116-390 Village Boulevard, Princeton, New Jersey 08540-5721 Phone: 609.452.8060 ▪ Fax: 609.452.9550 ▪ www.nerc.com Consideration of Comments — 1 st Draft of TPL-001-1 — Transmission System Planning Performance Requirements The Assess Transmission Future Needs Standards Drafting Team thanks all commenters who submitted comments on the first draft of the standard. This standard was posted for a 30-day public comment period from September 12, 2007 through October 26, 2007. The drafting team asked stakeholders to provide feedback on the standard through a special Standard Comment Form. There were more than 80 sets of comments, including comments from 236 different people from more than 80 companies representing 9 of the 10 Industry Segments as shown in the table on the following pages. Based on the comments received, the drafting team is recommending a second posting of the revised standard. Definitions and the following requirements have been changed due to industry comment as specifically cited in the responses: Definitions • Base Case - the SDT removed “Base Case” as a defined term. • Bus-tie Breaker – the SDT added a definition. • Consequential Load Loss – the SDT reworded the definition to better clarify that this is Load loss that occurs when the source to that Load is lost or Load that is lost due to the Load’s transient response to the event being studied and to eliminate confusion regarding references to concepts such as fault clearing action, mis- operation, or radial Load. • Extreme Events – the SDT revised the definition to clarify that Extreme Events have a “lower probability of occurrence than Planning Events.” • Long-Term Transmission Planning Horizon - the SDT revised the definition to clarify when the horizon may extend beyond ten years • Non-Consequential Load Loss - the SDT revised the definition to improve its clarity and to specify that this is non-interruptible load • Planning Assessment - the SDT revised the definition to be more succinct, to eliminate the description of the possible range of assumptions, and to clarify that the assessment is an evaluation of Transmission System performance (not needs) and Corrective Action Plans associated with identified deficiencies. • Planning Coordinator – the SDT added the definition from the Functional Model. • Plant Stability Study - the SDT replaced the word, “plant” with the term, “generating unit,” and modified the wording to improve its clarity. • System Stability Study - the SDT revised the definition to add further clarity • Year One - the SDT modified the definition to clarify that Year One is the first year that requires assessment, not study, and to clarify that the planning window begins 12 to 18 months from the completion of the previous assessment. Sensitivity Studies