2023 RFP: Frequently Asked Questions


DOC 00060
Published On: 05/30/2024

Question: We received an award in both the APA (UOT) and PPA tracks in this year’s RFP. After reviewing the documents, we are not clear on what would happen if we submitted a partially executed LOI (UOT) or PPA in advance of the 6/13 deadline, but Duke Energy fails to countersign by 6/13 at 12PM ET. Is Duke Energy given a grace period to complete their countersigning process? If so, how long is that grace period? Or would that scenario jeopardize that project’s ability to move forward?

Answer: Yes, there is a grace period for the Companies to complete the countersignature process. If the Companies need additional time beyond the 6/13 date to countersign, the Companies will communicate their need for additional time with the Interconnection Customer as soon as possible, and the Companies’ need for additional time to countersign will not jeopardize the project’s ability to move forward.

DOC 00059 (revised 05/31/2024)
Published On: 05/30/2024

Question: It appears the solar plus storage PPA [for the 2023 RFP] does not establish a maximum limit to delivered Product, or a limit after which compensation is not due. Please would you confirm that Duke will purchase any amount of product generated by the facility and delivered to the POI?

Answer: There is no maximum limit in the PPA, as long as the nameplate capacity rating of the project does not exceed the rating established by the PPA (Section 19.11). Duke will purchase any amount of product generated by the facility and delivered to the POI in accordance with the PPA, which provides that DEC/DEP have full charging and discharging rights of the battery.

DOC 00058
Published On: 05/29/2024

Question: Can you please point me to the RSC requirements and process?

Answer: Refer to Appendix O, available at https://www.dukeenergyrfpcarolinas.com/RFP-Documents.

DOC 00057
Published On: 05/29/2024

Question: Can Duke please share Exhibit B10 Form EPC Agreement that is noted in the LOI for BTA/Asset Proposals? Our team did not see this Form in Appendix L.

Answer: The EPC Agreement has been posted to the documents section for the 2023 RFP as “Solar_&_BESS_EPC Agreement_(2023)–Carolinas_RFP_Final”.

DOC 00056
Published On: 03/28/2024

Question: This question is regarding the Renewable Power Purchase Agreement (Appendix A1 in the RFP Documents). Referring to Section 5, the language in 5.3 states, “If Seller is Creditworthy and is not in default of any provisions under this Agreement the Seller shall be excused from the requirement to post Performance Assurance as required under Sections 5.1 and 5.2 above, as long as it remains Creditworthy." However, Section 5.1 says “For purposes of clarity, Seller shall not be permitted to provide a Guaranty as Performance Assurance for purposes of satisfying Seller’s obligations under this Section 5.1.” Can you please clarify if a Guaranty from a creditworthy seller is acceptable for Pre-COD Performance Assurance?

Answer: If Seller is required to post Performance Assurance as described under Sections 5.1 (Pre-COD) and 5.2 of the aforementioned document, such Performance Assurance shall be in the form of cash or a Letter of Credit. For post-COD Performance Assurance under Section 5.2, a parent company guaranty meeting the requirements under the PPA will be considered.

DOC 00055
Published On: 02/27/2024

Question: I am reaching out for additional information concerning required practice for ALTA surveys for projects that may be selected as UOT or asset transfer in the Duke 2023 RFP and would like to confirm that only Duke approved vendors may be used for these services. If this is the case, can you please provide information regarding the process for adding a surveying company to the AVL?

Answer: Additional information concerning surveys can be found in Appendix P, which includes a list of approved survey vendors (see attachment 2). The RFP encourages bidders to use survey vendors from the provided list. Should a bidder seek to request additional vendors be added, those requests can be submitted to the RFP Manager.


DOC 00054
Published On: 01/23/2024

Question: Can Duke confirm is Fortune Electric is an approved equipment vendor? We have been in discussions with them regarding GSUs and they are saying they've been approved by Duke, but we did not see them on the AVL.

Answer: Fortune Electric is not an approved equipment vendor, and is not listed in the AVL at this time.

DOC 00053
Published On: 01/19/2024

Question: 1) Do we need to leave the contract no., contract date and surety bond effective date on page 1 of the Surety Bond blank for the Step 2 Security submission on 1/22/24? It is my understanding that Duke would provide the contract no. and date. 2) If we leave the dates blank on page one, I assume we leave the signed and sealed date blank? Please advise?


  1. For the contract number please use the project’s 6 digit unique ID, the same one used on the bid forms. For the contract date please use TBD, or a blank is also acceptable; if the project has a signed interconnection agreement the execution date of that contract should be used. The surety bond effective date will be the date it is submitted but should be no later than January 22, 2024.
  2. The signed and sealed date (on page 4 of the surety bond form) should coincide with the effective date and shall be no later than January 22, 2024.  

DOC 00052
Published On: 01/18/2024

Question: Is there any flexibility on CODs for projects that were bid into this RFP? For example, would Duke be open to discussion regarding adjusting COD dates if we were to reach commercial operations earlier/later than what was originally bid, assuming it was prior to final PPA negotiations/execution?

Answer: Please see FAQ DOC 00015.

