Electric Storage Resource FAQs
What is the distinction between Stored Energy Resource (Type-I), Stored Energy Resource (Type-II) and Electric Storage Resource (ESR)?
Stored Energy Resource Type-I is storage but is Regulation-only. Stored Energy Resource Type-II allows storage resources to participate in MISO Markets using Demand Response Resource Type-II tools and templates allowing participation in Energy and Ancillary Services, but is not designed for storage resources. Electric Storage Resource has parameters that recognize and respect State of Charge (SOC), Charge and Discharge parameters, and an efficiency factor.
What does MISO mean by saying an ESR is 'In Front of Meter'?
A resource participating as an ESR in MISO Energy and Operating Reserve Market is modeled in MISO’s network models as if connected directly to the transmission system. MISO expects only wholesale transaction volumes to be telemetered and reported by the Market Participant
Can an ESR also be a Behind the Meter Generator?
No. A Behind the Meter Generator is a tariff-defined load modifying resource that is not dispatchable by MISO. An ESR is a resource that is capable of being offered to MISO for dispatch in the Energy and Ancillary Services Market.
Can an ESR be located on distribution or behind a retail customers meter?
Yes. An ESR may be connected to distribution or located behind a retail customer's meter. The Market Participant (MP) is responsible for reporting and telemetering only wholesale volumes of charge and discharge from the ESR to MISO, such configurations require an Attachment HHH attestation by the MP that coordination with Distribution Companies and Retail Regulators have been successfully completed. The ESR would be responsible for fees and studies that are applicable to the local jurisdiction.
For distribution connected Electric Storage Resources, where does the MISO meter need to be located? Does it matter if it is behind a customer’s retail meter?
The Electric Storage Resource must meet all measurement requirements specified in Section 38.2.5.e of the Tariff and in the Market Settlements Business Practices Manual BPM-005 through direct metering or its functional equivalent. (Attachment HHH, 2.g)
Will ESRs located at a retail customers site be treated as demand response?
No. ESRs are not demand response resources.
How should ESRs impact the Load Balancing Authority (LBA) Residual Load Calculation?
All ESRs are modeled similarly to generators within the LBA and therefore counted as generation when LBA Residual Load is calculated. Residual Load is the difference between wholesale metered load at the Load Serving Entity (LSE) level and the calculated load of the LBA as a sum of generation in the LBA minus tie-line flow in and out of the LBA. The residual load calculation method will not change but the calculated value could.
For distribution-connected ESRs, how will LBA load be impacted?
If the ESR is located on distribution such that its output also affects the wholesale metered value of the associated LBA, then the LBA load must be reconstituted to reflect the gross load before the ESR contribution. The LBA will be responsible for adjusting residual load to account for ESR’s operation.
Will ESRs impact the LBA's load forecast?
Because ESRs are modeled like generation within the LBA boundary, the LBA's short-term load forecast and medium-term load forecast should represent load absent the impact of ESRs within their metered boundary.
Can a storage resource continue to register as a Demand Response Resource?
A non-injecting, behind the meter storage asset may continue to participate as Demand Response.
Is the Attachment HHH relationship only between the ESR and MISO?
Yes. The Attachment HHH pro-forma agreement is only between the ESR and MISO, but requires the ESR to attest to following any other local/state guidelines and procedures.
How early is too early to register and Electric Storage Resource depending on its estimated go-live?
Market Participants can start the registration process early even if the go-live is estimated to be 2025 (for example).
What is the timeline and a general idea of costs involved in the MISO registration process for ESR?
The customer has to be a MISO Market Participant in order to register their Electric Storage Resource units in the MISO network and commercial model. The detailed process on how to become a MISO market participant is linked here: MISO Market Participation (misoenergy.org). This link above contains information on costs, required documentation, deadlines and minimum participation requirements. In general, the timeline to become a certified MISO Market Participant can take anywhere from 60 to 90 days. For existing MISO Market Participants, there is no charge for registration of Electric Storage Resource units with MISO, although additional studies and fees may apply as required. Registration of Electric Storage Resources will coincide with the MISO quarterly commercial model update procedure. Deadlines for upcoming MISO model updates are linked here: Microsoft PowerPoint - 2022-2023_Model_Update_Schedule.pptx (misoenergy.org)
If charges are based on the coincident peak, what transmission charges apply if the Electric Storage Resource is not charging during peak?
