2026-SC-INT 00009 Published On: 07/24/2026
Question: Duke's "Substation Configuration Guideline for Transmission Inverter Based Interconnections" says that for a greenfield substation for an inverter based resource, the total site capacity within 1 mile must be less than 100 MW. Does that mean that the inverter based resource (like BESS) that wants to tap a line must be less than 100MW? Since the RFP only allows bids in 25MW increments, would the only permissible size for a tap be 25, 50, or 75 MW?
Answer: An inverter based resource must be less than 100 MW to be considered for a single breaker tap interconnection. If an IBR project is 100 MW or greater or the third IBR interconnection on a single transmission circuit, the IBR will be required to connect via multi-breaker switching station (MBSS). Depending on location and configuration, being less than 100 MW does not guarantee that the interconnection will be via a single breaker tap interconnection.
In the 2026 SC Battery RFP document section IV.D. (Proposal Evaluation), during Step 2 when considering risk of Network Upgrade costs and interdependencies, the Companies reserve the option to request some Proposal size flexibility, but such flexibility will only be used if both parties agree. For example, if reducing a 100 MW project to 99 MW would avoid an MBSS, the Companies may ask the party if they would be willing to reduce the project size (however, there may be other reasons an MBSS is required for a site). As noted in the detailed footnote in section IV.D on page 21, the maximum reduction percentage is based on Sections 4.4.1 and 4.4.2 of the Modifications section of the FERC LGIP (decrease only). Also, the sizing change does not have to occur at the end of the RSC Phase 1 study (e.g., Phase 2 RFP Evaluation) if a benefit to the downward size is identified earlier.
2026-SC-INT 00008 Published On: 07/22/2026
Question: At what stage in the process will the evaluation team confirm that the point of interconnection (POI) requested is valid? If the POI validation occurs prior to the Step 1 RFP evaluation, and the POI is not valid and the bidder cannot be cured, will the bid fee be returned?
Answer: The RFP Evaluation team will confirm with the Renewable Integration team that the requested point of interconnection (POI) is valid during the RFP Step 1 evaluation phase and during the RSC pre-Phase 1 Customer Engagement Window, both of which occur after the close of the Cluster Request Window, currently scheduled for August 5.
The Proposal Fee is non-refundable; interconnection deposits are separate from the RFP proposal fees. Step 2 proposal security will not be collected for the RFP if there are issues identified with the POI. If the POI is determined to be invalid during the RSC pre-Phase 1 Customer Engagement Window, the Interconnection Customer will be responsible for and charged its share of the cost allocations incurred during that window. The remaining study deposit and the Commercial Readiness Deposit will be refunded to the Interconnection Customer (see DEC / DEP LGIP Section 3.4.4).
2026-SC-INT 00007 Published On: 07/22/2026
Question: Is there a mechanism to compensate for change in IFC estimates included in the bid price versus the actual IFC in the final accounting register of the project?
Answer: There is no mechanism to compensate for changes from estimated to actual Interconnection Facilities costs. Reference DEC and DEP Standard Interconnection Cost Estimates document for guidance on the Interconnection Facilities cost.
2026-SC-INT 00006 Published On: 07/22/2026
Question: If the COD of the project changes as part of IX study results, will there be an opportunity to adjust the pricing?
Answer: COD changes due to network upgrades identified in RSC Phase 1 interconnection study and any iterations during Step 2 of the evaluation process (see Section VI. D. of the RFP document “Step 2”) would not adjust bid pricing. The Companies may decline a proposal if the Companies determine through Step 2 of the evaluation process that network upgrades or interconnection facilities required to interconnect the facility cannot be constructed in time to achieve COD by December 31, 2031 (see Section II of the RFP document). A Finalist may decline to participate and receive a refund of their Step 2 Proposal Security if the in-service date identified in the Phase 1 RSC report or iterations is after December 31, 2032 (see Section V.B.2. of the RFP document). Network upgrade costs will be considered as part of evaluating cost effectiveness of the portfolio of selected proposals (see Section VI. E.2. of the RFP document).
2026-SC-INT 00005 Published On: 07/13/2026
Question: Is a PSCAD model needed by 8/5/26 for RFP submission? Or it can be provided later?
Answer: PSCAD / PSSE models are required at the time of the interconnection application submission. Sections 7h, 7i and 8h of the Inverter Based Resource Data Request form located on the OASIS site (Duke_Energy_Inverter_Based_Resource_Data_Request_Form_(DEC,DEF,DEP).pdf (oati.com)) provides guidance for inverter and reactive power PSSE modeling.
2026-SC-INT 00004 Published On: 07/08/2026
Question: For 2026 SC Battery RFP, can the study deposit be posted as a Letter of Credit or it needs to be posted as cash?
Answer: The Study Deposit must be posted as cash.
2026-SC-INT 00003 (revised 07/07/2026) Published On: 07/07/2026
Question: We would like to oversize our interconnection request at time of interconnection application over and above the max allowable 100 MW indicated by the RFP. Are we able to do that via the RSC, or do you require a separate interconnection application for the second phase?
Answer: RSC interconnection request amounts must relate to only eligible projects sizes in the 2026 SC Battery RFP document section B(a) for UOT proposals and section B(b) for ESSA proposals and not oversized.
2026-SC-INT 00002 Published On: 06/25/2026
Question: What date will the 2026 Resource Solicitation Cluster (RSC) open?
Answer: The 2026 Resource Solicitation Cluster (RSC) used for the 2026 SC Battery RFP will open July 15, 2026. This date will be updated in 2026 SC Battery RFP Document 11 and posted on or around July 7 with final documents to the RFP website.
2026-SC-INT 00001 Published On: 06/05/2026
Question: As we finalize our site selection and preliminary engineering, we have a question regarding transmission interconnection parameters. Could you please clarify where there are any interconnection restrictions by line voltages? If so, do they apply equally for DEC and DEP?
Answer: Projects must be directly interconnected to the Duke Energy Carolinas (DEC) or Duke Energy Progress (DEP) transmission system. For Utility Ownership Track (UOT) proposals, Preferred Battery Facility GSU Sizing is provided in Document 10, available at https://www.dukeenergyrfpcarolinas.com/2026-SC-Battery-Documents.