DOC 00051
Published On: 01/16/2024

Question: We have a few questions on the mechanics of posting the Surety as Step 2 Proposal Security: (1) Are Wet Signatures required for Appendix D (Form of Surety Bond)? (2) What date should go in section C of Appendix D? Should it be the RFP issuance date or the RFP award date? (3) If wet signatures are required, are there ways we can protect around unforeseen winter delays such as storms to avoid being excluded? For example in addition to putting in the mail, email over a tracking number, scanned documents, and/or a docusign for Appendix D?


  1. Electronic signatures are acceptable.
  2. For item c. of Appendix D, please use 06/28/2024.  
  3. Refer to FAQ DOC 00049 - hardcopies of the Surety Bond are not required. Please send the electronic documents to PPA@duke-energy.com.

DOC 00050
Published On: 01/11/2024

Question: Our treasury team would like to confirm to make sure that we just need to physically deliver the LC and we can just electronically deliver. Can you please confirm?

Answer: The response in FAQ DOC 00049 applies to Letters of Credit as well. Hardcopies of Step 2 Proposal Security documents are not required. 

DOC 00049
Published On: 01/10/2024

Question: We are intending to provide a Surety as Step 2 Proposal Security substantially in the form provided in the RFP documents. Do you require a hard copy be provided in addition to the electronic copy?

Answer: No, an electronic copy is acceptable.

DOC 00048
Published On: 12/11/2023

Question: We requested that Duke issue invoices to facilitate a cash posting for the Step 2 security. We would like to preserve the optionality to post in the form of a surety bond or a Letter of Credit. Can you please confirm that we have the option to select a different form of security through January 5th? We will provide any requested redlines to the letter of credit or surety forms by December 8th.

Answer: Confirmed, projects invited to Step 2 of the RFP will have 10 business days to post an acceptable form of Proposal Security. For details on what forms of security are acceptable to the Companies, see Section V. RFP Process, J. Step 2 Proposal Security.

DOC 00047
Published On: 12/07/2023

Question: I had a quick question regarding the Step 2 Proposal Security. I understand the form of Surety Bond can be found in Appendix D. For clarity of posting process, will Duke be providing a Word version of the Bond From that is acceptable in order for participants to fill in required information? Or will Duke be providing fully-populated bonds specific to each project with dollar amounts and project detail in PDF to just have blanks be filled in and signed/notarized by surety?

Answer: A fillable pdf will be posted for use by bidders once or before the Step 2 invitations are sent for bidders to update with all project-specific information.

DOC 00046
Published On: 12/07/2023

Question: Can you confirm that there have not been any changes to the surety bond form that will be used for [Step 2] bid security? I didn't see any redlines. We used that form successfully last year, and if there haven't been any changes, we'd prefer not to spin up any surety providers with a draft form until we know if we've been selected or not.

Answer: The surety bond form did not change for the 2023 RFP.

DOC 00045
Published On: 12/07/2023

Question: As requested in the correspondence from 11/27 ‘ Announcement regarding Step 2 Proposal Security’, we are working to prepare a draft of the surety for CRAI review in advance of the 12/8 response deadline. Our surety provider was wondering what should be listed in the “Contract Number” section of the bond form. Can you confirm what that refers to, specifically in the context of Step 2 proposal notifications?

Answer: Please use the project's Unique ID or queue number for the "Contract number."

DOC 00044
Published On: 12/02/2023

Question: A follow up question on DOC 00043. When does a Bidder submit Appendix E? By Dec 8th? Or, is there a time or process milestone that triggers its submission?

Answer: The information requested in Appendix E was also requested in the Bid Input Forms under the Required Financial Information section. This information was to be submitted by the proposal due date, September 29, 2023.

DOC 00043
Published On: 11/30/2023

Question: Is it appropriate to assume that information requested in Appendix E applies only to the Asset Transfer or Build Own Transfer bids and the associated evaluation of the credit support for those bids?

Answer: Appendix E (Required Financial Information) is applicable to all bids, not just Asset Transfer and Build Own Transfer.

DOC 00042
Published On: 09/28/2023

Question: Can you please provide clarification on what ratio you are looking for on line 51 in the SPS PPA Bid Input form that requests the “DC/AC Ratio: (Inverter Loading Ratio)”? Is this referring to the DC/AC ratio at the project’s POI (MWdc/MWac) or at the inverter terminals (MWdc/MWac)? If this is specifying the inverter terminals do you want it to represent the ratio of MWdc over Inverter Nameplate (MWac)?

Answer: Please use the installed nameplate MWdc divided by the MWac rating at the point of interconnection.

DOC 00041
Published On: 09/28/2023

Question: When is the interconnection request agreement due? The agreement says it is available to Oct. 28th 2023. I do not know if we should sign this agreement as soon as possible or wait for Duke feedback on any potentially identified deficiencies.

Answer: The Interconnection Request Agreement is your filled out Interconnection Application. It needs to be signed and dated for the Interconnection Request to be considered complete by the due date – September 29, 2023, at 12:00 pm EDT (noon) for third-party market participant-sponsored proposals; there should be an AdobeSign email in the Inbox of the primary contact listed on the Interconnection Portal.

