Arizona's Electricity Grid Impacted by Storms: Natural Gas Generation Maintains Grid Reliability

Strategic Insights -

Arizona's two largest electric utilities, APS and SRP, reported losing nearly 1,600 MW of utility-scale solar energy generation during a severe storm on August 25, 2025, which caused a significant strain on the grid. The loss of solar resources was equivalent to about 50% of APS' total utility-scale solar fleet and 45% of SRP's. Demand increased by 200 MW, further straining the system. Fortunately, the utilities relied on dispatchable natural gas resources to compensate for the loss in solar output and maintain grid reliability.

Key Takeaways:

  • Arizona's two largest electric utilities, APS and SRP, lost nearly 1,600 MW of utility-scale solar energy generation during a severe storm on August 25, 2025.
  • The loss of solar resources was equivalent to about 50% of APS' total utility-scale solar fleet and 45% of SRP's.
  • Demand increased by 200 MW, further straining the system, but natural gas generation maintained grid reliability.
  • The utilities relied on dispatchable natural gas resources to compensate for the loss in solar output and maintain grid reliability.
  • Without access to natural gas generation, an estimated 350,000 homes could have lost power during the storm.
  • Chairman Kevin Thompson emphasized the importance of natural gas generation in maintaining grid reliability, stating that "losing 1,600 MWs of generation that quickly is the equivalent to one of the units of the Palo Verde nuclear plant going offline."
  • Vice Chair Myers attributed the reliability of the grid to the flexibility and reliability of dispatchable natural gas generation.

Statistics:

  • 1,600 MW of utility-scale solar energy generation lost during the storm.
  • 50% of APS' total utility-scale solar fleet lost during the storm.
  • 45% of SRP's utility-scale solar fleet lost during the storm.
  • 200 MW increase in demand during the storm.
  • 350,000 homes that could have lost power during the storm without natural gas generation.
  • The storm caused a significant strain on the grid, but dispatchable natural gas generation maintained reliability.

Sources:

  • Arizona Corporation Commission, "ACC Discusses How Storms Impacted Arizona's Electricity Grid and How Utilities Responded" (August 26, 2025).