The URL can be used to link to this page

Home My WebLink About20190821Avista to Staff 135 Attachment A.pdfInterconnection Feasibility Study Report IINTERCONNECTION FEASIBILITY STUDY REPORT FOR PROJECT #33 March 29, 2013 Richard Maguire Avista System Planning Engineer Randy Spacek Avista System Protection Engineer Avista Project Account 77705194-186200 Staff_PR_135 Attachment A Page 1 of 30 Interconnection Feasibility Study Report PROJECT #33 March 29, 2013 Page 2 of 30 Executive Summary On February 18, 2011 the Project #33 Developer entered into an Interconnection Feasibility Study Agreement with Avista for a proposed 400 MW wind generating facility located near Lind, Washington. On April 12, 2012 a revised Attachment A to the Interconnection Feasibility Study Agreement was agreed upon which redefined the Point of Interconnection (POI) to be studied. The Interconnection Customer has given a projected initial operating date of December 1, 2014. The Interconnection Feasibility Study Agreement states that Avista will study the possible interconnection of Project #33 in the vicinity of Lind, Washington to a suitable 115 kV interconnection on the Avista Transmission System. Avista System Planning has determined the Lind 115 kV Substation as the POI for all options studied in this report. The goal of this study is to determine interconnection impacts and cost estimates associated with the integration of Project #33 as a network resource and an energy resource. A power flow study was conducted by Avista’s System Planning Group to determine transmission needs; no dynamics studies were performed. A short circuit analysis was completed by the System Protection Group to determine if the existing equipment is adequate for the interconnection. This study evaluated three possible options for interconnection: Option 1 – Add one breaker position to Lind 115 kV Substation Option 1 (2016) – Option 1 after two planned Avista Transmission projects Option 2 – 115 kV interconnection with 230 kV transmission line from Lind to Wanapum A summary of the options and their total estimated costs are given in the following table. Option Project Output Condition Total Cost ($000) Option 1 62 MW New Breaker Position at Lind $500 Option 1 (2016) 250 MW Benton – Othello & Lind – Warden 115 kV projects $600 Option 2 400 MW Generation tripping necessary for some contingencies $67,700 Preliminary study suggests Option 1 is feasible when the output of Project #33 is limited to 62 MW.1 Preliminary study suggests Option 1 (2016) is feasible when the output of Project #33 is limited to 250 MW.1 Preliminary study suggests Option 2 is feasible when the output of Project #33 is limited to 400 MW and generation tripping is employed for some contingencies.1 All construction costs are in 2013-year dollars and are based on engineering judgment only with +/- 50% error. These cost estimates assume that the Project #33 owners are responsible for all necessary facilities from their facility to the POI. Detailed cost figures will be determined during future studies. 1 Further studies conducted as a part of the Interconnection System Impact Study may identify additional issues or limits which must be addressed if the Interconnection Customer wishes to move forward with this project. Staff_PR_135 Attachment A Page 2 of 30 Interconnection Feasibility Study Report PROJECT #33 March 29, 2013 Page 3 of 30 TABLE OF CONTENTS EXECUTIVE SUMMARY ......................................................................................................................................... 2 INTRODUCTION ....................................................................................................................................................... 4 GENERAL ................................................................................................................................................................... 4 SCOPE OF FEASIBILITY STUDY ................................................................................................................................... 4 POINT OF INTERCONNECTION ........................................................................................................................... 6 INTERCONNECTION OPTIONS ..................................................................................................................................... 7 Option 1: 62 MW.................................................................................................................................................. 7 Option 1 (2016): 250 MW .................................................................................................................................... 8 Option 2: 400 MW ................................................................................................................................................ 9 POWER FLOW ANALYSIS .................................................................................................................................... 10 PROCEDURE ............................................................................................................................................................. 10 STUDY CASE DEVELOPMENT AND DESCRIPTION ..................................................................................................... 12 2012 Heavy Summer High Hydro ...................................................................................................................... 12 2012 Light Summer with High West of Hatwai Flows ....................................................................................... 13 POWER FLOW ANALYSIS RESULTS .......................................................................................................................... 14 Option 1 ............................................................................................................................................................. 14 Option 1 (2016) .................................................................................................................................................. 17 Conclusions from Option 1 power flow studies .................................................................................................. 19 Option 2: 400 MW .............................................................................................................................................. 20 Conclusions from Option 2 power flow studies .................................................................................................. 22 Impacted Transmission Facilities ...................................................................................................................... 