DOC 00040
Published On: 09/28/2023

Question: Following up on FAQ DOC 00038. In the “Appendix_Q1-UOT_Energy_Storage_Requirements_6-20-23.pdf” file, what is meant by “8. Aux Consumption” for the time series output? This is unclear as this does not represent a location.

Answer: Aux consumption represents the summation of auxiliary loads for battery containers, inverters, DC/DC converters (if applicable) and site control center (IT/telecom racks, relays, power plant controller racks etc.).

DOC 00039
Published On: 09/26/2023

Question: The Solar + Storage Additional Questions from Row 479 to Row 538 (BESS Facility, Battery Degradation), Row 555 to Row 579 (BESS Enclosure), and Row 590 to Row 606 (Power Conversion System PCS) of the SPS UOT Bid input form do not seem necessary for an Asset Transfer proposal, especially in light of answer DOC 00030 that many rows that are similarly detailed questions about the BESS will be answered "N/A". Can you confirm that Row 479 to Row 538, Row 555 to Row 579, and Row 590 to Row 606 of the SPS UOT Bid input are also "N/A" for Asset Transfer proposals?

Answer: Please reference DEC 00030. For SPS UOT proposals submitting as an Asset Transfer, rows 479 to 538 (Battery Degradation) are required, rows 555 to 579 (BESS Enclosure) are required and rows 590 to 606 (Power Conversion System PCS) are required.

DOC 00038
Published On: 09/26/2023

Question: In regard to RFP pg. 9 Section C. Requirements Specific to Solar Paired With Storage Facilities, it states "For SPS Facilities that bid into the UOT Track, the sponsor must demonstrate the initial storage capacity amount relative to the minimum guaranteed capacity complies with its battery system warrantees, as described in Section IV. A of this RFP and Appendix Q". Can you clarify what we are expected to submit for this - is the expectation that we will fill out Appendix Q2 UOT Bess Profile? If so this excel sheet only has a single time series on it, whereas Appendix Q1 asks bidders to provide a time series profile at 8 separate locations. Additionally, our understanding is that Duke would be controlling the dispatch of the battery, we aren't clear what Duke is looking for with the discharge schedule if that is the case. Clarification on what's expected with our bid submission would be helpful.

Answer: The expectation is that bidders will follow the requirements provided in Appendix Q1 and Q2 to size battery energy storage systems (BESS). Simply describing the operating characteristics of the cycle for proper sizing 365 cycles/year and duration are not enough, the type of cycle (depth of discharge, average SoC, max/min SOC, etc.) all have significant impact on degradation and impact battery sizing decisions. Duke Energy has provided guidance on parameters for sizing in Appendix Q1 and Q2. Appendix Q1 provides information about modeling assumptions and Appendix Q2 provides guidance on the dispatch profile, which should be used for sizing. Duke Energy expects bidders to follow these guidelines to deduce and provide the battery energy capacity degradation over 15 years. Bidders are expected to submit a time series profile similar to the guidance provided in Appendix Q2. Appendix Q2 shows the power profile at Point of Interconnect (POI), whereas Appendix Q1 establishes the power profile needs at seven (7) other locations. These details will help Duke Energy verify the BESS design and losses from the battery terminal all the way up to the POI.

DOC 00037
Published On: 09/25/2023

Question: For projects submitting both UOT and PPA proposals, understanding that both forms need to be submitted, do sections that are duplicated in both forms need to be filled out in each form? For example, does site control need to be filled out with the same information in both the UOT and the PPA form for the same project?

Answer: Each bid input form will only apply to the respective proposal type it is meant for. If certain information across PPA and UOT proposals is identical, it still needs to be included in each bid input form. 

DOC 00036
Published On: 09/25/2023

Question: Please provide the template for the SPS 8760s which is requested in the bid sheet.

Answer: Please use the guidelines in Appendix I1 – Site Layout and PVSyst Guidance in lieu of a template.

DOC 00035
Published On: 09/25/2023

Question: Appendix Q1, page 3 requests a "time series profile" at 8 identified locations. Can Duke elaborate on the meaning of "time series profile" in this context or share an example?

Answer: The “time series profile” refers to a profile similar to what is provided in Appendix Q2- UOT_BESS_Profile, posted at Duke Energy RFP Carolinas > RFP Documents on June 21, 2023.

DOC 00034
Published On: 09/25/2023

Question: Could you link to the 8760 template or confirm it is the same as what was used last year? It doesn't seem to be on your RFP documents section.

Answer: For PPA proposals, you may use the 8760 Production Profile Template from the 2022 RFP, now available at https://www.dukeenergyrfpcarolinas.com/RFP-Documents. Please also review the response in FAQ DOC 00023, which states that UOT proposals shall include an 8760 hourly production profile for all years of operation.

DOC 00033
Published On: 09/25/2023

Question: Regarding the S+S PPA, section 8.8 refers to tax credit losses but also notes "except as set forth in section 8.9", and section 8.9 refers to compensation for energy value but is not explicit about lost tax credits. Would you please confirm whether or not there is compensation for lost tax credits caused by a Dispatch Down due to compliance with Control Instructions, assuming not related to the limitations in 8.9.2?

