Quarter 3, 2007 (2007Q3) Generation Deliverability Assessment Study Plan

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George Brooks
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1 Quarter 3, (Q3) Generation Deliverability Assessment Study Plan Background and Purpose of Study Phases I & II Generation and Import Deliverability Studies were completed that established the deliverability of all existing and part of generation projects in the CAISO interconnection queue. The Phase I study included generation projects expected to be commercially operating during summer 2006 while Phase II focused primarily on new generation projects to be commercially operating after 2006 (up to queue number 92 in CAISO interconnection queue). However, as the new interconnection requests are gradually added to the queue, there are a number of new interconnection requests for which the Deliverability Assessments were not covered in the Phase II study. Starting from Phases I & II results, CAISO continues to perform Deliverability Assessment as required by LGIP tariff language. Due to the significantly different amount of interconnection requests received and different pace at which the LGIP study process moves along in three PTO areas, Phase III studied deliverability only on the northern (PG&E) system. The Phase III Deliverability Assessment completed in July, has covered generation interconnection requests from queue number in PG&E area. Since similar issues as in Phase III still exist, this Q3 Deliverability Assessment will focus on generation interconnection requests from queue number 128 to 212 in PG&E area and 93 to 156 in SCE and SDG&E. In addition, the study will update the deliverability of new generation projects from previous assessment because some generation projects have withdrawn from the queue since then. As a reminder, the Deliverability Study Methodology focuses on the Summer Peak load period, when the need for generation capacity is the greatest. The following excerpt from the Deliverability Study Methodology further characterizes the focus of the deliverability study methodology and its limitations. [A] generating facility s interconnection should be studied with the ISO Controlled Grid at peak load, under a variety of severely stressed conditions to determine whether, with the generating facility at full output, the aggregate of generation in the local area can be delivered to the aggregate of load on the ISO Controlled Grid, consistent with the ISO s reliability criteria and procedures. (This definition for deliverability comes from the FERC interconnection order, and this methodology for assessing deliverability has been developed from consultation with PJM officials about their already-established practices.)

2 In addition, the ISO recommends, based on guidance in FERC Order 2003, that the deliverability of a new resource should be assessed on the same basis as all other existing resources interconnected to the ISO Controlled Grid. Because a deliverability assessment will focus on the deliverability of generation capacity when the need for capacity is the greatest (i.e. peak load conditions), it will not ensure that a particular generation facility will not experience congestion during other operating periods. Therefore, other information (i.e. congestion cost analysis for all hours of the year) would be required in addition to the deliverability assessment to evaluate the congestion cost risk of energy purchase agreements, such as a take-or-pay contract with a particular generation facility. Base Case Study Year This Generation Deliverability Assessment will be performed on a power flow base case modeling the year Currently, all generation projects except one in the study have operating dates on or before the year 2011, and the ISO Transmission Planning process develops a detailed transmission plan for a minimum of five years. Therefore, the year 2012 is a good study year choice for the Annual Generation Deliverability Baseline analysis. As such, these Deliverability results will ensure the deliverability of generation for only the year 2012 modeling assumptions described in this study plan. For example, there may be a planned transmission project with initial operation in 2011, and without this project in service, a particular generation project may not be deliverable. However, for generators in this study that go into service between and 2010, System Impact Studies (SIS) have been or will be performed that should adequately assess their deliverability in earlier years. New Generation Projects to be included All new generation projects, with a queue number up to 212 in PG&E and up to 156 in SCE and SDG&E should be modeled in the study. New generation projects connected to the distribution system, but large enough to impact the transmission system should also be explicitly modeled on the electrically closest transmission bus. Appendix A provides information of these projects. New Transmission Projects to be included All ISO approved transmission projects expected to be operational by 2012 should be modeled in the base case. To account for uncertainties associated with some transmission projects such as PVD2 and LEAPS, a sensitivity study without these projects will also be performed. Transmission mitigation plans to mitigate deliverability problems identified in the Phase I and Phase II deliverability studies should also be modeled in the base case. In addition, all reliability and delivery transmission projects identified in generation interconnection studies for generation projects modeled should be included in the base case if they are needed to mitigate impacts identified under summer peak load conditions. If several alternative projects were identified in the SIS that solve the same summer peak problem, and the generation developer has not yet

