GE says most of the 63,000 transit buses and 480,000 school buses registered in the United States travel under 100 miles per day. Given that, why not go electric?
Well, buses are big and heavy, and powering all that mass takes big and heavy – and expensive – batteries. But at GE Global Research, they say they’ve demonstrated a dual battery system on a zero tailpipe emissions hybrid transit bus that with further advances “could achieve the optimal electric driving range and acceleration requirements at a more practical size scale and cost for larger vehicles.”
The system GE engineers are toying with pairs a high-energy density sodium battery with a high-power lithium battery. By doing so, they’re capturing the strengths of each battery type, they say: Lithium batteries “provide a lot of power for acceleration, but are not optimized to store energy for driving range,” while sodium batteries “are on the opposite side of the spectrum … they store large amounts of energy, but are less optimized for power.”
In addition to performance benefits, there’s a big cost advantage here, too, GE says – at least 20 percent over single-battery systems – because “a dual system provides flexibility to integrate less expensive battery chemistries without having to increase the size of the battery to address a vehicle’s power and energy storage needs.”
The research into what GE is calling the “electric bus of the future” is funded by the National Fuel Cell Bus Program, working with the Federal Transit Administration and Northeast Advanced Vehicle Consortium.
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