TEP presents Sanorita connection project and defends rate request as residents press for clarity on mine ties

Tucson Electric Power representatives told the Sahuarita Town Council on June 22 that the Sanorita connection — a new 138 kV transmission line and a Sanorita substation — is a reliability project identified through routine system planning and public regulatory review, not a backroom effort to serve the proposed Copper World mine. "There is no secret plan. There is no backroom deal," Steven Eddie, TEP director of public affairs, said.

TEP said the project would improve redundancy and handle growth, and that portions of the new line were being designed to "collocate" with other existing transmission facilities to reduce environmental impact and cost. Clark Briner, TEP manager for siting and community engagement, said a Department of Energy grant to Unisource Electric and other cost-sharing arrangements make one route (the preferred "collocated" route) cheaper overall for ratepayers than the alternative route the company also proposed.

Why the mine matters to the public: multiple residents and council members repeatedly asked whether the town, or local residential ratepayers, would be on the hook if Hudbay Minerals (Copper World) were to seek service. TEP said any customer that requires new service facilities is assigned a tariff and must pay the direct costs of service; the Rosemont (now Copper World) 2012 transmission approval includes strict conditions that the developer pay for the line and switchyard needed to serve the mine. "Any infrastructure required specifically to serve the mine would be paid for by that customer, not TEP customers," Briner said.

Council members and members of the public, however, pressed for simple answers and transparency: several speakers said earlier briefings had left them unsure whether the new line is needed without the mine and whether rate impacts could arise indirectly. "We need plain-language answers — are our rates going to go up if Hudbay connects?" asked Council Member Morales. TEP officials repeatedly declined to give a guaranteed yes-or-no for future hypothetical scenarios, saying rate setting is prescribed by the Arizona Corporation Commission (ACC) and is determined in a public regulatory proceeding that includes sworn testimony and intervenor review. Eddie summarized: "This rate case is backward-looking — it reviews costs we've already incurred — and a judge's recommendation and a final ACC decision will follow later this year."

What rate experts and TEP said: TEP executives explained that large, continuous (24/7) customers typically increase utility revenue and can put downward pressure on residential rates because of differences in usage patterns and cost-of-service allocation. TEP added that its current rate filing reflects investments made primarily from 2022–2024 and that the company reduced customer bills in 2024 and 2025 through fuel/energy adjustments. Still, council members and residents asked for more detail in public form: how a particular interconnection agreement would be structured, whether a new customer might cause wider system upgrades paid by all customers, and how any grant or collocation savings would be allocated.

Regulatory status and next steps: TEP said the line-siting committee recommended approval and forwarded the case to the Arizona Corporation Commission for a decision likely this summer for the Sanorita connection; the company also said the ACC will hold the rate case schedule, with an administrative law judge's recommended opinion due in the third quarter and a final ACC order anticipated in November. Council members asked staff to prepare options for any council statements to the ACC; residents urged the council to continue rigorous public oversight and demand full disclosure of agreements. TEP also agreed to return to town for further briefings if the council requests additional clarification.

Why it matters: The Sanorita connection and the related public debate tie together local reliability planning, federal and state grant opportunities, the town’s growth, and a high‑profile proposed mine. For local residents worried about water, traffic, visual impacts and long-term development patterns, the transmission discussion has become the focal point for questions about transparency and who ultimately bears the costs of new infrastructure.