# Arizona's Largest Utility Faces Scrutiny Over Decades-Long Gas Expansion
Arizona Public Service (APS), the state's largest electric utility, is locking ratepayers into fossil fuel infrastructure that could cost hundreds of millions of dollars over the coming decades, according to a new analysis released by the Sierra Club and Synapse Energy Economics.
The report, titled "Passing the Buck: How APS's Gas Rush Risks Ratepayer Dollars," examines APS's strategy to expand natural gas generation capacity even as renewable energy costs plummet and climate pressures mount. The analysis reveals a fundamental mismatch between APS's investment trajectory and market reality.
APS serves roughly 1.5 million customers across central Arizona. The utility operates one of the largest coal fleets in the nation but faces mounting pressure to retire aging coal plants. Rather than pivoting toward renewables and battery storage, internal company planning documents and regulatory filings show APS has pursued an aggressive buildout of natural gas infrastructure. The Sierra Club and Synapse determined that APS has added significantly more gas capacity than system reliability requires.
Natural gas plants built today operate for 30 to 40 years. Utilities depreciate these assets over decades, meaning costs flow to ratepayers long after the assets become economically obsolete. Stranded asset risk poses a genuine financial threat. If natural gas plants prove uncompetitive against cheaper solar, wind, and battery systems within 10 to 15 years, APS's shareholders and customers will absorb losses while the company still collects returns.
The report quantifies exposure through several metrics. APS's most recent integrated resource plan increased natural gas reliance beyond what independent analysis suggests the grid needs. Synapse modeled alternative pathways using aggressive renewable deployment and battery storage. These scenarios cost less than APS's planned approach while delivering comparable or superior reliability.
Arizona's regulatory framework creates perverse incentives. The Arizona Corporation Commission (ACC) approves utility investments and guarantees returns. Utilities profit from building new plants, regardless of whether cheaper alternatives exist. Renewable energy requires different business models. Solar farms and wind installations have minimal operating costs but require massive upfront capital. Batteries store energy but don't generate revenue without accompanying demand. Utilities face no financial reward for deploying these technologies efficiently.
The timing of this analysis matters. APS currently faces regulatory proceedings at the ACC over its long-term strategy. Environmental groups and consumer advocates have intensified scrutiny of utility planning. The company's recent rate cases have drawn public opposition to cost increases.
Natural gas represents roughly 40 percent of U.S. electricity generation and drives carbon emissions across the power sector. Arizona receives abundant solar resources. The state ranks second nationally in solar potential, yet renewables comprised only 20 percent of APS's generation mix in recent years.
The Sierra Club's analysis joins a broader chorus of criticism from economists, grid operators, and environmental researchers. The International Energy Agency concluded that new fossil fuel projects are incompatible with climate commitments. Wood Mackenzie, a global energy consultancy, projected that gas demand in developed markets will decline through 2030.
APS declined to comment on the report's specific findings but stated the company balances reliability, affordability, and environmental responsibility. The utility's gas strategy responds to retirements of coal plants that powered Arizona for decades, company officials argue.
The ACC will ultimately decide whether APS's gas investments align with ratepayer interests. The report provides commissioners with concrete data showing lower-cost alternatives existed when these decisions were made.