1. Estimating Available Capacity for New Generators Jonathan Rose Planning Engineer, Resource Integration Dept. Regional Planning Group September 24, 2013

2. 2 Goal: Provide Better Information for Generation Developers ERCOT Resource Integration Dept.

3. “Available Capacity” Tool – RPG – 9/24/2013 3 Providing a Tool for Prospective Generation Developers Generation Interconnection Process Observations Many generation developers unfamiliar with transmission network. –Buy maps from 3 rd party vendors. Do not know the rating (or voltage) of lines. –Often request a screening study in an obviously under-sized transmission location. –Sometimes request “investigative” screening studies just to understand transmission.

4. “Available Capacity” Tool – RPG – 9/24/2013 4 Program written by Jonathan Rose. Performs a “pseudo” screening study at every bus in ERCOT system. Estimates transmission capacity available for new generators. Results are tabulated by bus. Envision making results public. Introducing: Available Capacity Program

5. “Available Capacity” Tool – RPG – 9/24/2013 5 Report will be published with many disclaimers: –Analysis less comprehensive than an ERCOT Screening Study. –Analysis performed in Steady State only. –Errors may exist. SPSs and RAPs were not modeled. –Use at your own risk. –Recommend use only as informal guidance. Disclaimers…

6. “Available Capacity” Tool – RPG – 9/24/2013 6 Sample Map – 345 kV Network Available Transmission Capacity in North Texas Sample

7. “Available Capacity” Tool – RPG – 9/24/2013 7 Sample Tabular Results Available Capacity Shown for New Generators

8. “Available Capacity” Tool – RPG – 9/24/2013 8 For each bus… How Results Calculated Add prospective generator at bus. Perform FCITC Transfer Analysis Scale up prospective unit. Scale down faraway gas generation. Perform FCITC Transfer Analysis Scale up prospective unit. Scale down faraway gas generation. Scale up nearby generators. Calculate and save constraints.

9. “Available Capacity” Tool – RPG – 9/24/2013 9 How Does it Work? Python Code MS Access Database TARA PSS/E

10. “Available Capacity” Tool – RPG – 9/24/2013 10 Planning analysis tool similar to MUST. –Used by ERCOT Planning & Res. Integration. Can perform security-constrained economic dispatch. Good for reporting sensitivities & shift factors. http://www.power-gem.com/TARA.htm What is TARA? (Since people may not be familiar…)

11. “Available Capacity” Tool – RPG – 9/24/2013 11 QUESTIONS?