23 SHORT CIRCUIT ANALYSIS ................................................................................................................................ 24 GENERAL: ................................................................................................................................................................ 24 ASPEN MODEL DEVELOPMENT: ............................................................................................................................. 24 Station Transformers .......................................................................................................................................... 24 Collector String and Pad Mount GSUs .............................................................................................................. 24 Collector string - ................................................................................................................................................ 24 Pad Mount GSU – 87 units parallel ................................................................................................................... 25 Wind Turbines .................................................................................................................................................... 25 Transmission ...................................................................................................................................................... 25 FAULT ANALYSIS STUDY ......................................................................................................................................... 25 FAULT DUTY COMPARISONS ................................................................................................................................... 26 Option 1: ............................................................................................................................................................ 26 Option 1 (2016):................................................................................................................................................. 27 Option 2: ............................................................................................................................................................ 28 SUMMARY ............................................................................................................................................................... 28 CONCLUSION .......................................................................................................................................................... 30 Staff_PR_135 Attachment A Page 3 of 30 Interconnection Feasibility Study Report PROJECT #33 March 29, 2013 Page 4 of 30 Introduction General On February 18, 2011 the Project #33 Developer entered into an Interconnection Feasibility Study Agreement with Avista for a proposed 400 MW wind generating facility located near Lind, Washington. On April 12, 2012 a revised Attachment A to the Interconnection Feasibility Study Agreement was agreed upon which redefined the Point of Interconnection (POI) to be studied. The Interconnection Customer has given a projected initial operating date of December 1, 2014. The Interconnection Feasibility Study Agreement states that Avista will study the possible interconnection of Project #33 in the vicinity of Lind, Washington to a suitable 115 kV interconnection on the Avista Transmission System. Avista has chosen the Lind 115 kV Substation as the POI for all options studied in this report. The goal of this study was to determine interconnection impacts and cost estimates associated with the integration of Project #33 as a Network Resource and an Energy Resource. This study evaluated three possible options for interconnection: Option 1: Add breaker position to Lind 115 kV Substation Option 1 (2016): Option 1 after two planned Avista Transmission System projects Option 2: 115 kV interconnection with 230 kV transmission line from Lind to Wanapum In the application for Large Electric Generator Interconnection, the Project #33 Developer requested the study for Project #33 be conducted both for network resource interconnection service and energy resource interconnection service. Avista’s System Planning Group contends that if a generator is studied and can connect for Network Resource Interconnection Service then it can also connect for Energy Resource Interconnection Service. Energy Resource Interconnection Service allows the Interconnection Customer to connect the Large Generating Facility to the Transmission System and be eligible to deliver the Large Generating Facility's output using the existing firm or non-firm capacity of the Transmission System on an "as available" basis. Energy Resource Interconnection Service does not in and of itself convey any right to deliver electricity to any specific customer or Point of Delivery. For Network Resource Interconnection Service the Transmission Provider must conduct the necessary studies and construct the Network Upgrades needed to integrate the Large Generating Facility in a manner comparable to that in which the Transmission Provider integrates its generating facilities to serve native load customers. Network Resource Interconnection Service allows the Interconnection Customer's Large Generating Facility to be designated as a Network Resource, up to the Large Generating Facility's full output, on the same basis as existing Network Resources interconnected to the Transmission Provider's Transmission System, and to be studied as a Network Resource on the assumption that such a designation will occur. Network Resource Interconnection Service in and of itself does not convey transmission service. Scope of Feasibility Study As outlined in Section 6.2 of Avista’s Large Generator Interconnection Procedures (LGIP), this study evaluates the impact of the proposed interconnection on the reliability of the Transmission Staff_PR_135 Attachment A Page 4 of 30 Interconnection Feasibility Study Report PROJECT #33 March 29, 2013 Page 5 of 30 System, and it consists of a power flow analysis and a short circuit analysis. The study considers all existing generating facilities, pending higher queued interconnection requests in Avista’s queue (including associated identified network upgrades) and interconnections on Affected Systems that may have an impact on the studied interconnection request. The resulting Interconnection Feasibility Study report includes the following information: Preliminary identification of facility thermal overloads or facility voltage violations resulting from the interconnection Preliminary identification of any circuit breaker or equipment