3 selected a preferred option, then the project with the lowest expected cost that resolves the overload should be modeled, and noted in the case documentation. All transmission projects to mitigate non-summer peak congestion problems, already committed to by generation developers should also be modeled. Each of the PTOs will ensure that these projects are accurately modeled in the base case that they return to the ISO. A list of new transmission projects included in the base case along with their approval history should be provided to the ISO. Appendix B shows all transmission projects based on the CAISO transmission plan. In addition, Appendix C lists the network upgrades from each interconnection requests provided by PTOs. Transmission Facility Ratings The PTOs will ensure that transmission facility ratings are identical to ratings in the ISO transmission register. ISO approved Planned Transmission facilities upgrades that will increase the existing facility rating should be modeled in the base case. A list of new projects, including reconductorings and reratings, included in the base case, should be provided to the ISO. Load Modeling A coincident 1-in-5-year heat wave, ISO Control Area load will be modeled in the base case. Each of the PTOs will modify the load in their area of the starting base case to be 96% of their areas coincident 1 in 5 year heat wave load level. The 96% represents a diversity factor to convert the three area peak load levels to a coincident ISO peak load level. Generation Capacity (Pmax) and behind the meter load in the base case The generation capacity values used in the Phase II baseline study will also be used for this study unless more accurate data is available. Wind generation Pmax data will be updated using available data for the maximum production during summer peak load hours used to calculate the average production for Qualified Capacity valuation. The generation capacity values used in the Phase III study should be modeled in the base case. Generation Dispatch in the base cases Existing generation previously determined to be deliverable should be dispatched similar to the Phase III deliverability base case. New generation in the interconnection queue should be dispatched to balance load and resources. During the study, new generation will be grouped geographically and dispatched together in geographic groups, at a level similar to the existing generation, to balance loads and resources in the base case. Several base cases may be needed to assess the deliverability of each of the generation groups. In all cases, all new generation modeled should be available to be dispatched to full output, based on the study methodology, during the study. Import Levels The 2008 Maximum Import Capability for each branch group based on the methodology for Import Capability Assignment Process for resource adequacy (CAISO Tariff Section

4 ), has been modeled as fully utilized in the base case. Appendix D describes the amount and modeling of imports included in this study. The Study Contingencies to be analyzed The PTOs will provide contingency files with all NERC Category B, C.5 contingencies, and WECC-S2 contingencies on the 500 kv system (common corridor 500 kv lines) in a computer readable format along with a description of the format. The contingency files should include accurate modeling of all existing and ISO approved RAS/SPS assuming generation is at full output. The contingency files should be tested by the PTOs on the base case that they provide to the ISO for this study, to ensure that they are consistent. Updated detailed descriptions of the RAS/SPS included in the contingency files should also be provided by the PTOs. Study Methodology The study methodology is described in Generation and Import Deliverability to the Aggregate of Load (Baseline) Study Methodology on the ISO Website Study Results Generating units that do not pass the deliverability test will be identified. For each overloaded facility identified, the Deliverability Study methodology and tools will provide a list of all new generation units responsible for that overload. This list can then be ranked by queue position and units can be removed sequentially (last on, first off) until the overload is eliminated. The units removed would not pass the deliverability test. The ISO will also include in the study results, for PTO and stakeholder review, new conceptual transmission project alternatives that would allow the new generation projects to pass the deliverability test, or to correct deliverability problems that remain after all new generation projects are removed. The ISO will rely on available transmission studies, as much as possible, in the development of conceptual transmission project alternatives. Study Schedule CAISO anticipates completing this study by mid-november. Task Description Task duration 1 ISO to provide Q3 generation project and transmission project templates 2 PTOs to: 21 days - Fill in generation, transmission projects, after task 1 and network upgrades list (Appendix B,C) - Provide base case with accurate modeling in their area and change files to the ISO. Due Date August 29, 19,

5 3 ISO to consolidate base cases received from PTOs to create Q3 base case and finalize the base case. 4 PTOs will provide information on changes to contingency files and RAS/SPS needed due to modeling Q3 generation and transmission projects 5 ISO to provide list of new units that do not pass the deliverability test 6 ISO to work with PTOs on identifying new conceptual transmission project alternatives that would ensure deliverability for undeliverable units identified in step 7. 7 days after task 2 7 days after task 2 14 days after task 4 14 days after task 5 7 ISO to provide first draft Q3 Report 7 days after task 6 8 PTOs to provide initial comments on first draft 7 days Q3 Report, after task 7 9 ISO to incorporate PTO comments, post draft 7 days report, and schedule stakeholder meeting after task 8 26, 26, October 10, October 24, October 31, November 7, November 14,

Stakeholder Comments Template

Stakeholder Comments Template Submitted By Company Date Submitted Shannon Eddy (shannon@consciousventuresgroup.com) Rachel Gold (Rachel@consciousventuresgroup.com) Large-scale Solar Association (LSA) December