Projects and Resource Planning
Transmission Line Projects
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.
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.
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.