.
Moreover, the Commission found that in certain circumstances storage charging may be exempt from transmission charges. Customers who purchase wholesale power are already paying for transmission service and would effectively have to pay for it twice if their power came from a storage resource that had itself paid for transmission service when charging. This treatment significantly impairs the value proposition of energy storage in MISO and could hamper deployment of a badly needed dispatchable resource class across the footprint. Joint Commenters would support revisiting this treatment of energy storage charging in the tariff in a subsequent Issue Submission.
IV. If Storage Resources are studied to be charging in the interconnection queue, those resources should be guaranteed charging capability if the identified network upgrades are completed.
Under MISO’s current rules, Electric Storage Resources are studied at 100% charging during the shoulder peak case if the resource both (1) enters the queue at DPP 2022 and later and (2) indicates the need to charge when submitting an interconnection request. Studying an Electric Storage Resource as a load asset in the generator interconnection queue without g transmission service creates a charge without any clarity behind the service being provided. There are Electric Storage Resources in the MISO queue that have higher network upgrade results when studied as charging as compared to non-grid-charging resources. When an interconnection customer is assigned network upgrades, it must be clear to the interconnection customer why the upgrade is needed and how their resource benefits from it.
Stakeholders have previously raised confusion and concern over the seemingly duplicative nature of these studies. Joint Commenters would recommend that MISO either add to this issue scope or open a separate issue streamlining the studying and assignment of transmission service to storage resources.
Joint Commenters thank MISO for their time and look forward to future collaboration on this topic.
SB Energy appreciates the opportunity to provide comments on the MISO PAC topic Transmission Service Requirements for Charging Electric Storage Resources (Issue PAC-2023-2).
SB Energy would like to submit the following comments:
MISO should provide flexibility for storage resources to obtain any type of Transmission Service available per Module B of MISO Tariff i.e., to utilize non-firm, firm, short-term, long-term Point-to-Point (PTP) Transmission Service or Network Integration Transmission Service (NITS) depending on resource owner’s needs.
Note that MISO added the below footnote 9 in BPM-015 (Generator Interconnection) after several discussions at PSC, IPWG, PAC with the intention that Interconnection Customer (IC) has the option to choose whichever type of Transmission Service that the IC would like to obtain. These discussions were included in the 2019/2020 stakeholder PSC/IPWG/PAC presentations; however, MISO website does not store the presentations from that timeframe. BPM-015 or Attachment X does not have any requirement stating that Firm Long-Term TSR is required for storage resource to charge from the grid.
9 Storage requests need Transmission Service if they will be charging from the Transmission System; GIA does not grant Transmission Service. In order to obtain any type of Transmission Service for charging from the Transmission System, the IC will have to seek service as a Transmission Customer.
Note that HVDC Service is defined as follows in Attachment X “HVDC Service shall mean Firm and Non-Firm Point-To-Point Transmission Service provided by Transmission Provider on HVDC Facilities pursuant to Section 27A of the Tariff.” Attachment GGG requirements were presented to MISO stakeholders at PAC on 2/14/2018 assuming that MHVDC Customers can utilize firm or non-firm transmission service depending on MHVDC customer needs. Based on these, Firm and Non-Firm PTP Transmission Service is available for HVDC Facilities. It is not fair to storage resource owners if the same types of services available to HVDC customers are not offered.
The generator interconnection process (Definitive Planning Phase (DPP) Process) for a storage resource includes an analysis of storage charging at 100% (thermal, voltage, stability, short circuit) and the IC will have to pay for any network upgrades identified from these studies. Even though IC’s are paying for these upgrades in the generator interconnection process, the storage resources are not receiving any sort of Transmission Service. On top of this, if the storage resource is requesting a long-term PTP Transmission Service and if there are upgrades identified from that study, then IC’s are tagged with additional upgrades again. This additional stringency in the studies could be a hindrance for storage resources to get interconnected to the MISO grid. MISO should not repeat the same type of analysis and propose upgrades in both generator interconnection study and Transmission Service study for a storage resource charging from the grid. Storage charging from the grid and any “new load” connecting to the MISO grid should be treated the same and should have a similar set of studies. It appears that storage charging from the grid is going through additional studies than a new load.
There should be flexibility on the transmission service duration requirement due to the wide variety of technology advancements and no restrictions should be applied to storage resources (i.e., hourly, daily, monthly, yearly, five years with roll over rights etc. should be allowed per resource owner’s needs).
Storage projects should be allowed to request transmission service even when they are in queue or after GIA is signed.
Storage resources that only charge from a co-located resource should not require transmission service to charge because these resources are not charging from the MISO grid.
In summary, MISO should allow storage resources to utilize non-firm, firm, short-term, long-term Point-to-Point (PTP) Transmission Service or Network Integration Transmission Service (NITS) based on the above reasonings noted in Attachment X and BPM-015. Moreover, MISO should propose changes to the generator interconnection and/or Transmission Service study processes to avoid redundant studies and upgrades tagged to storage resources charging from the grid.
Thank you for the opportunity to provide feedback and MISO’s consideration of the comments.
Transmission Owners Comments on Transmission Service Requirements for Charging Energy Storage Resources
September 15, 2023
In the August 30, 2023 meeting of the Planning Advisory Committee (PAC), MISO shared initial thoughts on Transmission Service Reservation requirements for charging Energy Storage Resources, and posed the questions below for Stakeholder feedback.
• Should storage resources be allowed to utilize NITS to charge?
When ESRs are charged from the Wholesale system to serve Network Load is load, the withdrawal of energy should be allowed through NITS, if storage resource or its output is owned by the Load Serving Entity whose NITS is used for this purpose. If the ESR is not owned by an entity that is authorized to procure NITS, then PTP Transmission Service is needed to appropriate assess charges for transmission service associated with the energy withdrawn by the ESR. This approach is consistent with MISO's Order 841compliance filing.
• Should a storage resource be allowed to utilize non-firm transmission service to charge?
Non-firm transmission service should be allowed for withdrawals of energy for charging ESRs,
MISO’s presentation at the October 19, 2022 Planning Advisory Committee meeting on the issue of Dispatch of Stand Alone Storage Resources in the DPP, and proposed changes to the current dispatch assumptions in DPP Studies. The Owners support the overall objective of dispatching these resources in the DPP as they are likely to be operated, and the feedback below is in support of that objective.
As stated in the Owners’ comments on this issue in November 2022, the Owners agree that the operational data from ERCOT and CAISO referenced by MISO indicates that charging ESRs from the grid charging from the Transmission System is most likely to respond to energy prices.[1]
ESRs should be allowed to use NITS for charging because if the ESR is running during peak any additional Transmission Service charges will be captured in the NITS charges, and if it is charging outside of peak, no additional charges would be assigned to the load, which is consistent with FERC Order 841’s requirement that load not subsidize any profits associated with an ESR charging from the grid for later resale.
• What is the appropriate transmission service duration requirement for a charging storage resource (e.g. hourly, daily, monthly, yearly, five year with roll over rights)?
If the ESR is non-firm, then hourly transmission can be allowed; if the ESR is firm, then 5-year transmission with rollover rights should be required.
• For queued storage projects not yet online, how soon may transmission service be requested and/or procured (e.g. while in the queue, once a GIA a signed)?
A transmission request is presently only available in OASIS once GIA is signed; it should be the same as for a generator.
• What is the applicability of transmission service requirements for storage relative to behind-the-meter or distribution-connected resources?
An entity should generally not be mixing PTP or NITS to account for energy withdrawals, given the differences in the purposes of these two service types, but there is a related issue of the applicability of transmission service for storage relative to BTMG, which is independent of questions relating to Transmission Service charges for storing energy for charging ESRs.
• Do storage resources that only charge from a co-located resource require transmission service to charge?
Order 841’s requirement for storage resources to pay for transmission services for charging apply only to stand-alone storage resources charging from the grid for later resale and does not address whether storage resources that only charge from a co-located resource require transmission service to charges. Therefore other instances of applying transmission service charges are policy questions that should be discussed by the PAC, to the extent that there are policy issues to be addressed.
• Should any part of this issue be assigned to the Planning Subcommittee (PSC) or other stakeholder forum?
Any transmission system modeling or transmission reliability impact analysis questions should be addressed by the PSC.
[1] Please refer to prior TO comments on this issue) in November 2022 https://www.misoenergy.org/stakeholder-engagement/stakeholder-feedback/2022/pac-dispatch-of-storage-in-dpp-and-mtep-20221019/#1
In general, MISO should use “but for” logic to determine when an ESR should be charged for transmission service and how. In other words, does the ESR charging cause the need for new transmission to be built and paid for by transmission customers (or does it actually reduce the need for transmission), or does it somehow limit the amount of service that can be provided and sold without the need for any new transmission. If the answer is that it doesn’t cause the need for any upgrades based on planning and reliability studies, or doesn’t otherwise limit sales of transmission service, what is the purpose of charging the ESRs for transmission service (24/7 via point to point; thus NITS should be allowed)? With the “but for” logic in mind, it should be clearer as to how ESR charging should be handled given that it is not akin to any other load on the system. Below are the MRES responses to the questions from the presentation with the “but for” logic in mind.
Comments of the Environmental Sector on TSRs for ESRs - PAC -2023 - 2
An ongoing concern of our sector is the need for thoughtful integration of Electric Storage Resources (ESRs) in the MISO market that is responsive to the dynamic nature of battery ESRs capable of providing energy, capacity and/or a number of grid services, and are flexible in their ability to charge and discharge. A framework for transmission service for ESRs should be cognizant of the range of benefits to load that an ESR can provide and an ESR’s actual use of the transmission grid to charge. Therefore, any adjustments in MISO’s compliance with Order 841 should reflect this range of benefits, and provide for flexibility and efficiency in both dispatch and charging. MISO does not require long-term firm service for ESRs participating in the wholesale market and connected to the distribution system, thus we do not see justification for requiring long-term firm service for charging when charging does not require 8760 use of the grid. ESR charging is flexible, and timing can be adjusted to use transmission on an as available basis.
Given that this is a complex and multi-faceted issue, the Environmental Sector believes that further discussion of this topic at the IPWG or PSC stakeholder forums where stakeholders with issue specific expertise can discuss and debate the most optimal solution for transmission service for ESRs.
BPM / 841 Filing Language
In MISO’s Order 841 filing, including its responses to FERC’s Information Requests, MISO never indicated that ESRs would be required to utilize firm Point-to-Point (PTP) transmission service[1]. Rather, MISO only indicated that such service would be PTP or NITS, and did not indicate whether PTP Transmission Service would be Firm or Non-Firm, or Short-Term or Long-Term[2]. However, BPM 012 currently limits such charging to PTP Transmission Service, while both excluding NITS and being silent as to whether such PTP Transmission Service is to be Firm or Non-Firm, or Short-Term or Long-Term[3].
Furthermore, BPM 012 erroneously limits the FERC-directed exemption from required transmission service for ESRs to when ESRs are discharging only. This does not account for time when ESRs are providing ancillary services that inherently require charging, such as regulation service or down ramp capability. FERC required that MISO exempt ESRs from obtaining Transmission Service, and MISO corrected this in its 01/24/2020 filing, which included revised tariffs (see Module B, Section 31.0.0), and which FERC ultimately accepted[4]. However, BPM 012 does not fully follow through on this requirement.
TSR for ESR Considerations
While it is true that ESRs are a form of load that utilizes transmission service, and thus it may be appropriate to charge ESRs for transmission service, the nature of that service is qualitatively different from typical load. MISO and its stakeholders should explore this qualitative difference, which is a foundational issue that must be addressed before determining which level of transmission service, if any, is appropriate for ESRs.