short circuit capability limits exceeded as a result of the interconnection. Description and non-binding, good faith estimated cost of facilities required to interconnect the project to the Avista Transmission System and to address the identified power flow and short circuit issues. All construction costs are in 2013-year dollars and are based on engineering judgment only with +/- 50% error, and these estimates only reflect the cost of integrating the project onto the Avista Transmission System. Neighboring systems were not contacted or involved with this study work. If the Project #33 Developer moves forward with an Interconnection System Impact Study for Project #33, those neighboring systems that are identified as Affected Systems and which may be impacted by this interconnection will be sent a copy of this report. Avista will coordinate the continued study work with any such Affected Systems. Staff_PR_135 Attachment A Page 5 of 30 Interconnection Feasibility Study Report PROJECT #33 March 29, 2013 Page 6 of 30 Point of Interconnection The Interconnection Feasibility Study Agreement states that Avista will study the possible interconnection of Project #33 in the vicinity of Avista’s Lind 115 kV Substation, and Avista System Planning chose the Lind substation as the POI for all studied options. Figure 1 depicts the local 115 kV transmission system for the area surrounding the POI. All three options require construction within the Lind substation, and as this station is a major station in the area, construction schedules may be tightly constrained to coordinate outages. Figure 1: Project #33 map Project #33 Staff_PR_135 Attachment A Page 6 of 30 Interconnection Feasibility Study Report PROJECT #33 March 29, 2013 Page 7 of 30 Interconnection Options Option 1: 62 MW The interconnection cost of Option 1 is approximately $500k, and Option 1 consists of adding a breaker position at the Lind 115 kV Substation; see Figure 2. The Interconnection Customer is responsible for providing all necessary facilities up to the Change of Ownership. All construction costs are in 2013-year dollars and are based on engineering judgment only with +/- 50% error. Figure 2: Option 1 project drawing Staff_PR_135 Attachment A Page 7 of 30 Interconnection Feasibility Study Report PROJECT #33 March 29, 2013 Page 8 of 30 Option 1 (2016): 250 MW The interconnection cost of Option 1 (2016) includes: The approximately $500k cost of Option 1 Approximately $100k for circuit switcher upgrade necessary at Roxboro Completion of two Avista Planned Projects:2 o Benton – Othello 115 kV Reconductor Project (2014) o Lind – Warden 115 kV Reconductor Project (2016) Option 1 (2016) drawing is shown in Figure 3. The Interconnection Customer is responsible for providing all necessary facilities up to the Change of Ownership. All construction costs are in 2013-year dollars and are based on engineering judgment only with +/- 50% error. Figure 3: Option 1 (2016) project drawing 2 Proposed dates for Avista Planned Projects are subject to change Staff_PR_135 Attachment A Page 8 of 30 Interconnection Feasibility Study Report PROJECT #33 March 29, 2013 Page 9 of 30 Option 2: 400 MW The project cost of Option 2 is approximately $67.7 million, and Option 2 requires: Rebuild the Lind 115 kV Substation to breaker and a half configuration: $6.5 million Add 230 kV bus and breakers to Lind Substation: $3.5 million Install two 250 MVA 115/230 kV transformers at the Lind Substation: $7 million Reconductor 21.7 miles of the Lind – Warden 115 kV Transmission Line: $3.7 million Construct 66 miles of 230 kV 440 MVA transmission line from Lind to Wanapum: $46 million Add a new 230 kV breaker position at Wanapum: $1 million3 Option 2 project drawing is shown in Figure 4. The Interconnection Customer is responsible for providing all necessary facilities up to the Change of. All construction costs are in 2013-year dollars and are based on engineering judgment only with +/- 50% error. Figure 4: Option 2 project drawing 3 Cost estimates at Wanapum may be different from those provided as Wanapum is not owned by Avista Staff_PR_135 Attachment A Page 9 of 30 Interconnection Feasibility Study Report PROJECT #33 March 29, 2013 Page 10 of 30 Power Flow Analysis Procedure Steady-state power flow simulations were performed to identify any possible thermal or voltage violations as a result of connecting Project #33 to the Transmission System with all facilities in service. Preliminary contingency analysis was also performed to identify facility thermal and voltage violations under credible outage conditions. Results of the analysis were evaluated against the current NERC TPL-001 through TPL-004 and FAC-010 standards. The following criteria are used to determine acceptable performance with the Standards: 1. Category A: During normal operating conditions, no facilities shall exceed their applicable facility ratings or exceed the desired voltage range. 2. Category B: During single contingency scenarios, including but not limited to line end open and relocation of normally open points, no facilities shall exceed their applicable facility ratings nor shall they exceed the desired voltage. 3. Category C: During multiple contingency scenarios (including but not limited to bus outages, common mode outages, and adjacent circuit outages), no facilities shall exceed their applicable facility ratings nor shall they exceed the desired voltage range. NERC allows controlled load shedding or curtailment of transfers to be implemented; however, Avista does not have emergency ratings and therefore does not have the ability to utilize load shedding. A plan of service shall be developed such that the system meets the NERC Category C requirements using normal facility ratings. 