Answer: The Seller will not receive compensation for lost tax credits due to a Dispatch Down Control Instruction. Section 8.9.1 defines the compensation the Seller shall receive for a Dispatch Down Control Instruction as the “Contract Price times the amount of Energy that could have been generated but was not generated due to compliance with and implementation of the Control Instruction”. The Contract Price does not include the value of tax credits so this value will not be included in the compensation for control instruction dispatch down.  

DOC 00032
Published On: 09/22/2023

Question: I had a question about line 287 on the UOT SPS RFP response form. "Provide a Description of the Project's Access to Distribution Power for Construction, Transmission Interconnection Facilities, and O&M Facilities. Provide Map of Infrastructure." I have been having trouble trying to obtain this information from other departments within Duke Energy. It seems to cause some confusion when requested, unfortunately. I was wondering if you had any guidance or recommendations on who at Duke Energy to contact for this information. Can I call one source, or will it be different for DEP projects and DEC projects?

Answer: It’s typical that when constructing a solar or SPS facility, that distribution power will be needed for construction efforts, such as providing power to construction trailers and back-up power to the substation. Thus, the question seeks to understand what investigation the bidder has done to understand and confirm that distribution power is available to the project site. It should be noted that Duke Energy is not the distribution provider for every local area around company-owned transmission lines and could be served by a municipality or co-op.

DOC 00031
Published On: 09/20/2023

Question: Can you clarify the requirement in the Offer Form referring to "Details related to the Bidder's Banking Relationships or Liquidity" required in the Offer Form?

Answer: Please provide any bank letters or statements that demonstrate your company’s ability to finance a large Transmission Connected Generating Facility.

DOC 00030
Published On: 09/20/2023

Question: Is the Solar + Storage Additional Questions section beginning Row 479 of the SPS UOT Bid Input form required for Asset Transfer proposals?

Answer: For SPS UOT proposals submitting as an Asset Transfer, the following SPS bid form lines can be responded to with “N/A”: Battery Racks & Cells (rows 540-552), Battery Collection System (rows 582-584), BMS (rows 586-588), Codes & Standards (rows 621-623), Fire Safety (rows (625-627), Controls (629-633) and Battery Recycling/disposal (rows 635-636).

DOC 00029
Published On: 09/19/2023

Question: For the Offer Form, what type of files would serve as evidence of qualifying for the Prevailing Wage Requirements?

Answer: Please provide any and all relevant documentation to support the bidder’s claim that the project will or plans to qualify for the Prevailing Wage Requirements; examples include - signed contracts, language from proposed contracts or a file describing the bidder’s plan to qualify, etc.

DOC 00028
Published On: 09/19/2023

Question: Do UOT proposals required a full project schedule? Row 170 of the Bid Input Form is labeled Project Developement Schedule/Anticipated COD but unclear as to whether the full schedule is requested or only the information specified in Row 171 (all activities taken to advance the project to construction).

Answer: Row 171 of the Solar-Only UOT bid form requesting a document describing all activities taken to advance the project to construction is required of all UOT proposals. The same question is asked on the SPS UOT bid form as row 159 and is also required. The Key Milestone Schedule rows 174-195 on the Solar-Only bid form and rows 160-184 on the SPS UOT bid form are required of all Build-Own-Transfer (BOT) proposals only.

DOC 00027
Published On: 09/18/2023

Question: Can you expand on line 288 of the of the UOT SPS bid input form: "Provide the Project's Investigation into the Availability of Communications Required for Transmission, Such as OPGW, Fiber (Dedicated or Third-Party)"? Specifically, which speeds, and which internet types should we screen our project areas for? Are you only looking for fiber for instance? Is DSL relevant? Is it relevant if fiber is not on site, but is adjoining the property?

Answer: For projects submitting interconnection requests into the 2023 RSC,the response to line 288 on the bid form should be “project being studied in the 2023 RSC”. For projects not submitting into the 2023 RSC and that have instead executed interconnection agreements, please address the project’s plan for communications including transmission transfer trip. Additional information for inverter based resources is available on OASIS www.oatioasis.com/duk in the folder “Generator Interconnection Information\IBR Interconnection”.

DOC 00026
Published On: 09/15/2023

Question: Is the expectation that the production values provided in the PPA bid submission are from the PVSyst modelling requirements? Or are the PVSyst modelling requirements used for validation, should bidder choose to include production values from an internal energy modelling source?

Answer: The 8760 Generation Profile (P50) requested for PPAs is to be from PVSyst, and the intent of this information is for validation purposes, if needed. The Annual Plant Production requested should represent the bidders P50 estimate of the annual energy volumes, which possibly did not use PVSyst, and will be the basis for the LCOE calculation, and quantities that go into the PPA. 

DOC 00025
Published On: 09/13/2023

Question: In the Appendix I1 for Soiling Loss it says to use the PVUSA Dust profile and Duke Energy Soiling tool V11. Where can this soiling tool be found?

Answer: Bidders should follow the guidance for preliminary models and use 0% for all months in the soiling profile.

DOC 00024
Published On: 09/12/2023

Question: It appears that there are no .OND files in the provided zip folder for Appendix I. Can you please provide the approved inverter .OND files?

