Renewable Integration and Adapting to the Changing Resource Mix in ERCOT Sandip Sharma ERCOT Manager, Operations Planning Austin Electricity Conference April 12, 2018

Changing Resource Mix – Installed Capacity (MW) MW please *as of Feb. 2018

Addition of Flexible Gas Units

Key Features that further Renewable Integration Grid Code Renewable Forecast Ancillary Services (Operational Reserves) Real Time Operations

Wind Forecast Errors (Day-Ahead)

Ancillary Services Actual Demand Forecasted Demand 200 MW Error Regulation Non-Spin Responsive Load and generation are constantly changing, due to: Daily load patterns Instantaneous load variation Changes in variable generation output Generators tripping offline Ancillary Services are procured in the Day-Ahead Market to ensure sufficient resource capacity is reserved which can be deployed in a timely manner to restore the balance between the load and generation. Ancillary Services Products Regulation Service ERCOT sends signal every four seconds to increase or decrease output to the generators providing Regulation Responsive Reserve Service Capacity from generators or load resources that is readily available to respond to frequency events Non-Spin Reserve Service Capacity that can be started in 10 or 30 minutes to cover forecast errors or ramps

Discussion