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Boston is getting more propane school buses to combat pollution. They aren’t the cleanest option.

A safety supervisor stood near a propane-fueled school bus in Boston in this 2015 file photo.Craig F. Walker

The Massachusetts Department of Environmental Protection will spend $350,000 on 12 propane-powered school buses for Boston at a time when the state’s climate plan calls for a rapid shift away from fossil fuels in transportation.

The school buses are part of a $2 million round of Massachusetts grant funding provided by the US Environmental Protection Agency announced this week. The funding aims to cut pollution by getting rid of diesel-powered vehicles. The state said it will spend $740,324 on five electric school buses for Springfield contractor First Student Inc., and the 12 buses bound for Boston will use propane, a fossil fuel.


Governor Charlie Baker praised the funding announcements Tuesday.

“Our administration continues to identify and advance projects that better position the state in combating against the impact of climate change with an equitable approach,” he said in a statement. “The shift to cleaner vehicles will reduce the exposure of our citizens to diesel emissions, improve air quality, and assist us as we work to meet the Commonwealth’s ambitious climate goals.”

Those goals, part of climate legislation signed by Baker last year, are reducing the state’s carbon emissions at least 50 percent below 1990 levels by 2030, 75 percent below those levels by 2040, and getting to “net zero” emissions by 2050. Key to achieving those goals is electrifying most of the transportation sector, according to the state’s own road map.

The majority of Boston’s school bus fleet already runs on propane, but advocates bemoaned the city adding more vehicles powered by fossil fuels rather than moving to electric school buses as some other Massachusetts cities are doing.

“It’s time for the city to step up and be a leader on electric buses,” said Staci Rubin, vice president of environmental justice at the Conservation Law Foundation. “Ideally this would have been the time to get electric buses and figure it out.”


Data from the US Department of Energy Argonne National Laboratory’s transportation fuel calculator tool show that electric school buses far outperform propane school buses in reducing air pollutants and greenhouse gas emissions in Massachusetts. Compared to diesel school buses, propane school buses emit less nitrogen oxides, which contribute to harmful air pollution. Depending on the age and fuel efficiency of the diesel engine, propane buses can provide a slight reduction or a slight increase in greenhouse gases compared to diesel buses.

“It’s a detour at best, a dead end at worst,” said Daniel Sperling, founding director of the Institute of Transportation Studies at University of California Davis.

A spokesperson for Boston Public Schools said this week the agency has 739 buses in its fleet; 407 of those are propane and 332 are diesel. BPS began adding propane buses to its school fleet in 2015 and will purchase another 89 propane buses this year, in addition to the 12 funded through the state. School buses have a useful life of around 14 years, according to the Federal Transit Administration.

Mayor Michelle Wu campaigned on “full electrification of our school bus fleet by 2030,″ a goal that will be out of reach if Boston uses the propane buses purchased this year for their useful lifespan. The deadline to apply for this grant funding was in July of last year, before Wu became mayor. She took office in November.


“Moving to electric buses for our school bus fleet is key to our plans to advance a Green New Deal for Boston,” Wu said in a statement. “Our Environment Department and BPS are actively working with state and federal partners to achieve that goal as soon as possible, and pursuing funding opportunities to make electric buses a reality for all Boston schools.”

Baker’s office did not respond to a request for comment about how propane school buses fit with the state’s climate goals.

Courtney Rainey, deputy chief of staff and director of government affairs for the Massachusetts DEP, said applicants were awarded based on their project’s ability to reduce harmful diesel emissions.

“By providing grants to replace a range of diesel vehicles, engines, and equipment with newer, cleaner diesel, zero tailpipe emission, hybrid or alternative fuel versions, we can help to accelerate the retirement of older, less efficient, and more polluting vehicles across the Commonwealth,” she said via e-mail.

A spokesperson for BPS said the city has identified another grant to support a pilot project for electric school buses. The city is planning charging infrastructure and working with vendors that are testing electric buses in extremely cold weather similar to Boston’s, the spokesperson said.

“This interim propane step will help reduce BPS’s school bus environmental impact immediately, while BPS DOT works to electrify its fleet,” the spokesperson said in an e-mail.

Propane school buses are far less expensive than electric ones. The Massachusetts DEP said in its announcement that the new grant funding ranges from 25 to 45 percent of the vehicle replacement costs, depending on how much they will reduce nitrogen oxides and other emissions.


Argonne National Laboratory estimates the cost of an electric school bus is $300,000 and the cost of a propane school bus is $108,000.

Still, other cities and towns across Massachusetts are already adding electric school buses to their fleets, including Springfield through its school bus contractor as part of this round of grant funding. Arlington and Beverly have used federal funding sources administered by the state for school bus electrification.

Veena Dharmaraj, director of transportation for the Massachusetts Sierra Club, called Boston’s decision to use the grant funding for propane buses a “missed opportunity.”

Dharmaraj, Rubin, and other advocates want to see Boston commit to electrifying its entire school bus fleet by 2030.

“We should be done with incremental benefits,” she said. “We need the change to happen fast.”

Taylor Dolven can be reached at Follow her @taydolven.