Re:Buy a coal mine, drive a gas guzzler, and other uses of r...
by bobthepanda on Sunday December 26, 2021 @01:09AM
(#29690160)
IMO the case for all electric buses is a bit weakened by two things:
* for an electric hybrid bus with regenerative braking, the city bus is pretty much running on batteries most of the time anyways, because it never goes above 30MPH and there's so much stopping and starting to repower the batteries.
* in practice, BEB fleets need to be bigger than their diesel equivalent fleets because of the range anxiety. In particular, BEBs and their higher weight perform worse on elevation rises, where they are spending more energy to lug the heavier weight around, and in winter. Winter is interesting, because the way current bus heating works is that they take the waste heat from the ICE and dump that inside. Electrically heating a bus takes additional energy, and on top of that batteries perform worse in cold weather. The problem is severe enough that so far the most successful cold-weather BEBs maintain a fossil fuel system just to keep the bus warm.
* for an electric hybrid bus with regenerative braking, the city bus is pretty much running on batteries most of the time anyways, because it never goes above 30MPH and there's so much stopping and starting to repower the batteries.
* in practice, BEB fleets need to be bigger than their diesel equivalent fleets because of the range anxiety. In particular, BEBs and their higher weight perform worse on elevation rises, where they are spending more energy to lug the heavier weight around, and in winter. Winter is interesting, because the way current bus heating works is that they take the waste heat from the ICE and dump that inside. Electrically heating a bus takes additional energy, and on top of that batteries perform worse in cold weather. The problem is severe enough that so far the most successful cold-weather BEBs maintain a fossil fuel system just to keep the bus warm.