As it faces what to do about its aging bus fleet and outdated bus maintenance facilities, the MBTA is considering how to move to an all-electric bus fleet – and at what price.

Environmental groups urged T officials at a panel discussion in Boston sponsored by A Better City this week to go electric with the entire bus fleet, but the cost of buses and new charging sites and maintenance garages could run close to $1 billion. That would be a major step to help the state meet its goals to reduce greenhouse gases and eliminate harmful pollution from diesel buses that increases cases of asthma and other health problems among urban residents. 

But, like upgrades to the subway system in Greater Boston, any plan to replace 1,000 buses with all-electric vehicles is a long-term challenge. It’s interesting to note that China has the largest percentage of electric buses in the world, although it’s also a country that relies heavily on coal-burning power plants and massive hydro-electric dams for much of its energy needs. 

Commonwealth magazine said the T took delivery last week of five articulated, zero-emission electric buses and plans to purchase a mix of hybrid and battery-powered buses to replace the trackless trolleys — the ones that rely on overhead power lines — around Harvard Square.

Erik Stoothoff, the T’s chief engineer, told Commonwealth, “We have diesel-fueled buses today that our infrastructure is going to have to support, but we want to accommodate a modernized fleet that will probably be powered by electricity. While it would be great to go in and put the technology first, as an operating entity, we need to put the service first.”

Fred Salvucci, the transportation secretary when Mike Dukakis was governor, said he believed it’s more important to get commuters out of cars and onto buses to cut carbon emissions (and reduce growing congestion), no matter what fuels the buses. 

Cutting down on greenhouse gases that are driving climate change. Reducing our reliance on fossil fuels to get around. Getting people out of cars and onto public transit. These are all important goals that carry high price tags either way we go, but they are goals we need to reach for as a commonwealth.