<Another 100 billion barrels of oil found in Iraq?The Oil DrumAre Subsidies to Oil Companies Ever Justified?>
<DrumBeat: April 21, 2007DrumBeatDrumBeat: April 24, 2007>

225 comments on DrumBeat: April 23, 2007

Comments can no longer be added to this story.

AlanfromBigEasy on April 23, 2007 - 9:27am Permalink | Subthread | Parent | Comments top

Last time I calculated (a couple of years ago), diesel Amtrak (outside NEC) was getting ~85 pax mpg. Sleepers & 58% (memory) load factor hurt the #s. Electrification improves BTU efficiency (trade diesel for electricity) by x2.5 on plains and x3 in mountains and built up urban areas (industry rule of thumb).

Southwest Airlines got about 54 pax-mpg in 2006 (also memory).

Greyhound ?? I do not know real world load factors.

Best Hopes,

Alan

0
Comments can no longer be added to this story.
Planner on April 23, 2007 - 10:31am Permalink | Subthread | Parent | Comments top

The U.S. Department of Energy publishes a Transportation Energy Data Book.

It contains a tremendous amount of useful energy information on motorized transportation modes (passenger and freight) in the U.S.

For the passenger modes, Tables 2.11 and 2.12 (in Chapter 2) list the general BTUs per passenger mile as:

Mode BTUs/passenger mile (2003)
Cars 3,549
Light Truck 7,004
Bus (Transit) 4,160
Bus (Intercity) 932 (for 2000)
Air (Commercial) 3,587
Air (General Aviation) 10,384 (for 2001)
Rail (Intercity - Amtrak) 2,935
Rail (Transit) 3,228
Rail (Commuter) 2,751

As always, the devil's in the details. Tables 2.11 and 2.12 strongly warn that "Great care should be taken when comparing modal energy intensity data among modes. Because of the inherent
differences between the transportation modes in the nature of services, routes available, and many additional
factors, it is not possible to obtain truly comparable national energy intensities among modes." I have not yet looked into the various assumptions that went into the computation of the above numbers.

0
Comments can no longer be added to this story.
AlanfromBigEasy on April 23, 2007 - 10:42am Permalink | Subthread | Parent | Comments top

Those statistics ahve been roundly criticized for unrealistic assumptions (# of pax/car as one example). "Bush data manipulation" has been one allegation I have heard (no comment lacking facts myself).

I prefer private data in this case.

http://strickland.ca/efficiency.html

He takes real world and generally representative examples instead of "global averages" more subject to manipulation.

In any case, the changes in Urban form over time due to TOD effects save more energy than direct energy savings via substitution.

Best Hopes,

Alan

0
Comments can no longer be added to this story.
JustZisGuy on April 23, 2007 - 11:41am Permalink | Subthread | Parent | Comments top

Thank you for the positive reference, Alan. I would just like to add that if anyone has references to the real numbers for a particular Amtrak service I would be happy to add it to the table. Right now the data I have for diesel-electric locomotive-hauled trains is not the greatest. I have information from one trial service for the Colorado railcar+trailer (392 passenger-mpg if all seats taken), and one data point taken from the fact that commuter rail trains (which I've seen with my own two eyeballs :-) ) can be 10 bi-level cars long with only one 3000 hp locomotive, which apparently burns 761 L/100 km. Knowing the seating capacity of each car yields the number I calculated - 421 passenger-mpg with all seats filled. Amtrak single-level trains are likely to have less than half the seating capacity but not significantly different mass (less dense seating, a restaurant and baggage car perhaps) and if they're on average half full then you would expect something on the order of 1/4 the efficiency overall.

This is too much handwaving for my liking - I'd like to nail a more exact number down. The difficulty of finding such information continues to astound me - surely the energy efficiency of transportation service should be an important factor in public policy.

Maybe I'll try some more searching. I've started looking through the academic literature and there is a stunning paucity of data there as well. Maybe I'm just not searching in the right place - anyone have any ideas?

0
Comments can no longer be added to this story.
AlanfromBigEasy on April 23, 2007 - 12:17pm Permalink | Subthread | Parent | Comments top

I have been wanting to (time available) to get the annual #s for Long Island Railroad (some small % freight) as a valuable addition for you directly from LIRR. LIRR is, of course, electrified.

Best Hopes,

Alan

0
Comments can no longer be added to this story.
NeverLNG on April 23, 2007 - 2:04pm Permalink | Subthread | Parent | Comments top

thanks to all. Some great leads.

Obviously, there is no simple answer. Especially if people want to keep moving around, and apparently, they do.

Someone might fix the html tag that I typed wrong at the start of this thread, though obviously it doesn't impair readability-- it's just inelegant

0
Comments can no longer be added to this story.
PaulS on April 23, 2007 - 8:25pm Permalink | Subthread | Parent | Comments top

Yeah, I'm going to guess there's a fairly sulphurous devil lurking in the details. Rolling coefficient of friction for rail is only around 0.3%, more than an order of magnitude less than for a car, and wind resistance will be divided up among the passengers. Rail-car-plus locomotive weight per passenger can be surprisingly high, but at reasonable loading should still be less than for a car. So unless there are only two or three passengers per rail car, which rarely happens on any overall average because it's unsustainably expensive, this just doesn't seem physically reasonable - and especially not for multiple-unit electric transit trains, which need no locomotive weight. For very high speed trains it may be a different story, but there are none of those in the USA for the DOE to keep tabs on.

0
Comments can no longer be added to this story.