DERTF: Aggregation Size Requirements (IR070) (20210412)

MPPA generally agrees with WPPI Energy's feedback.

David Sapper

dsapper@ces-ltd.com

NIPSCO appreciates this opportunity to comment on DER aggregation size requirements. 

While NIPSCO's  believes having a maximum capacity limit of no higher than 5 MW per DER (individual resource) is not unreasonable, NIPSCO believes there are additional benefits to consider with having a lower maximum limit of 1 MW. NIPSCO believes there is more opportunity for a greater number of participants and diverse resource types at the 1 MW level. This will help prevent one single applicant from absorbing all the available hosting capacity. The 1 MW level will help provide potential for more participants needing less costly infrastructure upgrades, compared to allowing and accommodating the higher limit of 5 MWs. NIPSCO has successfully been accommodating and has better met customer expectations using capacity limits focused around a maximum of 1 MW. While NIPSCO believes 1 MW should be considered, we do not believe the maximum should exceed 5 MW.

The Organization of MISO States’ Distributed Energy Resources Working Group (OMS DERWG) appreciates the opportunity to submit the following comments. This feedback does not represent the position of the OMS Board of Directors.

The workgroup understands that large resources on the distribution system have the potential to cause system reliability issues, incur large system upgrade costs, or trigger adjacent-distribution system or larger bulk system-affected system studies. Most states have some level of state-based interconnection processes or requirements which are used to assess what cost are reasonable, the speed at which resources are interconnected, or the studies that are required to be evaluated before interconnection. States have established these processes to ensure that the state-regulated distribution system and these resources, their costs, and system effects are reasonable and in line with reasonable ratepayer costs, a reliable system, and individual state policy. That being said, the OMS DER WG does not believe that MISO needs to institute a cap on either DER or DERas at this time due to these state processes and current oversight.

While the OMS DERWG appreciates MISO’s proposal to defer to the EDCs and states to “identify system impacts or limits due to size”, the DERWG would be willing to consider reasonable proposals for why an individual maximum size limitation may be appropriate, if there are reasons why a state-based review or interconnection process is not sufficient, or there are RTO/ISO needs for metering, verification, or settlement requirements for a larger DERs.

Additionally, from a market access standpoint, large individual DERs would be able to participate in MISO markets as a DERa consisting of a single DER. Large DERs would likely represent sophisticated customers and may not need to be bundled with other DERs to access wholesale revenue streams. OMS DER WG also acknowledges that while the voltage of the distribution line and the maximum size of an individual DER are likely correlated, connection of a very large DER (20MW+) for the purpose of DER aggregation is likely not feasible without substantial system upgrades for that new resource. While the OMS DERWG currently supports MISO’s proposal to not set a maximum size for DERas, if MISO decides to modify this proposal in the future, the OMS DER WG would like to see an analysis of the merits of various individual size limitations, in order to align with QF rules and DER conversations occurring in other RTOs.

In response to MISO’s second question, OMS does not recommend a limit on the maximum size of a DER aggregation, assuming the scope of DER aggregation is limited to a single EP node as proposed.    

Xcel Energy appreciates the opportunity to provide feedback to MISO regarding the aggregation size requirements.  

Maximum Size Limit for DERs within a DERa

Xcel Energy recommends that the maximum size limit of 5 MW for DERs participating within a DERa.  In markets with substantial interconnection activity, where there are many projects in a queue, it is important that the queue contains projects that have reasonable viability for interconnection success, especially in a fledging market.  Maintaining efficient use of engineering resources to perform studies and assessment of remediation costs, with costs the demining factor for interconnection viability, can be critical in limiting queue backlog.  An individual maximum limit of 5MW for a DER within a DERa is consistent with maintaining DERa registration viability where such registration will require review of localized distribution company impacts of a large DER facility participating within the wholesale market.    Both PJM and NE-ISO have made proposals to set the size limit of individual DERs at 5 MW participation in a DERa. MISO should consider adopting a  similar proposal.

Maximum Size Limit for DERas

The current proposal to restrict aggregation to an EP node sets a natural limit on the size of the DERa so we do not believe MISO needs to set a DERa maximum size limit at this time.  However, if aggregation is allowed to extend beyond the EP node level, this limit would need to be revisited. 

Voltus agrees with MISO’s recommendation not to impose a maximum size limitation for individual resources to participate in aggregations. It is reasonable to defer to EDCs, States, and MISO interconnection studies to identify if limits are required in particular circumstances. 

Allowing relatively large resources to aggregate with smaller resources will have the overall effect of increasing DER participation. Resources that are too small on their own to meet minimum participation requirements will be able to “piggyback” on larger resources within the same aggregation. As MISO pointed out during the April 12 meeting, such aggregations of heterogeneous resources reduce the number of small DERAs in the market, easing the technical challenge of modeling and dispatching many small assets. 

Ideally, DER aggregators will be able to form aggregations large enough that they resemble traditional generation assets to grid operators and MISO’s IT system. Telemetry and M&V for these “virtual power plants” will also be handled at the aggregation level. Encouraging fewer, larger aggregations that each behave as a single resource will ease the DERA transition.  MISO and transmission owners can continue to use existing MISO systems designed for large-scale assets. The aggregators will in turn be responsible for managing the assets within an aggregation. 

