As part of our commitment to provide safe, reliable and efficient energy to our customers, Rocky Mountain Power is undertaking a transmission line reconstruction project in order to mitigate wildfire risk along the wildland-urban interface (WUI) areas in the foothills of Salt Lake City.
In June 2020, Rocky Mountain Power filed its Wildland Fire Protection Plan with the Utah Public Service Commission, which was approved in October 2020. The plan represents the response, here in Utah, to increased wildfire risk in the Western United States.
Rocky Mountain Power has closely followed the actions taken by other regional utilities and has created its own response designed to meet Utah’s specific wildfire risk profile.
The plan identifies Fire High Consequence Areas (FHCAs), which are areas where higher likelihood of wildfires coincides with population centers. In those areas it proposes enhanced environmental monitoring systems, including soil moisture monitors, enhanced vegetation management guidelines, more frequent inspections, new operational practices and extensive system hardening measures. The system hardening measures take a variety of forms, including the installation of non-combustion fuses, covered distribution lines, steel poles, fire-resistant pole wraps or coatings for wood poles, and, in certain cases, the full reconstruction of a given line.
Transmission lines located in a designated FHCA, with an average pole age of 45 years or older, were identified as candidates for wholesale reconstruction.
One line identified for near-term reconstruction under the Wildland Fire Protection Plan protocols is the line extending from the Company’s Capitol Substation, which is at the southeast corner of Warm Springs Park, through the Marmalade and Capitol Hill neighborhoods, through the Foothill area, above (northeast of) the University Hospital, and terminating immediately North of Red Butte Canyon Road, adjacent to Red Butte Garden. The project will not affect Red Butte Garden. See project map.
This line meets the standards for reconstruction outlined in the Wildland Fire Protection Plan and is quite close to a significant number of homes, businesses, medical and institutional buildings.
Crews will replace the aging wooden 46 kilovolt structures with new 138 kV weathering steel (COR-TEN) structures that will be an average of 6’ taller than those currently in place. There is the possibility that the poles could be replaced not pole-for-pole, but in some smaller number; and though the poles themselves will be taller, with the exception of structures located at points where the line changes directions, they will not be appreciably larger in diameter. And the conductors themselves will be higher, and therefore less visually obtrusive.
By replacing older wood poles with the new weathering steel, we will reduce the flammability of the structures. The new lines will include optical ground wire (OPGW), which provides a fiber optic communication path between substations, so that electrical protection devices can operate within milliseconds, as opposed to seconds, ensuring that far less energy is released to the ground in the event of a fault. This reduces the likelihood that power lines will be an ignition source that causes a wildfire.
Although 90-plus percent of the project described above is located in the Fire High Consequence Area in the Foothills, a small percentage of the line goes through neighborhoods because transmission lines run from one substation to another, e.g. from the North Bench Substation, through Marmalade, and to the Capitol Substation. Rocky Mountain Power cannot achieve the plan’s mitigation goals for the section of that line that is in the Fire High Consequence Area without replacing the entire line, both the section in the designated high-risk area and the sections which go through neighborhoods.
Importantly, the project is a reconstruction project with no change to the alignment of the current 46 kilovolt line, so to the extent that a given property’s value may be affected by the presence of a transmission line, those effects already exist. Most of the line is either in the public right of way, i.e. typically in the park strip, or on City- or University-owned land, across which Rocky Mountain Power has private utility easements. In only a few cases does the line traverse private residents’ properties, and easements exists that allow the company to maintain and upgrade its facilities.
All power lines in our system are built to meet or exceed the standards of the National Electrical Safety Code, which is the foundation for utility safety standards. The safety of our community is the primary consideration in the design and installation of poles and wires. For more information from the National Institute of Environmental Health Sciences (NIEHS) on electromagnetic fields, please visit the NIEHS site.
For more information, you can call 801-220-4221 or email us at ConstructionProjects@pacificorp.com. Please be sure to include the project name – "Foothills Wildfire Mitigation Project" – in your inquiry.