Powering Strong Communities
Electric Vehicles

Study Will Help Inform Seattle City Light’s Charging Infrastructure Strategy Development

A recently released report will help inform the development of Seattle City Light’s charging infrastructure strategy as it plans for medium- and heavy-duty vehicle electrification in the future.

The report, “Powering Seattle fleets: A Charging Infrastructure Strategy for Battery-Electric Medium and Heavy-Duty Vehicles,” was completed by the International Council on Clean Transportation and commissioned by Seattle City Light.

“The results of the study will help us shape our electrification strategy to ensure adequate systems and grid capacity to meet their growing energy requirements,” Seattle City Light noted Seattle City Light Media Manager Jenn Strang in a recent “Powerlines” blog.

The electrification of Class 4–8 medium- and heavy-duty vehicles is projected to accelerate through 2040 due to reduced costs, improved technology performance, and a favorable policy landscape, the report noted.

Within the Puget Sound region, King County Metro, Seattle’s main bus transit provider, and the robust local freight and distribution network serving the Ports of Seattle and Tacoma, are positioned to lead a surge in electric MHDVs, the ICCT said.

Seattle City Light is responsible for ensuring sufficient infrastructure and grid capacity to meet the future energy requirements of transportation electrification, the report noted.

“Downscaling methods from the International Council on Clean Transportation’s recent analysis of near-term nationwide charging infrastructure deployment, we incorporate local vehicle activity data and other information specific to the Seattle area to determine the associated future charging needs within the SCL service territory from 2025 through 2040,” the ICCT said.

The report divides charging station types into public charging and depot chargers located at a fleet’s home base. The modeling predicts a marked increase in MHDV charging stations around 2030 based on fleet electrification goals and supporting regulation.

“We expect fleets will mostly rely on lower-powered overnight chargers for their energy needs due to fleet operations and lower cost,” the ICCT said.

“Between 2025 and 2040, we project total charger nameplate capacity and peak loads in the service territory will increase by an order of magnitude, or a factor of 10,” the ICCT said.

 An expected increase in charging demand in the southern part of SCL’s service territory, where most warehouse and distribution centers in the service territory are located, will increase demand for local distribution grid capacity. This industrial area will likely require assessment in the near-term to determine needed substation upgrades and investment in existing infrastructure, the report said.


The ICCT said its results and discussions with Seatle City Light “suggest actions the utility could assess to guide charging infrastructure planning efforts and ensure its success in supporting the transition to electric MHDVs.”

The ICCT said its analysis leads to seven broad recommendations the utility could consider including gathering information from fleets, particularly those with known transition plans.

The first recommendation is to gather information from fleets, particularly those with known transition plans.

“As SCL prepares to deploy future charging infrastructure, the utility could consider strategies to connect with fleet operators throughout its service territory to collect information on their vehicles and electrification plans. Potential outreach methods include establishing a fleet database and developing relationships through fleet advisory services.”

Another recommendation is to prioritize infrastructure development in “no regrets” zones.

“Information gathered from fleets could be used to identify areas within SCL service territory where there will likely be high battery electric truck adoption and associated charging station deployment. This analysis suggests distribution upgrades will likely be required in South Seattle areas zoned for industrial activity,” the report said.

A third recommendation is to address potential grid capacity constraints.

“If grid infrastructure is insufficient to meet future energy requirements, particularly within southern Seattle, there could be delays that inhibit the transition to battery electric trucks.”

Possible ways to address this capacity challenge include deploying flexible front-of-meter infrastructure solutions, like mobile substations, and promoting customer-owned microgrids and other behind-the-meter technologies to reduce demand on the grid.

If the utility cannot expand existing infrastructure, it could begin site procurement efforts to ensure new construction is ready for future electric fleets’ energy demands.

NEW Topics