Report For: Orion Renewable Resources LLC ( Customer ) Queue #: Service Location: Rockingham County, NC Total Output Requested By Customer: 100 MW Commercial Operation Date Requested By Customer: 11/1/2019 Feasibility Study Report () - REDACTED.docx
Prepared by: Orvane Piper, Duke Energy Carolinas Table of Contents 1.0 Introduction... 3 2.0 Study Assumptions and Methodology... 3 3.0 Interconnection Facilities... 4 3.1 Tap on Dan River Bl 100 kv Line... 4 3.2 Tap on Dan River Wh 100 kv Line... 4 3.3 Switching Station on Dan River Bl/Wh 100 kv Lines... 4 4.0 Relay and Communication Equipment... 5 5.0 Thermal Analysis Results... 6 5.1 NRIS Evaluation... 6 5.1.1 Tap on Dan River Bl 100 kv Line... 6 5.1.2 Tap on Dan River Wh 100 kv Line... 8 5.1.3 Switching Station on Dan River Bl/Wh 100 kv Lines... 9 5.2 ERIS Evaluation... 11 5.2.1 Tap on Dan River Bl 100 kv Line... 11 5.2.2 Tap on Dan River Wh 100 kv Line... 12 5.2.3 Switching Station on Dan River Bl/Wh 100 kv Lines... 13 6.0 Short Circuit Analysis Results... 13 7.0 Reactive Capability Analysis Results... 14 Page 2 of 14
1.0 Introduction Following are the results of the Generation Feasibility Study for the installation of 100 MW of generating capacity (solar) in Rockingham County, NC. This site is located between Dan River Steam Station and N Greensboro Tie, and the Customer has requested a Commercial Operation Date of 11/1/19. This study includes both Network Resource Interconnection Service (NRIS) and Energy Resource Interconnection Service (ERIS). 2.0 Study Assumptions and Methodology The power flow cases used in the study were developed from the Duke Energy Carolinas (DEC) internal year 2020 summer peak and off-peak cases. The cases were modified to include 100 MW of generation at the Customer s facility, which was modeled assuming one of three interconnection options: 1) tap on Dan River Bl 100 kv line, 2) tap on Dan River Wh 100 kv line, or 3) new switching station on Dan River Bl/Wh 100 kv lines. A switching station configuration requires a minimum buildout of 6 breakers (4 circuit breakers [1 associated with each black/white circuit at the switching station], 1 bus tie breaker and 1 bus line breaker). The economic generation dispatch was changed by adding the new generation and forcing it on prior to the dispatch of the remaining DEC Balancing Authority Area units. The study cases were re-dispatched, solved and saved for use. The impacts of changes in the Generator Interconnection Queue were evaluated by creating additional models with earlier queued transmissionconnected generation included. The NRIS thermal study uses the results of DEC Transmission Planning s annual internal screening as a baseline to determine the impact of new generation. The annual internal screening identifies violations of the Duke Energy Power Transmission System Planning Guidelines and this information is used to develop the transmission asset expansion plan. The annual internal screening provides branch loading for postulated transmission line or transformer contingencies under various generation dispatches. The thermal study results following the inclusion of the new generation are obtained by the same methods, and are therefore comparable to the annual internal screening. The results are compared to identify significant impacts to the DEC transmission system. The ERIS thermal study utilizes a model that includes the new generation with relevant earlier queued projects and associated known upgrades. The new generation economically displaces DEC Balancing Authority Area units. Transmission capacity is available as long as no transmission element is overloaded under N-1 transmission conditions. The thermal evaluation will only consider the base case under N-1 transmission contingencies to determine the availability of transmission capacity. ERIS is service using transmission capacity on an as available basis; therefore, adverse generation dispatches that would make the transmission capacity unavailable are not identified. If the full output of the Customer s facility cannot be delivered at the time of the study, the study will identify the maximum allowable output at the time of the study that does not require additional Network Upgrades. Short circuit analysis is performed by modeling the new generation and any associated transmission upgrades. The impacts of changes in the Generator Interconnection Queue were evaluated by creating additional models with earlier queued transmission-connected generation included. Various faults were placed on the system and their impact versus equipment rating was evaluated. Any significant changes in short circuit current resulting from the new generation s installation were identified. Page 3 of 14
Reactive Capability is evaluated by modeling a facility s generation and step-up transformers (GSU s) at various taps and system voltage conditions. The reactive capability of the facility can be affected by many factors including inverter capability limits and bus voltage limits. The evaluation determines whether sufficient reactive support will be available at the Connection Point based on the requirements set forth in DEC s Facilities Connection Requirements (FCR) for generation connected to the Transmission System. For more information on reactive requirements for generation, reference the Generator Power Factor Requirements document on the DEC OASIS site 1. Any costs identified in the short circuit or reactive capability analyses are necessary for both NRIS and ERIS. 3.0 Interconnection Facilities The following table includes a preliminary estimate for the Transmission Provider s Interconnection Facilities associated with the Customer s generating facility. Details are further defined in subsequent phases of the interconnection process. 3.1 Tap on Dan River Bl 100 kv Line Associated Facilities Time Prior To Back Feed for Start of Activity (months) 100 kv Interconnection $2.5 MM 24 3.2 Tap on Dan River Wh 100 kv Line Associated Facilities Time Prior To Back Feed for Start of Activity (months) 100 kv Interconnection $2.5 MM 24 3.3 Switching Station on Dan River Bl/Wh 100 kv Lines Associated Facilities Time Prior To Back Feed for Start of Activity (months) 100 kv Interconnection $6 MM 36 1 http://www.oatioasis.com/duk/dukdocs/generator_interconnection_information.html Page 4 of 14
4.0 Relay and Communication Equipment Network Upgrade Modify Relay and Communication Equipment Station(s) Dan River Steam Station, N Greensboro Tie Time Prior To Back Feed for Start of Activity (months) $0.3 MM 12 Optical Ground Wire (OPGW) is the recommended communication solution for generator installations tapping a single circuit. DEC currently allows the use of 3rd party communications, in lieu of the recommended installation of OPGW. The 3rd party communications should include a continuous path of leased fiber to ensure communications reliability. Regardless of the communications medium utilized, DEC will implement protection settings that automatically trip the delivery for loss of communications and for violating the latency requirements. Some of the sites currently utilizing 3rd party communications are experiencing significant communications interruptions, resulting in automatic trip events. If unacceptable reliability performance occurs, DEC will evaluate alternatives and require additional improvements to meet reliability requirements. This study report identifies the installation of OPGW as a Network Upgrade. If the developer elects to utilize 3rd party communications, the cost for the line rebuild to install OPGW can be omitted from the initial estimate. Network Upgrade Time Prior To Back Feed for Start of Activity (months) Install OPGW (Dan River Steam Station-N Greensboro Tie) 2,3 25.89 $42 MM 60 2 The Dan River 100 kv lines (Dan River-N Greensboro) do not currently have OPGW installed, and the line structures cannot support the addition of OPGW. Installation of OPGW requires a rebuild of 25.89 miles of transmission. 3 If the Customer interconnects via a switching station on the Dan River Bl/Wh 100 kv lines, installation of OPGW is neither required nor necessary. Page 5 of 14
5.0 Thermal Analysis Results 5.1 NRIS Evaluation The following Network Upgrades are required to mitigate thermal loading issues attributable to the Customer s generating facility. 5.1.1 Tap on Dan River Bl 100 kv Line If no earlier queued generation projects are built, the following Network Upgrades are required to mitigate thermal loading issues attributable to the Customer s generating facility: Network Upgrade 4 (Customer s Generating Facility- Lake Townsend Retail) (Lake Townsend Retail-N Greensboro Tie) Time Prior To Back Feed for Start of Activity (months) 10.01 $15 MM 48 3.78 $5.7 MM 48 ESTIMATED TOTAL THERMAL ANALYSIS $20.7 MM 48 4 If the Customer elects to pursue OPGW on the Dan River 100 kv lines, identified thermal loading issues on the loading issues on the Dan River 100 kv lines is attributable to the Customer. Page 6 of 14
