Have they thought this through? To install batteries that are much heavier than what the bus trip requires makes the bus less efficient. Sure they need to store energy for to smooth out peak grid consumption but probably better to do that with batteries that are not mobile -- if they must use batteries. Another way to store energy: pump water to the top of a mountain. To get the energy back open a dam that turns a hydro turbine.
from the article:
Pollution from buses and other vehicles contributes to chronic asthma among students, which leads to chronic absenteeism.
Seems like a stretch.