4. Category D: During extreme contingencies, system performance is analyzed on a case- by-case basis for performance and potential mitigation. Additionally, a sensitivity analysis was conducted to provide the Project #33 Developer with information regarding what other parties might be affected by the project interconnection. Important Notes: This study considers all other higher queued interconnection requests that directly impact the Project #33 interconnection. The transmission additions simulated in the study cases, were based on the best information available at the time the study was initiated. It is likely that the actual plan of service will differ from the plan of service studied, and Avista reserves the right to restudy this request if necessary. Transmission capacity impacts and upgrades beyond the Transmission Provider’s Interconnection Facilities identified by this Interconnection Feasibility Study Report are provided for informational purposes only. A complete analysis of these transmission capacity impacts associated with Project #33 and any facilities needed to mitigate the Staff_PR_135 Attachment A Page 10 of 30 Interconnection Feasibility Study Report PROJECT #33 March 29, 2013 Page 11 of 30 impacts would be identified through the study process for Transmission Service, once a request for Transmission Service has been made. Staff_PR_135 Attachment A Page 11 of 30 Interconnection Feasibility Study Report PROJECT #33 March 29, 2013 Page 12 of 30 Study Case Development and Description Steady state and contingency power flow analysis were performed using two Avista Planning Cases: the 2012 Heavy Summer, High Hydro scenario, and the 2012 Light Summer with High West of Hatwai Flows scenario. Avista Planning Cases are tailored from approved WECC cases, and a standardized set of steady state contingency scenarios are run against each case for different levels of Project #33 generation. These contingencies include outages within the Avista Transmission System as well as select outages in adjacent Planning Coordinator and Transmission Planner areas. Contingencies are also added or modified to include elements added to the Transmission System for the purposes of this study. 2012 Heavy Summer High Hydro This is the typical summer peak study where the balancing area load is heavy, hydro generation is high, and the transmission system is at its most limiting condition due to high temperatures. A summary of regional flows is shown in Table 1 for reference. The Avista case AVA-11hs2a-12BA2085 is used with the following modifications: Lind Capacitor Project added Project #8 added (75 MW) Table 1: Heavy Summer High Hydro case loadings Western Montana Hydro 1099.0 MW West of Hatwai (Path 6) 701.9 MW Noxon Rapids (562MW) 400.0 MW Lolo-Oxbow 230kV 276.8 MW Cabinet Gorge (265MW) 185.0 MW Dry Creek-Walla Walla 230kV 159.8 MW Libby (605MW)324.0 MW Hungry Horse (430MW) 190.0 MW West of Cabinet 1610.6 MW Montana-Northwest (Path 8) 1007.2 MW Colstrip Total Colstrip 1 (330MW)330.0 MW Idaho-Northwest (Path 14) -569.9 MW Colstrip 2 (330MW)330.0 MW Midpoint-Summer Lake (Path 75) -62.8 MW Colstrip 3 (823MW)795.7 MW Idaho-Montana (Path 18) -287.4 MW Colstrip 4 (823MW)805.0 MW South of Boundary 582.2 MW Rathdrum Thermal (175MW) 0.0 MW North of John Day (Path 73) 6820.6 MW Lancaster Thermal (270MW) 249.0 MW TOT 4A (Path 37)402.3 MW Spokane River Hydro 88.2 MW Miles City DC 142.0 MW Boundary Hydro (1040MW) 635.0 MW Path C (Path 20)133.8 MW Lower Snake/N.F. Clearwater Borah West (Path 17)844.9 MW Dworshak (458MW)316.0 MW Bridger West (Path 19) 2190.9 MW Lower Granite (930MW) 554.2 MW Pacific AC Intertie (Path 66) 4207.5 MW Little Goose (930MW)555.5 MW Pacific DC Intertie (Path 65) 2980.0 MW Lower Monumental (930MW) 531.5 MW Northwest Load 25129.6 MW Coulee Generation Idaho Load 3702.5 MW Coulee 500 kV 2221.2 MW Montana Load 1836.8 MW Coulee 230 kV 1292.7 MW Avista Native Load -1594.3 MW Avista Balancing Area Load 2007.2 MW Clearwater Load 58.2 MW Staff_PR_135 Attachment A Page 12 of 30 Interconnection Feasibility Study Report PROJECT #33 March 29, 2013 Page 13 of 30 2012 Light Summer with High West of Hatwai Flows During light summer (night time loading), high western Montana hydro and high Montana thermal generation, the WECC rated path ―West of Hatwai‖ (WECC Path #6) reaches its heaviest loading. During this scenario, elements of the transmission system are nearing their stability limits. These limits define some of the operating constraints for the region and also establish some of the trigger points for local Remedial Action Schemes (RAS). This case is also limited by the summer thermal limits on all transmission equipment, which helps to indicate where the system is near capacity in normal and contingency operation. A summary of the case MW flows is shown in Table 2 for reference. The Avista case AVA-11ls1ae-12BA1251-WOH4277 is with the following modifications: Lind Capacitor Project added Project #8 added (75 MW) Table 2: Light Summer case loadings Western Montana Hydro 1650.0 MW West of Hatwai (Path 6) 4210.1 MW Noxon Rapids (562MW) 501.2 MW Lolo-Oxbow 230kV 128.3 MW Cabinet Gorge (265MW) 230.3 MW Dry Creek-Walla Walla 230kV 175.8 MW Libby (605MW)539.2 MW Hungry Horse (430MW) 379.4 MW West of Cabinet 3335.1 MW Montana-Northwest (Path 8) 2073.4 MW Colstrip Total Colstrip 1 (330MW)330.0 MW Idaho-Northwest (Path 14) 753.1 MW Colstrip 2 (330MW)330.0 MW Midpoint-Summer Lake (Path 75) 819.7 MW Colstrip 3 (823MW)791.2 MW Idaho-Montana (Path 18) -190.2 MW Colstrip 4 (823MW)796.5 MW South of Boundary 960.3 MW Rathdrum Thermal (175MW) 140.0 MW North of John Day (Path 73) 4479.9 MW Lancaster Thermal (270MW) 249.0 MW TOT 4A (Path 37)455.2 MW Spokane River Hydro 183.8 MW Miles City DC 200.0 MW Boundary Hydro (1040MW) 975.0 MW Path C (Path 20)539.6 MW Lower Snake/N.F. Clearwater Borah West (Path 17)1579.5 MW Dworshak (458MW)361.7 MW Bridger West (Path 19) 2105.0 MW Lower Granite (930MW) 155.0 MW Pacific AC Intertie (Path 66) 2824.3 MW Little Goose (930MW)155.0 MW Pacific DC Intertie (Path 65) 1999.9 MW Lower Monumental (930MW) 273.5 MW Northwest Load 17796.4 MW Coulee Generation Idaho Load 2326.0 MW Coulee 500 kV 450.0 MW Montana Load 1339.5 MW Coulee 230 kV 120.4 MW Avista Native Load -837.0 MW Avista Balancing Area Load 1102.4 MW Clearwater Load 58.2 MW Staff_PR_135 Attachment A Page 13 of 30 Interconnection Feasibility Study Report PROJECT #33 March 29, 2013 Page 14 of 30 Power Flow Analysis Results Option 1 Category A Facility Violations The Light Summer case is the limiting case for normal operating conditions for Option 1, showing a facility violation on the Lind – Warden 115 kV Transmission Line when Project #33 generation exceeds 62 MW; see Figure 5. The Lind – Warden Transmission Line is approximately 21.7 miles, and it is primarily 7#8 CU with a summer operating limit of 57 MVA. Figure 5: Light Summer limiting Category A scenario for Project #33 Option 1 Category B and C Facility Violations The most limiting contingency scenario involves the Benton – Othello 115 kV Transmission Line during the Light Summer case for failure of Breaker GB1250 at the Grant County Public Utility District owned Sand Dunes 115 kV Switching Station. This contingency opens two transmission lines north out of the Warden Substation, resulting in the Benton – Othello line carrying generation from both Project #33 and Project #8. Avista has a project planned to reconductor the Benton – Othello 115 kV Transmission Line in 2014. Table 3 shows all facility violations for Option 1 when Project #33 output is 62 MW. Staff_PR_135 Attachment A Page 14 of 30 Interconnection Feasibility