The report also explored five extreme scenarios. In four of them, the ERCOT grid would fall short.


Texas should have sufficient power to meet demand this winter in all but the most challenging scenarios, according to a new seasonal report from the state’s primary grid operator.

However, the report also explored five extreme scenarios — and in four of them, the ERCOT grid would face a significant shortage of power this winter.

Released November 19, ERCOT’s Seasonal Assessment of Resource Adequacy (SARA Report) for the winter of 2021/2022 includes reliability projections under a number of potential scenarios for generation output, resource losses and consumption. The new SARA Report forecasts sufficient generating capacity this winter to meet system-wide peak demand under normal winter grid conditions, as well as under a number of scenarios that include higher than expected load or generation losses.

ERCOT releases SARA Reports seasonally. Key forecasts in this new update include:

  • Total Resources at winter peak:  84,861 megawatts
  • Peak Demand Forecast:  62,001 MW
  • Reserves at winter peak:  22,860 MW
  • Operating Reserve Margin:  43.3 percent

The new winter SARA Report also included considerations of a number of less typical scenarios, including High Unplanned Outages (4,393 MW above typical outages), Low Renewable Output (6,267 MW below forecast), and Unusually Cold Weather (10,771 MW additional heating load).  In each of these unusual scenarios or in combinations, the report estimated that the system would maintain a level of reserves sufficient to avoid emergency conditions.

However, as part of its response to last February’s statewide outages, ERCOT now has begun including extreme scenarios in its SARA Reports — and it’s here that this new update exposes the potential for difficulties this winter.

The new report includes consideration of additional Planned Outages (762 MW), Extreme Unplanned Outages (3,268 MW above High Unplanned Outages) and Extreme Low Renewable Output (2,502 MW additional below forecast). In all but one combination of the extreme scenarios, the report finds that Operating Reserves would fall sufficiently as to lead to emergency conditions, i.e., where Physical Responsive Capability (PRC) falls below 2,300 MW.  In several of the scenarios, reserves fall sufficiently below safety margins to indicate Load Shed.


ERCOT and the PUC have ordered system improvements since last February’s winter storm, including winter weatherization at power plants, new inspections of generation resources and transmission service providers, and improved notice by gas industry participants of locations of critical loads. These improvements should mitigate some reliability risk to the system.

However, the imputed level of load on the system during this year’s weather emergency exceeded even the extreme scenarios described in the new SARA Report. Similarly, resource outages during the winter storm also far exceeded the extreme scenarios included in the new SARA Report.

— R.A. Dyer