PROPOSED TEP SUN CITY SUBSTATIONFrequently Asked Questions

How can I find out more?

If you have questions or comments, please contact The Planning Center at (520) 623-6146 or visit the project website at tep.com.

What is a substation?

An electrical substation is part of the overall distribution system that provides power to neighborhoods. This facility is necessary to step high voltage down to the low voltage required for residential uses. It also provides a protective function to the distribution circuits, similar to a circuit breaker in your home.

Why is this substation needed?

Currently there is only one substation serving the northern half of Oro Valley: the Rancho Vistoso Substation. The circuits served by this substation are stressed during the summer months and are projected to get more overloaded each year. The proposed Sun City Substation will alleviate current and future overload conditions. These proposed additions will extend the life of the existing equipment and ultimately increase the reliability of service to all Oro Valley residents.

Does Arroyo Grande need this substation and the upgraded transmission lines?

This substation has been part of a planned electrical expansion since 1979. It is the final stage of a grid system required for current residents. As part of that planning, this substation and the accompanying installation of transmission lines will accommodate both current and future projected needs.

How will my electricity rates be affected?

When rate increases are considered, costs of substations are factored in as part of the overall costs. However, you will not necessarily see an increase in your electric bills as a direct result of the Sun City Substation installation.

What are the future plans/needs for this area?

TEP plans are based on local jurisdiction’s plans. In this case TEP is working closely with the Town of Oro Valley to account for growth identified in Oro Valley’s General Plan as well as Pima County’s Comprehensive Plan for the area surrounding Oro Valley. Will the substation ever be expanded?

As growth occurs in the area, more equipment will be added to the substation, but all changes and additions will be within the substation wall.

Why here? What other sites did you consider?

By its nature, a substation must be close to the customers it serves. The further away it is placed the less reliable the electrical power is to your home. At the same time, a number of other factors must be considered.

During site selection, many sites were evaluated. The recommended site achieves sufficient reliability for nearby residents minimizing cost and environmental impact.

Once constructed, what will the maintenance schedule be?

The substation will be maintained with typical maintenance checks each month. It is remotely monitored on a daily basis.

Will water be used at the facility?

Water will only be used temporarily for new vegetation until it has matured.

How much noise will be generated by the substation?

The maximum amount of noise generated will be a humming that is no more than 45 decibels. 45 decibels of sound is between a whisper and the normal sound of talking.

How will the substation and transmission line be accessed?

The substation will be accessed from Oracle Road west onto Edwin Road (which turns into Chalk Mine Road) then south along an existing maintenance road used for the existing WAPA transmission line.

Exisiting TEP Del Cerro Substation

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What will the substation look like? What is its height? Will my views be impacted?

The design for this substation is based on TEP’s standard for a low profile neighborhood substation. There will be 10 foot earth tone walls with drought tolerant landscaping surrounding the perimeter. Because of its location it will be only partially visible to the closest residents.

What size is this substation?

TEP’s 138 kV substations are typically located on 2.5 acres, enclosed by 10-foot walls, encompassing an area that is approximately 250 feet by 450 feet. The size is necessary for truck access to maneuver within the walls. In addition, Pima County requires that the substation be surrounded by 12.5 acres of vacant land as a buffer to adjacent residences.

Why not underground the transmission lines?

TEP does not underground transmission lines due to the environmental impact, the costs to the customer and the maintenance required.

How much land will be disturbed for the substation and the transmission line,and what are the mitigation efforts for the areas disturbed?

As with any construction, some of the land and vegetation will be disturbed. Dust abatement measures will be used during construction to keep dust at a minimum. TEP plans to re-vegetate to mitigate impacts from disturbance to the landscape.

What will the transmission line look like?

The line will look very similar to the section of line that is south of Tangerine Road, west of Rancho Vistoso Boulevard, exiting TEP’s Rancho Vistoso Substation.

How will my property values be affected?

Research has been conducted to determine the impacts on residential property values as a result of their proximity to transmission lines. A study done in three large metropolitan cities found that high-voltage transmission lines had minimal impacts on residential property values. The study concluded that other factors such as location of the property, type and condition of improvements, and the level of real estate activity are far more important than the presence of transmission lines in determining the value of residential property.

In this case, there is an existing transmission line so any incremental impact to property value cannot be determined. To the extent the new line will improve on the appearance of the existing line, the impact could be to improve property values.

What is the construction and clean-up schedule?

The overall construction of this project should be completed in 14-18 months. Substation construction will take 4-6 months including landscaping and clean up. Installation of the transmission line will take 6-8 months including site clean up. And feeder installation will take 2-4 months including clean-up.

While some construction activity overlap may occur, these construction activities will not take place simultaneously because of material delivery, engineering sequencing and site interference with each other.

How much traffic will be generated?

The construction of the substation has multiple phases and the potential for a couple different contractors working on the project at the same time. These contractors usually have no more than 6-8 people. During the construction of the substation site inspectors will be present daily.

The construction of the transmission line will also take place in phases. The hauling, framing and setting of the poles, is an 8-10 person operation. And the installation of the wire is a 10-14 person operation. This operation will be inspected by 1 person coming to the site daily.

Substation maintenance crews will visit the site on a monthly basis and line patrol of the transmission line will be completed each year.

What is the approval process?

The substation will require a Power Substation Permit issued by Pima County. This process will include public input.

What is the risk of fire at this facility?

Fire risk at the substation is very low. Only a major equipment failure could result in a fire. TEP has taken proactive steps to reduce any risks by designing its equipment to contain and control any fire risk. Are any hazardous materials going to be kept on-site?

There are no hazardous materials on-site. The transformers at the site will contain mineral oil for cooling. This oil is not considered hazardous.

Will TEP lease or own the property?

TEP will lease the property from the Arizona State Land Department (ASLD)

Will there be any lighting?

There will only be lighting used when the substation is being serviced.

What are the health risks associated with the substation and the power lines?

To date, there is no universal agreement among researchers on answers to the key questions about possible Electric Magnetic Field (EMF) health risks. EMF exposure to residents adjacent to a substation or line will be less than that which occurs in everyday exposure to electrical appliances in the home, such as televisions, hair dryers, microwave ovens, etc.

NOTE: please ask for our brochure for more information about EMF.

Photo Simulation of Proposed Sun City Substation

Elevation of Proposed Sun City Substation