With more than 37 GW’s of batteries designated ‘Active’ in the interconnection queue, it is imperative that MISO elevate the issue of transmission service for ESRs so that sufficient staff time and stakeholder meeting time are devoted to this issue to address it correctly and quickly.
Requiring ESRs to obtain long-term PTP transmission service would result in inequitable and inefficient treatment for energy storage resources that will not charge during peak load periods when LMP prices soar, and when these resources instead will be incentivized to both dispatch energy and/or provide grid stability services. Owners of ESRs should not be required to pay for transmission service that they do not use, which will unnecessarily increase their costs and diminish the ability of these resources to come online and bring a variety of benefits to the MISO system. Use of NITS for charging should only be allowed if short term, non-firm transmission service is also allowed, providing a level of equity with utility owned ESRs who are able to obtain NITS at a much lower cost. We support the availability of all three of these forms of transmission service for both efficiency and equity reasons.
In approaching the issue of TSR for ESRs, MISO should take account of emerging trends in ESRs providing ancillary services and energy in more advanced markets like CAISO (figure provided in attached comments)[5]. The treatment of ESRs in CAISO allows for a flexible charge and discharge pattern in the bulk power system that maximizes contributions to reliability across a spectrum of energy and ancillary services.This provides evidence that short-term non-firm point-to-point transmission service, instead of long-term firm transmission service, is a more appropriate approach for charging battery resources. As stated in the tariff, ESRs should not have to pay for service when directed to charge by MISO as is the case with ancillary services. ESR’s should be allowed to use this service on an hourly, daily, monthly, or yearly duration under Schedule 7, and there should not be a single requirement for ESRs to be locked into only one choice. Additionally, ESRs that are charging solely from co-located resources such as wind and solar, should not be required to have transmission service for charging.
In conclusion, the Environmental Sector looks forward to the forthcoming stakeholder discussion on the topic of TSR for ESRs. We are hopeful that provisions for more efficient usage of transmission for charging ESRs, and more clarity in MISO’s BPM and tariff will support more energy storage development. More importantly, an increase in ESRs on the grid will support MISO’s desire for increased flexibility and other reliability services.
[1] Docket No. RM16-23-000, MISO Transmittal Letter, at C.5.,, Pg. 10, (https://elibrary.ferc.gov/eLibrary/filelist?accession_number=20181203-5244&optimized=false)
‘5. Exclusion of Transmission Charges for Dispatched ESRs
As required by Order No. 841, MISO is revising Schedule 26-A and Attachment MM to provide that ESRs that MISO dispatches to provide a service shall not be treated as Load, and will not be assessed transmission charges applicable to Load. Point-to-Point Transmission Service is based on reserved capacity and is independent of actual system usage, whether injections or withdrawals. MISO’s Network Integrated Transmission Service billing procedures, including coordination with Transmission Owners on peak load reporting, will account for any ESRs being dispatched to provide a service, and that such will be excluded from the assessment of Transmission Service charges. This appropriately excludes Regulating Reserve deployments to consume or withdraw Energy under MISO’s Tariff.48’
[2] MISO, Response to Letter Requesting Information – Section 205 Filing to Amend Tariff Regarding Compliance with Order No. 84, May 1, 2019, Docket No. ER19-465-000, page 16, where MISO states, “The ESR can elect to serve the Load with either Point-to-Point Transmission Service or Network Integration Transmission Service under the existing Tariff.” MISO repeats this statement, absent the words, “under the existing Tariff,” again on the same page.
[3] BPM 12 also erroneously limits the FERC-directed exemption of TSRs for ESRs to when ESRs are discharging only – this does not account for when ESRs are providing ancillary services that inherently require charging, such as regulating service or down ramp capability. FERC required that MISO exempt ESRs from obtaining Transmission Service, and MISO corrected this in its 01/24/2020 filing, which included revised tariffs (see Module B, Section 31.0.0).