Answer: Please see the 'PVsyst OND Files' zip folder added to the Documents section of the RFP website on September 12, 2023. Linked here: https://www.dukeenergyrfpcarolinas.com/RFP-Documents.

DOC 00023
Published On: 09/08/2023

Question: Under the "Other" section in the Bid Input Form, a 8760 Generation profile for Year 1 is requested for Solar-Only and SPS project. However, on page 36 of the RFP Protocol, it says that "Solar-Only (and SPS) Facility Proposals shall include an 8760 hourly production profile for all years of operation as part of their Proposal. Should these be submitted in the same document or separately?

Answer: For PPA Track proposals, an 8760 hourly production profile for all years of operation is not required; bidders shall provide all data requested in the bid form.

For UOT proposals, pursuant to Section IX.C (Production Estimates) of the RFP, all proposals shall include an 8760 hourly production profile for all years of operation, in accordance with Appendix I. Row 236 of Solar-Only UOT bid form requests “Provide PVSYST Project Files (.zip archive).”  Row 225 of Solar Plus Storage UOT bid form requests “Provide PVSYST Project Files (.zip archive).”

DOC 00022 (revised 09/07/2023)
Published On: 09/07/2023

Question: As our team has been filling out the UOT bid forms, we noticed a few issues and wanted to get guidance on how to address the items below.

Duplicative rows for Geotech:

  • Solar-Only UOT Bid Form: Rows 128-129 are duplicates of rows 108-109.
  • SPS UOT Bid Form: Rows 112-113 are duplicates of rows 92-93.

Row requires file name but can only input Yes/No:

  • Solar-Only UOT Bid Form: Row 131 (Wetlands Report) and row 135 (Additional Site Specific Studies).
  • SPS UOT Bid Form: Row 115 (Wetlands Report) and row 120 (Environmental Liabilities).

Answer: Thank you for your feedback.

  • Duplicative rows for Geotech: Please provide the Geotech info in the duplicate rows as well.
  • Row requires file name but can only input Yes/No: Use the Notes section (to the right of each field) to provide the file names.

DOC 00021
Published On: 09/04/2023

Question: Will Duke Energy be accepting any redlines that are submitted with the NDA?

Answer: Duke Energy declines to adopt proposed changes to the NDA/Confidentiality Agreement; the NDA contains commercially reasonable, standard contract provisions that are applicable to all Market Participants and used by the Companies in similar transactions. Duke Energy is committed to treating confidential Market Participants appropriately and in accordance with the NDA.

DOC 00020
Published On: 09/04/2023

Question: Can you clarify this question in the Bid Input Form: "Has the project been evaluated for environmental justice in accordance with the Justice40 Initiative?" Is this something done at glance by the developer? Or does an EEJ assessment need to be submitted to the DOE?

Answer: This bid form question seeks to understand what, if any, environmental justice screening or due diligence the developer has completed related to the proposed project. The U.S. Government has created the Climate and Economic Justice Screening Tool (“CEJST”), a geospatial mapping tool designed to identify disadvantaged communities that are marginalized and overburdened by pollution and underinvestment. The CEJST can be found here: Justice40 Initiative | Environmental Justice | The White House. Additionally, the EPA developed an EJ mapping and screening tool called EJScreen, a nationally consistent dataset and approach for combining environmental and demographic socioeconomic indicators. EJScreen can be found here: EJScreen (epa.gov).

DOC 00019
Published On: 08/30/2023

Question: Is there a requirement for maximum rest period for the Solar-plus-Storage PPA? It doesn't seem to be defined in Exhibit J.

Answer: There is not a requirement for the maximum rest period for the SPS PPA projects.

DOC 00018
Published On: 08/28/2023

Question: Two questions regarding Appendix I: In the "PVsyst Project Model Configuration Specifications and Settings," on page 5, for preliminary tracking models, Duke has specified Backtracking should be ON (checked) and the Use Electrical Effect option should be checked. This is not possible to do in PVSyst. The option for Electrical Effect is removed when Backtracking is on. Please clarify. On page 7, the setting for Loss Fraction at STC shows lower losses for string inverters than for central inverters. Assuming the string inverters are distributed, we would not expect a lower loss fraction. Please confirm that these values are correct.

Answer: Part 1) for unlimited trackers, The Electrical Effect option is disabled and not used when Backtracking is enabled. Electrical Effect should be selected when Backtracking is not used. Note: Per the PVsyst Guidance, “Near Shading 3D Scenes shall be implemented as part of the model or a 1.5% Net Capacity Factor reduction will be applied to ensure these losses are accounted for.”

Part 2) there is an error in the AC losses for the inverter > Loss Fraction at STC section. The values are reversed and the correct guidance is: Calculated from wire length and wire size. 1.5% for string / 0.5% for central inverters for preliminary. An updated Appendix I1 has been posted at https://www.dukeenergyrfpcarolinas.com/RFP-Documents.