Study Report PROJECT #33 March 29, 2013 Page 15 of 30 Table 3: Facility violations during contingencies for Option 1 Contingency Facility in Violation Percent Case BF: GB1250 Sand Dunes 115 kV, Larson-Sand Dunes-Warden TAUNTON (48425) -> BENTNAVA (48039) CKT 1 at TAUNTON 170.77 HT BF: GB1250 Sand Dunes 115 kV, Larson-Sand Dunes-Warden OTHELOSS (48309) -> SOTHELOT (48393) CKT 1 at OTHELOSS 169.22 HT BF: GB1250 Sand Dunes 115 kV, Larson-Sand Dunes-Warden SOTHELOT (48393) -> TAUNTON (48425) CKT 1 at SOTHELOT 162.11 HT BF: GB1250 Sand Dunes 115 kV, Larson-Sand Dunes-Warden OTHELOSS (48309) -> SOTHELOT (48393) CKT 1 at OTHELOSS 115.62 HSHH BF: GB1250 Sand Dunes 115 kV, Larson-Sand Dunes-Warden TAUNTON (48425) -> BENTNAVA (48039) CKT 1 at TAUNTON 108.56 HSHH N-1: Devils Gap - Lind 115 kV (LIN-RIT)LIND (48187) -> ROXBORO (48375) CKT 1 at LIND 106.27 HT BF: GB1250 Sand Dunes 115 kV, Larson-Sand Dunes-Warden SOTHELOT (48393) -> TAUNTON (48425) CKT 1 at SOTHELOT 103.3 HSHH N-1: Lind - Washtucna 115 kV LIND (48187) -> ROXBORO (48375) CKT 1 at LIND 102.53 HT N-1: Lind - Shawnee 115 kV (LIN-EWN)LIND (48187) -> ROXBORO (48375) CKT 1 at LIND 101.74 HT N-1: Devils Gap - Lind 115 kV (LIN-RIT)LIND (48187) -> ROXBORO (48375) CKT 1 at LIND 100.84 HSHH Voltage Violations Option 1introduces no voltage violations when Project #33 generation level is limited to less than 62 MW. Figure 6 shows a PV plot for local bus voltages as Project #33 generation output is increased. The plot is for informational purposes only. Figure 6: Light Summer case PV Curve for generation increments at Project #33 Staff_PR_135 Attachment A Page 15 of 30 Interconnection Feasibility Study Report PROJECT #33 March 29, 2013 Page 16 of 30 Incremental Generation Analysis The software program Simulator from PowerWorld Corporation was used to analyze steady state power flow for this study. Simulator includes a tool allowing one to analyze impacts to the Transmission System for incrementing levels of Project #33 generation. When combined with results generated from traditional steady state contingency analysis, this tool returns a table of ―next most limiting‖ facility violations as generation output increases. Table 4 is provided for informational purposes only. Table 4: Incremental Generation Study for Project #33 Option 1 Case Project Output Limiting Element Limiting Contingency HT 26.03 Line OTHELOSS (48309) TO SOTHELOT (48393) CKT 1 [115.00 - 115.00 kV] BF: GB1250 Sand Dunes 115 kV, Larson-Sand Dunes-Warden HT 28.08 Line BENTNAVA (48039) TO TAUNTON (48425) CKT 1 [115.00 - 115.00 kV] BF: GB1250 Sand Dunes 115 kV, Larson-Sand Dunes-Warden HT 31.02 Line SOTHELOT (48393) TO TAUNTON (48425) CKT 1 [115.00 - 115.00 kV] BF: GB1250 Sand Dunes 115 kV, Larson-Sand Dunes-Warden HSHH 54.29 Line BENTNAVA (48039) TO TAUNTON (48425) CKT 1 [115.00 - 115.00 kV] BF: GB1250 Sand Dunes 115 kV, Larson-Sand Dunes-Warden HT 57.05 Line LIND (48187) TO ROXBORO (48375) CKT 1 [115.00 - 115.00 kV] N-1: Devils Gap - Lind 115 kV (LIN-RIT) HSHH 57.89 Line OTHELOSS (48309) TO SOTHELOT (48393) CKT 1 [115.00 - 115.00 kV] BF: GB1250 Sand Dunes 115 kV, Larson-Sand Dunes-Warden HT 61 Line LIND (48187) TO ROXBORO (48375) CKT 1 [115.00 - 115.00 kV] N-1: Lind - Shawnee 115 kV (LIN-EWN) HT 61.32 Line LIND (48187) TO ROXBORO (48375) CKT 1 [115.00 - 115.00 kV] N-1: Lind - Washtucna 115 kV HT 62.15 Line LIND (48187) TO ROXBORO (48375) CKT 1 [115.00 - 115.00 kV] BUS: Noxon East 230 kV HT 62.31 Line LIND (48187) TO ROXBORO (48375) CKT 1 [115.00 - 115.00 kV] BF: A1222 Boundary West 230 kV, Bell-Boundary #3 HSHH 63.62 Line LIND (48187) TO ROXBORO (48375) CKT 1 [115.00 - 115.00 kV] N-1: Devils Gap - Lind 115 kV (LIN-RIT) HT 66.08 Line ROXBORO (48375) TO WARDEN A (48455) CKT 1 [115.00 - 115.00 kV] N-1: Devils Gap - Lind 115 kV (LIN-RIT) HSHH 67.62 Line SOTHELOT (48393) TO TAUNTON (48425) CKT 1 [115.00 - 115.00 kV] BF: GB1250 Sand Dunes 115 kV, Larson-Sand Dunes-Warden HT 69.03 Line ROXBORO (48375) TO WARDEN A (48455) CKT 1 [115.00 - 115.00 kV] N-1: Lind - Shawnee 115 kV (LIN-EWN) HT 69.46 Line ROXBORO (48375) TO WARDEN A (48455) CKT 1 [115.00 - 115.00 kV] N-1: Lind - Washtucna 115 kV HT 70.12 Line ROXBORO (48375) TO WARDEN A (48455) CKT 1 [115.00 - 115.00 kV] BF: A1235 Boundary 230 kV, Boundary-Usk HT 70.37 Line ROXBORO (48375) TO WARDEN A (48455) CKT 1 [115.00 - 115.00 kV] BF: A1234 Boundary East 230 kV, Bell-Boundary #1 Note: All but one of the limiting violations shown in Table 4 are resolved by currently planned Avista Transmission System projects: Benton – Othello Transmission Line 115 kV rebuild (2014) Lind – Warden 115 kV Transmission Line rebuild (2016) These projects greatly impact the Avista Transmission System in the vicinity of Project #33; therefore, further study results are provided below for operating Option 1 in the 2016 timeframe. Staff_PR_135 Attachment A Page 16 of 30 Interconnection Feasibility Study Report PROJECT #33 March 29, 2013 Page 17 of 30 Option 1 (2016) Category A Facility Violations The Light Summer case is the limiting case for normal operating conditions for Option 1 (2016). During this scenario, a facility violation exists on the Warden Tap transmission segment when Project #33 generation exceeds 250 MW; see Figure 7. The Warden Tap is owned by Grant County Public Utility District, and the line is approximately 1.7 miles long with a summer operating limit of 91 MVA. Figure 7: Light Summer limiting Category A scenario for Project #33 Option 1 (2016) Category B and C Facility Violations The most limiting Category B and C contingency scenario occurs during the Light Summer case for an outage of the Grant County Public Utility District owned Sand Dunes – Warden 115 kV Transmission Line. Loss of this line overloads the Grant County Public Utility District owned Warden Tap. Table 5 shows all facility violations for Option 1 (2016) when Project #33 output is 250 MW. Staff_PR_135 Attachment A Page 17 of 30 Interconnection Feasibility Study Report PROJECT #33 March 29, 2013 Page 18 of 30 Table 5: Facility violations during contingencies for Option 1 (2016) Contingency Facility in Violation Percent Case BF: GB1250 Sand Dunes 115 kV, Larson-Sand Dunes-Warden WARDEN A (48455) -> OTHELOSS (48309) CKT 1 at WARDEN A 217.12 HSHH N-1: Sand Dunes - Warden #2 115 kV WARDEN A (48455) -> WARDEN T (46117) CKT 1 at WARDEN A 137.54 HSHH BUS: Sand Dunes 115 kV WARDEN A (48455) -> WARDEN T (46117) CKT 1 at WARDEN A 128.83 HSHH BF: B544 Benton 115 kV, Benton-Othello Switching Station WARDEN A (48455) -> WARDEN T (46117) CKT 1 at WARDEN A 128.12 HSHH N-2: Benton - Midway #2 230 kV and Benton - Othello SS 115 kV WARDEN A (48455) -> WARDEN T (46117) CKT 1 at WARDEN A 128.09 HSHH N-2: Benton - Midway #1 115 kV and Benton - Othello SS 115 kV WARDEN A (48455) -> WARDEN T (46117) CKT 1 at WARDEN A 128.02 HSHH N-1: Benton - Othello SS 115 kV (OSS-SOT)WARDEN A (48455) -> WARDEN T (46117) CKT 1 at WARDEN A 128.01 HSHH N-1: Benton - Othello SS 115 kV Open @ OSS WARDEN A (48455) -> WARDEN T (46117) CKT 1 at WARDEN A 128.01 HSHH N-1: Benton - Othello SS 115 kV (BENT-SOT)WARDEN A (48455) -> WARDEN T (46117) CKT 1 at WARDEN A 122.81 HSHH N-1: Benton - Othello SS 115 kV Open @ BNT WARDEN A (48455) -> WARDEN T (46117) CKT 1 at WARDEN A 122.63 HSHH N-1: Sand Dunes - Warden #2 115 kV WARDEN T (46117) -> SCHRAG T (46091) CKT 1 at WARDEN T 111.31 HT BF: A562 Othello SS 115 kV, Othello Switching Station-Warden #2 WARDEN A (48455) -> WARDEN T (46117) CKT 1 at WARDEN A 110.29 HSHH PSF: Othello SS 115 kV WARDEN A (48455) -> WARDEN T (46117) CKT 1 at WARDEN A 110.29 HSHH N-1: Sand Dunes - Warden #2 115 kV SCHRAG T (46091) -> RUFF TP (46085) CKT 1 at SCHRAG T 103.5 HT BUS: Sand Dunes 115 kV WARDEN T (46117) -> SCHRAG T (46091) CKT 1 at WARDEN T 102.98 HT N-1: Sand Dunes - Warden #2 115 kV RUFF TP (46085) -> BASS JCT (46130) CKT 1 at RUFF TP 102.14 HT Voltage Violations Option 1(2016) introduces no major voltage violations when Project #33 generation level is limited to 250 MW. It is possible reactive voltage support will be necessary for Option 1 (2016), and the amount and location of any reactive support will be determined in a future Interconnection System Impact Study if the Project #33 developer wishes to proceed with Option 1(2016). Figure 8 shows a PV plot for local bus voltages as Project #33 generation output is increased. The plot is for informational purposes only. Figure 8: Light Summer case PV Curve for generation increments at Project #33 Option 1 (2016) Staff_PR_135 Attachment A Page 18 of 30 Interconnection Feasibility Study Report PROJECT #33 March 29, 2013 Page 19 of 30 Incremental Generation Analysis Table 6 shows the incremental generation analysis results for Option 1 (2016). The table is provided for informational purposes only. Table 6: Incremental Generation Study for Project #33 Option 1 (2016) Case LGIR #33 Output Limiting Facility Limiting Contingency HT 131.96 Line WARDEN A (48455) TO WARDEN T (46117) CKT 1 [115.00 - 115.00 kV] N-1: Sand Dunes - Warden #2 115 kV HSHH 143.1 Line OTHELOSS (48309) TO WARDEN A (48455) CKT 1 [115.00 - 115.00 kV] BF: GB1250 Sand Dunes 115 kV, Larson-Sand Dunes-Warden HT 144.58 Line WARDEN A (48455) TO WARDEN T (46117) CKT 1 [115.00 - 115.00 kV] BUS: Sand Dunes 115 kV HSHH 189.37 Line WARDEN A (48455) TO WARDEN T (46117) CKT 1 [115.00 - 115.00 kV] N-2: Benton - Midway #2 230 kV and Benton - Othello SS 115 kV HSHH 189.82 Line WARDEN A (48455) TO WARDEN T (46117) CKT 1 [115.00 - 115.00 kV] BF: B544 Benton 115 kV, Benton-Othello Switching Station HSHH 189.85 Line WARDEN A (48455) TO WARDEN T (46117) CKT 1 [115.00 - 115.00 kV] N-1: Benton - Othello SS 115 kV Open @ OSS HSHH 189.9 Line WARDEN A (48455) TO WARDEN T (46117) CKT 1 [115.00 - 115.00 kV] N-2: Benton - Midway #1 115 kV and Benton - Othello SS 115 kV HSHH 189.97 Line WARDEN A (48455) TO WARDEN T (46117) CKT 1 [115.00 - 115.00 kV] N-1: Benton - Othello SS 115 kV (OSS-SOT) HT 219.48 Line WARDEN A (48455) TO WARDEN T (46117) CKT 1 [115.00 - 115.00 kV] BF: A562 Othello SS 115 kV, Othello Switching Station-Warden #2 HT 219.99 Line WARDEN A (48455) TO WARDEN T (46117) CKT 1 [115.00 - 115.00 kV] PSF: Othello SS 115 kV HT 226.17 Line WARDEN A (48455) TO WARDEN T (46117) CKT 1 [115.00 - 115.00 kV] N-1: Othello SS - Warden #2 115 kV (OSS-L&R) HT 235.89 Line SCHRAG T (46091) TO WARDEN T (46117) CKT 1 [115.00 - 115.00 kV] N-1: Sand Dunes - Warden #2 115 kV HT 242.88 Line RUFF TP (46085) TO SCHRAG T (46091) CKT 1 [115.00 - 115.00 kV] N-1: Sand Dunes - Warden #2 115 kV HT 244.27 Line BASS JCT (46130) TO RUFF TP (46085) CKT 1 [115.00 - 115.00 kV] N-1: Sand Dunes - Warden #2 115 kV HT 247.81 Line BASS JCT (46130) TO WHEEL TI (46119) CKT 1 [115.00 - 115.00 kV] N-1: Sand Dunes - Warden #2 115 kV Conclusions from Option 1 power flow studies The configuration suggested in Option 1 is feasible when the output of Project #33 is limited to 62 MW. Option 1 (2016) is a feasible option once the above mentioned Avista Transmission System projects are completed, Project #33 would be limited to 250 MW. Further studies conducted as a part of a Interconnection System Impact Study may identify additional issues which will be addressed if the Interconnection Customer wishes to proceed with one of these options. Staff_PR_135 Attachment A Page 19 of 30 Interconnection Feasibility Study Report PROJECT #33 March 29, 2013 Page 20 of 30 Option 2: 400 MW Category A Facility Violations Operating Project #33 at full output of 400 MW introduces no facility violations in either the Heavy Summer or Light Summer cases during normal operating conditions. Category B and C Facility Violations The most limiting Category B and C contingency scenario occurs during the Light Summer case for an outage of the new Lind230 – Wanapum 230 kV Transmission Line. Loss of this line overloads the Warden Tap. Figure 9 shows this most limiting contingency, and Table 7 shows other facility violations for Option 2. Figure 9: Light Summer limiting Category A scenario for Project #33 Option 2 Staff_PR_135 Attachment A Page 20 of 30 Interconnection Feasibility Study Report PROJECT #33 March 29, 2013 Page 21 of 30 Table 7: Facility violations during contingencies for Option 2 Contingency Facility in Violation Percent Case N-1: Lind230 - Wanapum WARDEN A (48455) -> WARDEN T (46117) CKT 1 at WARDEN A 154.99 HT N-1: Lind230 - Wanapum LIND (48187) -> ROXBORO (48375) CKT 1 at ROXBORO 126.91 HT N-1: Lind230 - Wanapum ROXBORO (48375) -> WARDEN A (48455) CKT 1 at ROXBORO 123.46 HT N-1: Sand Dunes - Warden #2 115 kV WARDEN A (48455) -> WARDEN T (46117) CKT 1 at WARDEN A 115.31 HT BUS: Sand Dunes 115 kV WARDEN A (48455) -> WARDEN T (46117) CKT 1 at WARDEN A 103.6 HT Voltage Violations Option 2 introduces minor voltage issues, and this option could require the addition of reactive voltage support. The amount and location of any reactive support will be determined in a future Interconnection System Impact Study if the Project #33 developer wishes to proceed with Option 2. Figure 10 shows a PV plot for local bus voltages as Project #33 generation output is increased. The plot is for informational purposes only. Figure 10: Light Summer case PV Curve for generation increments at Project #33 Option 2 Staff_PR_135 Attachment A Page 21 of 30 Interconnection Feasibility Study Report PROJECT #33 March 29, 2013 Page 22 of 30 Incremental Generation Analysis Table 8 shows the incremental generation analysis