[4] FERC, Order on Compliance and Addressing Arguments on Rehearing, August 8, 2020, paras. 9 and 62(B).
[5] CAISO, Special Report on Battery Storage, July 7, 2023, pg. 12 (http://www.caiso.com/Documents/2022-Special-Report-on-Battery-Storage-Jul-7-2023.pdf)
REV Renewables (REV) is a developer, owner, and operator of renewable and storage projects across the country. REV has four battery storage projects operational in CAISO and is developing storage resources in MISO and other regions. REV appreciates MISO reconsidering its transmission service requirements for charging storage, and offers this feedback based on its years of experience with battery storage and the development process.
As a preliminary matter, REV requests that MISO clarify what issue it is addressing in requiring transmission service for charging storage resources. For example, is it to address resource adequacy requirements for capacity resources? Or reliability concerns with charging in general? Or another issue? Identifying the specific concern could help stakeholders hone in on solutions.
REV specifies that a storage operating in MISO for energy and ancillary services should not be required to have specific transmission service to charge. Transmission service should be for the capacity portion of the resource only. Storage should be allowed to charge from the grid at the LMP price for energy and ancillary services without specific transmission service. As a grid-connected resource, storage can provide benefits for MISO system overall because the storage could use excess energy from the grid. Charging should not have its capabilities limited by tying it to a specific generation resource with point-to-point transmission service. As more renewables come online in MISO, allowing storage to charge from the grid can also help limit curtailment of renewable energy and shift that energy to later in the day when it is needed.
Should storage resources be allowed to utilize NITS to charge?
Should a storage resource be allowed to utilize non-firm transmission service to charge?
What is the appropriate transmission service duration requirement for a charging storage resource (e.g. hourly, daily, monthly, yearly, five year with roll over rights)?
For queued storage projects not yet online, how soon may transmission service be requested and/or procured (e.g. while in the queue, once a GIA a signed)?
What is the applicability of transmission service requirements for storage relative to behind-the-meter or distribution-connected resources?
Do storage resources that only charge from a co-located resource require transmission service to charge?
What other questions would you like to see addressed?
Should any part of this issue be assigned to the PSC or other stakeholder forum?
Sept. 15, 2023 Comments of Cordelio Power to MISO Issue PAC-2023-2
Cordelio Power appreciates the opportunity to submit comments to the Planning Advisory Committee (PAC) on Issue PAC-2023-2 regarding Transmission Service Requirements for Charging Electric Storage Resources. As the PAC has recognized, there is a need to adjust MISO’s rules regarding transmission service for charging energy to better facilitate the full participation of electric storage resources in MISO’s markets. Battery storage systems and other types of electric storage resources play a critical role in the clean energy transition, and MISO has a unique opportunity to address a serious impediment to the widespread development and deployment of such resources across its footprint.
Currently, MISO’s Tariff requires customers to obtain transmission service for electric storage resources when those resources are withdrawing energy to maintain their State of Charge except when those resources are dispatched to provide regulating service or down ramp capability. Cordelio requests that MISO revisit this issue and work with stakeholders to develop rules that will exempt electric storage resources from paying transmission service charges when providing capacity to the MISO market or when directed to charge by MISO to provide energy or ancillary services.
By revising its rules, MISO would recognize the benefits to the transmission system that electric storage resources provide.
Battery storage systems and other types of electric storage resources have the ability to serve a critical function by flattening the load curve and making it easier for system planners to plan generation and meet demand. As the PAC knows, MISO is facing significant capacity shortfalls in the near term, and battery storage systems could become a key resource to help solve these projected shortfalls. Also, an ideal load curve is a flat load curve 24/7/365, and batteries can help adjust MISO load curve towards this ideal objective. Electric storage resources enable market participants to engage in energy arbitrage, which flattens the load curve, takes the burden off the network at large, and makes it easier for generators to meet load projections. Batteries connected to the transmission system effectively serve as distributed capacity; batteries can be located anywhere on the grid to provide quantized capacity spread across the grid. Batteries that are connected behind the meter (i.e., behind the pricing node) provide an additional benefit by making it easier for MISO to achieve its capacity objectives for the load behind that pricing node. In other words, behind-the-meter batteries flatten the load curve by actually offsetting that load. In both situations, batteries provide unique benefits that cannot be provided by traditional generation.
