City Transport Authorities Expand Electric Bus Fleets with Battery Swap Pilot
SEATTLE, Wash. – November 20, 2025
Seattle Metro Transit Authority (SMTA) today announced plans to pilot an innovative battery swapping system for its expanding electric bus fleet, marking the first U.S. municipal deployment of technology that promises to eliminate charging downtime and accelerate fleet electrification timelines. The pilot program, launching in early 2026, will equip 15 new battery-electric buses with modular battery systems and install two automated swapping stations at key transit hubs.
The initiative addresses critical operational barriers that have slowed transit electrification nationwide. Recent research identifies charging infrastructure and vehicle downtime as primary obstacles, with nine major U.S. transit agencies citing difficulties in scaling electric bus operations beyond pilot programs . While conventional depot charging requires buses to remain idle for 3-4 hours, battery swapping completes energy replenishment in under five minutes, enabling 24-hour route capability without increasing fleet size .
The technology builds upon a successful commercial vehicle model demonstrated in Tokyo, where Mitsubishi Fuso, Mitsubishi Motors, and battery swapping specialist Ample deployed 150 commercial EVs across 14 modular stations beginning September 2025 . That program achieved swapping times of five minutes and demonstrated compatibility across multiple vehicle platforms, establishing a blueprint for high-utilization municipal fleets. SMTA’s pilot adapts this proven architecture for transit buses, with Ample providing customized battery modules and automated swapping stations at SMTA’s South Base and Westlake Transit Center.
“After testing multiple electric bus models through subzero temperatures and analyzing comprehensive cost data, battery swapping emerged as the only solution that maintains service frequency while meeting our 2035 zero-emissions mandate,” said SMTA Chief Executive Officer Margaret Chen. “Our January 2024 trials showed newer electric buses performing reliably in extreme cold, but charging logistics remained our bottleneck. This pilot eliminates that barrier.”
Financial modeling supports the transition. Analysis of full fleet electrification shows in-route charging infrastructure reduces capital costs by $69 million compared to depot-only systems while avoiding a 15% fleet expansion . The PAYS® financing mechanism, pioneered by Michigan’s DTE Energy, allows utilities to capitalize battery costs and recover expenses through service charges below diesel fuel savings, addressing upfront cost barriers . SMTA projects $1.7 million in annual net operating savings once scaled, accounting for battery replacement cycles and reduced maintenance .
The pilot’s 15 buses will operate on RapidRide routes and high-frequency urban corridors, supported by single 450-kW overhead pantograph chargers at each swapping station for overnight depot charging of spare modules . Battery capacity is rated at 450 kWh per module, providing 130-mile reliable range with supplemental heating systems for Pacific Northwest winter conditions . SMTA will implement 10-minute layover periods at swapping locations to ensure consistent energy replenishment without disrupting schedules.
Implementation follows lessons from King County Metro’s phased approach, which opened its South Base Test Facility in 2022 and will launch five opportunity charging locations by 2028 . However, SMTA’s battery swap model eliminates the need for 50 dispersed chargers, reducing infrastructure complexity and land acquisition requirements . The program also incorporates DART’s operational insights, including managed deployment to prevent range limitations and delayed overnight charging to reduce peak demand costs .
Environmental impact projections align with federal climate goals. Transportation accounts for 19% of total CO₂ emissions in similar metro regions, making fleet electrification critical to achieving 46% emissions reductions by 2030 . SMTA’s zero-emissions commitment, established in 2017, mirrors King County Metro’s 2035 target and positions the authority to leverage Federal Transit Administration Low or No Emission Grant funding .
The pilot will run through 2027, with performance metrics tracking battery degradation, mechanic response times, and route efficiency. Success metrics include maintaining less than four-hour charger repair response times and achieving sub-2.4% annual battery capacity loss . Data will inform a full fleet conversion plan covering 1,200 buses by 2040, potentially saving $27 million in net operating costs over the transition period .
About Seattle Metro Transit Authority
Seattle Metro Transit Authority operates the Pacific Northwest’s largest public transportation network, serving 450,000 daily riders across 200 routes. SMTA has operated a diesel-hybrid fleet since 2004 and retired its final diesel buses in 2020. The authority maintains seven operating bases and is committed to achieving 100% zero-emissions operations by 2035.
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