Depending on the earlier queued generation projects that are built, one or more of the following Network Upgrades may be required to mitigate thermal loading issues attributable to the Customer s generating facility: Network Upgrade 5 (Customer s Generating Facility-Lake Townsend Retail) (Lake Townsend Retail-N Greensboro Tie) Rebuild Lake Jeanette 100 kv Lines (N Greensboro Tie-Jessuptown Retail) Rebuild Pine Hall 100 kv Lines (Madison Tie-Walnut Cove Tie) Time Prior To Back Feed for Start of Activity (months) 10.01 $15 MM 48 3.78 $5.7 MM 48 6.63 $10 MM 36 14.49 $21.7 MM 36 5 If the Customer elects to pursue OPGW on the Dan River 100 kv lines, identified thermal loading issues on the loading issues on the Dan River 100 kv lines may be attributable to the Customer. Page 7 of 14
5.1.2 Tap on Dan River Wh 100 kv Line If no earlier queued generation projects are built, the following Network Upgrades are required to mitigate thermal loading issues attributable to the Customer s generating facility: Network Upgrade 6 (Customer s Generating Facility- Lake Townsend Retail) (Lake Townsend Retail-N Greensboro Tie) Time Prior To Back Feed for Start of Activity (months) 10.01 $15 MM 48 3.78 $5.7 MM 48 ESTIMATED TOTAL THERMAL ANALYSIS $20.7 MM 48 Depending on the earlier queued generation projects that are built, one or more of the following Network Upgrades may be required to mitigate thermal loading issues attributable to the Customer s generating facility: Network Upgrade 7 (Customer s Generating Facility-Lake Townsend Retail) (Lake Townsend Retail-N Greensboro Tie) Rebuild Lake Jeanette 100 kv Lines (N Greensboro Tie-Jessuptown Retail) Rebuild Pine Hall 100 kv Lines (Madison Tie-Walnut Cove Tie) Time Prior To Back Feed for Start of Activity (months) 10.01 $15 MM 48 3.78 $5.7 MM 48 6.63 $10 MM 36 14.49 $21.7 MM 36 6 If the Customer elects to pursue OPGW on the Dan River 100 kv lines, identified thermal loading issues on the loading issues on the Dan River 100 kv lines is attributable to the Customer. 7 If the Customer elects to pursue OPGW on the Dan River 100 kv lines, identified thermal loading issues on the loading issues on the Dan River 100 kv lines may be attributable to the Customer. Page 8 of 14
5.1.3 Switching Station on Dan River Bl/Wh 100 kv Lines If no earlier queued generation projects are built, the following Network Upgrades are required to mitigate thermal loading issues attributable to the Customer s generating facility: Network Upgrade 8 (Customer s Generating Facility- Lake Townsend Retail) (Lake Townsend Retail-N Greensboro Tie) Time Prior To Back Feed for Start of Activity (months) 10.01 $15 MM 48 3.78 $5.7 MM 48 ESTIMATED TOTAL THERMAL ANALYSIS $20.7 MM 48 8 If the Customer elects to pursue OPGW on the Dan River 100 kv lines, identified thermal loading issues on the loading issues on the Dan River 100 kv lines is attributable to the Customer. Page 9 of 14
Depending on the earlier queued generation projects that are built, one or more of the following Network Upgrades may be required to mitigate thermal loading issues attributable to the Customer s generating facility: Network Upgrade 9 (Dan River Steam Station-Customer s Generating Facility (Customer s Generating Facility-Lake Townsend Retail) (Lake Townsend Retail-N Greensboro Tie) Rebuild Lake Jeanette 100 kv Lines (N Greensboro Tie-Jessuptown Retail) Rebuild Pine Hall 100 kv Lines (Madison Tie-Walnut Cove Tie) Time Prior To Back Feed for Start of Activity (months) 12. 1 $18.2 MM 60 10.01 $15 MM 60 3.78 $5.7 MM 60 6.63 $10 MM 36 14.49 $21.7 MM 36 9 If the Customer elects to pursue OPGW on the Dan River 100 kv lines, identified thermal loading issues on the loading issues on the Dan River 100 kv lines is attributable to the Customer. Page 10 of 14
