Transmission programmatic environmental impact statement (PEIS)

In 2023, the Legislature asked us to study the environmental effects of building, upgrading, and operating transmission facilities in Washington. This page lays out: (1) the background that led to this study; (2) details about the study's goals, areas studied, requirements for environmental review, and contributors to the study; and (3) explanation of the process used and presentation of the individual chapters with links to the draft programmatic environmental impact statement (PEIS) for electrical transmission facilities.

Background for the Programmatic EIS

We followed the requirements under the State Environmental Policy Act (SEPA) in preparing the Programmatic Environmental Impact Statement (PEIS) examining electrical transmission facilities with a voltage of 230 kilovolts (kV) or more.

Released on March 31, 2025, the Draft PEIS for Transmission Facilities analyzes potential direct, indirect, and cumulative impacts of the building, operating, maintaining, upgrading, and modifying transmission facilities in Washington. It includes an analysis of the potential impacts on the natural and built environments mentioned in RCW 43.21C.405(3), WAC 197-11-444, and WAC 463-60-535. We expect to finalize the draft in the fall of 2025 after considering all comments.

This Programmatic EIS differs from most other SEPA EISs. The Legislature's direction to us under RCW 43.21C.405 required us to analyze additional topics when preparing the document. Also, under RCW 43.21C.408, SEPA lead agencies must consider this document during environmental reviews for transmission facilities. When a specific proposal uses recommendations (mitigation measures) from this Programmatic EIS, those proposals “are considered to have mitigated the probable significant adverse project-specific environmental impacts under this chapter for which recommendations were specifically developed.”

Goals of the Programmatic EIS

This Programmatic EIS analyzes the environmental effects of large electrical transmission facilities but doesn't review any specific facility. Specific proposed transmission facilities will need their own SEPA environmental reviews.  

Our goals for this Programmatic EIS are to:

  • Broadly assess environmental impacts
  • Help simplify planning
  • Support informed decision-making
  • Identify strategies to reduce negative effects
  • Initiate public and stakeholder engagement

Areas we studied

The geographic scope, or study area, of this Programmatic EIS includes areas throughout Washington where developers are likely to build transmission facilities. Tribal lands and undersea cables aren't part of the study area. For details, see Section 1.5.1 Geographic Scope in Chapter 1 of the Draft PEIS (link, 5.7 MB pdf).

Requirements for environmental review

This Programmatic EIS includes three categories of requirements for project-level environmental review:

  • General conditions
  • Avoidance criteria
  • Mitigation measures

For details, see Chapter 3 of the Draft PEIS (link, 84.8 MB pdf), especially Sections 3.1.3.1 General Conditions, 3.1.3.2 Avoidance Criteria, and 3.1.3.3 Mitigation Measures.

Project-specific applications would include details about the precise location and site-specific conditions. For most environmental details, the Draft Programmatic EIS provides a GoldSET suitability map (see Section 3.1.6 Suitability Map in Chapter 3). Using this map can make environmental planning more informative and efficient.  

Participants

We directed the preparation of this Programmatic EIS with the support of WSP USA, Inc. and contributions from the following state and federal agencies:

  • Department of Ecology
  • Department of Fish and Wildlife
  • Department of Natural Resources
  • Department of Archaeology and Historic Preservation
  • Department of Transportation
  • Utilities and Transportation Commission
  • U.S. Department of Defense

The Department of Ecology released its final Programmatic EISs for onshore wind energy, utility-scale solar energy, and green hydrogen production and storage facilities (link, webpage) on June 30, 2025.

Process

In June 2024, EFSEC took the first step in developing the PEIS. It published the SEPA Scoping Document (link, 890 KB pdf) and opened a 30-day public comment period from June 28, 2024, until July 28, 2024. As part of this process, EFSEC also held two virtual public comment meetings during this period.

On March 31, 2025, EFSEC released the Draft PEIS for high voltage electrical transmission facilities. EFSEC staff made a public presentation of the Draft PEIS on April 8 and held two public comment meetings in April 2025. A full list of the Draft PEIS chapter with links to the chapters follows:

  1. Cover Letter (English) (link, 237 KB pdf)
  2. Fact Sheet (English) (link, 1070 KB pdf)
  3. Executive Summary (English) (link, 1161 KB pdf)
  4. Chapter 1 - Introduction (English) (link, 5.7 MB pdf)
  5. Chapter 2 - Considerations and Regulations (English) (link, 1024 KB pdf)
  6. Chapter 3 - Affected Environment (English) (link, 84.8 MB pdf)
  7. Chapter 4 - Cumulative Impacts (English) (link, 8.1 MB pdf)
  8. Chapter 5 - Consultation and Public Engagement (English) (link, 2.7 MB pdf)
  9. Chapter 6 - References (English) (link, 839 KB pdf)
  10. Chapter 7 - Glossary (English) (link, 302 KB pdf)
  11. Chapter 8 - List of Preparers (English) (link, 219 KB pdf)
  12. Chapter 9 - Distribution (English) (link, 154 KB pdf)
  13. Appendices (English) (link, 14.7 MB pdf)