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    RFP 2023 QA

    AES Indiana Truck Driver with Sunglasses
    RFP 2023 Q&A

    Answers to questions about AES Indiana's RFP process

    Sargent & Lundy will provide responses to all questions.

    Sargent & Lundy requests that all questions concerning this RFP be submitted in writing via the RFP Question Form below. Written responses to all submitted questions will be posted to the website. Sargent & Lundy will accept written questions until the date identified in the RFP project schedule. Respondents should check the website periodically for updates and postings.

    If you experience technical issues accessing RFP documentation or submitting documents, please contact for assistance. Respondents should not contact AES Indiana directly.

    Questions & answers
    Will AES consider awarding / separating the BESS and High Voltage scope for two or more vendors? We are very interested in bidding and executing the HV scope and would only do so with confirmation that our approach would be considered.

    Based on how the RFP was issued, AES cannot accept an offer just for the HV construction scope. Those services will be required to be performed by the company awarded through this RFP process.

    1. Please clarify line of demarcation between BESS scope of work and the HV Substation / Gen-Tie? 2. Can you please provide CAD files of the preliminary design?

    1. Collector Substation (34.5/345 kV) for the project will be included as part of the Contractor project scope.

    • Owner to contract with an engineering firm to create 60% electrical drawings in order to procure GSUs, 345 kV breakers, and control house due to long-lead times.
    • Owner to furnish transmission line up to the dead end structure inside the substation fence.
    • Owner to furnish OPGW to substation dead end; Owner to furnish Emerson DCS server; Owner to furnish control house enclosure and associated relays.

    2. Please refer to the CAD drawings on the "RFP 2023 Documents" page.

    Please provide additional information for the GSU(s). If a cut / spec sheet is available, please provide.

    Please refer to AES Indiana GSU Transformer Technical Specification, previously provided to bidders.

    Please clarify which use cases the BESS is intended to perform? In section 3.2 Use Cases of "Exhibit-F only Generation Capacity or RA is listed as applicable to Project. However, in section 4.2.13 states use case as Anti-islanding or black start.

    Anti-islanding or black start requirement will be considered as a technical value added on the technical requirements but not as a minimum technical requirement.

    We'd like to request a two-week extension.

    One-week extension to be granted, resulting in submission date of March 20, 2023. The project schedule has been updated accordingly.

    DOR 3.15 and 3.16 says owner to do site survey and geotech. Has AES started or soon to complete a geotech report for the area of the project? Geotech report with the RFP is for a neighboring site. Geotech is critical path.

    AES will conduct a geotechnical survey and report for the BESS site in April. The current geotechnical report for the adjacent site, previously provider to bidders, is to be utilized for the estimating basis.

    Please provide specific requirements that align with Project Interconnection Agreement requirements so supplier can conform.

    Interconnection applications can be accessed once the Respondent submits the signed NDA.

    Please provide Exhibit Y Project Labor Agreement.

    No AES-specific PLA required for this project, the requirements are to adhere to the Prevailing Wage and Apprenticeship Requirements outlined in the Inflation Reduction Act

    Is there a list of subcontractors AES does not want to work with / does AES require subcontractor vetting prior to approval?

    A non-exhaustive list of approved major subcontractors is defined in the EPC specification document, previously provided to bidders. However, any contractor not on the list may be added, subject to approval by AES. This is for subcontractor project scopes of >$250,000.

    Is the BESS control system to be setup as 2x100MW or 200MW? With regards to bidding, operational independence, etc.

    To be set up as an independent 2 x 100MW. AES to confirm.

    Temporary power source: can contractor tap into existing electrical supply or are generators required?

    Contractor is permitted to connect to the existing transmission line next to the site. Please see the AES Indiana - Existing Utilities for clarity.

    Water source. Is there a water source nearby available for construction water usage?

    There is a nearby water source available for construction water usage.

    Is there a discount rate for Total Cost of Ownership (TCO) valuation?

    This number will not be disclosed. Bidders must include any discount rate considered in their proposal.

    Is there electrical resistivity information?

    To be included as part of the geotechnical campaign, which will be available prior to contract execution in April.

    Are there coal mine drawings for area under the site. Does AES possess abandoned coal mine survey drawings. The geotech report provided said there are abandoned coal mine workings under the site? Does AES or S&L consider the abandoned coal mine workings under the site to be an issue for the project or not?

    AES is in the process of conducting geotech investigations and results will be available before contract execution in April. Geotechnical / mining risk will be considered under unforeseen conditions for the contract

    Has AES performed a permit review by permit consultant or permit counsel?

    AES conducted a preliminary permit applicability assessment (available); however is conducting a deeper review based on the 30% design and doing proper consultations with the authorities. No changes on permit as indicated on Exhibit D-1 permit. Final permit applicability assessment will be available by April 2023. Also, there are current discussions in Indiana about requesting a Building Permit for Energy Storage Projects, that is currently in progress and could formally add this obligation to the project schedule (already included in Exhibit D-1) even though it is not included yet on the permit applicability assessment. 

    Is T&Cs Exhibit D-1 a general list that has not been specifically reviewed by Owner for this project?

    Exhibit D-1 the most comprehensive list of permits that should be considered for this project. After more detailed consultations to the authorities are in progress could discard some of these requirements. See preliminary Permit List Assessment for a clearer understanding

    EPC T&Cs Exhibit D-1 Contractor Permits says to comply with Owner Conditional Use Permit. AES to provide CUP. If it is not in hand, then when is it expected to be obtained?

