While the analysis focused on Seattle, researchers said the findings highlight a challenge that could await other cities and states with emission-cutting commitments.
As the state emerges as a leader in electric transportation, it’s grappling with unique challenges from its geography.
Several utilities are testing new programs and technology to encourage drivers to fill up batteries during off-peak hours.
A new state law allows charging station operators to resell electricity without being regulated as a public utility.
State officials are expected to award funding this month for several dozen public electric vehicle charging stations.