Monday, October 19, 2009
A Small Charge
I thought this article on ultracapacitor buses was interesting in that they have been used in China for a number of years. One of the surprising things to me was that they didn't recharge for much shorter intervals at more charging stations but for a long time at a single station for 5 to 10 minutes. It seems to me that with improvements this type of tech could also be used for trams. It will come at some point, but I still don't think its worth discharging overhead wires.
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4 comments:
Ohhh, this makes sense. Buses and trains usually have relatively long scheduled dwell times at a small number of stations, which matches the "charge for 5 or 10 minutes at a few places" methodology.
I think you might get into a catch-22 when it comes to traditional commuter heavy rail. The energy required to get a loaded train moving maight be so great that the energy store would take up too much room to leave room for passengers.
clever-title: if a train is more efficient than a bus per tonne-mile, then surely it would take less energy relative to the vehicle size.
There's no good reason *not* to use overhead wires on most trains; if you can justify a high-capacity train line economically, you can justify the overhead wiring. I would expect batteries and ultracapacitors to be used on trains purely for cruising through phase gaps and across junctions, and similar areas where the overhead wiring could truly be complicated and trouble-prone. (Switching engines are actually a good example, because they live in an environment consisting of nothing *but* switches.)
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