You likely won’t see one regularly crossing Capitol Hill until 2020 but King County Metro is accelerating its efforts to reduce emissions and become a carbon neutral system with a $90 million-plus plan to add more than 100 battery-only electric buses to its fleet.

“This puts us in on the forefront of innovation and technology,” King County Council member Rod Dembowski said. “We were innovators in wheelchair lifts. We were innovators in hybrid electric. Transit agencies look to us for what they’re going to adopt.”

“We are signaling that is is proven technology,” the county District 1 rep tells CHS.

Details of the new “significant acquisition of all-electric battery buses” will be announced at a Tuesday briefing with King County Executive Dow Constantine. “The package will make Metro a national leader in all-electric buses as the agency challenges bus manufacturers to innovate and meet the demand for clean transportation,” the announcement of the acquisition reads.

The Seattle Times reports the battery-powered coaches that “connect to an overhead docking device that recharges their batteries” have been tested in a Bellevue pilot since last February.

Dembowski says the buses run quieter and cleaner than the diesel-hybrids Metro depends on today, factors especially important in areas like Capitol Hill.

“These will really be a factor in dense neighborhoods — there is no more dense neighborhood than Capitol Hill,” Dembowski said.

Last year, Dembowski sponsored a County Council bill pushing Metro to reach zero emissions or carbon-neutral operations. The Metro fleet is currently estimated to be responsible for around 150,000 metric tons of emissions every year.

A county spokesperson described the plan as “mostly self funded,” adding that money from the Federal Transit Administration’s Low-or No-Emission Vehicle Deployment Program will also be utilized. Each bus costs roughly $750,000.

Here’s how Metro described the battery buses used in the Bellevue trial:

The 38-seat prototype buses, manufactured by Proterra Inc., have a composite body and can travel 23 miles or more between charges. Batteries take 10 minutes or less to charge. The prototype buses are expected to get the equivalent of 15 miles per gallon more than a regular hybrid bus. The automated, state-of-the-art charging station at Eastgate requires minimal work by the driver. Sophisticated software helps position the bus below a charging head that transmits electricity wirelessly. Recharging the battery takes 10 minutes or less, and when complete the driver is alerted and drives away. According to data collected by other transit agencies operating the Proterra bus, the battery-powered vehicles generate a cost savings of 49 percent per mile compared to a hybrid bus, and a 40 percent savings over a diesel bus.

In the coming decade, trolleys using the overhead wires won’t be going away — they handle the hills better, for one. But eventually, battery buses might be a more efficient, simpler answer. Metro began rolling out 174 new electric trolleys last summer that utilize its overhead wire system. In the meantime, Metro says the new trolley buses use up to 30% less electricity than the old fleet “and will significantly reduce operating costs.” A project to electrify Route 48 is also underway on 23rd Ave.

Joining the Metro fleet of diesel-hybrids and on-wire trolleys, the new battery buses will be deployed over the next two years beginning in 2017. Dembowski says routes will be determined, in part, through equity and social justice policy with a priority on areas with high reliance on public transit and clean air issues. That will likely mean routes originating out of Metro’s South Base, some of which cross the Hill.