Goodbye Old King Coal Generation.

mapj1:

 

Where does the electricity come from? If it is from burning fossil fuels I should probably stick with diesel buses

Not so simple. Firstly I may be trying to clean the air in the city, but less worried about the pollution from the power station.

Secondly, a diesel bus will not allow regenerative braking, and the engine runs even when you are stopped at the bus stop or in traffic (at least in older buses).

Consider this  very modern 7900 electric volvo bus

an 8 hour day of perhaps 150-200km on a full  charge.

or this
diesel figures, same manufacturer    this sort of  thing, perhaps 30 litres per 100km.


Looks like a winner - 30 litres for one hour only is 140kVA genset (  ish  -   link)

And electricity generation is a touch more efficient that a diesel genset in a proper power station.

And a lot better if like the UK we have some nuclear and some wind generation to throw in the mix.



So how far can we go on a 140 kVA battery?

usual caveats

so more like 100 to 200km in reality then.

Not clear that the electric option is worse, it may be better, even just as it is.

I'd be the first to agree there have been some noticable cock ups  on early systems 

example the Albuquerque Rapid Transit   but I suggest that shows the technology is immature, not impossible

(battery temperature control was a large part of the failure of that pilot, and the longer range per day required compared to a typical

European city bus route.)


 

 

Some interesting information  ?  If air quality is part of the requirement than gas is also a fairly good option. The exhaust is probably subjectively cleaner than a Euro 6 diesel. Gas powered fork lift trucks have been used in factories for years. If your electricity is generated at Aberthaw you probably get the 'benefit' of it's pollution in Bristol if the wind is in the right (wrong) direction.


The range/energy consumption figures are interesting but as you say the usual caveats apply. Some semi random thoughts:


Volvo 7900 bus- I guess the 19kWh battery is a typo although as they are offering roof mounted charging rails (OppCharge) maybe not. From the other information it may be 190kWh but the voltage and hence the energy storage are not given. It could be anywhere between 400 and 750V.


It offers 'Ramp heating' so you can pre heat the bus in cold weather from a fixed supply to reduce the demand on the battery. 'Hotel' load is not so much of a problem in the UK but in other lands where you have to maintain the saloon at a reasonable temperature when the outside temp can be between -20°C and 40°C is a significant load. The battery temperature will also have to be controlled. My Smart would never really warm up at town speeds in sub zero temps. The diesel version had an additional electric heater powered by the alternator as the engine delivered even less waste heat. My present diesel Touran has an additional Webasto heater to deal with the problem of a fairly large cabin and a lack of waste heat from the engine.


The consumption figures for the diesel powered buses appear to be real world, including idling time and heating and aircon loads. It is not completely clear if the figures are just for longer distance coaches or city buses? 30L of diesel will run your bus for 100km or generate 140 kWh at 400V 3 phase in a genset. Will an electric bus cover an equivalent 100km of service on 140 kWh (assuming a 400V battery)? If they are using OppCharge ( https://www.oppcharge.org/  ) The real range per charge may be much less. The data from Volvo suggests a working range up to 200km. This is probably with the largest 250kWh battery and minimal heating and aircon loading. Are they also allowing for OppCharge? Guesstrapolating suggests that in the real world it will be possible but with a lot of caveats.


As I have said before I live in an ideal public transport part of the world. The electric trains, trams and trolley buses are powered by hydroelectricity with a bit of nuclear in the background. We live over a shopping complex so we can just push the trolley from the cash desk to the lift and then into the kitchen. The railway station is 5 minutes walk with a very regular service to Zürich. The car is rarely used, generally when supporting our daughter and grandchildren, and may well be got rid of in the near to middle future.


Best regards


Roger

mapj1:

 

Where does the electricity come from? If it is from burning fossil fuels I should probably stick with diesel buses

Not so simple. Firstly I may be trying to clean the air in the city, but less worried about the pollution from the power station.

Secondly, a diesel bus will not allow regenerative braking, and the engine runs even when you are stopped at the bus stop or in traffic (at least in older buses).

Consider this  very modern 7900 electric volvo bus

an 8 hour day of perhaps 150-200km on a full  charge.

or this
diesel figures, same manufacturer    this sort of  thing, perhaps 30 litres per 100km.


Looks like a winner - 30 litres for one hour only is 140kVA genset (  ish  -   link)

And electricity generation is a touch more efficient that a diesel genset in a proper power station.

And a lot better if like the UK we have some nuclear and some wind generation to throw in the mix.



So how far can we go on a 140 kVA battery?

usual caveats

so more like 100 to 200km in reality then.

Not clear that the electric option is worse, it may be better, even just as it is.

I'd be the first to agree there have been some noticable cock ups  on early systems 

example the Albuquerque Rapid Transit   but I suggest that shows the technology is immature, not impossible

(battery temperature control was a large part of the failure of that pilot, and the longer range per day required compared to a typical

European city bus route.)


 

 

Some interesting information  ?  If air quality is part of the requirement than gas is also a fairly good option. The exhaust is probably subjectively cleaner than a Euro 6 diesel. Gas powered fork lift trucks have been used in factories for years. If your electricity is generated at Aberthaw you probably get the 'benefit' of it's pollution in Bristol if the wind is in the right (wrong) direction.


The range/energy consumption figures are interesting but as you say the usual caveats apply. Some semi random thoughts:


Volvo 7900 bus- I guess the 19kWh battery is a typo although as they are offering roof mounted charging rails (OppCharge) maybe not. From the other information it may be 190kWh but the voltage and hence the energy storage are not given. It could be anywhere between 400 and 750V.


It offers 'Ramp heating' so you can pre heat the bus in cold weather from a fixed supply to reduce the demand on the battery. 'Hotel' load is not so much of a problem in the UK but in other lands where you have to maintain the saloon at a reasonable temperature when the outside temp can be between -20°C and 40°C is a significant load. The battery temperature will also have to be controlled. My Smart would never really warm up at town speeds in sub zero temps. The diesel version had an additional electric heater powered by the alternator as the engine delivered even less waste heat. My present diesel Touran has an additional Webasto heater to deal with the problem of a fairly large cabin and a lack of waste heat from the engine.


The consumption figures for the diesel powered buses appear to be real world, including idling time and heating and aircon loads. It is not completely clear if the figures are just for longer distance coaches or city buses? 30L of diesel will run your bus for 100km or generate 140 kWh at 400V 3 phase in a genset. Will an electric bus cover an equivalent 100km of service on 140 kWh (assuming a 400V battery)? If they are using OppCharge ( https://www.oppcharge.org/  ) The real range per charge may be much less. The data from Volvo suggests a working range up to 200km. This is probably with the largest 250kWh battery and minimal heating and aircon loading. Are they also allowing for OppCharge? Guesstrapolating suggests that in the real world it will be possible but with a lot of caveats.


As I have said before I live in an ideal public transport part of the world. The electric trains, trams and trolley buses are powered by hydroelectricity with a bit of nuclear in the background. We live over a shopping complex so we can just push the trolley from the cash desk to the lift and then into the kitchen. The railway station is 5 minutes walk with a very regular service to Zürich. The car is rarely used, generally when supporting our daughter and grandchildren, and may well be got rid of in the near to middle future.


Best regards


Roger