While hybrids are generally termed to be environmentally
friendly due to its lower fuel consumption, its quite important to
compare the fuel consumption of each model on a particular route.
That's because if the fuel savings does not overcome the cost in
replacement of batteries, then its not really environmentally
friendly anymore as the batteries do require rare minerals to
produce (lithium).
Also, Parallel hybrids (both the Sunlong and Zhongtong are
parallel hybrids) are generally more useful (save more fuel) on
routes that do not have much start and stop operations as the fuel
savings is brought about by the use of a lesser powerful engine and
some electric motor assist while moving off. This is probably why
sbst decided to put the hybrids on 502 instead.
Series hybrid (none at the moment) are more useful in start stop
environment because they have a small diesel engine that basically
always runs at peak efficiency to charge the batteries. The
batteries are then used to drive the electric motors. The fuel
savings are brought about by the use of a small engine which is
always running at peak efficiency.
So i feel that before they buy a fleet of environmentally
friendly hybrid bus fleet, its important to consider how much fuel
savings they can yield from using the hybrids, and also consider to
trial a series hybrid before any decision is made.
How about considering using biodiesel and CNG for some buses? For
CNG buses, our PTOs can also consider setting up CNG refuelling
stations inside the bus depots and can also double-up to serve
their CNG taxis and earn extra income? For biodiesel, our PTOs can
also consider setting up a division to collect used cooking oils
from foodcourts, SFI, hawker centres etc and setting up small
refinery to process them into biodiesel and use or even sell.
There's a recent newspaper article about biodiesel in Singapore and
it even mentioned Bedok Transport is using biodiesel for its
buses.
