Frequently asked questions about the Price Road Corridor 230 kV transmission project

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Project details

SRP is planning to construct new electrical infrastructure to enhance reliability for current customers and support new and expanding businesses in Chandler's Price Road Corridor. The corridor is a thriving employment center and innovation hub that will provide new jobs during the next two decades.

SRP must be prepared to accommodate higher demand for power that comes with the eventual build-out of this area. With recent renewed interest for businesses to locate in the Price Road Corridor, the 69 kV system currently providing power to the corridor must be supported by our higher voltage 230 kV system. SRP anticipates the additional growth will require increased energy-delivery capacity.

The project was submitted to the Arizona Corporation Commission in SRP's January 2012 Ten Year Plan.

Electric system upgrades along the Price Road Corridor will enhance the reputation of the area as a great place to work, live and play. The community benefits from a strong, diverse economy that provides high-paying jobs and a strong tax base. System upgrades will increase electric service reliability to current residential, commercial and industrial customers in the area and ensure that we can meet future demand caused by growth.

A typical 230 kV pole is 120–150 feet tall, depending on final span lengths and whether the pole also holds 69 kV circuits.

No, SRP is a community-based, nonprofit utility. We do not have stockholders or pay dividends. Earnings, called "net revenues," are reinvested into power plants, power lines and other facilities to serve our customers and keep our prices low.

A typical substation serves about a 40-square-mile area. However, an industrial area such as the Price Road Corridor requires more power than a primarily residential area. As a result, a substation that provides power to several large businesses may serve a smaller geographic area.

SRP calculates electric forecast demand using data from a variety of sources including existing customer power usage, anticipated customer expansion, potential growth on undeveloped land, inquiries from potential developers, and zoning and planned area development. For example, the City of Chandler Economic Development Division shares economic development information with SRP. SRP combines all this information with SRP electric forecast information to determine future need for each localized area (69 kV distribution station areas). SRP then groups the information within larger energy delivery areas (230 kV receiving station areas).


Public process

From 2012–2017 SRP conducted an extensive public process with multiple rounds of public open house meetings. The open houses allowed the public to review informational displays, discuss the project with SRP team members and provide valuable feedback. In addition, SRP offered to meet with homeowner and civic associations for areas adjacent to proposed route segments. The SRP team met with many of these neighborhood organizations to present project information and address homeowner questions.

Input provided by stakeholders, property owners, residents, businesses, agencies and interested organizations was an important factor in the siting study. The process was specifically designed to evaluate route options based on specific, electric-industry-supported criteria that allowed for an objective analysis. Public input helped to identify community sensitivity toward each of the criteria and where facilities fit best within the community (referred to as siting opportunities). Any comments submitted on our website were considered in the permitting process for this project. SRP seriously considered all the comments submitted concerning this project. However, the comments received were not considered a popular vote.

On June 13, 2017, SRP filed an application for a Certificate of Environmental Compatibility (CEC) with the Arizona Corporation Commission (ACC) for a new 4.8-mile line from the Knox substation to a new RS-27 substation.

The Arizona Power Plant and Line Siting Committee held public hearings July 24–25 and recommended approval of the CEC application. The ACC granted approval of a CEC for the project on Sept. 12. The approval, by unanimous vote, is the final step of the application process and enables SRP to move forward with project construction.


Siting considerations

SRP applies four specific considerations to each route possibility:

  1. Ability to obtain land rights/rights of way – Can SRP acquire an easement wide enough to physically accommodate the new transmission lines with minimal impact to existing homes and businesses?
  2. Constructability – Can SRP construct new poles along this alignment? Are there obstacles above or below the ground?
  3. Maintenance access – Can SRP maintenance crews get the necessary equipment (cranes, trucks, etc.) to the poles and wires to perform required maintenance? Would the work require SRP to shut down a lane or more of traffic?
  4. Cost – What are the total costs for rights of way, construction and maintenance?

The project team needs to address these considerations with each possible route.

No, the project design will comply with federal aviation standards, and we will work with local airports to avoid safety issues.


Electric and magnetic fields

Electric and magnetic fields (EMF) are part of our everyday lives. They occur wherever there is a flow of electricity and everyone is exposed to EMF in modern society. All electric devices and lines – appliances, computers, wiring in homes and offices, power-lines – produce EMF. The earth also produces a strong natural static magnetic field.

Electric fields result from electric voltage. These fields are measured in kilovolts per meter (kV/m).

Magnetic fields result from the flow of electric current. The fields are measured in milliGauss (mG).

Exposure to EMFs in a home is generally from electric appliances and house wiring. Some typical levels are listed below. Field levels at normal operating distances are shown in bold.

