Driving

[Aggie]

I've been keeping track of how many km I have driven since I started my new job (start of October), and so far I'm at 8760 km / 5443 mi.

This is enough to drive from Deadhorse, Alaska to Key Largo, Florida. 


I don't want to think about how much CO2 that represents (it's approximately 1500 L of gasoline). 

[Griffin NoName]

Wondering about "driving" as "sin". Perhaps in future we will all have to keep our driving secret. If asked, how did you get here, we will always say by bus or train.

[Aggie]

Oh, it's not a problem, we don't have those things in Alberta.

[Swatopluk]

I use public transport. About 250 km per weekday. On the other hand this way I do not have a flat in the town I work with the accompanying energy consumption. And the trains are running anyway with my added weight probably not making much difference.

[Pachyderm]

Regularly do over a thousand miles in a month. If possible, we share cars, but there are many occasions where we are all off in different directions, to different sites, and for varying lengths of time.

And all this is a country approximately 5400 sq. miles. There are now very few bits I haven't been to.....

[Lindorm]

Well... considering my line of work, I think I have you all beaten. 

Sometimes I drive about 1200 km in 22-hour period, including an overnight lodge. A week last summer, when I had lots of long-distance work and did some extra duties, I clocked up about 4000 km in a single week. Of course, there are then those days when I only do local work, and sometimes just move back and forth within a goods yard.

When it comes to CO₂ and other emissions, it can vary widely. Most of our trains run on electricity, bought only from sustainable sources (mostly hydroelectric), so for a 600 km-trip with a 450-ton mail train at 160km/h from Stocholm to Malmö, the total CO₂ emissions are on the lines of 40kg, mostly from petrol-powered equipment used for building and maintenace of the power distribution system. Total energy use is on average about 40 Mjoule for the trip, but can be significantly lower if you use energy-management techniques when driving -unfortunately, not something that is possible with the mail trains, considering their very tight schedule and need for high point-to-point speeds.

An X2-class high speed passenger train travels the same route at about 200 km/h, using even less energy, since they are fitted with regenerative braking. When braking , the traction motors are used as generators, converting the kinetic energy of the train to electricity and feeding it back to the catenary, to be used by other trains.

As a comparison, moving the same amount of mail on lorries between the same terminals would require about 9 times as much primary energy, and cause about 25400 kg of CO₂ emissions.

Now, all our trains are not run by electricity. The "final 10 kilometres" are often handled by either diesel-powered shunting loco, or by lorries and trucks, since a lot of freight originatingf and receiving points are either not connected to the railway at all, or have unelectrified tracks for various reasons. It is a bit difficult to load wagons with an overhead gantry crane of there is high-voltage knitting in the way...

These final ten kilometres, the capilarry net, is of course not as energy-efficient as the mainline freight. However, by using it for local distribution and transfer, the environmental impact can be kept as low as possible, and we can use existing infrastructure for final distribution. On the average, we have CO₂ emissions of about 2,8 grams per tonne per kilometre for rail transport -including use of diesel locos for capillary services and connections.

For example, imported consumer goods, including perishables and fresh meat and vegetables, are packed in a trailer in a logisitcs centre in Helsingborg, the very south of Sweden. These trailers are then loaded on railway wagons, and operated in a block train from Helsinborg up to Stockholm overnight, arriving in Stockholm at about 03:40. The first block of wagons are shunted into the terminal tracks an unloading of perishable goods start at  about 04:00. The first trailer tractors arrive at about 04:15, hitch up ot the trailers, and then do their distribution circuits around the greater Stockholm area for a large Swedish food and grocery chain. The first unloading at the grocery stores start at around 05:00 in the morning, with the first empty trailers arriving back at the terminal at around 07:00. They are then loaded back onto the wagons, a train formed and dispateched back to Helsingborg at about 11:40 in the morning. This merry-go round then continues all week, sunday evening dispatch in Helsingborg to friday afternoon arrival in Helsingborg.