results for Option 2. The table is provided for informational purposes only. Table 8: Incremental Generation Study for Project #33 Option 2 Case LGIR #33 Output Limiting Element Limiting CTG HT 246.68 Line WARDEN A (48455) TO WARDEN T (46117) CKT 1 [115.00 - 115.00 kV] N-1: Lind230 - Wanapum HSHH 294.56 Line WARDEN A (48455) TO WARDEN T (46117) CKT 1 [115.00 - 115.00 kV] N-1: Lind230 - Wanapum HT 322.47 Line LIND (48187) TO ROXBORO (48375) CKT 1 [115.00 - 115.00 kV] N-1: Lind230 - Wanapum HSHH 333.35 Line LIND (48187) TO ROXBORO (48375) CKT 1 [115.00 - 115.00 kV] N-1: Lind230 - Wanapum HT 333.92 Line ROXBORO (48375) TO WARDEN A (48455) CKT 1 [115.00 - 115.00 kV] N-1: Lind230 - WanapumHT337.05 Line WARDEN A (48455) TO WARDEN T (46117) CKT 1 [115.00 - 115.00 kV] N-1: Sand Dunes - Warden #2 115 kV HSHH 358.44 Line ROXBORO (48375) TO WARDEN A (48455) CKT 1 [115.00 - 115.00 kV] N-1: Lind230 - Wanapum HT 389.66 Line WARDEN A (48455) TO WARDEN T (46117) CKT 1 [115.00 - 115.00 kV] BUS: Sand Dunes 115 kV HSHH 403.93 Line OTHELOSS (48309) TO WARDEN A (48455) CKT 1 [115.00 - 115.00 kV] BF: GB1250 Sand Dunes 115 kV, Larson-Sand Dunes-Warden Conclusions from Option 2 power flow studies The configuration suggested in Option 2 is feasible for the full requested output of 400 MW at Project #33 when generation tripping is employed for select contingencies. The transmission system proposed by Option 2 would be adequate at 400 MW. Further studies conducted as a part of a Interconnection System Impact Study may identify additional issues which will be addressed if the Interconnection Customer wishes to proceed with Option 2. Staff_PR_135 Attachment A Page 22 of 30 Interconnection Feasibility Study Report PROJECT #33 March 29, 2013 Page 23 of 30 Impacted Transmission Facilities A preliminary sensitivity analysis was performed in order to determine the various WECC monitored paths and transmission elements affected by the proposed Project #33 interconnection. This analysis was completed through the use of the Power Transfer Distribution Factor (PTDF) tool within PowerWorld Simulator. The point of receipt (POR) modeled was the generation facility. The selection of the point of delivery (POD) presumes an assumption on where the energy from the interconnecting project is delivered therefore yielding different sensitivity results. Therefore, the studies included the POD as all load within Avista’s Balancing Area (representing the interconnecting project as a network resource) and the POD as all generators owned and/or operated by Avista, excluding generators at Project #33 and Project #8, and the POD as all generators in the Western Interconnection excluding those owned and/or operated by Avista (representing an energy resource). These studies do not cover all possibilities of where the energy from the interconnecting project may be scheduled, but they do provide a strong indication of what WECC monitored paths and transmission elements are affected. Common elements showing sensitivity with different POD assumptions indicate transmission elements that should be monitored closely and may indicate other Affected Systems. A review of the results indicates that the Affected Systems that should be informed of the Project #33 interconnection process include the following: Avista Corporation (conducted the Feasibility Study—deemed as informed) Bonneville Power Administration Grant County Public Utility District Chelan County Public Utility District Big Bend Electric Cooperative, Inc.4 If the Project #33 Developer moves forward with an Interconnection System Impact Study for Project #33, those neighboring systems that are identified as Affected Systems and which may be impacted by this interconnection will be sent a copy of this report. Avista will coordinate the continued study work with any such Affected Systems. 4 Included in this section because of interactions found during the Short Circuit analysis below Staff_PR_135 Attachment A Page 23 of 30 Interconnection Feasibility Study Report PROJECT #33 March 29, 2013 Page 24 of 30 Short Circuit Analysis General: The proposed Project #33 Wind generation is 400 MW in size and the studied location was approximately 14 miles from the Lind 115 kV Substation. Three options were identified by Avista System Planning to integrate Project #33 as an Energy or Network Resource. A fault analysis study was performed for each option. The common assumptions for the Project #33 model are: 1. The facility topology of collector strings to station GSU transformers was not provided. Two equivalent collector systems per Table 1 of WECC Wind Power Plant Power Flow Modeling Guide 2008 were used. 2. 2 - 185 MVA wye-wye-delta 3 winding transformer 34.5/115/13.8 kV step up each with a 10% impedance was used. 3. 87 - Parallel 3MVA pad mount delta-wye 0.69/34.5 kV GSU transformers stepping up the generation to a 34.5 kV collector system. The pad-mounted transformer impedance is approximately 6% on the transformer MVA base. 4. 2 –200 MVA machines the equivalence of 87 - 2.3 Megawatt Type 4 machines providing approximately 1 per unit fault current at 26 degrees. ASPEN Model Development: Station Transformers The 115/34.5/13.8 kV 111/148/185 MVA three winding transformer connected wye-wye-delta impedances were based on Zps=10% on 111 MVA base provided in the Interconnection Application. The impedance of primary to tertiary (Zpt) and secondary to tertiary (Zps) were estimated from a similar transformer connected to the Avista transmission system. All impedances were converted to the ASPEN base of 115 kV and 100 MVA. The calculated impedances are as follows: Z1ps = 119/132*10% ∠88 = 0.00315 + j0.09001 Z1pt = 119/132*15% ∠88 = 0.00472 + j0.13514 Z1st = 119/132*3% ∠88 = 0.00094 + j0.02703 The zero sequence impedances were set equal to the positive sequence parameters. Collector String and Pad Mount GSUs The impedances were converted a 100 MVA base is as follows: Collector string - From Table 1 WECC Wind Power Plant Power Flow Modeling Guide 2008, 100 MW block, all underground: R(200)=2*0.0168=0.0336 X(200)=2*0.0139=0.0278 Staff_PR_135 Attachment A Page 24 of 30 Interconnection Feasibility Study Report PROJECT #33 March 29, 2013 Page 25 of 30 Values for zero sequence impedance were estimated based on typical Avista underground cable at 7*R1 and 3*X1: R0= 2*7*0.0168 = 0.2352 X0= 2*3*0.0139 = 0.0834 Pad Mount GSU – 87 units parallel Z1 = (0.06*100/3)/87 = 0.023 R1 = )18( 1 2 2Z = 0.0029 X1 =221RZ = 0.0228 The zero sequence impedances were set equal to the positive sequence parameters. Wind Turbines The generators for Project #33 will be modeled as two 200 MVA machines the equivalence of 87 – 2.3 MVA wind generators. The wind