The main impediment to this future is MISO’s proposal to limit aggregations to a single EP Node. This limitation will have the de facto effect of making aggregation impossible. Locating a meaningful number of different DER resource types within a single EP Node is not feasible given the small geographic reach of any given node. Limiting aggregations to a single EP Node therefore violates the express purpose of Order No. 2222, which requires that the ISOs create meaningful market participation models for DER aggregations.

Order No. 2222 also requires ISOs to allow aggregations that are “as geographically broad as technically feasible.” Limiting aggregations to a single EP Node does not pass this test: aggregations across CP Nodes are “technically feasible,” as is evident from the hundred of megawatts of Demand Response Resources as well as several gigawatts of Load Modifying Resources and Emergency Demand Response that are already active in MISO. As Voltus discussed in its prior public comments in March, what is feasible could reasonably vary by product, with higher levels of aggregation available to capacity versus reserves versus energy. MISO must investigate the question of feasibility on a product-by-product basis.  

Emily Orvis

____________________

Senior Energy Markets Manager

Voltus, Inc.

(703) 785-8269

The Environmental Sector does not recommend that MISO implement a maximum DER size within an aggregation in its FERC Order 2222 compliance. Any limits placed on DER sizes should be done in the context of interconnection.

MISO should not place a maximum size limitation on DER aggregations.

AES Indiana generally supports MISO's recommendations to restrict DER aggregations to a single EPNode for most resources, with the exception MISO recommended that DRR I resources 1 MW and over be allowed to participate in multinode aggregation.

AES Indiana also generally support's MISO's recommendation to not establish a maximum size threshold to individual resource participating in larger DERa.

Maximum DER size to participate in an aggregation

WPPI: This question appropriately concerns the maximum DER size to participate in an aggregation from MISO’s perspective. To the extent the size any individual DER in an aggregation does not pose concerns for MISO operations, including their monitoring of the transmission/distribution interface (apparently to be addressed by NERC SPIDER DER modeling), MISO’s recommendation of no maximum seems appropriate. The distribution utility may have additional considerations that may limit the size of an individual DER in an aggregation. In addition, MISO notes that any applicable MISO interconnection studies may impose limits in the case of a specific DER.

Maximum DER aggregation

WPPI: It would seem similar considerations would apply to this question, maximum DER aggregation, as to the question above, maximum size to participate in an aggregation. Therefore, please see WPPI’s response to the question above.

Advanced Energy Management Alliance (“AEMA”) [1] respectfully submits the following comments to the MISO Distributed Energy Resource Task Force (DERTF) on the Questions about Aggregation Size Requirements arising from FERC Order 2222 that were presented at the April 12, 2021 meeting of the DERTF. AEMA is a trade association under Section 501(c)(6) of the Federal tax code whose members include national distributed energy resource companies and advanced energy management service and technology providers, including demand response (“DR”) providers, as well as some of the nation’s largest demand response and distributed energy resources. AEMA members support the beneficial incorporation of distributed energy resources (“DER” or “DERs”), including advanced energy management solutions, into wholesale markets as a means to achieving electricity cost savings for consumers, contributing to system reliability, and ensuring balanced price formation. These comments represent the collective consensus of AEMA as an organization, although they do not necessarily represent the individual positions of the full diversity of AEMA member companies.

            AEMA offers the following feedback on the two questions raised by MISO at the April 12 DERTF.

• Should MISO limit the maximum size of an individual DER to participate in an aggregation?

MISO has suggested that there should be no individual resource maximum size limitation for participation within an aggregation. AEMA supports that recommendation because it creates no barriers. However, MISO has also proposed to restrict aggregation to single EP nodes. AEMA does not believe this limited aggregation proposal from MISO meets the intent of FERC Order 2222. This limitation would create an unnecessary barrier to participation of DERs in the MISO market. AEMA has recommended and continues to propose that MISO allow limited scope aggregation. AEMA proposes that MISO might examine a limited scope aggregation across multiple nodes with a maximum size of an individual DER that could be accommodated in the MISO operating system. If an aggregation is a single node, then there is no maximum size of an individual DER to participate. 

• Should MISO limit the maximum size of a DER aggregation?

As stated above, MISO has proposed to restrict aggregation of DER to single EP nodes. If an aggregation is limited to a single EP node, then MISO should not limit the size of a DER aggregation. However, AEMA does not believe this limited aggregation proposal from MISO meets the intent of FERC Order 2222. This limitation would create an unnecessary barrier to participation of DERs in the MISO market. AEMA has recommended and continues to propose that MISO allow limited scope aggregation. AEMA proposes that MISO examine limited scope aggregation across multiple nodes with a maximum aggregated size that could be accommodated in the MISO operating system. If an aggregation is a single node, then there is no maximum size for the DER aggregation, but if the aggregation is across multiple nodes, then AEMA suggests a 5 MW limit on the DER aggregation. 