However, assigning a transmission service charge to batteries and other electric storage resources represents a redundant transmission service charge that is already covered by NITS. Batteries do not consume additional load. Batteries shift load from one time period to another. Assessing this redundant charge to batteries creates a market entry barrier against batteries that blocks them from providing important services to the MISO market and a net benefit to transmission network reliability. Batteries charge when load is lower on the MISO system and discharge when load is higher. The higher load has already met MISO’s transmission revenue requirement paid by NITS customers, and a battery when charging is simply using excess transmission that’s already available off-peak. Thus, exempting electric storage resources from paying transmission service charges when participating in the MISO capacity market or when directed to charge by MISO to provide energy or ancillary services removes a barrier to competition that currently exists within the MISO Tariff and allows batteries to provide the aforementioned net benefit to the MISO transmission system.
MISO has the opportunity to revise its rules, per FERC Order Nos. 841 and 841-A.
In Order No. 841, FERC found that “electric storage resources that are dispatched to consume electricity to provide a service in the RTO/ISO markets (such as frequency regulation or a downward ramping service) should not pay the same transmission charges as load during the provision of that service.” 162 FERC ¶ 61,127 at P 293 (2018) (Order No. 841). When electric storage resources are charging in response to dispatch instructions, their physical impact on the bulk power system is comparable to traditional generators providing the same service. Id. As FERC explained, electric storage resources would be disincentivized from providing critical services to the grid if they are charged for transmission in such situations. Id.
Subsequently, in Order No. 841-A, FERC clarified that the “service” provided by the electric storage resource is not limited to ancillary services, but can include any service defined in an ISO’s or RTO’s tariff. 167 FERC ¶ 61,154 at P 120 (2019) (Order No. 841-A). FERC declined to clarify that charging pursuant to economic dispatch always qualifies as a service, but acknowledged that participation of electric storage resources in the markets “may convey a range of benefits,” and states that specific ISOs and RTOs can create new services that involve charging pursuant to economic dispatch under certain system conditions. Id.
Finally, FERC explained that an RTO or ISO may propose rules allowing it not to assess transmission charges to an electric storage resource that is not being dispatched to provide a service if the RTO “demonstrate[s] that exempting such a resource from these charges is reasonable given its existing rate structure for transmission charges.” Order No. 841-A at P 121.
Thus, while MISO addressed this issue in its compliance filings to Order No. 841, FERC has expressly stated that RTOs like MISO can come in with changes to their rules at any time that would further these FERC policies. Cordelio encourages MISO to take this opportunity to revisit these rules now, with such proposed revisions as described below.
Other RTOs and ISOs have done so, and they provide a good model that MISO could follow.
MISO should take this opportunity to review other regions that have adopted rules that better facilitate the development and deployment of electric storage resources, including both CAISO and ISO-NE.
CAISO, for example, had market rules in place prior to Order No. 841 that treat Non-Generator Resources (i.e., electric storage resources) as negative generation rather than as load. Negative generation is settled at the wholesale nodal LMP and does not incur transmission charges. CAISO stated that “[c]harging during periods of high supply and low demand is a critical reliability service that mitigates system ramping challenges and helps avoid negative pricing and curtailment during oversupply, two issues becoming more pervasive in the CAISO.” CAISO Transmittal Letter, ER19-468, at 25-27. FERC agreed that CAISO’s proposal to exempt all electric storage resources from transmission access charges when charging is consistent with its existing rate structure, and thus is consistent with requirements of Order No. 841 as clarified in Order No. 841-A. 169 FERC ¶ 61,126 at P 138.
