The laws of physics tend to be immutable, at least until you get into esoteric disciplines like quantum science.
In the case of electric vehicles, one law provides that higher energy capacity in a battery allows a vehicle to travel further.
That's the principle electric-bus maker Proterra has used to set a new world record for distance traveled by an electric transit bus on a single battery charge.
The company said today that on September 4, a 40-foot Proterra transit bus traveled 1,101 miles at the low speed of 15 miles per hour on the energy contained in its 660-kilowatt-hour battery.
The test took place at the Navistar Proving Grounds in New Carlisle, Indiana, which confirmed the record.
For context, the battery in the record-setting Proterra Catalyst E2 Max bus held 11 times the energy capacity contained in the 60-kwh battery of a 2017 Chevrolet Bolt EV electric car.
Lithium-ion cells for the battery were provided by Korean maker LG Chem, which also provides cells for battery-electric cars to numerous automakers globally.
They are assembled into battery packs for U.S.-built buses in a new factory in Burlingame, California.
The largest battery pack in any volume electric car sold today is 100 kwh in top-end versions of the Tesla Model S hatchback sedan and Model X crossover utility vehicle.
Proterra has set similar records before, covering 603 miles last September in a bus equipped with a 440-kwh battery and 258 miles in 2015 using a battery of 257 kwh.
The publicity stunt is likely designed to raise awareness of electric transit buses and to counter inchoate public fears of buses quietly grinding to a halt on busy streets as their batteries run out of charge.
Battery-electric powertrains offer an excellent way to eliminate emissions in urban and suburban areas previously generated by the diesel engines used in transit buses and other commercial vehicles, some of which may cover 1 million miles in a typical service life.
Cost remains a challenge, however: a typical Proterra transit bus may run $750,000 against the $500,000 or so usually charged for a diesel-powered bus of comparable size and capacity.
While operating costs to run on grid electricity are far lower than diesel fuel at efficiencies of 3 to 5 miles per gallon, that initial cost presents a hurdle, and municipalities are moving slowly to experiment with electric buses before committing fully.
Public-transport agencies in many cities, including the enormous Metropolitan Transit Authority that serves New York City and its surrounding areas, have already converted to diesel-hybrid buses, which increase fuel economy substantially.
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The goal, however, remains to eliminate emissions entirely from a variety of commercial vehicles—delivery vans, garbage trucks, service equipment, and transit buses—that cover predictable routes and in some cases relatively low daily mileage.
Proterra sold 190 electric buses last year, it said.
Toyota, meanwhile, is planning to launch hydrogen fuel-cell buses for the 2020 Tokyo Olympics.