​Two new reports are renewing the focus on electricity as the main power source for school buses, transit buses and heavy-duty trucks.

The first, published by the U.S. Public Research Interest Group, touts the environmental benefits and operational savings of all-electric school and transit buses.

U.S. PIRG’s electric bus report noted that some 95 percent of America’s roughly 480,000 school buses run on diesel. Where the nation’s 70,000 transit buses are concerned, more than 60 percent are diesel-powered, with 18 percent running on natural gas, while 0.2 percent are all-electric.

The group’s report said that replacing all of the country’s school buses with electric models could avoid an average of 5.3 million tons of greenhouse gas emissions each year, while doing the same for diesel-powered transit buses could save more than 2 million tons of greenhouse gas emissions annually.

U.S. PIRG’s data also highlight the cost-savings potential of electrifying both school and transit buses, noting in its report school districts can cut nearly $2,000 a year in fuel expenses per vehicle and reduce annual maintenance costs by $4,400 per vehicle by switching to all-electric school bus models. The group noted that all-electric school bus pilot programs are now underway in several states, including California, Massachusetts, and Minnesota.

Meanwhile, on the transit bus side of the ledger, U.S. PIRG said the Chicago Transit Authority estimated two years ago that its electric transit buses reduced annual fuel costs by $25,000 per vehicle – and its planning to beef up its all-electric bus fleet by 20 to 30 units over the next few years. Gaining those kinds of savings is also a reason U.S. PIRG said the mayors of Los Angeles and Seattle joined a pact with 10 other city mayors around the world to purchase only electric transit buses after 2025, with Los Angeles County’s transit agency, Metro, committing to go “all-electric” by 2030.

Costs savings are at the heart of a new “guidance report” covering Class 3 through 8 commercial battery electric vehicles or “CBEVs” compiled by the North American Council for Freight Efficiency – especially when it comes to fuel expenses.

Over the past decade, NACFE said fuel costs for commercial truckers reached a high of 65 cents per mile driven before dropping to a low of 34 cents per mile driven in 2016 – numbers representing, respectively, 39 percent and 21 percent of the total cost of operating a commercial vehicle in the U.S. Currently, the price of diesel is more than $3 per gallon, equating to 44 cents per mile driven, the group said.

NACFE’s research also dovetailed with some of U.S. PIRG’s findings regarding operating cost savings, which can be less for CBEVs because electric drives are more “energy efficient” than diesels and the reduction in diesel-based friction-sensitive mechanical systems such as pumps, valves, transmissions, and belts should reduce maintenance and servicing.

Yet the higher “tare weight” of CBEVs due to battery storage systems, less range, and re-charging system needs remain negatives, though they are being addressed, the group noted.

“The rapid pace of improvements in battery technologies – increased capacity and decreased cost and weight – could spur increases in CBEV efficiency that likely cannot be matched by evolutionary changes to internal combustion engines,” NACFE explained in its report. “These competing technologies are at different points in maturing on their innovation S-curves, with the greater potential going to the newer CBEVs.”