Photo montage showing uses of electricity

Design and Construction

While the project is still in the early stages of design, PGE is working to minimize impacts to landowners and the environment. PGE will refine the design of the Cascade Crossing towers, substations and other features throughout the project.

Design

Main Route

Preliminary Project Design Standards

While design has not begun, PGE is considering the following design guidelines:

Tower height (average): 150 to 190 feet
Tower width (average): 30 to 50 feet
Right of way width (average): average 150 to 300 feet
Span length (average): 1,000 to 1,500 feet (less than five towers per mile)

 

Tower Structures

PGE plans to use a variety of structures for the project depending on location, terrain and other factors. PGE proposes both single- and double-circuit lattice steel structures.

Single-circuit lattice towers are proposed for Segment 1 from Coyote Springs Substation to Grassland Substation, while double-circuit lattice towers are planned for the other segments.
Image compares heights of typical neighborhood electric poles at 40 to 50 feet, a typical 500 kilovolt tower at 150 feet and wind turbines at PGE’s Biglow Canyon at 397 feet.
From left to right: Typical neighborhood poles, typical 500 kV tower and wind turbines at PGE’s Biglow Canyon
 Image shows two tower structures PGE is considering for the project. On the left is a Lattice Steel Structure which has a height of approximately 150 feet, and on the right is double-circuit lattice steel structure which has a height of approximately 150 to 190 feet.
Left: Single-Circuit Lattice Steel Structure
Right: Double-Circuit Lattice Steel Structure

Possible Willamette Valley upgrades

PGE may need to upgrade its existing 36-mile, 230 kV transmission line from Salem to Oregon City. In most places, this would involve removing existing wooden H-frame structures which hold a single-circuit 230 KV line, and replacing them with two parallel monopole structures which each carry a 230 kV line. The exceptions are 1) in some places where transmission lines cross; 2) in the 1-mile section south of the McLoughlin substation and 3) in the 4-mile section north of the Bethel substation.

Construction

If the state and federal agencies approve the project, PGE will begin construction and expects to complete Cascade Crossing in 2016 or 2017.

Cascade Crossing has three main construction components, which include:

  • Building a new 500 kilovolt, double-circuit alternating current (AC) transmission line.
  • Building new substations and upgrading existing substations.

Building the Transmission Line

While constructing the transmission line, PGE will conduct the following actions:

  • Survey the route.
  • Construct access roads.
  • Install towers foundations.
  • Haul steel to the structure sites.
  • Assemble and erect structures.
  • Install the transmission line wire.
  • Cleanup, reclaim and restore temporary facilities and roads.

After construction of the transmission line is complete, PGE will restore each property as close to its original condition as possible. PGE will routinely inspect the transmission line, as well as maintain the rights of way to ensure safe operation of the line.