So just how inefficient are cars...?

[AER]

I was walking along the metro railway line near home a wee while ago and a near empty six car train trundled past and it got me wondering just how inefficient train travel must be, so I set out to do some calcs to see what I could find out.

I found this handy document from Metro Trains Melbourne which makes the following claims:

Melbourne Metro said:

The Melbourne rail network is comprised of:

- 830km of track (and approximately the same length of 1500V DC overhead wiring);
- 271 stations;
- 203 six-carriage trains made up of a fleet of Comeng, Hitachi, Siemens and X'Trapolis;
- 14,400 train services per week;
- Approximately 415,000 customers using the train services each day;
- Over 230 million passenger journeys per annum, and;
- Over 4,200 staff members.

it also claims that:

Melbourne Metro said:

The Melbourne Railway System is a major customer of the Electricity Distribution Businesses in Victoria. It consumes 377 MWh p.a. and has a coincident maximum demand of approximately 100MW...

Now, taking these figures and adding some estimates for average journey length of between 10 and 20km, this reduces to a per-passenger energy consumption of somewhere between 80mWh/km and 160mWh/km. That's milliwatt hours, take note!

Compare that to a Tesla driver self-reporting at around 160Wh/km, which is kind of the values I expected, this puts train travel at somewhere between 140x and 2000x more energy efficient than private transport, depending on how many Tesla seats you fill.

A disappointingly bad figure, IMO.

Does anyone have any traceable data that contradicts this?

[gangzoom]

AER said:

Now, taking these figures and adding some estimates for average journey length of between 10 and 20km, this reduces to a per-passenger energy consumption of somewhere between 80mWh/km and 160mWh/km. That's milliwatt hours, take note!

Compare that to a Tesla driver self-reporting at around 160Wh/km, which is kind of the values I expected, this puts train travel at somewhere between 140x and 2000x more energy efficient than private transport, depending on how many Tesla seats you fill.

A disappointingly bad figure, IMO.

Does anyone have any traceable data that contradicts this?

Ofcourse public transport is more efficient, a pedal bike is even more so. At least EVs are nearly twice as efficient as petrol cars.

[bigbob77]

gangzoom said:

Ofcourse public transport is more efficient, a pedal bike is even more so.

Is it, though? When you take into account the extra food energy required by the cyclist and the process around creating that food - I'm not sure.

[JonV8V]

Top Gear made a different claim once about a car being more efficient to carry 4 people from Manchester to London than the train. Probably made 10 years ago and from a very bad memory it was something like a VW passat (so make of the accuracy what you will)


edit - found a reference to the story in an article and it was a passat

http://forums.digitalspy.co.uk/showthread.php?t=13...

Edited by JonV8V on Monday 30th May 19:18

[Raize]

AER said:

Melbourne Metro said:

The Melbourne Railway System is a major customer of the Electricity Distribution Businesses in Victoria. It consumes 377 MWh p.a. and has a coincident maximum demand of approximately 100MW...

This does not seem right:

The average demand is 43KW based on the p.a. figure - 377,000Kw/365/24
The maximum demand is 100,000KW

[AER]

Raize said:

AER said:

Melbourne Metro said:

The Melbourne Railway System is a major customer of the Electricity Distribution Businesses in Victoria. It consumes 377 MWh p.a. and has a coincident maximum demand of approximately 100MW...

This does not seem right:

The average demand is 43KW based on the p.a. figure - 377,000Kw/365/24
The maximum demand is 100,000KW

You're right, it does seem counter to logic and good maths, but if you think about 203 six-car trains accelerating simultaneously, that might be quite a bit of power. I guess there's a bunch of statistics that determine this is an improbable event. The 337MWh covers losses only though, not acceleration power, most of which is recovered and shared throughout the network through regenerative braking.