Phoenix gets its electricity from two major utilities, Arizona Public Service (APS) and Salt River Project (SRP), which together serve the vast majority of the metro area. The power itself comes from a mix of natural gas, nuclear energy, coal, solar, and a smaller share of hydroelectric from dams on the Colorado River. That mix is shifting fast, with solar and battery storage growing rapidly while coal plants are closing.
Two Utilities Split the Metro Area
If you live in Phoenix, your electricity comes from one of two providers depending on your exact address. APS is the state’s largest investor-owned utility and serves most of the city of Phoenix proper along with large portions of the surrounding metro. SRP is a community-based, not-for-profit utility that delivers power and water to more than 2 million people across central Arizona, covering a broad swath of the East Valley and parts of the city itself.
You don’t get to choose between them. Your address determines your provider, and both utilities maintain their own generation portfolios, meaning the actual sources powering your home differ slightly depending on which one serves you.
Natural Gas and Nuclear Carry the Load
Natural gas is the single largest electricity source for the Phoenix area. SRP generated about 14,277 gigawatt-hours from natural gas in a recent reporting period, making it roughly 45% of its total energy mix. APS relies on natural gas for about 19.3% of its portfolio, a smaller share because it leans more heavily on nuclear power.
That nuclear power comes primarily from the Palo Verde Nuclear Generating Station, located about 50 miles west of downtown Phoenix. It’s the largest nuclear plant in the United States by output, and it gives APS a significant carbon-free baseload source. Nuclear accounts for about 20.9% of APS’s energy mix. SRP also holds a stake in Palo Verde, though it represents a smaller portion of SRP’s overall generation.
Together, natural gas and nuclear form the backbone of Phoenix’s electricity supply. Gas plants can ramp up and down quickly to match demand, which matters enormously in a city where air conditioning drives massive swings in power consumption between afternoon and evening. Nuclear runs around the clock, providing steady output regardless of temperature or time of day.
Coal Is on Its Way Out
Coal still contributes to the Phoenix grid, but its role is shrinking year by year. APS reported coal at about 14.6% of its energy mix, while SRP generated roughly 7,312 gigawatt-hours from coal, representing about 23% of its portfolio.
Several coal plants that historically supplied Phoenix are closing or scheduled to close. The Cholla Power Plant is expected to shut down in 2025. SRP’s Coronado Generating Station is scheduled to close by 2032. The Four Corners Power Plant in New Mexico, which has long sent electricity to Arizona via high-voltage transmission lines, is also winding down. As these plants retire, their generation capacity is being replaced primarily by natural gas and solar paired with battery storage.
Solar and Battery Storage Are Growing Fast
Phoenix sits in one of the best solar resource zones in the world, and utilities are capitalizing on that. APS plans to add nearly 2,500 megawatts of solar and battery storage to Arizona’s grid through power purchase agreements with nine new facilities. These are owned by third-party developers who build and operate the solar farms while APS buys the electricity they produce.
Renewables currently make up about 15.8% of APS’s energy mix. SRP’s renewable share is smaller but expanding. What’s making this growth practical is battery storage. Arizona now ranks among the top three states in the country for utility-scale battery capacity, with nearly 3,900 megawatts of operational battery systems as of mid-2025 and another 3,807 megawatts planned to come online by 2026. These batteries store excess solar energy generated during the afternoon and release it in the evening hours when demand peaks but the sun is going down.
A Small Share Comes From Hydroelectric Dams
Glen Canyon Dam on the Colorado River generates about five billion kilowatt-hours of hydroelectric power annually, distributed across seven western states through the Western Area Power Administration. Two 345-kilovolt transmission lines run directly from the dam to Phoenix. SRP generated about 819 gigawatt-hours from hydroelectric sources in a recent year, roughly 2.6% of its total mix.
Hydropower’s contribution is modest and depends heavily on water levels in Lake Powell, which have fluctuated dramatically during the ongoing drought across the Colorado River basin. It’s a useful, flexible source since dam operators can increase or decrease output relatively quickly, but it’s not something Phoenix can count on growing.
Summer Heat Drives Record Demand
Phoenix’s electricity system faces its biggest test every summer, when air conditioning pushes demand to extremes. On July 9, 2025, both utilities set new all-time records for peak demand: APS hit 8,527 megawatts and SRP reached 8,324 megawatts. That was the third consecutive year both utilities broke their own records.
Combined, that’s nearly 17,000 megawatts of peak demand for the metro area on a single day. To put that in perspective, one megawatt can power roughly 750 to 1,000 homes under normal conditions, but Phoenix homes with air conditioning running full blast consume far more during a heat wave. Meeting these peaks requires every available power plant, stored battery energy, and sometimes electricity purchased from other utilities across the western grid.
The city of Phoenix has set a goal of reaching 100% clean energy and carbon neutrality by 2050. Getting there will mean continuing to replace coal with solar and storage, maintaining the nuclear output from Palo Verde, and finding ways to manage summer peaks that keep growing as the metro area adds population and temperatures trend upward.