5.2 ERIS Evaluation 5.2.1 Tap on Dan River Bl 100 kv Line Under the terms of ERIS service, the full output of the Customer s facility cannot be delivered at the time of the study. At the time of the study, the maximum output that can be delivered without requiring network upgrades is 20.8 MW. At the time of the study, delivery of the full output of the Customer s generating facility under the terms of ERIS service requires the following Network Upgrades to mitigate thermal loading issues attributable to the Customer s generating facility: Network Upgrade 10 (Customer s Generating Facility-Lake Townsend Retail) Rebuild Pine Hall 100 kv Lines (Madison Tie-Walnut Cove Tie) Time Prior To Back Feed for Start of Activity (months) 10.01 $15 MM 48 14.49 $21.7 MM 36 10 If the Customer elects to pursue OPGW on the Dan River 100 kv lines, identified thermal loading issues on the loading issues on the Dan River 100 kv lines is attributable to the Customer. Page 11 of 14
5.2.2 Tap on Dan River Wh 100 kv Line Under the terms of ERIS service, the full output of the Customer s facility cannot be delivered at the time of the study. At the time of the study, the maximum output that can be delivered without requiring network upgrades is 47.4 MW. At the time of the study, delivery of the full output of the Customer s generating facility under the terms of ERIS service requires the following Network Upgrades to mitigate thermal loading issues attributable to the Customer s generating facility: Network Upgrade 11 (Customer s Generating Facility-Lake Townsend Retail) (Lake Townsend Retail-N Greensboro Tie) Rebuild Pine Hall 100 kv Lines (Madison Tie-Walnut Cove Tie) Time Prior To Back Feed for Start of Activity (months) 10.01 $15 MM 48 3.78 $5.7 MM 48 14.49 $21.7 MM 36 11 If the Customer elects to pursue OPGW on the Dan River 100 kv lines, identified thermal loading issues on the loading issues on the Dan River 100 kv lines is attributable to the Customer. Page 12 of 14
5.2.3 Switching Station on Dan River Bl/Wh 100 kv Lines Under the terms of ERIS service, the full output of the Customer s facility cannot be delivered at the time of the study. At the time of the study, the maximum output that can be delivered without requiring network upgrades is 1.4 MW. At the time of the study, delivery of the full output of the Customer s generating facility under the terms of ERIS service requires the following Network Upgrades to mitigate thermal loading issues attributable to the Customer s generating facility: Network Upgrade (Dan River Steam Station-Customer s Generating Facility (Customer s Generating Facility-Lake Townsend Retail) (Lake Townsend Retail-N Greensboro Tie) Rebuild Lake Jeanette 100 kv Lines (N Greensboro Tie-Jessuptown Retail) Rebuild Pine Hall 100 kv Lines (Madison Tie-Walnut Cove Tie) Time Prior To Back Feed for Start of Activity (months) 12. 1 $18.2 MM 60 10.01 $15 MM 60 3.78 $5.7 MM 60 6.63 $10 MM 36 14.49 $21.7 MM 36 6.0 Short Circuit Analysis Results There are no breakers that need to be replaced as a result of the new generation. At the time of the study, the identified short circuit ratio for the Customer s generating facility is 16.8. Page 13 of 14
7.0 Reactive Capability Analysis Results The maximum allowable size for a capacitor bank associated with the Customer s generating facility is 18.8 MVAR, which allows the Customer to compensate only for plant losses. With an 18.8 MVAR capacitor bank installed and in service, the requested output of the facility meets the reactive capability requirements set forth in DEC s FCR document, and the reactive power range will be between 39.5 MVAR lagging and 25 MVAR leading. If the Customer does not install the capacitor bank or the capacitor bank is not in service, the maximum output of the facility that meets the reactive capability requirements set forth in DEC s FCR document is 94.5 MW, and the reactive power range will be between 37.2 MVAR lagging and 23.5 MVAR leading. At the requested output, the Customer s generating facility cannot meet the reactive capability requirements without installation of an appropriately sized capacitor bank. The MW value included in the Interconnection Agreement shall not exceed a MW value higher than that which meets the reactive capability requirements. The recommended tap setting at the high side of the GSU is 105 kv. Study completed by: Orvane Piper, Duke Energy Carolinas Reviewed by: Edgar Bell, Duke Energy Carolinas Director, Transmission Planning Page 14 of 14