If the Electric Storage Resource is charging, the customer has to support it with Point-to-Point (PTP) service. If that occurs during the peak hour, the Transmission Owner will have to remove the PTP from their Network Integration Transmission Service calculation in order to avoid double charges.
Is it correct that Stored Energy Resource (Type-I) is required to be in front of the meter because MISO needs visibility in order for the Resource to provide Regulating Reserve?
Yes, Stored Energy Resources (Type-I) must be in front of the meter to be a market unit to clear Regulating Reserve.
Is Regulation Mileage available to Electric Storage Resources?
Regulation mileage is available to Electric Storage Resources.
Asset Specific Questions:
How are storage losses (over time) accounted for?
The Efficiency factor should help with charging efficiencies. Storage resources will also communicate their State of Charge with MISO in Real-Time.
Does MISO’s ESR model account for wear and tear and general degradation and deterioration of storage resources?
MISO’s ESR model does not have offer parameters specific to wear and tear, but MPs can account for these costs in their offers.
Are there any size limitations for an Electric Storage Resource?
FERC Order 841 established and MISO implemented a 100 kw minimum size for an Electric Storage Resource.
If resource is in continuous mode, how would MISO decide to switch between charging and discharging?
MISO will dispatch the ESR economically based on the offers. MP will be able to set the P/MW pairs from negative minimum to positive maximum. Resource will be dispatched economically based on those offers.
What is the significance of Commitment Status of Charging, Discharging and Continuous Must-Run treatment by MISO systems? And how is the ESR dispatched?
Certain commitment modes are treated as must-run by MISO market systems. The Market Participant is telling MISO when it is going to operate, and MISO is not committing these resources. The Market Participant tells MISO what mode it is in (i.e., discharge), then depending on offer parameters, MISO will dispatch the unit economically within those offers.
If an Electric Storage Resource is in Continuous mode, how would MISO decide to switch between charging and discharging?
MISO will dispatch the Electric Storage Resource economically based on its offers. The Market Participant will be able to set the P/MW pairs from negative minimum to positive maximum. The Electric Storage Resource will be dispatched economically based on those offers.
Are there any special considerations for Transmission charges for ESRs?
When an Electric Storage Resource is dispatched to charge to provide a service such as Regulation, it qualifies for an exemption from Transmission charges. In all other circumstances, an Electric Storage Resource is responsible for any Transmission charges that would apply.
How quickly will MISO potentially oscillate batteries between charge and discharge for Electric Storage Resource?
An Electric Storage Resource with a Continuous Dispatch Status can move between charge and discharge freely. In Continuous Dispatch Status with Regulation limits spanning from a negative minimum to a positive maximum, Regulation deployment setpoints can change between Charge and Discharge in each 4-second Automatic Generation Control (AGC) cycle.
Do Electric Storage Resources participate in the Day-Ahead and Real-Time Markets?
Yes. ESRs participate in both the Day-Ahead and Real-Time Markets and can clear differently in each.
How does the MISO Day-Ahead Market handle the Electric Storage Resource State of Charge (SOC)?
The MP provides an initial MW SOC and clearing proceeds off of that initial SOC MW. SOC impact on any Operating Reserve clearing is assumed to be zero (0) because the market won’t know how those reserves will be used in Real-Time.
In market clearing, if prices were right, could MISO continue to discharge or is there a catch so the Electric Storage Resource would only discharge for four hours (if four-hour battery)?
The market could continue to clear the resource if it is economic, and market would also respect the efficiency factor, SOC min and SOC max to account for feasibility based on SOC.
What are the must-offer requirements for ESRs that clear the Planning Reserve Auction (PRA) as Capacity Resources.
ESRs qualify as use-limited capacity resources are required to offer over the four hours of peak.
How often can an ESR update its offers, including Commitment Status.
Offers can be updated hourly. The MP can also use Real-Time Offer Override Enhancement (RTOE) to update up to ten minutes before a market interval.
