In the October 16, 2024, meeting of the Planning Advisory Committee (PAC), MISO summarized the status of this issue and progress made with the IPWG. Feedback was requested on the proposed edits to BPM-015 (for short-term resolution).
Comments are due by November 1.
The Southern Renewable Energy Association (SREA) appreciates the opportunity to comment on MISO’s short-term proposal to address storage charging limitations for energy storage facilities. There is currently a mismatch between the dynamic nature of energy storage facilities and their ability to obtain transmission service which allows for economical charging and providing capacity in the MISO marketplace, and we appreciate MISO’s effort to provide short term solutions to bridging the gap short term.
It should be noted that only two out of the three solutions offered by MISO could be reasonably considered ‘short term’ solutions; procuring long-term transmission service or working with a TO to submit charging load in the MTEP process. Entering into a subsequent queue is not a desirable solution considering the average duration of a queue cycle, and possible delays in entry from a pending MW Cap proposal from MISO that would be applied to each queue cycle.
SREA supports the concept of investigating multiple charging rates that reflect system conditions and LMP’s which can send market signals on where congestion occurs. These system dynamics are not captured in shoulder charging studies in the DPP, and oftentimes constraints are identified in modeling that restrict charging behavior for a storage asset so much that it results in queue dropouts. Energy storage resources can even integrate charging rates into BESS system programming to ensure fluid integration of charging needs.
It’s critical that MISO move forward much faster than their current stated timeline to address this issue. Beyond the impact to Interconnection Customers developing storage assets, which is leading to queue dropouts, it’s critical to address this issue expeditiously for ongoing MISO concerns related to congestion management, resource adequacy and integration of renewable energy resources. Energy storage can play a critical role in mitigating these challenges, but there must be a process in place that allows it.
MISO to move forward with a long-term solution that covers the charging needs of storage developers sooner than MISO’s stated plans of beginning discussions in Q1 2025. IC's with storage in the queue need this for certainty as to what their options are beyond longterm transmission service, re-entry into the queue and submission into the MTEP process that actually addresses the functionality of their resources, and when it is optimal for them to charge. MISO should pursue possibly having a separate process like surplus interconnection where they pursue different charging rates for instance, which can capture impacts of load on the transmission system, but also impacts on LMP prices which are not captured in the current shoulder charging studies in the DPP.
The MISO Environmental Sector appreciates the work MISO has done to develop some short-term pathways for storage resources with charging limitations to have those amended or removed. It is critical to create reasonable pathways so that storage resources do not have to maintain unnecessarily prohibitive charging limitations for the life of these projects, especially when those limitations may result from modeling differences and not actual constraints that would show up if storage charging was studied like other loads in MTEP reliability studies under BPM 20, or if changes in system conditions no longer warrant them.
MISO is proposing to allow storage resources three options at this point to address charging limitations:
Submitting a new interconnection queue request;
Submitting a transmission service request; and
Working with the local Transmission Owner for study and submittal into MISO’s annual MTEP process.
But none of these solutions is an ideal or expeditious solution to re-evaluate whether the charging limitations are still necessary. And none can provide an adjustment in charging limitations in time to prevent viable storage projects that have invested millions of dollars from dropping out of the MISO queue. MISO and its member utilities need these new storage resources to help meet capacity needs, address near term congestion, particularly as LRTP lines are being constructed, and to integrate renewables. We urge MISO to move quickly to develop more appropriate long-term solutions such as a separate dedicated charging study that can be done in the Generator Interconnection Process, with qualities more like a MTEP load study, a direction which stakeholders have generally supported. This separate study could be similar in process to the separate study processes MISO currently has for Surplus Interconnection Requests and Generator Replacement Studies.
Additionally, we encourage MISO to explore multiple charging rates based on system conditions which can be programmed into energy storage devices and algorithms to address any storage charging constraints that are not a byproduct of the modeling process.
The Environmental Sector reiterates the urgency of implementing a more appropriate and expeditious solution for storage generation facing these charging limitations. The issue was submitted in January 2024, and MISO has recently proposed to push out initial discussion of the “long term issue” of modeling practices until 2025. Meanwhile, storage projects that could and should be providing capacity and addressing the continuing congestion throughout MISO are unnecessarily forced to drop from the queue. We urge MISO to make this issue a top priority in the IPWG and PAC to allow viable and ready storage projects to move forward and serve MISO’s needs.
CGA supports the environmental sector comments submitted by Natalie McIntire