How much power does it take to charge a bus in a reasonable amount of time?
I heard 100kw. If I have 100 buses charging overnight at 100kw I guess I need 10Mw grid connection? Is that an easy thing to get to a city bus depot in the US. In the UK I believe that would require moving to a location with a HV line and building a sub-station.
If you charge the buses over night, then you don't need 100 kW. I think the battery sizes are something like 100-300 kWh. So with 9 hours of charging, you need only perhaps 30 kW at the most.
Anecdotally, the town I live in invested in probably around 100 buses. They did build a new depot with charging stations.
Batteries are coming down in price, so if getting a good grid connection is a problem, you can put in a buffering battery.
The comfort of the BEV buses is much better than the old diesel buses, by the way, and they are much less noisy in the city.
Ok so you still need 3MW or with a buffering battery as big as your fleet you could spend half the day charging the batteries. So you still need what, 1.5MW? Or is it half that. It is still a grid connection that is larger than you could easily find in an old inner city bus depot, I would have thought?
No, that is not right. The correct answer is "it depends", but let's run some indicative numbers on data for Boston:
On average and excluding the minority of routes with dedicated lanes (which may be best run on diesel), the Boston metro buses are in use for 6.6 hours per day, covering on average 53 miles.
A full size electric bus uses electricity at a rate of approx 2 kWhr/mile.
So, on average the bus would have around 17 hours to charge up with 106 kWhrs of juice, and this averages out to about 6.2 kW. On average.
However, the smart thing to do would be to charge the buses when the power costs the least, say between 10 pm and 8 am, so you'd need ~10 kW/bus, maybe ~1MW for the 100 bus fleet. Not difficult.
Dunno about US but globally this is really a "it depends" answer. In developed countries, there are plenty of former factories and power plants with strong HV power line connections. Long term, with the electrification of everything, locations in close location to HV lines become prime estate.
I heard 100kw. If I have 100 buses charging overnight at 100kw I guess I need 10Mw grid connection? Is that an easy thing to get to a city bus depot in the US. In the UK I believe that would require moving to a location with a HV line and building a sub-station.