AUSTIN (KXAN) — For the second time in three days, the Electric Reliability Council of Texas (ERCOT) is asking Texans to voluntarily conserve power as grid conditions tighten during intense summer heat.

The request to conserve is for peak usage hours between 2 and 9 p.m. Wednesday, ERCOT said. ERCOT told KXAN Texans responded to Monday’s request, and 500 megawatts (MW) of demand, enough to power 100,000 homes, dropped from the grid around 2 p.m.

ERCOT said this request is not an emergency alert but a voluntary appeal. Currently, no systemwide outages are expected.

The “conservation alert” is one step above “normal” grid conditions and one below the first emergency alert level.

ERCOT said conservation notices are given when projected energy reserves fall below 2,300 MW for at least 30 minutes.

As a reminder, local outages are still possible in this extreme heat. That could include a tree branch falling on a transmission line or a car crashing into a pole. Local outages do not indicate greater grid issues. Be sure to contact your local power provider if your power does go out.

What are the reasons for the conservation request?

ERCOT provided several reasons for Wednesday’s request, including record-high demand and low wind.

  • Record-high electric demand: The heat wave that has settled on Texas and much of the central United States is driving increased electric use. Other grid operators are operating under similar conservative operations programs as ERCOT due to the heatwave.
  • Low wind: Wind generation is currently generating less than what is historically generated in this time period.
  • Forced thermal outages: The number of forced outages in thermal generation exceeds ERCOT forecasts.
  • Solar: Developing cloud cover in West Texas has reduced the amount of solar generation.

Understanding ERCOT’s emergency alerts

KXAN’s Maggie Glynn broke down what ERCOT’s emergency alert levels actually mean and how ERCOT works to prevent rolling blackouts.

  • Normal grid conditions
  • Conservation alert
  • Energy Emergency Level 1: Conservation is considered to be critical. We reach this stage when operating reserves drop below 2,300 MW and are not expected to recover within 30 minutes.
  • Emergency Level 2: Triggered when reserves are less than 1,750 MW and are not expected to recover within 30 minutes. At this point, ERCOT can reduce demand on the system by interrupting power from large industrial customers who have contractually agreed to have their electricity turned off during an emergency.
  • Emergency Level 3: The final level hits when reserves drop below 1,430 MW. If operating reserves then drop below 1,000 MW and are not expected to recover within 30 minutes and/or the grid’s frequency level cannot be maintained at 60 Hz, then ERCOT will implement “controlled outages,” also known as rolling blackouts.