turbines were identified as Type IV. Type IV turbines typically will not provide more than 1 per unit short circuit contribution at an angle of approximately 26 degrees into the system. The wind turbine model used the worst case scenario with all machines on line (400 MVA). Since the WTG transformer is a Wye-Delta blocking the negative and zero sequence contributions to a single line to ground 115 kV transmission fault, all sequence parameters were set equal. The subtransient, transient and synchronous impedances were all set the same. The 200 MVA machine parameters are as follows: Transmission All 115 kV and 230 kV transmission line network upgrades identified in each option were modeled as 230 kV single pole construction with 1590 ACSS. The 1590 ACSS is capable of 400 MVA at both the 230 and 115 kV levels. Fault Analysis Study A short circuit analysis study was performed for each option to determine if Avista’s installed equipment is adequate for the proposed Project #33 POI. All normally open star points on the 115 kV transmission system were closed to obtain maximum fault duties. Identified and budgeted system improvements in the Big Bend area were not modeled. The following analysis was performed: Staff_PR_135 Attachment A Page 25 of 30 Interconnection Feasibility Study Report PROJECT #33 March 29, 2013 Page 26 of 30 1. Perform 3LG and SLG close in faults on each line terminal breaker at the affected Lind bus by the interconnection. 2. Perform 3LG and SLG close in faults on each 115/13 kV substation bus affected by the interconnection 3. Compare resulting fault duties to breaker, Circuit switcher or power fuse interrupt ratings. Fault Duty Comparisons Option 1: The changes in fault duties in amperes due to the addition of the Project #33 400 MW of generation networked to the Big Bend area are shown below. Station Breaker/Device Ratings - The three-phase and single line to ground fault magnitudes increased in the area as expected. The new 115 kV breaker ratings at Lind are 40 kA symmetrical interrupt. The 115 kV power fuses at Marengo, Washtucna, Ritzville and Lind are rated at 10,000 kA interrupt. The Mark III circuit switcher rating at Roxboro is 6000/3000 interrupt. The fault duty at the Roxboro 115 kV bus is approximately 88% of the circuit switcher capability. The interrupting devices at Ralston and Delight are not Avista. Staff_PR_135 Attachment A Page 26 of 30 Interconnection Feasibility Study Report PROJECT #33 March 29, 2013 Page 27 of 30 Option 1 (2016): The changes in fault duties in amperes due to the addition of the Project #33 400 MW of generation networked to the Big Bend area are shown below. Station Breaker/Device Ratings - The three-phase and single line to ground fault magnitudes increased in the area as expected. The Lind 115 kV breaker ratings are 40 kA symmetrical interrupt. The 115 kV power fuses at Marengo, Washtucna, Ritzville and Lind are rated at 10,000 kA interrupt. The Mark III circuit switcher rating at Roxboro is 6000/3000 interrupt. The fault duty at the Roxboro 115 kV bus is approximately 112% of the circuit switcher capability. The interrupting devices at Ralston and Delight are not Avista. Staff_PR_135 Attachment A Page 27 of 30 Interconnection Feasibility Study Report PROJECT #33 March 29, 2013 Page 28 of 30 Option 2: The changes in fault duties in amperes due to the addition of the Project #33 400 MW of generation networked to the Big Bend area are shown below. Station Breaker/Device Ratings - The three-phase and single line to ground fault magnitudes not only increased due to the addition of the wind generation but for the proposed 230 kV source into the area. The overall increase to fault duties in the area were approximately 380 %. The Lind 115 kV and 230 kV breaker ratings are 40 kA symmetrical interrupt. The 115 kV power fuses at Marengo, Washtucna, Ritzville and Lind are rated at 10,000 kA interrupt. The Mark III circuit switcher rating at Roxboro is 6000/3000 interrupt. The fault duty at the Roxboro 115 kV bus is approximately 166% of the circuit switcher capability. The interrupting devices at Ralston and Delight are not Avista. Summary Integrating Project #33 Wind generation of 400 MW onto Avista’s transmission system increased fault duties in the Big Bend area. The increased fault duties are well below the Staff_PR_135 Attachment A Page 28 of 30 Interconnection Feasibility Study Report PROJECT #33 March 29, 2013 Page 29 of 30 interrupting capability of the Lind 115 and 230 kV breakers. The results show integrating Project #33 Wind generation onto Avista’s 115 kV system at the requested POI will not impact the capability of the Lind Substation line breakers to interrupt three phase or single phase faults for all three options. For Options 1 (2016) and Option 2, the fault duty is above the Roxboro circuit switcher rating and must be replaced. Non Avista facilities in the area affected by the increase in fault duties should be reviewed by the facility owner. All transmission and distribution relay settings will require a review and coordination verification for the Big Bend area. Staff_PR_135 Attachment A Page 29 of 30 Interconnection Feasibility Study Report PROJECT #33 March 29, 2013 Page 30 of 30 Conclusion Project #33 is a feasible project based on the preliminary analysis performed. The power flow and short circuit analysis analyzed three different interconnection options with the point of interconnection at Lind Substation. A summary of the options and their total estimated costs are given in below. Option Project Output Condition Total Cost ($000) Option 1 62 MW New Breaker Position at Lind $500 Option 1 (2016) 250 MW Benton – Othello & Lind – Warden 115 kV projects $600 Option 2 400 MW Generation tripping necessary for some contingencies $67,700 Preliminary study suggests Option 1 is feasible when the output of Project #33 is limited to 62.5 Preliminary study suggests Option 1 (2016) is feasible when the output of Project #33 is limited to 250 MW.2 Preliminary study suggests Option 2 is feasible when the output of Project #33 is limited to 400 MW and generation tripping is employed for some contingencies.2 All construction costs are in 2013-year dollars and are based on engineering judgment only with +/- 50% error. These cost estimates assume that the Project #33 owners are responsible for all facilities from their project to the POI. Detailed cost figures will be determined during future studies. 5 Further studies conducted as a part of the Interconnection System Impact Study may identify additional issues or limits which must be addressed if the Interconnection Customer wishes to move forward with this project. Staff_PR_135 Attachment A Page 30 of 30