What are Make-Whole Payment impacts of MP chosen Commitment Status?
The Electric Storage Resource model includes unique Commitment Status. Certain Commitment Status are treated as must-run by MISO market systems. The Market Participant is telling MISO when it is going to operate and MISO is not committing these resources. If MISO/operators dispatch the resource in a way that does not align with those offers then the resource would be eligible for Make Whole Payments.
What Make Whole Payments are Electric Storage Resources eligible for and how are Make Whole Payments effected by the Electric Storage Resource requirement to provide a Commitment Status as a part of its market offers?
Electric Storage Resources are eligible for Day-Ahead Margin Assurance Payment (DAMAP) and Real-Time Offer Revenue Sufficiency Guarantee Payment (RTORSGP). When called for an Emergency, Electric Storage Resources are eligible for Day-Ahead Revenue Sufficiency Guarantee Make Whole Payments and Real-Time Revenue Sufficiency Guarantee Make Whole Payments. On April 5, 2022, MISO filed a DAMAP tariff change in Docket No. ER22-1579 which would require the Commitment Status for Day-Ahead to match the Real-Time 5-minute Commitment Status in order to be eligible for DAMAP in a given hour. The specific rules for RTORSGP and DAMAP are in the draft Post Operating Process 5 Minute Calculation Guide which was posted with the March 2022 Settlements User Group (SUG) meeting materials.
Is MISO looking at implied spread in ESR offers or just using outright offers?
Only explicit ESR offers are considered in MISO markets. MISO is not including a spread bid in its ESR participation model.
Can a storage resource on Distribution participate in the Wholesale MISO market sometimes, but also provide services at the distribution level such as peak shaving?
As a part of Attachment HHH, the Market Participant is required to inform MISO if it is performing / being paid for any other services at retail. Any time the resource is providing a service outside of MISO, the Electric Storage Resource would need to be transparent and provide an accounting of the retail and wholesale functions. Offers in MISO Markets should reflect when the Electric Storage Resource is available to MISO.
If an Electric Storage Resource is discharged manually by MISO which prevents it from honoring its Day-Ahead schedule in a later interval, what are the Make Whole Payment implications? Is the Market Participant required to buy back its later Day-Ahead position that is may not be able to meet because of MISO’s manual dispatch to discharge the resource? Any additional rules or caveats that may apply to an Electric Storage Resource with a capacity resource must-offer obligation?
An Electric Storage Resource would need to buy back their day ahead position but would be eligible for Day Ahead Margin Assurance (DAMAP) make whole payment. For the second question, since Electric Storage Resources are self-committed and are treated as Must-Run, Electric Storage Resources are ineligible for Day-Ahead and Real-Time Revenue Sufficiency Guarantee make whole payments except for when committed for an Emergency. Electric Storage Resources are eligible for DAMAP and Real-Time Offer Revenue Sufficiency Guarantee Payment make whole payments. There are no special rules for units with capacity must-offer obligations.
Does MISO ’s ESR participation model optimize ESR State of Charge and/or choose the most profitable hours to charge and discharge?
MISO does not optimize the ESR SOC or choose the best hours to charge and discharge. The MP is responsible to manage its SOC through commitment statuses and other offer parameters. The Market will clear the resource in each interval based on their offers. MISO does not make commitments of ESRs to bring them online except Emergency and Contingency Reserve Deployment instructions.
Will Storage Energy Resource -Type II be retired and replaced with the Electric Storage Resource participation model?
Yes. Although MISO is providing a transition period, MISO intends to retire Stored Energy Resource – Type II as soon as June 2023. If a storage resource intends to participate as Demand Response after this transition, the Market Participant should explicitly register the resource as a Demand Response Resource.
How is MISO’s Electric Storage Resource Participation applicable to hybrid resources?
MISO doesn’t have a Hybrid participation model. MISO has been considering Hybrid Resource participation and looking at how these Resources can participate in MISO markets existing models. Although MISO has been investigating the possibilities for hybrid resource participation, it has not yet determined whether and to what extent a hybrid resource could operate as an Electric Storage Resource.