Assessment of Non-Wires Alternatives for Eastside, Washington

City of Newcastle
Project Completed December 2022

Puget Sound Energy (PSE) is projecting rapid load growth in the Eastside area of Lake Washington in Washington State. As a result, the utility has identified the need to upgrade its substation and transmission infrastructure. To meet this need, PSE proposed the Energize Eastside project, which entails building a new substation and upgrading transmission lines. PSE also investigated alternatives to building the substation, including energy conservation, batteries, and solar panels. However, the company concluded such alternatives would not sufficiently address the expected load growth problem. Along with two other local communities affected by the project, the City of Newcastle investigated PSE’s Eastside filings to assess the need for the Energize Eastside project and to determine whether to provide the utility with a city permit to build a substation.

On behalf of Newcastle, MaxETA and Synapse evaluated PSE’s filings. In particular, we assessed whether PSE’s load forecast is reasonable and technically sound; whether there is a regional need for additional transmission capacity to maintain reliability; and whether PSE has taken all necessary and cost-effective measures (including demand-side measures) to prevent an operational need from arising. Our analysis found that the current summer electric peak demand in King County has already triggered an operational need for the proposed transmission expansion to address system contingency scenarios. We concluded that PSE has demonstrated that the proposed transmission upgrades are needed to safeguard the operational reliability of the electric system as a whole.