DOC 00017
Published On: 08/28/2023

Question: The response to FAQ DOC 00014 said that a 40-year total term (our form lease is currently 41 total years) does not meet Duke’s UOT site control requirements, but I am failing to understand how a lease that only contains Duke’s minimum requirements of “18 months for construction” and “35 years of operation” is preferable to having 40 (or, in our case, 41) total years. In practice, if the lease only allows 18 months for the construction term (Duke’s stated minimum), and then only 35 years of operation (again, Duke’s stated minimum), that equals 36.5 total years. There is no mention of extraordinary rights nor discrepancies in rent paid during the “construction term”, so this feels like a semantics discussion around “construction term”. Even though our form lease doesn’t explicitly call it a “construction term”, Duke would have 6 years to build the system while maintaining the required 35 years of operation. Conversely, assuming a lease conformed with the minimum requirements of an 18-month construction term and a 35-year operation term, if, for whatever reason, construction lasted longer than 18 months, Duke would have less than a 35-year operational term as the residual construction time would carry into the operational term. I am not clear on how that is a preferable structure. Can you shed some additional light on the reasoning here?

Answer: As stated in DOC 00014, Duke requires a minimum of 35 years of an operating term commencing at placed in service, it should be noted that the operating term should start at placed in service, such that the operating term aligns wholly with the 35 year asset life of the plant. To illustrate, if a lease had a 40 year term commencing at start of construction and construction lasted 17 months, the timing of when the lease ends no longer aligns with the period being 35 years from placed in service. That is the primary challenge Duke is attempting to solve with this guidance. For selected UOT winners, Duke may work with the bidder on modification needs to the site control agreements.

DOC 00016
Published On: 08/25/2023

Question: Can you please provide a checklist of all the documents required for submission by the 9/29 deadline for Solar-Only and SPS projects? It is unclear in the RFP Protocol when some documents are due. For instance, there is an NDA document among the RFP documents but there is no mention of when it should be executed.

Answer: Proposals in this RFP are expected to include the following:

All items listed above must be submitted by the Proposal Due Date - September 29, 2023 at noon ET for third-party sponsored proposals.

DOC 00015
Published On: 08/22/2023

Question: Could you please clarify whether the requested start date of 12/31/2027 listed under the BESS specifications in the SPS bid input form is the target COD for all SPS Controllable PPA track proposals (barring delays from interconnection timelines)?

Answer: The general assumption is that projects in the 2023 RSC will be able to come online by the end of 2027, but the Companies recognize that there may be certain interconnection timing issues that would push the COD to a later date. Per RFP Section III.A., the companies reserve the right to decline a proposal with a COD past 11/30/2028.

DOC 00014
Published On: 08/22/2023

Question: Several questions regarding listed UOT requirements: (1) In Q&A response DOC 00010 (revised 08/12/2023), it was stated that "Appendix I has been updated to allow crystalline bifacial 550-580W modules", however the current version of Appendix I only lists QCells 570W as an acceptable module. Can we take the Q&A response to mean that MPs can propose either 570W or 580W since QCells offers both sizes in the same module model? (2) Appendix I states that areas listed as having potential for bedrock at 150cm or less, according to NRCS, should be excluded. Is this an absolute requirement? Or can the MP propose to utilize those areas since the presence of bedrock has not yet been confirmed by geotechnical investigation, provided that a mitigation method (such as pre-drilled mechanical installation) is also explained within the bid? (3) The RFP document states that UOT projects require leases to include at least 18 months of a "construction term" and a minimum of 35 operational years. If the existing leases are structured to commence rent during construction, but include a 40-year total term, does this meet that requirement (since 35 years + 18 months = 36.5 total years, which is safely covered by the 40 available years)?

Answer: (1) Yes; however, for Asset Transfer bids, the specified module wattage of 570 W in Appendix I represents what the UOT feels most comfortable in representing on a site layout given the volatility of the module market and ensuring there is adequate space allocated for the PV array. The module restriction only applies to Asset Transfer bids and allows for a more direct initial evaluation of projects.  

(2) It is acceptable that the bidder overlays the NRCS layer on the site plan, detailing how many acres of the project fall within the specified bedrock depth in lieu of excluding all together. A cost adder for pre-drilling or other mitigation method should be included, if BOT bid, for Asset Transfer bids, the Utility Ownership Team will account for this in the cost to build the project that it submits to the RFP Manager.  

(3) No, as outlined in section IV.A of the RFP, bidders that use lease agreements for site control are expected to provide (i) a minimum of 18 months of a construction term and (ii) a minimum of 35 years of an operating term commencing at placed in service. Please note that the requirement is that the operating term commence at placed in service and be a minimum of 35 years from that milestone. Thus a lease that terminates 40 years after start of construction would not satisfy this requirement.

DOC 00013
Published On: 08/22/2023

Question: Can you please confirm that the site layout requirements (specifically the module assumptions) in Appendix I apply only to asset transfer and BOT proposals, and not Controllable PPA track proposals?

Answer: Duke Energy confirms the layout requirements apply only to asset transfer and BOT proposals.

DOC 00012
Published On: 08/18/2023

Question: Can you please provide the Canadian Solar 565W module Datasheet and PAN file?

Answer: Please see Appendix I and I1 updated August 14, 2023 and available at https://www.dukeenergyrfpcarolinas.com/RFP-Documents.