ISO-NE proposed to exempt electric storage resources from transmission charges for charging energy, arguing that such resources “are always providing a service because they are subject to central dispatch to economically balance supply and demand and can be dispatched at any time to address a reliability concern and provide contingency reserves.” 172 FERC ¶ 61,125 at P 47. ISO-NE also argued in the alternative that electric storage resources warrant an exemption for transmission charges because the manner in which these charges were assessed, by monthly peak usage, was incompatible with the interval-by-interval basis that Electric Storage Resources operate. Id. FERC accepted ISO-NE’s proposal that transmission charges do not apply to energy withdrawn by electric storage resource that are centrally dispatched (that is, dispatched to: (1) balance energy supply and demand on an economic basis or (2) address a reliability concern), but disagreed that all electric storage resources are always providing a service when charging for later resale. Id. at PP 49-50.
Through a related practice, ISO-NE also “nets” out behind the meter (BTM) load from network service charges, which applies to electric storage as well. ISO-NE explains that it nets out generation in such circumstances in part because of the recent shift toward a “hybrid grid,” with increasing amounts of widely distributed behind-the-meter generation that do not operate like traditional generation. FERC found this proposal to be just and reasonable because “unregistered behind-the-meter generation reduces the Network Customer’s load that must be served from the transmission system.” 178 FERC ¶ 61,086 at P 51 (2022). MISO does not provide a similar “netting” treatment for behind-the-meter generation, but MISO should take this opportunity to re-visit its policy and consider netting in similar circumstances, like ISO-NE.
In both CAISO and ISO-NE, batteries and other types of electric storage resources have greater ability to compete and provide the crucial services described above. MISO should take a close look at their respective tariffs and rules and work with stakeholders to adapt them to meet the needs of MISO’s transmission owners and market participants.
In conclusion, Cordelio requests that MISO work with stakeholders to develop revisions to its Tariff that would exempt electric storage resources from paying transmission service charges when directed to charge by MISO to provide capacity, energy or ancillary services. MISO should also consider netting of behind-the-meter load for purposes of network transmission charges.
Sincerely,
Franklin Bristol
Vice President, Energy Storage
Cordelio Power
General Comments:
AES Clean Energy (AES CE) appreciates the opportunity to provide comments on the TSRs for ESR issue scope. AES CE agrees with MISO’s assessment that point-to-point transmission service is overly restrictive and should be re-evaluated and clarified in BPM-012. In evaluating these issues, MISO should ensure that storage resources have access to equitable transmission service regardless of whether it is IPP-backed or utility-back generation. MISO should also use this initiative as an opportunity to streamline the study and deployment of storage resources and should consider whether the DPP study process could be streamlined and used to grant transmission service rather than requiring storage resource to go through separate DPP and TSR study processes. If MISO maintains the separate study processes, it should also evaluate whether the DPP and TSR study processes can trigger duplicative network upgrades to support grid charging, and what additional rules or methodology changes should be made to eliminate any duplicative efforts.
Finally, MISO should revisit the charging assumptions utilized in any DPP or TSRs studies to ensure that they align with realistic storage operation. FERC 2023 will allow interconnection customers to request alternative charging assumptions to be used in studies, and thus MISO could save itself additional work by ensuring that the default charging profiles align with the majority of project’s expected charging behavior. For instance, AES CE believes that the current charging dispatch assumptions in the shoulder case do not match reality and should be re-evaluated.
Comments on Questions to Address through this initiative:
Finally, AES CE believes that the PSC should be informed of the PAC activities in this initiative, but the bulk of the stakeholder process should remain in the PAC to reduce any confusion or further complexity in the stakeholder process.
In response to MISO’s request for feedback on the August 30 PAC presentation regarding Transmission Service Requirements (TSRs) for Charging Electric Storage Resources (ESRs), the Muni/Coop/TDU Sector submits the following.
ESRs have the ability to support MISO’s Reliability Imperative. Transmission service requirements when charging ESRs from the grid should not impede or limit that support.
The TSRs for ESRs is a policy issue that should remain at the PAC. If the PAC needs input from a subordinate group, it should seek that input but the policy discussions should remain at the PAC.
