5/4/22 3:54 PM

M-B050422-01 Implementation of NPRR935 and updates related to Solar Forecasting at ERCOT

NOTICE DATE: May 4, 2022

NOTICE TYPE: M-B050422-01 Operations

SHORT DESCRIPTION: Implementation of NPRR935 and updates related to Solar Forecasting at ERCOT

INTENDED AUDIENCE: Market Participants

DAYS AFFECTED: May 24 - May 26, and June 23, 2022

LONG DESCRIPTION: ERCOT is in the process of integrating a second vendor to forecast PhotoVoltaic (PV) production potential for every PhotoVoltaic Generation Resource (PVGR). As a part of this effort, ERCOT will implement the remaining section of NPRR 935: Post All Wind and Solar Forecasts. Following is a summary of the changes that will be implemented.

  • Between May 24 and May 26, 2022
    • The report "Aggregated Solar Resource Power Potential Forecast" (NP4-739-SG | Report Type ID 13498) will be discontinued. Contents of this report are available in the existing report "Solar Power Production - Hourly Averaged Actual and Forecasted Values" (NP4-737-CD | Report Type ID 13483).
  • On June 23, 2022
    • ERCOT will start receiving a second set of hourly solar forecasts, namely, Short-Term PhotoVoltaic Power Forecast (STPPF) and PhotoVoltaic Generation Resource Production Potential (PVGRPP), and an additional Intra-Hour Photo Voltaic Power Forecast (IHPPF). ERCOT Operations will have the ability to select an active STPPF and IHPPF for use in grid operations.
    • Pursuant to Nodal Protocol 3.9.1(8), the selected STPPF will be used to validate and update High Sustained Limits (HSLs) in Current Operating Plans (COPs); if needed, a QSE representing a PVGR may submit a lower COP HSL based on operating conditions.
    • ERCOT will implement six Photo Voltaic solar regions and make reporting changes to provide solar forecast and solar generation by regions. The six solar regions to be implemented were discussed at the June 14, 2021 Congestion Management Working Group.
    • Pursuant to NPRR 935, Post All Wind and Solar Forecasts, the following new reports will be posted on
      • Solar Power Production - Actual 5-Minute Averaged Values by Geographical Region | NP4-746-CD | Report Type ID 21810
      • Solar Power Production - Hourly Averaged Actual and Forecasted Values by Geographical Region | NP4-745-CD | Report Type ID 21809
      • Hourly System-Wide and Regional Solar Forecasts by Model | NP4-443-CD | Report Type ID 21811
      • Intra-Hour Solar Power Forecast by Geographic Region | NP4-752-CD | Report Type ID 21812

ERCOT will host a workshop titled Update to reports related to Photo Voltaic (PV) Forecasts and Implementation of PV regions on May 16, 2022 to provide additional details on the changes related to this effort.

ADDITIONAL INFORMATION: This workshop will be held in person at the ERCOT Austin Campus. A WebEx meeting will be provided for those attending remotely. Please visit the meeting calendar on the ERCOT website for further information on this workshop.

NPRR935 and its associated documents can be found on the ERCOT website.

CONTACT: If you have any questions, please contact your ERCOT Account Manager. You may also call the general ERCOT Client Services phone number at (512) 248-3900 or contact ERCOT Client Services via email at

If you are receiving email from a public ERCOT distribution list that you no longer wish to receive, please follow this link in order to unsubscribe from this list: