BOISE, Idaho (AP) — Two electric utilities and a federal energy agency with millions of customers in eight western states have reached a tentative agreement centered on a new energy transmission line connecting their power grids.

Idaho Power, PacifiCorp and the Bonneville Power Administration announced the complex proposal Wednesday ahead of the expected 2026 completion of a 500-kilovolt, 290-mile (467-kilometer) transmission line from eastern Oregon to southwestern Idaho.

The entities said the Boardman to Hemingway transmission line will help them meet increasing demand and support their clean-energy goals while increasing the reliability and safety of the region’s transmission system. Energy will move in both directions on the line.

The agreement still needs to be finalized and approved by regulators.

“This arrangement paves the way toward a promising and economic solution for serving all of the participants and supports efforts to meet the region’s clean energy goals,” said Kim Thompson, Bonneville Power Administration’s vice president of Northwest Requirements Marketing.

The Portland, Oregon-headquartered BPA is a U.S. Department of Energy agency that markets electricity generated at 31 hydroelectric facilities operated by the U.S. Bureau of Reclamation and the U.S. Army Corps of Engineers on the Columbia River and its tributaries. It also markets power from the Columbia Generating Station, a commercial nuclear facility north of Richland, Washington.


The BPA markets the energy to public utility districts, municipal electric utilities and rural electric cooperatives in eight states.

Boise, Idaho-based Idaho Power is a public utility that operates as a state-regulated monopoly. It has about 600,000 customers in eastern Oregon and southern Idaho. Most of its energy is produced from its 17 hydroelectric facilities on the Snake River and its tributaries. The company plans to phase out coal-fired power by 2028 and provide only clean energy by 2045. The new transmission line is a key part of that strategy.

PacifiCorp is a regulated public utility with two operating divisions, Pacific Power and Rocky Mountain Power, that combined have about two million customers in Oregon, Washington, California, Utah, Idaho and Wyoming.

PacifiCorp would benefit with the deal by improving its ability to move power into its central Oregon service area. It will also acquire Idaho Power transmission assets across southern Idaho that will increase the company’s ability to transfer power between the eastern and western parts of its service area. The company’s long-range planning includes significantly expanding its wind and solar energy, and battery storage. The company is looking to eventually move away from coal energy in the 2040s.

BPA is guided through statutes created by Congress. Idaho Power and PacifiCorp are both regulated by state utility commissions in the states they operate as well as by the Federal Energy Regulatory Commission.

Notably, the transmission line connects deeply conservative Idaho with the more liberal Oregon. Idaho Republican Gov. Brad Little, a rancher, has publicly recognized climate change, and his recently released proposed budget includes money to deal with those realities on state-owned land.


Oregon Democratic Gov. Kate Brown, as a member of the Western Governors’ Association, has pushed to improve the region’s electric-vehicle charging infrastructure.

Under the proposal between the three energy entities, PacifiCorp will own 55% of the new transmission line and Idaho Power 45%. BPA is transferring its ownership interest in the line to Idaho Power and will not participate in its construction. BPA will acquire transmission service over Idaho Power’s transmission system, including the Boardman-to-Hemingway line.

The proposal also includes the transfer of some assets between Idaho Power and PacifiCorp that each entity said will strengthen their systems and provide access to key energy markets to meet growing demand.

“This agreement solidifies and simplifies a path forward for a project that will help us continue our century-long tradition of reliable, affordable, clean energy,” said Mitch Colburn, Idaho Power’s vice president of planning, engineering and construction.