BPM language should reflect the commitments made by MISO in its May 1, 2019 response to the FERC’s Request for Information – Section 205 Filing to Amend Tariff Regarding Compliance with Order No. 841, Docket No. ER19-465-000. In that response, MISO states that an ESR can elect to use Network Integration Transmission Service (NITS) under the existing Tariff when charging from the grid. Since that filing, neither MISO, the IMM, nor stakeholders have identified any concerns or issues with the use of NITS when charging ESRs from the grid. Nothing in the tariff precludes a NITS customer from using NITS when that customer charges its ESR from the grid. BPM language should reflect this fact.
Similarly, the Sector believes that MISO’s tariff already allows the use of any transmission service product when charging an ESR from the grid, including all durations of firm and non-firm point-to-point (PTP) service. As MISO stated in their May 1, 2019 response to the FERC, question 8.A.a.i and ii:
When an ESR is charging, and that charging results in a withdrawal from the Transmission System, transmission service reservations are required. The ESR can elect to serve the Load with either Point-to-Point Transmission Service or Network Integration Transmission Service under the existing Tariff. This treats ESRs comparably with other types of Resources that are required to obtain and pay for transmission service to use the Transmission System.
ESRs are required to procure transmission service due to the fact that when the ESR is charging, its consumption of Energy constitutes Load, including Load under the definition of Network Load. The ESR can elect to serve the Load with either Point-to-Point Transmission Service or Network Integration Transmission Service.
Reponses to other questions raised by MISO:
SunEnergy1 respectfully submit the following feedback for top "TSRs for Charging ESRs"
General: SunEnergy1 agrees with MISO and TO that the addition of new load in the form of ESR requires adequate studies (in the same way as other load additions). This study can be accomplished in many ways and should not be the reason to impose ongoing transmission service charges on ESR at times when ESR is not using transmission service. Also, Open Access Transmission Tariff provides all transmission service product to all load. Storage should not be discriminated against comparing to other load (including load with behind of meter generator or battery).
Should storage resources be allowed to utilize NITS to charge? Yes. NITS is a tariff product available to Transmission Customers with load. There is a know potential loophole of avoiding NITS charge by avoiding peak hour usage. However, this is not unique to ESR load and existed before ESR. In zones where this can be an issue it should be addressed for all loads and is not a reason to discriminate against ESR load.
Should a storage resource be allowed to utilize non-firm transmission service to charge? Yes. A storage resource, by its nature, only charges from the grid at very limited hours. It fits the nature of non-firm transmission service very well. MISO had load serving entities with behind the meter generator serving load using non-firm transmission services and ESR should not be discriminated against. However, to ensure system stability, a one-time study should be performed before ESR can request for non-firm transmission services. This can be at the interconnection stage or a new step before granting ESR the right to request for non-firm transmission service.
What is the appropriate transmission service duration requirement for a charging storage resource (e.g. hourly, daily, monthly, yearly, five year with roll over rights)? See answer to the last question. All duration should be available to ESR load, the same way as to other loads. Especially hourly service fits the nature of storage and should be available. Non-firm transmission service could require a one-time study to ensure system stability. Such study can be at the interconnection stage or a new step before granting ESR the right to request for non-firm transmission service.
For queued storage projects not yet online, how soon may transmission service be requested and/or procured (e.g. while in the queue, once a GIA a signed)? At interconnection stage, only long term firm transmission service window is open (Tariff Attachment J). Currently MISO allows a generator to request for transmission service when it is still in the queue, but the transmission service is dependent on a successful GIA. MISO should continue this practice.
What is the applicability of transmission service requirements for storage relative to behind-the-meter or distribution-connected resources? It is a complicated topic. In general, if it is beyond the specification studied and service provided with the existing network load, it needs a new study the same way as a new ESR load.
Do storage resources that only charge from a co-located resource require transmission service to charge? No. It is consistent with existing power plant station load treatment.