Transmission Lines

What are transmission lines?

Think of the electrical grid like a network of roads. Transmission lines are the interstate highways. They move large amounts of electricity across long distances, from the places it is generated to the communities that use it. The smaller powerlines that deliver electricity directly to homes and businesses are called distribution lines.

Idaho Power strategically chooses and builds transmission lines to provide several benefits to customers:

  • Reliability. Just like a network of roads, a well-connected grid provides access to a variety of energy sources — from natural gas, to geothermal, to solar and batteries. Transmission lines that might stretch hundreds of miles are a key component of that access, giving our customers confidence they can get the energy they need when they need it, even if some sources are off-line.
  • Affordability. We’re always looking for the lowest-cost energy available so our customers can warm and cool their homes, irrigate their crops, and run their businesses for reasonable prices. Affordable energy is almost always available somewhere. Transmission lines give us the ability to reach that energy and deliver it to our customers. And when Idaho Power’s own resources generate more power than our customers need, we can sell energy across transmission lines to utilities who need it and use the proceeds to keep our customers’ costs down.
  • Security. A well-connected grid with transmission lines connecting lots of generation sources to customers is crucial to national, state, and local security. These connections ensure our energy system can withstand everything from bad weather to terrorist attacks. Owning transmission lines is key to securing Idaho Power customers’ energy future, giving us the flexibility to develop the generation sources that make the most sense.
  • Responsibility. Unprecedented growth is occurring in Idaho Power’s service area. We expect to see demand for electricity to grow by almost 8% every year for the next five years. Meeting that demand will take an all-of-the-above approach. New generation plants, batteries, and transmission lines will be necessary.

Major Projects

These are the three largest transmission line projects Idaho Power is developing:

Boardman to Hemingway (B2H)

This 500-kilovolt (kV), 290-mile transmission line will deliver reliable, affordable energy between the Pacific Northwest and Mountain West. Idaho Power will import up to 500 megawatts over B2H to help cover our customers’ peak demand during the summer months.

B2H is a less expensive, lower-risk solution than building new natural gas plants, solar farms, or battery storage plants. It will improve reliability — reducing the likelihood and duration of outages — while helping to keep energy prices affordable. Visit idahopower.com/b2h for more information on the project.

Gateway West

Gateway West is a 500-mile, 500-kV transmission line stretching from Wyoming through much of southern Idaho. This multi-segment project will help Idaho Power’s customers reliably get the energy they need when they need it, even as population grows and energy demand soars. This transmission line will enable Idaho Power to move energy efficiently across our system or import it from outside our service area to meet customer needs, especially during the summer peak.

PacifiCorp, Gateway West’s majority owner, has begun construction on Gateway West in Wyoming. Pre-construction, which includes siting, permitting, and engineering studies, has begun in Idaho. We expect the portions of the line we partly own to start coming online in 2028.

Visit idahopower.com/gww for more information.

Southwest Intertie Project-North (SWIP-North)

The Southwest Intertie Project-North (SWIP-North) is a proposed 285-mile, 500-kV transmission line that will run from Idaho Power’s Midpoint Substation near Twin Falls to NV Energy’s Robinson Summit substation near Ely, Nevada. SWIP-North will enable Idaho Power to tap into abundant energy sources in the Desert Southwest, especially during the winter months.

Idaho Power’s only interest in the project is to import energy for our customers. Our agreement with its developer does not include using the line to send energy out of our service area.

SWIP-North is being developed by independent energy company LS Power, who is also the developer of the proposed Lava Ridge project. The SWIP-North project is separate from Lava Ridge. Idaho Power is not affiliated with the Lava Ridge project.