1. Mustang Solar Site Project

2. Project Overview (Scott Milanowski) Solar Plant Overview Grid Ops Team (Thea Matlock) Maintenance Team (Michelle Rodriguez-Pico) Analytics Team (Steven Chisholm) Future Opportunities Q&A Introduction

3. Prices have Declined Dramatically Slide for SOLAR ADOPTION AND PRICE

4. Solar Growth has been Exponential

5. Oklahoma Ranks #7 in Solar Potential

6. Why are we doing this? Solar is coming !!! Gain experience and knowledge of solar deployment and operation Identify and test grid planning, engineering and operational impacts of large solar DG Identify and validate operational and business benefits of community solar

7. What will we learn? Plant Performance Output levels, variability, predictability, peak coincidence, tracking benefits, effects of temperature, contamination and weather Grid Performance Voltage regulation, reverse power flow, variability, power quality, harmonics, fault protection, power factor, effect on Integrated Volt-Var Control (IVVC) Operations Impact Maintenance, training requirements, reliability, switching, monitoring, dispatching, controlling

8. What are the benefits? Help position OG&E as a leader and supplier of solar power in our region Understand the value that is created for the customer and the grid Establish a platform/test bed for possible future DER and grid modernization efforts (e.g. energy storage, micro-grids) Test customer acceptance of a solar energy product

9. Solar Plant Overview

10. ® Mustang Site Overview 10 2 MW Solar site, potential for future expansion 0.5 MW Solar Site Confidential – For Internal Company Use Only

11. 11 Mustang South Conceptual Layout Confidential – For Internal Company Use Only

12. Mustang South

13. 13 Mustang North Conceptual Layout Confidential – For Internal Company Use Only

14. Mustang North

15. DC 600-1000V AC 480V AC 12.5kV SCADA Remote Monitoring and Control Solar Plant Overview

16. OGE Step-up Transformer Panels / Modules Switch Board (Main Disconnect) SCADA / DAS Solar Plant Overview Distribution Control Center Inverter

17. Grid Operations Team Thea Matlock

18. Grid Operations Team Who is the DCC? Distribution Control Center Operators are responsible for directing the operation of the 34.5 kV and below distribution system from the high side disconnects though the substation transformers, and all distribution devices.

19. Grid Operations Team – Objectives Review SOP’s and SSOP’s – specifically looking at the safety for distribution lines Changes to DCC and field processes Remote Monitoring of Solar Plant Analyze how solar affects distribution and implement solutions to mitigate any negative effects

20. Transformer Purchased a transformer specific to solar applications that withstands higher harmonic currents that are created from the inverters If we lose the transformer, it can be replaced temporarily with one of the OGE's stock transformers until the Solar transformer arrives

21. Inverter Meets the UL 1741 and IEEE 1547 standard Doesn’t create high fault currents so Arc Flash is minimal Requires the frequency of the grid to be able to convert power from DC to AC Anti-islanding prevents solar system from being on if the grid is down If the voltage drops a certain % on any of the three phases the inverter will automatically shut off System has to be in stable conditions for 5 minutes before inverters turn back on Designed and Tested to not back feed into a de-energized grid

22. DMS – Distribution Management System Team worked to try to determine best way to present the alarms and control points to the Operators Grouped alarms to not overwhelm operators but still identify problem.

23. DMS – Distribution Management System Control points On/Off Power Factor Output KW Output KVAR Output

24. DMS – Distribution Management System Inverter modes Standby Check Running Derate Fault

25. DMS – Distribution Management System Alarm Codes

26. Grid Ops Team – Outcome 24/7 Monitoring of the site through SCADA or Web interface Operation Authority of the Solar Plant Monitor and dispatch alarms Remote control of inverters (ON, OFF, PF) PD crews- Normal operations of the primary riser, underground and transformer feeding the Solar Plant System Lab may help locate cables inside the Solar Plant System Maintenance / Protection / Control will own / operate SCADA devices at the Solar Plant

27. Maintenance Team Michelle Rodriguez-Pico

28. Maintenance Team – Objectives Recommend which business unit should owned the site and self-maintain vs. contact labor Recommend and implement integration of Solar Plant in SAP including assets, materials, etc. Analyze the need to manage spare parts Warranty / life cycle asset Establish an optimize schedule preventive maint. plan Identify, create and modify SOP’s, SSOP’s, OI’s related to the solar plant including items such as: switching, troubleshooting, monitoring, clearances, etc.

29. Maintenance Team – Site Ownership Business Unit – Facilities, Power Delivery, Power Supply Categories – Skill Set = Does the business unit possess these skills? Wiring, cabling (splice, UG, AG, conduit) Hi/Low Voltage Electric, AC/DC troubleshooting capabilities Power Quality knowledge, read diagrams Mechanical capabilities (trackers, metal frame, hinges, etc) Electronics / SCADA capabilities / SCHW relays / Cable locating Wireless communication knowledge (trackers) – Resources Level = Do we have available resources in this BU? – Location = Where the workforce is traveling from?

30. South Solar Unit 504 KWac (648.2KWp dc) 2,091 Panels (310wdc) 18 Inverters (28KWac) – 6 or 7 string per inverter – 17 panels per string 5 Panel board (ac) 1 Switchboard 500KVA Step-up Transformer (K rated) North Solar Unit (E and W) 2,016 KWac (2.372MWp dc) 7,776 Panels (305Wdc) 72 Inverters (28KWac) – 6 string per inverter – 18 panels per string 16 Panel board (ac) 2 Switchboard (E and W) 2x 1000KVA Step-up Transformer (K rated) Maintenance Team – Equipment

31. Maintenance Team – SAP Structure

33. Maintenance Team – Outcome 24/7 Response to any Distribution Control Center (DCC) calls Maintenance Authority of the Solar Plant Troubleshoot and resolve alarms and resets Perform seasonal inspections (with contractor during warranty period) Manage spare parts as needed Manage warranty of assets Vegetation Management

34. Grid Ops Team and Maintenance Team Reviewed all SSOP – no changes SOP – 323.042 “Using Three-Part Communication” will be utilize to communicate with DCC – 224.395 LOTO – no changes Operation Instruction – 325.103 “Reporting Switching to Generation Dispatchers and System Operation” will be similar to switch with DCC ArcFlash – OGE is currently reviewing the study performed at the site Safety

35. Grid Ops and Maintenance Security – Lighting and radar based camera Environmental Safety

36. Analytics Team Steven Chisholm

37. Sources of Analytical Data Smart Meter – 1 sample every 15 minutes of entire facility. AlsoEnergy Web Portal – 1 sample every 15 from all inverters and weather station. SCADA – 1 sample every 10 seconds. SynchroPhasors – 30 samples per second. Event Reports – 30,720 samples per second for triggered events

38. Solar Production Aug 1 to Aug 8

39. Comparing Days (Meter Data)

40. Comparing Days (SynchroPhasor Data)

41. Output With Cloud Coverage

42. “Edge of Cloud” Effect

43. Voltage Impact of Variable Output

44. AlsoEnergy Dashboard

45. AlsoEnergy Inverter Production

46. Future Opportunities

47. Community Solar Product Offering Battery storage Larger Solar Plant Landfill Solar Plant Rooftop Solar / Solar carport

48. TO ALL OF THE TEAM MEMBERS THE SOLAR SYSTEM THANKS YOU

49. QUESTIONS