Projects and Resource Planning

Transmission Line Projects

Rio Rico-Harshaw

The Rio Rico-Harshaw Line will involve the construction of an approximately 20-30 mile, single-circuit 138 kV transmission line mounted on steel monopole structures. The project will interconnect UNSE’s existing 138 kV transmission system to the planned Harshaw Substation through a planned 138 kV switchyard in Rio Rico.

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Nogales Tap to Kantor Upgrade

The proposed project includes upgrading a 27.5-mile segment of UES’ existing 138-kilovolt (kV) transmission line that serves customers in Santa Cruz County and building a new substation west of Nogales.

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Golden Valley 230 kV

UniSource is developing plans for a double-circuit 230kV transmission line from the Harris Substation to the new Mineral Park Substation to improve reliability, replace aged equipment, and accommodate a projected 5 to 35 megawatt increase in load over the next decade in the north Golden Valley area of Mohave County.

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UniSource Energy Services: Resource Planning

Resource Planning

UniSource is planning a path toward a cleaner energy future and changes in our customers’ energy needs.