DOC 00011
Published On: 08/16/2023

Question: Under Utility Ownership Track (page 11) one of the points states the it must be designed to meet Dukes design criteria "see Appendix L EPC Agreement exhibits", that Appendix is for BESS projects. Will this EPC agreement apply to both BESS and solar only?

Answer: Duke Energy has added the Appendix L documents at https://www.dukeenergyrfpcarolinas.com/RFP-Documents.

DOC 00010 (revised 08/12/2023)
Published On: 08/09/2023

Question: After reviewing Q&A DOC 00007, I see that Duke is open to accepting layouts with bifacial c-Si 550-580W modules. However, some of the vendors on the AVL are only supplying 650W+ modules so we believe Duke should be willing to accept layouts with this wattage class also. Would Duke be open to receiving layouts for bifacial c-Si 650W+ modules as these modules are now more common and even with the vendors on the AVL?

Answer: Appendix I has been updated to allow crystalline bifacial 550-580W modules, per stakeholder request. This module guidance for site layouts only applies to Asset Transfer proposals, whereby DEC/DEP will be procuring the modules. Understanding the c-Si module market is moving to larger wattages and sizes, DEC/DEP seek to strike a balance between forecasted module manufacturer roadmaps and establishing a reasonable basis for a site layout, a target MWdc capacity and a reasonable energy production profile. Appendix I allows Market Participants to choose from either a thin film or C-Si module option. Market Participants are required to submit a site layout that complies with Appendix I. Market Participants can also submit additional site layouts with higher bin class wattage assumptions if they so choose.

DOC 00009
Published On: 08/01/2023

Question: Section VII from the RFP states that the MP must “have completed or directly managed the completion of the development, engineering, equipment, procurement, and construction of >50 MW or 3x the nameplate capacity of the Proposal, whichever is greater, of solar or SPS (if applicable) facilities, including at least one project of comparable size to the proposed facility within the United States or Canada.” If our company does not meet this requirement in North America, but exceeds the experiential threshold in other regions (i.e., 3 countries in Europe, India, and Australia with a 12GW+ of generation pipeline) would this satisfy this requirement? Is this a minimum offer requirement or would it only reduce points on the evaluation criteria?

Answer: This Section VII excerpt is part of the non-economic scoring criteria of proposals in the RFP. Proposals will not be disqualified for not meeting these Development Risk criteria but may have points deducted in the non-economic score of their proposals. Experience outside of the United States or Canada will not fully satisfy these criteria.

DOC 00008
Published On: 07/27/2023

Question: Could you please clarify Exhibit D part 5 in the PPA? The Exhibit seems to imply that only AC coupled facilities will be accepted ("Type of Battery Storage Design" is listed as AC-Coupled), but the body of the PPA includes options for DC and AC coupled facilities.

Answer: Exhibit D, Part 5, in 'Appendix A2-PPA (SPS) Revised' will be updated to clarify that DC-coupled facilities will be acceptable in the RFP. The Appendix can be accessed at https://www.dukeenergyrfpcarolinas.com/RFP-Documents.

DOC 00007 (revised 07/06/2023)
Published On: 07/06/2023

Question: We are reaching out regarding a concern that we have with one of the bulleted requirements in Appendix I’s (“Site Playout and PVSyst Guidnace”) Asset Transfer section. One of the bullets on page 2 stipulates that the “module in the layout shall assume First Solar S6+ 470W,” and goes on to cite creating conservative layout as justification. However, this doesn’t seem appropriate nor reflect the current state of the solar module market. Below are some of our concerns with this requirement:

  • It appears inconsistent with many of the RFP documents. Several examples include, the AVL includes 8 vendors for c-Si modules; The PVSyst specs in Appendix A of UOT guidance reference c-Si bi-facial modules.
  • Duke cites “procurement uncertainty” as justification for this selection, but in reality, FSLR S6 modules may have the most procurement uncertainty of any product on the AVL. FSLR themselves are currently selling their Series 7 products, and beyond that, they are not readily replaced by another vendor on the AVL without redesigning the site’s layout, in the even the FSLR product is unavailable at procurement.
  • Broadly, First Solar products are also not readily available. They are effectively sold out through 2026 and, depending on what happens in Q3 and Q4, could be sold out through 2027 in EOY. Because of this dynamic, we (and other MPs may have a similar view) have to contemplate a c-Si bi-facial module in our base designs. The inclusion of this requirement creates a likely scenario where a divergence between the mandated UOT design (due to a smaller, mono-facial S6+) and the PPA track design, will be likely. For MPs interested in proposing the facility in both tracks, this makes sizing and optimizing the PV unnecessarily challenging.
  • Due to the asymmetrical R&D capital going into improving c-Si modules, the likelihood of advancement and improvement with c-Si modules over the coming years is high. Because of this, we feel the “conservative” option with the least “procurement uncertainty” is a 550-580W c-Si bi-facial module, as it is not single-vendor dependent.

We do not have an issue with Duke Energy maintaining a preference for layouts that reflect the S6+, but making it a requirement does not align with the current state of the solar module market. Would Duke Energy be willing to revise that bullet to say that inclusion of the FSLR S6+ is a preference, but not a requirement for the layouts?

