Montana-to-Washington Transmission System Upgrade Project (M2W)

PROJECT DESCRIPTION:

Bonneville Power Administration (BPA) is proposing to upgrade parts of its existing transmission system in Montana, Idaho, and Washington as a result of recent requests for transmission service from its customers.  

In April 2012, BPA initiated preparation of an environmental impact statement on its proposed Montana-to-Washington Transmission System Upgrade Project to increase the electrical capacity of its transmission system to meet customer requests.  In September 2014, BPA was informed that most of the transmission service requested by customers was no longer needed and decided in 2015 to no longer pursue the proposed project at that time.  Based on current requests for long-term transmission services, BPA reinitiated the project in May 2023, with a revised proposal to conduct necessary engineering design to inform its National Environmental Protection Act analysis.  For more information on the previous intent to prepare an environmental impact statement, please visit 2012 Montana to Washington Project Webpage.

BPA’s current proposed upgrade project includes several types of physical improvements and additions to the BPA transmission system in multiple locations in Montana, Idaho, and Washington. These improvements and additions would include:

• Construction of a new Moose Gully Compensation Substation adjacent to the existing BPA Garrison-Taft No. 1 & 2 500-kilovolt (kV) transmission lines, located near the Miller Creek neighborhood in Missoula, Montana, and a new microwave tower either within the new substation yard or a short distance away to facilitate a communications pathway to the Miller Peak Radio Station.
• Replacement of electrical wires along approximately 11 miles of BPA’s existing Dworshak–Taft No. 1 500‐kV transmission line in northeastern Idaho and western Montana, which would also require improvements to existing transmission line access roads.
• Electrical equipment upgrades at five existing BPA substations and possible expansion of substation yards at BPA’s Hatwai Substation in Idaho and Bell Substation in Washington.
  
   

An interactive project location map is available at the link below. Directions about how to use the online project map are available on the landing page.
https://bpagis.maps.arcgis.com/apps/instant/media/index.html?appid=5ed2b436ec704a12aeddea73ceba99a7.  

ENVIRONMENTAL REVIEW:

To understand the potential environmental impacts of this proposal, BPA may prepare an environmental assessment (EA).  If BPA determines that an EA should be prepared, the EA will describe anticipated impacts to natural and human resources and include mitigation measures that would help avoid or minimize impacts.  We are asking for your comments to help determine the issues that should be addressed in the environmental review and in BPA’s compliance with Section 106 of the National Historic Preservation Act, which requires BPA to consider the effects from this proposal on historic properties.  During this process, BPA will work with Federal, state, and local agencies; Tribes; potentially affected landowners; and other interest groups.  The proposed schedule for the environmental review process is as follows:

Scoping comment period – July 10, 2025 to August 10, 2025

EA determination (if warranted) – Spring 2026

Draft EA available for public comment (if warranted) – Spring/Summer 2026

Final EA (if warranted) – Fall 2026

Finding of No Significant Impact (if warranted) - Fall 2026

If decision to build, construction start – Summer 2029 (at the earliest)

CURRENT STATUS:

BPA is requesting public scoping comments to help determine the issues that should be addressed in the environmental review by August 10, 2025.  When commenting, refer to the full project name. All comments will be posted on the BPA comment website. 

There are several ways to comment:

Online: https://publiccomments.bpa.gov/
Mail: Bonneville Power Administration
Public Affairs – DKE-7
P.O. Box 14428 Portland, OR 97291-4428

Toll-Free: 800-622-4519
Fax: 503-230-4019

CONTACT:

For environmental information, contact:
Laura Roberts
Environmental Protection Specialist
Bonneville Power Administration – EC-4
PO Box 3621, Portland, Oregon 97208-3621
Toll-free: 800-622-4519
Direct line: 503-230-5073
Email: laroberts@bpa.gov

For project information, contact:
Mike Henjum
Project Manager
Bonneville Power Administration – TEPS-TPP-1
PO Box 3621, Portland, Oregon 97208-3621
Toll-free: 800-622-4519
Direct line: 503-230-5167
Email: mbhenjum@bpa.gov

DOCUMENTS:

SCOPING:
Scoping comments received 
Public Letter July 10, 2025
Project Map July 10, 2025
Comment Form  July 10, 2025