King County may be able to move more quickly on its goal of electrifying Metro’s vehicle fleet should the King County Council approve a proposed ordinance.

The ordinance would require King County Executive Dow Constantine to “jump start” vehicle electrification, require Metro to speed up its transition to an entirely zero-emissions bus fleet by 2035 instead of 2040, and move up deadlines for other services like Paratransit and Rideshare.

Transportation generates nearly half of all greenhouse gas emissions in the state, and it is one of the top sources for emissions in King County. Metro’s fleet is more efficient than personal vehicles, but the agency still uses about 10 million gallons of diesel annually and produces about 80 percent of the county’s emissions, according to the county.

The proposal carries a $60 million price tag — money the county would use to buy 120 battery buses, build out the needed charging infrastructure and continue planning. The county’s goal is to have around 51 percent of Metro’s fleet running on batteries, or running off the electric grid, by 2030.

Another 250 buses will be purchased by 2025. A new Metro base in South King County would house 250 of these zero-emissions buses and is expected to open in 2030.

Additionally, charging stations for the public could be expanded at county parks and Park and Ride locations. The executive could further require that new multi-family housing and commercial developments include charging infrastructure for electric vehicles.

Since 2016, Metro has piloted three fast-charge battery buses in Bellevue. Metro owns eight short-range battery buses with a range of 25 miles, which it uses in the city. About 12 percent — or 185 buses — of its bus fleet is expected to be electrified by this fall, most of them from its trolley bus fleet. It is also leasing and testing 10 buses with ranges of up to 140 miles.

The county hopes to put about 2,200 battery or electric buses and trolleys on the streets over the course of the next 20 years.

A full transition to electric buses in Washington state could avoid nearly 90,000 tons of pollution annually, according to a report by the Environment Washington Research and Policy Center. That’s the equivalent of taking more than 170,000 cars off the road. And owing to declines in electric vehicle battery costs, governments that use electric buses have saved around $30,000 per bus each year compared to diesel-powered buses, according to the report.

Metro operates a fleet of more than 1,600 buses.