Rio Rico-Harshaw Transmission Line Project
UNS Electric, Inc. (UNSE), a subsidiary of UniSource Energy Services, is developing plans for the new Rio Rico-Harshaw 138 Kilovolt (kV) Transmission Line Project.
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.
The Rio Rico-Harshaw Line will serve the Hermosa Project, a mine exploration project currently in the pre-feasibility phase, which is owned by Arizona Minerals Inc. (AMI), a subsidiary of South32, located in Santa Cruz County (Hermosa Project). The line also will improve service reliability for all electric customers in the San Rafael Valley, Washington Camp and Lochiel areas of Southern Arizona. The Hermosa Project currently is served by UNSE through an existing 13.2 kV distribution line that is not adequate to support the Hermosa Project’s anticipated energy needs.