AEMA appreciates MISO’s consideration of these comments as part of the Order 2222 compliance approach being discussed in the DERTF. We welcome any questions, and encourage you to contact either Katherine Hamilton, Executive Director of AEMA, or DeWayne Todd, representative of AEMA, should you wish to meet with AEMA members.

Respectfully Submitted, 

Katherine Hamilton

Executive Director, Advanced Energy Management Alliance

Katherine@aem-alliance.org

202-524-8832

or

DeWayne Todd

DDT LLC

dewaynetodd1297@gmail.com

812-573

Consumers Energy appreciates the opportunity to provide feedback on this important topic.

MISO is proposing that there be no limitation placed on the maximum size of any one individual DER resource included in a DERa and further proposes to defer to Electric Distribution Companies (EDCs), States and MISO interconnection studies (if applicable) to identify system impacts or limits due to size.  The maximum size of an individual DER in a DERa may be limited by technical realities on the distribution system and, as such, it is appropriate to defer such decisions to the EDC.  Furthermore, current and future State interconnection processes and programs may contain limitations that need to be respected, so deferral to the States also makes sense. 

While Consumers Energy supports the idea of deferring to the EDCs and/or States, MISO should consider codifying the maximum participation amount in some form as many market participation and design elements are yet to be determined.  For example, it has been concluded that the technically broadest location possible for a DERa is a single EP Node (a proposal supported by Consumers Energy).  It may make sense, therefore, to limit the maximum size of an individual DER to the capabilities of a single EP Node.  Also, since DERa participation is a new endeavor, it is entirely possible that there are ramifications and consequences that cannot currently be anticipated and, as such, an initial size limitation is warranted until there actual operational performance data is available.  Potential considerations for size limitations could include (i) a 5 MW limit as is being proposed by PJM; (ii) tying the allowable size to the State interconnection processes; and (iii) tying size thresholds for participation to other, existing MISO participation models where appropriate (e.g. DIRs).  These can all serve as guard rails for limiting the maximum size of individual DER participation.

 We appreciate the opportunity to respond to MISO’s question on maximum size aggregations/and maximum size to participate in an aggregation by offering questions and comments around size in terms of the reliability, operation, and coordination of activities that potentially impact the BES.

 We encourage consideration of the interactions between the maximum size question of a DER Aggregation and DER aggregation member size and:

• Telemetry requirements
• Will there be a size requirement for telemetry to accomplish dispatch? How will performance relative to dispatch instruction be measured?
• Will there be a max size component as part of an aggregation that would trigger telemetry within an aggregation?
• Will telemetry be solely between the aggregator and MISO? If this is the decision, again, how will performance of distributed energy resource aggregations be monitored?
• Will MISO send dispatch signals to the aggregator and the aggregator in turn send dispatch instructions to the components of the aggregation? If so, again how is performance evaluated? Will it be at the aggregator level or the membership level of the aggregation? Depending on the telemetry requirements, aggregation dispatch could create a zonal dispatch inside of a nodal dispatch. However, the limitation to one node may fix this issue. Could MISO comment on this potential concern? It may have been discussed earlier, but it may have not been discussed in terms of size, telemetry and performance requirements.
• The DER aggregation and associated telemetry should be at a level to accurately indicate the potential dispatchable amount of each aggregation behind each T-D “meter.”  Would MISO’s proposal to limit the aggregation to a single node accomplish this with telemetry at the node or would more granular telemetry be required to accomplish measurement at the T-D meter level? Modeling potential performance of aggregations across multiple T-D meter  will be more difficult/less precise. Is there a size threshold for an aggregation that MISO is considering as a modeling cut off?

Outage Scheduling

• What are the coordination expectations for aggregation outage scheduling? The max size might impact such coordination expectations. Would all coordination at the distribution level be done by the distribution entity coordinating with the aggregator to work with MISO and Transmission Owners to accomplish outage scheduling on the BES?
• Will aggregators be part of the outage scheduling process in place for other Resources and if so will they have  performance requirements and communication requirements to plan for outages?

Relay Settings & Modeling

• Who will coordinate  relay backflow limits onto the BES if any exist where aggregations might be locating? This again would seem to be related to size of aggregation/members.
• What are the locational requirements for modeling of DER aggregations and locational MW limits for DER aggregations and do these differ by the LBA? How would such limits be known and modeled as DER aggregations do not go through the interconnection process.
• Are there limits on siting (in terms of maximum size) that would exist at the bus, branch, or breaker level? Again, this would seem to be related to max size of aggregation and aggregation components. Is there a MW threshold that MISO would want to model at the BES level?
• Will performance standards for participation of DER aggregations at the wholesale level be the same as for all resources, specifically, other resources on the system that go through the MISO generator interconnection process?

Thank you. We look forward to working with Stakeholders and MISO to further understand these issues and how they relate to aggregation size and max component size of an aggregation.

MGE can support the recommendation:  "No individual resource maximum size limitation for participation within an aggregation. Defer to EDCs, States, and MISO interconnection studies (if applicable) to identify system impacts or limits due to size."