Electrical appliance mG at 1 inch mG at 1 foot mG at 39 inches
Hair dryer 60 – 20,000 0.1 – 70 0.1 – 0.3
Electric shaver 150 – 15,000 0.8 – 90 0.1 – 0.3
Vacuum cleaner 2,000 – 8,000 20 – 200 1.3 – 20
Microwave oven 730 – 2,000 40 – 80 2.5 – 6
Iron 80 – 300 1.2 – 3 0.1 – 0.3
Television 25 – 500 0.4 – 20 0.1 – 1.5

Source: World Health Organization

Please note: Magnetic field levels decrease rapidly as you move away from the source. Field levels from similar devices can vary a lot based on the brand and design of the device.

Electric transmission lines produce magnetic fields. The strength of a magnetic field from a transmission line decreases rapidly with increasing distance from the source. Below are typical ranges of magnetic fields calculated at 1 meter above the ground underneath the wires and at other perpendicular distances from a 230 kV transmission line:

Line configuration Range of magnetic fields (mG) at lateral distance of:
  0 feet 50 feet 250 feet
230 kV line with two underbuilt 69 kV circuits 10 – 20 5 – 10 0.5 – 1
230 kV line with no 69 kV underbuild 30 – 60 12 – 25 0.7 – 1.4

The major research on health effects of low frequency (60-Hz) EMF has been performed in the following areas:

  • Epidemiological studies attempt to establish patterns, links or association between environmental agents and diseases in human populations, such as cancer or leukemia.
  • Animal studies have been performed on animals over several generations at exposures that are thousands of times higher than the EMF in a typical residential setting.
  • Biological studies look for EMF responses on individual cells or DNA.
  • Clinical studies have been performed on human volunteers in residential or work environments.

The overall scientific consensus about EMF and health effects is summarized by information currently posted on the World Health Organization (WHO) website. "Based on a recent in-depth review of the scientific literature, the WHO concluded that current evidence does not confirm the existence of any health consequences from exposure to low level electromagnetic fields."

Several thousand scientific papers have been published and over two dozen expert panels have reviewed this research. For most diseases, the epidemiology has been inconclusive and inconsistent, although some childhood leukemia studies have found an increased risk with magnetic field exposures. Epidemiological studies do not provide a conclusive cause and effect between EMF exposure and disease, and the animal, biological and clinical studies which have been done do not support a hypothesis that EMFs are harmful. Additionally, no plausible bio-mechanism is known by which 60 Hz magnetic fields would be harmful.

The overall scientific consensus about EMF and health is summarized by information currently posted on the WHO website. "Based on a recent in-depth review of the scientific literature, the WHO concluded that current evidence does not confirm the existence of any health consequences from exposure to low level electromagnetic fields."

Neither the U.S. government nor the State of Arizona has established exposure standards for public exposure to power frequency EMF.

Two international organizations, the International Commission on Non-Ionizing Radiation Protection (ICNIRP) and the Institute of Electrical and Electronic Engineers (IEEE), have developed exposure guidelines:

Established EMF Exposure Guidelines for Power Frequency Magnetic Fields
International Commission on Non-Ionizing Radiation Protection 2,000 mG¹
Institute of Electrical and Electronic Engineers 9,040 mG

There are many different types of medical implants and many different manufacturers. People with implanted devices should follow the manufacturer's recommendations for their particular device and may want to consult with their physician about potential sources of electromagnetic interference (EMI). One leading manufacturer (St. Jude Medical) notes that their current generation of implanted devices are designed to meet electromagnetic compatibility requirements of American National Standard ANSI/AAMI PC69-2007 and European Standards EN 45502-2-1 and prEN 45502-2-2. If so, they are designed to avoid EMI from stronger electric and magnetic fields than will be produced by the Price Road Corridor 230 kV lines.

Source: document is a .pdf


Property questions

Soon after SRP receives a CEC for the line, we will design the line within the certified corridor. At that time, SRP engineers will determine if an easement is needed across your property. If an easement is needed, SRP will hire an independent appraiser to value your property and the easement. You, as the property owner, will receive a copy of the appraisal report with an offer letter from SRP to purchase the easement.

We don't know at this time. There are many variables to consider in the valuation process. Since each home is different, an appraiser will have to take into account the home itself (e.g., square footage, age, condition, etc.) along with its characteristics (e.g., carport, two-or three-car garage, pool or no pool, lot size, etc.). The appraiser also will consider current market conditions of the neighborhood and its unique amenities (e.g., quality of schools, available retail shopping, restaurants, parks, other recreational amenities, ease of access via freeways and local streets, etc.).

Generally, transmission lines are not considered to be a material factor in the determination of property values. Given the number of variables to evaluate in the appraisal process, it would be inaccurate and misleading to give any specific response regarding the value of any specific property without an appraisal. If the appraiser determines that the presence of the easement on the parcel reduces the parcel's value, SRP will compensate the owner for this reduction in value. SRP compensates property owners only if an easement is needed across a specific parcel.


Comments and information

If you have questions for SRP, please use our online comment form or call the toll-free line at (855) 584-1484.