PSC: Dispatch of Energy Storage in MTEP and DPP Studies Redlines (20220719)

Entergy Operating Company Comments on Dispatch of Storage in MTEP and DPP Studies, proposed BPM Language

August 16. 2022

At the July 19, 2022, Planning Subcommittee (PSC) meeting, MISO reviewed proposed modifications to BPM-015, and posted draft redlines in the Fuels Table and Technical Requirements with the July 19, meeting materials.

In response to MISO’s request for stakeholder feedback, the Entergy Operating Compaanies request that MISO respond to the following questions regarding the details of how the charging mode will be studied:

1. Before moving forward with this proposal, request that MISO present on how storage in charging mode is being evaluated in the TSR process (study models, study types, contingency types, etc.?). TOs and Interconnection Customers (ICs) should have a clear understanding on how storage in charging mode would be evaluated in MISO TSR studies if that would be the only process for evaluating storage in charging scenarios.  For large storages connecting to an area with limited transmission sources, steady-state voltage stability and/or dynamic stability on voltage recovery could be an issue when storage is in charging mode.
2. Does MISO assume that the TSR study could limit storage’s charging rate to 0 MW if system constraints are identified at IC’s requested charging level?  If so, is that practical?  If the storage needs to maintain a min charging rate to be commercially operational and there is a TSR constraint,  would system upgrades be developed to support the storage project, and is that also part of the TSR study process?

• If MISO wants a stand-alone battery facility to have its charging function studied as a TSR, MISO should require completion of the TSR before the GIA is executed given that all stand-alone battery storage facilities will need to be able to be charged for commercial operation.
• TSR studies have a firm 60 day timeline. Stability studies for the charging scenario would need to be performed during this time which includes creation of models and study input files. Given that the files are already available during the DPP studies, why would it not be more efficient to utilize the DPP process to assess charging capability (at least from a stability perspective)?
•  An IC needs to be aware of any constraints (steady-state or stability) associated with the charging scenario for a stand-alone battery project before it can commit to signing a GIA and begin construction on the project. A stand-alone battery project that cannot be charged is not a realistic project

Additionally, The title of MISO’s presentation (Dispatch of Storage in MTEP and DPP Studies), seems to imply that the proposal would apply to the MTEP process as well through use of economic tier order dispatch changes in “MISO Planning Modeling Manual: Reliability Planning Model Data Requirements & Reporting Procedures.”   However, it is not clear how MISO is planning to incorporate charging scenarios in MTEP with these changes if at all.  MISO notes that “Storage Requires two Economic Tier Orders for Standby and Discharging,” but has not presented any changes relating to batteries into the MISO Economic dispatch yet, so it is unclear what the battery statuses will be for the individual models. 

Key Capture Energy ("KCE") is a developer, owner, and operator of standalone battery storage projects.  Founded in 2016, KCE has 370 MW of standalone battery projects in construction or operation and a development pipeline of over 3.5 GW, including 870 MW located in MISO.KCE appreciates the opportunity to provide feedback on MISO's proposed BPM-015 redlines to the Fuel Type Dispatch Table.  KCE strongly supports the change to the Shoulder Peak Dispatch of storage from +/-100% to 0%.  Consistent with data assembled by KCE and shown at the April PSC, this fuel dispatch assumption more accurately aligns with real-world operation of storage in response to low load conditions and wholesale market pricing signals.KCE would like to thank MISO for proposing this change, which we expect will better align siting decisions for storage with the value that storage can provide to the MISO system.

ATC appreciates the information presented on this topic at the July 19, 2022 Planning Subcommittee Meeting and previous meetings.  We have a few items for comment and suggestion.

1. Before moving forward with this proposal, ATC would request that MISO present on how storage in charging mode is being evaluated in the TSR process (study models, study types, contingency types, etc.?). TOs and Interconnection Customers (ICs) should have a clear understanding on how storage in charging mode would be evaluated in MISO TSR studies if that would be the only process for evaluating storage in charging scenarios.  For large storages connecting to an area with limited transmission sources, steady-state voltage stability and/or dynamic stability on voltage recovery could be an issue when storage is in charging mode. 

2. Does MISO assume that the TSR study could limit storage’s charging rate to 0 MW if system constraints are identified at an IC’s requested charging level?  If so, is that practical?  If the storage needs to maintain a min charging rate to be commercially operational and there is a TSR constraint,  would system upgrades be developed to support the storage project, and is that also part of the TSR study process?

• If MISO wants a stand-alone battery facility to have its charging function studied as a TSR, MISO should require completion of the TSR before the GIA is executed given that all stand-alone battery storage facilities will need to be able to be charged for commercial operation.  An IC needs to be aware of any constraints (steady-state or stability) associated with the charging scenario for a stand-alone battery project before it can commit to signing a GIA and begin construction on the project. 
• TSR studies have a firm 60 day timeline. Stability studies for the charging scenario would need to be performed during this time which includes creation of models and study input files. Since stability files are available in the DPP studies, would it be more efficient to utilize the DPP process to continue assessing charging capability (at least from a stability perspective)?

3. The title of MISO’s presentation (Dispatch of Storage in MTEP and DPP Studies), seems to imply that the proposal would apply to the MTEP process as well through use of economic tier order dispatch changes in “MISO Planning Modeling Manual: Reliability Planning Model Data Requirements & Reporting Procedures.”   However, it is not clear how MISO is planning to incorporate charging scenarios in MTEP with these changes if at all.  MISO notes that “Storage Requires two Economic Tier Orders for Standby and Discharging,” but has not presented any changes relating to batteries into the MISO Economic dispatch yet, so it is unclear what the battery statuses will be for the individual models. 

MidAmerican Energy Company (MEC) supports the proposal to study storage resources at a 0% dispatch in the shoulder case beginning with the 2022 cycle.

As noted in MEC's previous comment to the April 12^th, 2022 PSC presentation, MEC does not agree that batteries (or other storage resources) in a hybrid facility should be studied at a 100% dispatch as compared to storage as a standalone resource at a 0% dispatch in the same shoulder case. Similar to storage as a standalone resource, storage in a hybrid or co-located configuration is designed with a control narrative to decrease congestion at the point of interconnection based on market prices. Modeling storage (in any configuration) at a 100% dispatch in the shoulder case does not align with the resource's objective to operate in times to decrease congestion and ultimately reduce the need for new transmission. MEC does not believe a hybrid configuration will affect the dispatch of the storage resource as compared to a standalone storage resource in close proximity. 

As a result, MEC suggests all new storage facilities should be modeled at 0% dispatch in the shoulder case. If MISO disagrees, MEC would appreciate a further explanation in the next PSC. 

The new clause in 4.2.1.2 of BPM-015 appears to contain improper capitalization.  Please consider rendering "A Proposed" as "a proposed"