1. Thermal Plant Data and Assumptions TEPPC – Data Work Group Call Tuesday, September 29, 2015

2. Overview Review of “Thermal Plant” Data and Assumptions Generator Cost Parameters – Guidance from Intertek-APTECH Startup and Cycling Cost Variable O&M Ramping Penalty Final assumptions for forced outage rates How to apply Ramp Rate Penalty in GridView? Better alignment with historic Operation 2

3. Intertek-APTECH Data WECC – TEPPC joint with NREL hired Intertek-APTECH Engineering in response to stakeholders concerns about the increased cycling and ramping of thermal generation in recent studies, due to the increased penetration of variable generation. The APTECH data formatted for TEPPC that impacts the dispatch decision included: – Hot, warm, and cold start costs Load follow/ramping cost impacts Base-load Variable Operation and Maintenance (VOM) costs Base Load and Cycling Costs: APTECH agreed for use of low-end cost data in public domain with some exception given “typical” values for large coal plants. The reason for just low-end data is a hedge for APTECH to protect their business. 3

4. Definition of “Buckets” Costs aggregated into seven plant groups – Small subcritical coal plants (35-300 MW) – Large subcritical coal plants (300-900 MW) – Large supercritical coal plants (500-1300 MW) – Combined Cycle Units (CT, ST, HRSG) – Simple Cycle Large Frame CT – Simple Cycle aero-derivative CT (LM 6000) – Gas-fired steam plants (50-700 MW) 4

5. Better Alignment with Historic Operation 5 Kevin Harris

6. Production Cost Model What is a Production Cost Model (PCM) – It economically commit and dispatch supply to serve load of the modeled footprint – There are no hard constraints – Everything is evaluated as a cost ($) – The objective is to mimic utility or market operations 6

7. The Rules The rules of Production Cost Modeling Single owner dispatch – Everything is evaluated as a cost ($) – WECC is composed of 38 balance areas each optimizing their supply to economically serve their load and contractual obligations A modeler can only layer in constraints to mimic a desired behavior – Backcasting provides a know behavior to mimic – What inaccuracies are you willing to accept? 7

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