Re: Economics of electric buses
  Matthew Geier

You are missing the significant issue of 'fear of overhead wires'.

Sydney's George Street line probably would have never gotten built if
'simple overhead' was the only option.

This 'FOW' is dragging down many sensible projects and compromising the
engineering of those that get to go ahead.

But then the modern low floor tram car is one big engineering compromise.


I'm currently in Luxembourg who have a 'shiny new' tram line. (With an
extension that's only been open 7 days!).

About 3-4 km and 5 stops are wire free. The CAF trams run on ultra
capacitors in that section. They have batteries too, but watching the
drivers console, the don't normally touch the batteries. But it appears
they didn't want the 'visual intrusion' of the 'rabbit ears' charging
bars, so each city station has a 3rd rail in the middle of the stop.

Due to the safety system and the need for a secure comms to turn the
centre rail one and off, they have a system that locks them into CAF for
further cars.

And due to 'urban planning' considerations the line does a couple of
sharp turns around the city centre which the 7 section Urbos 100 have to
crawl through at low speed, but with flange squeal. Planners vs sensible
engineering again.


CAF have added a lot of automation - the drivers don't control the power
at all. The control system lets the capacitors self discharge under the
wire. The state indicator drops slowly when under the wire. But when
approaching the wire-free section, at the stop before transition, the
system starts charging the capacitor banks again. At the by the
transition stop the capacitors are charged and the pantograph
automatically drops. The driver just waits for the 'hold' lamp to go out
on the console before proceeding. Each city centre stop's dwell time is
governed by the charging time of the capacitors and not passenger flow.

It also appears the pickup shoes don't retract like Alstom's APS, the
3rd rail at the stops appears to be slightly raised, and on the
extensive grassed sections there is a furrow in the grass from the
passage of the shoes.

The regen brake is aggressive - there is a constant grade between two of
the stops. The car arrives at the next stop with the same charge state
as it left the prior one, with the percent capacity indicator going up
not down as the driver 'regen brakes' down the grade.

I assume due to climate, they don't have huge power hungry
air-conditioning systems to run.

I do wonder how much 'loss' of kwhrs occurs by the 'leakage' from the
capacitor system.

No one seems to care about the loss of power efficiency all these wire
free systems cause. FOW.


As for battery electric buses - yes the batteries will need replacing
after about 5 years. But how long does a diesel route bus run before the
engine is pulled out, stripped down and rebuilt ?

Rebuilding of diesel engines is well understood and often something done
in house, but it must be a significant cost.

As battery electric vehicles become more mainstream, not only are
battery prices dropping, a recycling ecosystem will appear over time.
The batteries will be broken down and the valuable materials recycled.

People will ignore the whole micro-plastic from tyres thing as that
would make them environmental vandals for even driving their 'clean'
electric car. Can't have that can we :--)

Our next stop is a city with a TVR system. They were to replace the TVRs
with 'proper' trams, but that project has apparently succumbed to a
'financial crisis' (and change of city government) and they are looking
at just acquiring 'standard' trolley buses to replace the increasingly
problematic TVR vehicles. They already have the wires up, so a
'standard' trolley bus could be a sensible option.

However I wouldn't mind betting there will be a significant push to get
rid of the 'unsightly wires' now that 'technology doesn't require them'.

Saw another 'tech news' article recently about these amazing 'contact
free' charging pads you will be able to just park your EV over and have
your batteries recharge. No mention of how terrible the coupling
efficiency of these inductive systems is. Especially on road vehicles
where you need quite large distance between the transmitter coil and the
receiver.