Idaho Power needs the Southwest Intertie Project-North (SWIP-North) transmission line to meet customers’ energy needs reliably and affordably on cold winter days. Without SWIP-North, Idaho Power will have to pursue alternatives that will cost customers millions more.
Idaho Power’s ownership interest in SWIP-North is only to bring energy into Idaho, not to sell energy to California or elsewhere.
Project Details
This 500-kilovolt line would run from eastern Nevada to Idaho Power’s Midpoint Substation near Jerome, Idaho. SWIP-North gives us an opportunity to tap into the desert Southwest’s energy market, where prices fall during the winter as cooler weather reduces electricity use. Southwest utilities will sell that energy to Idaho Power at a low cost — if we can get it here. SWIP-North provides that connection. SWIP-North will enable Idaho Power to import up to 500 megawatts of power from south to north. That’s enough for more than 225,000 homes during peak winter use.
Project Status
The SWIP-North project is the final segment of the larger SWIP project, which began decades ago. The urgency of completing the project has grown as energy demand increases across all areas of the economy. Much of the preliminary work on siting and permitting SWIP-North has been completed. Easements are in place for SWIP-North’s entire 76-mile path through Idaho. No additional land is needed.
Idaho Power expects construction of the project to begin as early as 2026 and take approximately two years to complete.
Common Questions
How will SWIP-North help Idaho Power customers?
SWIP-North will help keep power costs affordable for Idaho homes, businesses, farms, and ranches as the demand for energy from Idaho Power customers continues to grow. SWIP-North will provide power by importing it from the southwestern U.S, which has as much as 13,000 megawatts of surplus power in the winter. That’s 3.5 times the amount of power our entire service area uses on our hottest summer day. With SWIP-North, we can purchase some of this energy — at low costs — when customers in the southwestern U.S. don’t need it as much.
How does SWIP-North benefit the Magic Valley?
SWIP-North will help keep energy affordable while meeting the growing energy needs of homes, farms, and businesses in the Magic Valley.
Transmission investment also brings long-term local benefits. The project will generate new property tax revenue for counties and schools.
Is Idaho Power building SWIP-North to send energy to California?
No. Idaho Power’s only ownership interest in the project is to import affordable power and improve grid resiliency by expanding our connections to neighboring states and electric markets. The project will increase our ability to import power to keep customer costs low.
Idaho Power’s ownership in SWIP-North only allows us to import energy from south to north. Our ownership stake does not involve selling energy to California or anywhere else.
Why doesn’t Idaho Power just build more local energy resources?
We are. Our approach to reliably serving our growing customer needs is an “all of the above” approach. Idaho Power evaluates all available resources every two years, looking at cost, risk, and reliability to determine the best resource options for our customers. Our analysis identifies the SWIP-North project as a critical piece of our ability to continue delivering affordable energy to our customers.
Idaho Power is already adding natural gas, battery storage, and transmission lines to our system. We’ll continue adding resources in the coming years to ensure our customers can get the energy they need.
There has been a recent increase in local opposition to local resource development (wind and solar). However, given the significant electricity demand growth in Idaho Power’s service area, Idaho Power must meet those needs whether the resources are local or out of state.
Why doesn’t Idaho Power build Gateway West instead of SWIP-North?
Gateway West is another important transmission project, but its purpose is different from SWIP-North’s. Gateway West will help Idaho Power move energy more efficiently and affordably inside the Mountain West.
SWIP-North, on the other hand, will bring energy into southern Idaho from outside the region so our customers can heat their homes and run their farms and businesses during the winter.
Regardless of the project, Idaho Power needs new high-voltage transmission lines that move energy within our service area and connect our customers to neighboring regions.
Other transmission projects have taken decades to build. Will this be any different?
SWIP-North is not a new project. It is the final segment of the larger Southwest Intertie Project, which began decades ago. Idaho Power was SWIP-North’s original developer in the 1990s. Much of the preliminary work required for siting and permitting SWIP-North has been completed.
Will SWIP-North take up farm ground?
Most of SWIP-North’s route in Idaho will parallel existing high-voltage transmission lines that cross remote, unfarmed land between Twin Falls and the Nevada border. In places where the line crosses agricultural land, we’ll work with farmers to minimize its impact on irrigation pivots and other farming activities.
Will Idaho Power own SWIP-North?
Idaho Power owns 23% of the SWIP-North Project. Idaho Power’s ownership interest in SWIP-North is only to bring energy into Idaho, not to sell energy to California or elsewhere.
What public vetting of SWIP-North has occurred?
SWIP-North has undergone years of federal and local reviews, including public hearings and commenting in Twin Falls, Jerome, and Cassia counties. The project’s line corridors are approved for Cassia and Twin Falls counties.
The application process for a special-use permit is currently underway in Jerome County. The County Commission decided to sustain and remand the decision to the Planning and Zoning Commission. The U.S. Bureau of Land Management has issued a Record of Decision, permitting the construction of SWIP-North across land the agency manages, following a full Environmental Impact Statement, which included extensive public outreach, tribal consultation, and agency coordination. Idaho Power’s Integrated Resource Plan has for many years identified SWIP-North as a cost-effective solution for improving winter reliability. The Idaho Public Utilities Commission (PUC) has adopted Idaho Power’s Integrated Resource Plan, which identifies SWIP-North as an important asset for meeting customer needs, following substantial public engagement and examination.
In October 2025, the PUC held a public hearing in Twin Falls on Idaho Power’s request for a Certificate of Public Convenience and Necessity (CPCN) for SWIP-North. The CPCN would recognize SWIP-North’s importance to Idaho Power customers and pave the way for Idaho Power’s participation in the project.
Does SWIP-North enable Lava Ridge?
No. Idaho Power’s need for SWIP-North has nothing to do with Lava Ridge. Lava Ridge is not a project for Idaho Power or its customers.