Answer: Thank you for the thoughtful feedback on the module assumption for site layout development. The Company will accept site layouts utilizing bifacial c-Si 550-580W modules, and Appendix I will be updated accordingly. The Company will provide the datasheet and PAN file for a suggested AVL module for use in proposal layouts for UOT.

DOC 00006
Published On: 06/30/2023

Question: We were wondering if there will be supplemental attachments to send to Duke i.e. an offer form? Or would you like the info presented in a proposal summary?

Answer: RFP respondents will be asked to provide a proposal summary/ overview together with completed bid input form(s). Supplemental attachments will also be required and will vary based on the type of resource and contract structure.

There will be an informational session in early August for all market participants planning to bid into the 2023 RFP.

The bid input forms will be available at https://www.dukeenergyrfpcarolinas.com/RFP-Documents prior to or at the opening of the bid submission window on August 15. The bid submission materials and process will be similar to those used in the Companies' 2022 Solar RFP.

DOC 00005
Published On: 06/29/2023

Question: If the storage facility is charged from a co-located solar facility using solar generation that would have otherwise been dispatched into the grid, would Duke be willing to pay for the associated loss in solar generation due to round trip efficiency at the PPA price instead of requiring the bidder to assume a dispatch profile and adjust the PPA price according to anticipated, but not real, losses?

Answer: Duke Energy declines to change the Delivery Point for pricing. Market participants should adjust their bid prices to account for estimated losses due to battery round trip efficiency.

Refer to FAQ DOC 00003, available at https://www.dukeenergyrfpcarolinas.com/FAQ/Documents.

DOC 00004
Published On: 06/28/2023

Question: Please provide the 2023 LOI, Term Sheet, PPAs, and APA documents in Word format to facilitate easier comparison and detection of differences vs. forms the MPs have from their participation in prior processes.

Answer: The LOI, form APA, and PPA documents are only provided in PDF. Adobe has a document comparison feature to compare two PDFs to each other.

DOC 00003 (revised 06/27/2023)
Published On: 06/27/2023

Question: During our review of the RFP’s BESS documentation, we would like some clarification on two fundamental issues pertaining to how storage roundtrip losses are treated:

  1. Storage roundtrip losses that pertain to charge coming from solar energy will be netted out of solar generation (thus reducing the solar generation number which receives the PPA rate). However, the volume (MWh) of those losses will be based on Duke’s operations of the battery, for which Seller by and large cannot control; for example, charging and discharging at very slow rates will incur proportionally higher losses, versus charging and discharging in a full-power cycle which would create lower losses. Accordingly, under the current construct, the Seller would need to assume the highest loss scenario, which will result in increased toll or PPA pricing for Duke. We recommend that either (a) Duke commits to a prescribed operational schedule or that (b) round trip losses are not netted out of solar generation (which would require a metering schematic that values the solar generation before it goes into the battery).
  2. It is unclear how Duke intends to net out the energy that was charged into the battery from grid charging when it is then dispatched back onto the grid. Can you clarify the methodology? The same issue applies above for what the application roundtrip loss factor might be under this scenario. These two issues are best addressed with the following structures that provide Duke the most flexible operations at the cheapest price: (1) meter solar generation before it goes into the battery and (2) exclude grid charging and the discharge of grid-charged energy from any settlements; provided that (3) seller conducts a roundtrip efficiency (RTE) test annually and pays RTE damages for any amounts below the guaranteed RTE schedule.

Answer: DEC and DEP decline to change the Delivery Point in the contract. The Companies retain operational flexibility to maximize the value of the Storage Facility. DEC and DEP intend to operate the Storage Facility as efficiently as possible to maximize the energy delivered to the grid, which will mean charging and discharging in a full-power cycle when possible. When grid charging, DEC and DEP will back out energy delivered to the Delivery Point that results from grid charging. To determine this amount, the Companies will multiply Grid Charging Energy obtained at the Delivery Point by the Storage Round Trip Efficiency. The Storage Round Trip Efficiency is the result of the most recent Storage Round Trip Efficiency Test, which is performed according to Exhibit M. Therefore, the Seller will not assume the risk if the Buyer inefficiently discharges the Storage Facility when grid charging. Additionally, the Seller will receive a credit for the value of the Grid Charging Energy procured pursuant to a Charging Notice.

DOC 00002
Published On: 06/21/2023

Question: Please clarify who needs to adhere to the PVSyst guidelines? Is it only those proposals that fall into the Utility Ownership track?

Answer: Both PPA and UOT projects shall follow the PVSyst guidelines. The PVSyst guidelines are included in Section IX Additional Information, subsection C. Production Estimates on page 28 of the RFP Plan Draft posted on April 21, 2023.

DOC 00001
Published On: 05/11/2023

Question: Appendix I states that SolCast must be used as the irradiance source for PVSyst, but the RFP document has a footnote that SolCast is preferred but other data sources are accepted. Is SolCast required or just preferred?

Answer: The footnote in the RFP document is an error and will be updated. SolCast is the required irradiance source, as described in Appendix I.