On a more serious note, I believe that future buses will use
some combination of rechargable electric batteries and some kind of
fuel (clean diesel, CNG, or hydrogen) to power them in the future.
Such buses already exist, yes, but not on our roads yet. I do
expect to see them in significant numbers by the middle of the next
decade or so.
Also, I envision that such electric-hybrid buses of the future
to also use solar power for auxiliary power (eg. air conditioning),
and that their batteries will be rechargable wirelessly. The latter
technology is already available to power light-rail streetcars; I
envision such technology being applied to buses, in the form of
wireless charging stations built right into bus berths and parking
bays at bus interchanges, and inside bus depots.
That is why I love Japanese buses and their technology... In
fact they are about the first few to have a hybrid bus, like a
hybrid car, it uses power from engine and stores it in batteries to
reduce engine work load... Power stored can be used for braking and
powering some of the vehicle's electrical components... For this
particular HEV (Hybrid Electrical Vehicle) it uses the electric
power to move the bus...
Mitusbishi Aero Star KL-MP37JM改 (Kai) of 名鉄バス (Nagoya Tetsudo
Bus). HEV type.
Also a Mitusbishi Aero Star HEV type vehicle of Entetsu Bus. Two
photos from Wikipedia.
