Arizona

Arizona is home base for ESS. Here is the grid it has worked since 1978.

ESS clients in Arizona

Salt River Project (SRP), Arizona Public Service (APS)

How Arizona makes its power

Arizona's electricity comes primarily from natural gas, which supplied roughly 47 percent of in-state generation in 2024, followed by nuclear at about 28 percent from the Palo Verde Generating Station, one of the largest nuclear plants in the United States. Renewables, led by solar, provided approximately 16 percent, and coal has fallen to under 10 percent as older units retire.

Grid challenges

Extreme summer heat drives high peak demand while utilities plan for large new loads from data centers and manufacturing; APS has projected that most of its energy-need growth through 2038 will come from data centers and large industrial customers. Meeting that growth requires new generation, expanded transmission, and continued solar and battery storage interconnection. Arizona sits in the Western Interconnection with no traditional ISO, so utilities coordinate reliability as regional balancing authorities and are moving into Western energy markets.

Major utilities and grid operators

  • Arizona Public Service (APS)
  • Salt River Project (SRP)
  • Tucson Electric Power (TEP) / UNS Energy
  • Rural cooperatives (Trico, Mohave, Sulphur Springs Valley)
  • WECC / Western Interconnection (no RTO; utilities operate as balancing authorities)

Sources

Substation work in Arizona?

Tell us the voltage class, the site, and the timeline. ESS mobilizes across the West.

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