Saguaro-Marana Line Serves Growing Area

ACC unanimously approves project to address growth and increase reliability

BENSON – Expanding communities and increasing electricity demand require more infrastructure to power the new homes and businesses in these areas. In Marana, Trico Electric Cooperative has planned another substation, the Adonis Substation, that will serve an expanding part of the area. But a substation needs power. Arizona Generation and Transmission Cooperatives (AzGT) will purchase an existing 138kv transmission line that runs approximately seven miles from a the Saguaro Substation to near the proposed Adonis Substation. Additionally, a new transmission line has been sited from the proposed Adonis Substation to AzGT’s existing Marana Substation.

“This will increase electric reliability and serve growing energy needs,” said Kevin Barnes, AzGT, environmental permitting and land services manager. “This will also add transmission capacity to support the development of future energy generation projects.”

The official name of the project is the Saguaro to Marana 115/138kV Transmission Line Project. Neighboring utility TEP is also adding a substation to serve Marana, and will have a 138kV transmission line on the same structures for a portion of the route.

“The co-location of these assets minimizes environmental impacts and provides efficiencies in the permitting process required to build this line,” Barnes explained.

Those efficiencies include using one right-of-way for one route instead of two separate ones. The new line will start at the planned Adonis Substation east of Interstate 10, cross the highway, ultimately connecting to the other utility’s planned substation, then continue to AzGT’s  Marana Substation. The new line will include steel monopole structures that range 65 to 95 feet tall with spans 500 to 700 feet will require a right-of-way about 100 to 120 feet wide.

“During initial routing options, we consider locating along existing roads and other utility rights-of-way,” Barnes explained. “Routes that result in the least amount of impact on the area, while also providing an efficient path, are of great interest to us.”

Determining what will have the least impact on the area included reaching out to area residents, landowners, as well as local planning authorities   The feedback from them was crucial for AzGT and TEP identify the preferred and alternative routes that were submitted in the  application for a Certificate of Environmental Compatibility (CEC) to the Arizona Power Plant and Transmission Line Siting Committee.  This committee reviews the application and hears evidence from the study team and any stakeholders in the process. The hearing was open to the public and provided time for public comments.

“An important part of this process is to receive and consider comments from the residents, property owners and businesses within the study area,” Barnes explained. “We specifically asked members of the community within the study area to identify issues that are important to them in regard to the proposed transmission lines and any preferences for the preliminary route alternatives we provided on the map.”

That map was included with a newsletter that outlined the purpose, need, permitting, construction and timeline of the entire process. They were mailed to approximately 1400 addresses within the study area to make sure the public found the virtual open house at and understood that they could submit comments on the website, by telephone at 520-586-5252 or email at The information was also posted through targeted advertising and social media. These efforts were important as the siting committee considered issuing a CEC that forwarded to the Arizona Corporation Commission for final approval in June.

Even after the committee unanimously approved the route, some residents near the proposed route had concerns. Barnes and other members of AzGT environmental and land services staff met in person with members of the concerned party to hear their thoughts and incorporate them into the final plan. As a result, the line will be placed in the right-of-way as far as possible opposite of where those residents live.

“Because other routes would have put the line through an area with archeological significance, the Arizona State Land Department would not have permitted the alternate from the start,” Barnes explained. “This route was our only option; however, we made sure to accommodate the neighboring residents as best we could. Fortunately, the ACC understood that, also.”

The Arizona Corporation Commission also unanimously approved the project. Barnes says he appreciated hearing the thoughts and concerns of members of the nearby community and that AzGT was able to incorporate the mitigating factor into the final design.

“We want to be good neighbors and understand how we can serve the growing demand for electricity in these communities while doing so in a way that addresses their concerns,” Barnes said. “We documented our efforts so that the siting committee and the commission understood the lengths we took as we plan and build infrastructure that will be in service for decades to come.”



About Arizona G&T Cooperatives
Arizona Electric Power Cooperative (AEPCO) and Sierra Southwest (Sierra) together comprise Arizona G&T Cooperatives ( AEPCO owns and operates the 625-megawatt (combined gross) Apache Generating Station, located at Cochise, east of Benson. AEPCO also owns, operates and maintains 866 miles of electric power transmission line—including line owned in part with other utilities—and 36 substations to provide wholesale electric power from Apache to six Member distribution cooperatives in southern Arizona, western New Mexico, northwestern Arizona and California.

Sierra is the vehicle to develop new ways to serve the renewable energy needs of AzGT Member cooperatives and customers, and helps maximize solar and other renewable tax credits. Sierra has initiated two utility-scale solar projects. AEPCO’s 20 MW Apache Solar project is located on AEPCO property adjacent to and northeast of Apache Generating Station. The second project includes SunAnza Phase I, a 2 MW solar array, as well as SunAnza Phase II, which includes an additional 1.35 MW solar array and a battery storage system, all on property owned by Anza Electric Cooperative adjacent to its headquarters in Anza, California.

Combined, the distribution cooperatives that receive AEPCO’s wholesale power serve more than 161,000 meters representing more than 420,000 individual residential, commercial, agricultural, and industrial member/consumers.

The Class A Member cooperatives that receive wholesale power from AEPCO include Duncan Valley Electric Cooperative, Duncan; Graham County Electric Cooperative, Pima; Mohave Electric Cooperative, Bullhead City; Sulphur Springs Valley Electric Cooperative, Willcox; Trico Electric Cooperative, Marana; and a California member, Anza Electric Cooperative, Anza.

These Member cooperatives own AzGT and, by extension, AzGT’s Member distribution cooperatives are owned by their members—the people at the end of the line who use the power.

AEPCO also serves five Class D energy services Members which are scheduling and trading customers and which include the Central Arizona Water Conservation District, Phoenix, AZ; Lincoln County Power District #1, Pioche, NV; Metropolitan Water District of Southern California, Los Angeles, CA; Southwest Public Power Agency, Maricopa, AZ; and Valley Electric Association, Pahrump, NV.

AEPCO is also a Member/owner of ACES, a nationwide energy management company ( that helps its Members and customers buy, sell, and manage energy more efficiently and with less risk. The AEPCO/AzGT Benson campus hosts the ACES West Regional Trading Center (WRTC), which benefits AEPCO/AzGT Members and customers.