Wednesday, December 10, 2008

Transit Energy Efficiency & Lifecycle Costs

We've seen any number of calculations of energy efficiency and green house gases in transit modes. Some a bit out there because of crazy assumptions for autos. Even our favorite libertarian O'Toole played the game. The problem with all of these is that they don't consider the whole picture, or what happens when buildings are built closer together and transportation makes it easier for people to walk. But I digress.

At Rail~Volution I saw a presentation by Tina Hodges at the FTA that had some cool charts and comparisons of modes. The one I've seen before is the increase in VMT versus what CAFE standards will do. Now we've seen that there is a bit of a drop recently due to the economy but with gas prices as they are and no change in habits, I still believe this will happen.

Then here is the difference between current occupancies vs. all of the vehicles full and over the lifecycle of the vehicle in the second chart. These are based on a UC Berkeley study by Mikhail Chester that considered vehicle construction, guidway construction etc. The list of items lifecycled are at the link. Apparently buses off peak are the worst and peak are the best, even better than rail lines. Yet rail lasts longer and attracts more passengers overall so on average is better. I didn't really have time to read the 332 page tome, but if you're interested go for it.

But the most interesting in the presentation to me was the difference between the Heavy Rail modes. BART is the most efficient while Cleveland is almost as bad as a single occupancy vehicle. The relative inefficiency of the EL was surprising to me as well.

Thought this would be of interest to folks. I have to say again that its necessary to not just measure the lifecycle and modes but rather the land uses and transportation, but its interesting to learn that this work is being done.


Mario Tanev said...

Can you please have a post encouraging people to vote in the now official moderator to question the president-elect on what he would commit to in terms transit and inter-city rail and to remind him that there is high enthusiasm for it?

There have already been a few questions posted:

Thank you

V Smoothe said...

Do you know why it is that BART is so much more efficient than other systems? What is it about Cleveland that makes it so bad?

Pantograph Trolleypole said...

I'm going to guess that its because of the way the energy is produced. Northern California has a more diverse portfolio with more alternative energy sources than other parts of the country with heavy rail. The numbers come from eGRID subregion data apparently.

Cleveland just has low ridership for a heavy rail line.

Chris said...

In regards to energy portfolios, in the Pacific Northwest, there are several utilities that are operating very close to 100% non-co2 emitting energy sources.

In Tacoma, WA, I think we're at 98.84% carbon free electricity. Tacoma Link light rail, for example, would thus have quite low life cycle co2/p-km - as would the Seattle trolleybuses.

Cap'n Transit said...

Pan, I hate to give you a hard time, but can you please try not to mix up efficiency and pollution? It's true that efficiency plays a role: the lower the occupancy, the more pollution per passenger. But the cleanliness of the electricity source is also significant.

Alon Levy said...

How is the New York City Subway, which gets its electricity from coal, so low-emissions?

Pantograph Trolleypole said...

Ah yes, thanks for pointing that out Cap'n. Next time i'll watch my wording a bit closer. Alon, is it all coal?

Anonymous said...

A lot of that CO2 emissions difference in the last graph is due to electrical generation. Cleveland and Chicago are *heavily* coal-burning areas; San Francisco is largely hydropowered.

Nothing to do with the transit system efficiency there. :-/

Cleveland does suffer from underuse, however -- more seats full means better efficiency. Chicago's jam packed, however, so it's obvious that the method of electrical generation is the main influence here.

Anonymous said...

NYC subway gets a little nuclear power and a little hydropower from upstate.

It also gets a fair amount of natural gas and oil powered electricity, for odd reasons.

However, I'm sure the reason for its super performance is that it's always packed and it's running long, long trains -- the longest of any metro system in the US, and longer than any I've identified in Europe.

Winston said...

BART has very low CO2 emissions because most of the power in northern California comes from low CO2 sources - Gas, hydro and nuclear are the big ones. BART also runs pretty light equipment in long trains and has a respectable load factor. The other factor that makes BART efficient is that it has fairly infrequent stops, meaning that it doesn't spend as much time as, say, the DC Metro accelerating and decelerating.

In fact, comparing DC's MetroRail with BART is very interesting because both systems are the same length and use very similar equipment. At first glance METRO appears far more successful in that it has 3 times as many boardings as does BART, however, when you look at passenger miles BART and METRO are nearly identical (1.4 billion/year for BART vs. 1.6 billion/year for METRO). This is because METRO serves a major role circulating people around DC while BART is focused on getting people across the bay and the Muni Metro serves the urban circulator role in San Francisco.

Anonymous said...

Here's another discussion of Mikhail Chester's report: Energy Use and Pollution of Travel Modes. I made a chart summarizing the energy usage results, and included a chart that shows how ridership affects energy usage. There's also a discussion of why urban context is so important for energy use, pollution and land consumption by transportation.

-Laurence Aurbach