The company I work for operate several such shuttle systems for consumer goods -time-sensitive, high value cargo, and not just the traditional railway goods of iron ore, lumber, cement and other high-bulk, low-value goods, which is a very interesting break of a trend that has been evident since the rise of mass car ownership.

[Bob in a quantum-state-of-faith]

...
An X2-class high speed passenger train travels the same route at about 200 km/h, using even less energy, since they are fitted with regenerative braking. When braking , the traction motors are used as generators, converting the kinetic energy of the train to electricity and feeding it back to the catenary, to be used by other trains.
...

As that little kid said near the end of The Incredibles [movie]:

That's Totally Awesome!

I had no idea they used regenerative braking on electric trains-- but it's an obvious energy conservation move.

I wonder how much increased maintenance it creates?

I know that it would increase the load-time on the motors, as during non-regenerative braking, the motors basically coast, and their bearings are not under significant load.  But for regenerative, they are working all the time-- generating torque when moving, and generating electricity from torque when braking, thus there's little "down time" for them, as compared to non-regen trains.

Then, there's the added complexity of the on-board electronics to handle this reverse flow, and feed it backwards in such a way it doesn't create hazards.   And, you'd reduce the life of the electrical brushes/contacts between the overhead wires and the engine, although I suspect these don't care which way the power if flowing, if you're using A/C anyhow-- current is current-- and I strongly suspect the life of these is more related to miles-driven, than current-passed.  Which would mean they wear regardless if they are conducting significant load or no-- if the trains are moving, they are wearing (for example).

All of that, I would imagine, would be subtracted from any savings from the regen braking, but I also imagine that the initial energy costs are still much higher than that, so that even subtracting this built-in burden, it's still a net gain-- just thinking out loud, here.

I know that most electric motors have a lifespan measured in hours of operation, meaning hours under load.  In the case of reversible motors, there has to be brushes involved because as far as I know, nobody's figured out how to make an induction generator.     And the time spent braking would have to be included, obviously.

On the third hand, these things are very old tech (the motors).  As I recall, they were first invented in the late 1800's?   Incremental improvements since then, but the basic idea is still the same.  And the life on a large motor is very long--even one with brushes.



I love to consider the whole picture, when talking about issues of "green".  So many times, "green" advocates do not do that:  they seem to imagine that electricity just appears as if by magic, and the same for the energy needed to create the batteries, solar panels, etc.

You have a cool job, Lindorm!

[Aggie]

Well... considering my line of work, I think I have you all beaten. 

Sometimes I drive about 1200 km in 22-hour period, including an overnight lodge. A week last summer, when I had lots of long-distance work and did some extra duties, I clocked up about 4000 km in a single week. Of course, there are then those days when I only do local work, and sometimes just move back and forth within a goods yard.

Total km? Absolutely.  My best week since I started here looks like it was 3475 km (ok, it was 8 days at 525/690/150/495/175/460/180/800).  The most I've probably done in a short period of time was 1050 km in a 16-hour period (drove from home to the site - 600 km - did 4 hours of groundwater monitoring - drove back to Red Deer as I was too tired to make it home - 450 km).

In my defence, I should point out that driving is only an incidental part of my line of work. 

In any case, railroad tracks contain many more severe curves and extreme slopes than Alberta roads: 



I wonder if this is a factor in why I hate commuting and insist on living within walking distance of the office?

All of that, I would imagine, would be subtracted from any savings from the regen braking, but I also imagine that the initial energy costs are still much higher than that, so that even subtracting this built-in burden, it's still a net gain-- just thinking out loud, here.

Ayuh, but then there's less maintenance and wear on the friction-braking system, in addition to the energy gains.

[Swatopluk]

The principle used for regenerative breaking is nothing new. The Swedish ore trains to Norway (Narvik) use it for many decades. There is steep slope downwards at one point. The loaded trains wait for unloaded ones from the other (lower) side. They then drive down and generate electricity which is used to pull up the other.
I think that was at the time unique in the world.