    Currently, Indiana is under regulatory discussions for adding a Permit Issued by the Homeland Security Department for any BESS system over 10 MW. As this permit would require engineering design after 30% design would be pursued during engenieering stage under Owner scope but based on Contractor engineering design. This permit will replace the Conditional Use Permit as typically managed.

    EPC T&Cs Exhibit D-1 Contractor Permits has a number of items on it. Does AES have a permit review that states timing, costs and deliverables required for each item?

    Exhibit D-1 the most comprehensive list of permits that should be considered for this project. After more detailed consultations to the authorities are in progress could discard some of these requirements. See preliminary Permit List Assessment and Preliminary Permit Assessment for a clearer understanding. Schedule and costs assumptions for implementation on contractual scope should remain under EPC assumptions.

    BESS SCADA programming in DOR, item 1.6. Says Owner to design and construct, Contractor to commission. Could you please define scope split?

    Please review Exhibit F-BESS Technical SCADA for clearer description of scope of work (Section 2.0)

    For Exhibit D-2 Owner Permits, please provide schedule of when permits will be obtained in order for supplier to incorporate schedule in their RFP response. Are any owner permits precedents to start engineering or break ground?

    Neither of the permits are required for starting engineering of the facilities. Groundbreaking will be subject to the foillowing permits:

    Construction Stormwater General Permit 

    • Indiana Department of Environmental Management Permits
    • Approved SWPPP Notice of Termination per Indiana Department of Environmental Management Construction Stormwater

    General Permit effective December 18, 2021

    • Drainage Permit(s)

    All this set of permits is expected to be delivered during engineering stage and pre-mobilization.

    • Construction in a Floodway Permit(s)
    • Construction Plan Approval by the Pike County Soil and Water Conservation District
    • Consultation in compliance with the National Historic Preservation Act
    • Consultation in compliance with the Endangered Species Act
    • Spill Prevention Control and Countermeasure Plan
    Please send grid fault current available, required fault clearing times, and grid X/R or impedance as seen by the BESS at 345 kV.

    ASPEN model to be provided with NDA, please reach out at to confirm you have submitted the NDA, and the model can be provided.

    Please provide specific requirements that align with Project Interconnection Agreement requirements so supplier can conform.

    Interconnection agreements can be accessed once Respondent submits a signed NDA, please submit the signed NDA to

    Exhibit A 6.1 and DOR on Site Topo Survey, ALTA Survey. Please provide stand alone CAD and pdf file versions of the site topo survey and site ALTA survey.

    Topo survey is available in the "CAD drawings and related documents" folder. 

    Please specify location where Fire Safety Water tie in is located pursuant to DWG BFS-F_100. Please specify size of pipe tie in and pressure and flow test data.

    Water requirements:
    A standard approach to fire water is a minimum of 500 gpm at 50 psi. Bidders should plan to provide a water line or a pump sufficient to meet these requirements. With regards to available water for construction and fire & life safety, there are two options for water supply:

    1. Wells near the site
    2. Potential municipal water source
    3. For the well: Please find the Pike County water records for well locations and well test pump flow rates attached in Folder RFI 030123
    4. Additional info: For the potential municipal water source, there is a fire hydrant in Petersburg at the intersection of county road 650 north and 57. Bidder could look for potential water source.
    Main Power Transformer (MPT, also known as GSU). Please provide data sheets and specs including full load efficiency, impedance, confirm fitted with On Load Tap Changer.

    Please see spec attached in the newly uploaded CAD drawings and related documents folder. Impedance values found in interconnection application.

    Please provide data sheets for 345kV circuit breakers in AES Indiana Substation.

    Please refer to the specs included in the newly uploaded CAD drawings and related documents folder.

    Please provide specifications and layout of the substation control house.

    Control house layout is pending. Powell is a preferred vendor for enclosures. SEL equipment is AES Indiana's preferred vendor, and Emerson is the DCS provider. 

    Exhibit P Schedule of Approved Subcontractors doesn't list Power Electronics. Please confirm that AES approves Power Electronics inverters, given that they are in the project drawings.

    Correct. Power Electronics inverters were included in the original application to MISO and therefore, used for general specs. However, this equipment is not included in the approved vendor list for this particular project and should therefore be adjusted on final design.

    Please provide the Exhibit S-6 Post Energization Harmonics Test.

    See document in the newly uploaded CAD drawings and related documents folder.

    Exhibit S-1 Performance Testing. Ancillary Services MISO Certification Test. Please send the MISO Auxiliary Services certification test requirements that will apply.

    This is currently in progress and will be updated accordingly.

    Pleae provide interconnection Utility Grid information, Short Circuit of the Grid, X/R ratio.

    Please refer to ASPEN model and Interconnection request. Info after signed NDA.

    Is the BESS control system to be setup as 2x100MW or 200MW? With regards to bidding, operational independence, etc.

    Project control system will be managed as an independent request for each set of 100 MW as projects were requested with separated interconnection requests. 

    In your response to Question #1 specifically the delineation between the substation responsibilities and the BESS yard you indicate that 60% Design will be done. Can we get a date when this will be delivered? It will definitively impact schedule.

    This will be issued alongside the LNTP.

    Submit your RFP questions

    All fields are required (*) unless otherwise indicated.

    Additional resources

    RFP overview

    All about the 2023 BESS RFP.

    Project schedule

    RFP milestone dates and deadlines.

    RFP documents

    Learn how to submit an RFP proposal.

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