In message , at 11:49:54 on Mon,
21 Jan 2019, Theo remarked:
As I say, the electric buses here seem to manage a full day on a fairly
intensive service without needing more than an overnight charge at the
depot.

It's certainly feasible to have 100% battery buses. They are just very
expensive, and hence why they only show up when subsidised - Stagecoach,
First et al are not buying them as the natural option instead of diesel
buses. China has made good progress in this area, but with heavy government
subsidies.

It's a tradeoff whether more fixed infrastructure (charging at bus stations,
route wiring) costs less than larger batteries in vehicles. I suspect that
will depend on a case-by-case basis.

Bear in mind also that the infrastructure to charge overnight includes
extra grid feeds to provide the power to the garage/parking-lot.

If the buses were running on power from overhead lines, not only is the
demand spread over 16hrs rather than 8hrs, but it's likely that at least
some could come from existing feeds for the overhead lines as they
traverse the wider area.
--
Roland Perry