Department of Energy Gets Basic Math Wrong in its Rail Analysis

When it comes to the carbon consumption of cars, trains, and buses, the
U.S. Department of Energy’s (DoE) Transportation Energy Data Book [PDF] is an indispensable resource. But this year’s Data Book contains an eyebrow-raising error in its analysis of rail’s energy use.

Edition28.jpg(Image: DoE)

Page 66 of the Data Book, reprinted
on the DoE’s website on Inauguration Day, contains a table ranking the
energy intensity of various light rail systems across the country.

DoE lists the "average" energy efficiency of all light rail systems as
7,605 Btus per passenger mile, while the average for cars was 3,514
Btus per passenger mile.

Those numbers were enough to spark inflammatory headlines about the energy consumption of light rail. The only problem: The rail data is wrong.

eagle-eyed Streetsblog Capitol Hill reader discovered that the DoE used
simple averaging to obtain its light rail number, without weighting
each city’s light rail network based on how many passengers it carries.

So Kenosha’s streetcars, which carry a bit more than 60,000 passengers annually, were treated the same as Seattle’s light rail, where ridership is exceeding 60,000 every week.

Even famously anti-transit Randal O’Toole
recognized the DoE’s error and pointed out the actual average energy
efficiency for light rail is 3,642 Btus per passenger mile —
comparable with the numbers for cars, which don’t fully account for the
choice of auto driven.

The same averaging error is made on
page 67 of the Data Book, which states that the "average" energy
efficiency of heavy rail is more than 3,600 Btus per passenger mile.
That average put Cleveland’s energy-chugging system, which carry
about 30,000 passengers on an average weekday, on equal footing with
the New York City subway, where the average weekday ridership tops 7

When the Streetsblog reader contacted the DoE to
inform them of the error, he got a quick acknowledgement and a promise
to correct the data as soon as possible. The incorrect averaging should
never have been used, the DoE said.

One wonders how many misleading commentaries transit critics can publish using the false data before the government corrects it.

  • limit

    The analysis is still wrong. Apples to apples.

  • Spokker

    “comparable with the numbers for cars, which don’t fully account for the choice of auto driven.”

    So all we need then is for everybody to drive hybrid cars or something? It sounds like from an environmental point of view that taking light rail uses up the same energy as taking the car. What’s missing?

  • Spokker

    I guess it depends on where you get your energy from:

    California, for example, uses less coal than the rest of the country does. We do 20% hydroelectric and 20% renewables. Our light rail is a lot cleaner than say, Denver’s, which gets 57% of its energy from coal.

    As energy efficient as a Prius is, it’s still burning gasoline.

  • DJB

    That’s the exciting thing about electricity as a delivery system for energy: society can choose how the electricity is generated.

    Those choices include clean renewables like wind and solar. You can solve the intermittancy problem by pumping water upwards with solar and wind energy and draining it through a turbine at night and when there’s no wind. (The only real drawbacks are the amount of land you’d have to use and the number of birds that would be killed.)

    Hence, the door to fossil-fuel-free transportation is opened by electrification.

  • Erik G.


    Modern Wind Turbines are less lethal to birds than outdoor cats:

    And Elana! This data was posted on either 13 or 19 January, 2009. Mr. Obama did not take office until 12 noon on 20 January 2009. This is the work of a USDOT under the guidance of the likes of Tyler Duvall, a Bushie-idealogical political hack with no transportation background father of the idiotic HOT lane concept that is currently preventing users of I-10 eastbound from accessing the HOV lanes between Downtown and El Monte.

  • walker o

    A recent study predicts that global change would still cause havoc if we stopped ALL carbon emissions (buses, trains, and farm tractors included) today. If you care about global warming you can’t just go after reducing relatively minor reductions in energy use PER CAPITA. You have to reduce total emissions. We need policies that reduce population growth greatly. No solution without this sustainable (in the real sense, not in the happy talk delusional sense).

    If everyone took the bus we are still screwed. If everyone rides a bike we are still screwed. Why won’t people address the most important factor in the global change equation-population size?

  • DJB

    @ Erik

    All the better then.

  • DJB

    @ Walker

    You’re quite right to point out that population size is an important variable in humanity’s environmental impact. Environmentalists shy away from talking about it because it’s sure political suicide to suggest, as Garret Hardin does, in his classic essay, “The Tragedy of the Commons” that “the freedom to breed [without limit] is intolerable”.

    I don’t share your gloomy assessment of the efficacy of reducing transportation GHG emissions. Given a growing population, per capita reductions are the first step towards overall reductions in GHG emissions. Yes, population matters too, as do GHG emissions for things besides transportation, but ignoring per capita reductions to pursue politically damn-near-impossible population controls seems like a mistake to me.

  • Spokker

    “Why won’t people address the most important factor in the global change equation-population size?”

    Vote yes on Measure Q. Limit families to one child before it’s too late!

  • walker o

    to spokker,
    I say vote No on measure Q. Family sizes do not need to be capped. Public policies should provide incentives for small families and not subsidize large families like we do now.

  • walker o

    to DJB,

    Regarding your assesssment, do you have data or analysis to back you up? I do. I’ll post some ref’s later. I look forward to seeing the studies you cite.

    If population growth is impossible to stop, the world will eventually be doomed to unsustainable resource utilization levels and have very unpleasant lives.

    Fortunately, it is not impossible to stop. Many human populations have negative internal population growth rates (without targeted public policies for this).

    Ignoring the population growth rate and focusing on short-term (very short term in a geological time scale) per capita reductions that save us less than 3-4 decades seems like a mistake to me.

    A huge delusional mistake. Way bigger than the real estate always goes up delusion.

  • Spokker

    “Public policies should provide incentives for small families and not subsidize large families like we do now.”

    And then what do we do about social security and the increasing proportion of older people that need an income and medical care without the young people to work and support them? As it stands, social security is going to go broke in 15-20 years.

    But hey, we might get to see some dystopian films begin to come true before we are about to check off the planet. Haha.

  • walker o

    Because we have a giant ponzi scheme for retirees that means we should say screw the planet?

    Here is what I heard from you: Rape the planet because I want my generation to be able to retire comfortably.

    SS is poorly designed and should have been changed long ago. Maybe it is time.

    FORTUNATELY, economies do not need to grow their populations to have increasing productivity. It sure is easier to to grow the size of the economy with simply adding more people and its a lot easier to do that in a socially unjust way.

    Unfortunately, more people means more resource utilization, more pollution, and less space to grow an urban farm.

  • limit


    “…pumping water upwards with solar and wind energy and draining it through a turbine at night and when there’s no wind.”

    What of the laws of thermodynamics? Or you are purporting an inefficient energy system? The kinetic energy stored in water compared to the chemical energy in batteries are magnitudes different.

  • walker o

    Limit’s point is about number. Mother nature again.

    We should build this non-fossil fuel system before growing our population further, just in case we can’t pull it off. We should not be reckless with our children’s future.

  • Spokker

    “Here is what I heard from you: Rape the planet because I want my generation to be able to retire comfortably.”

    So let old people starve until they die off and won’t be a burden anymore!

    I’m just saying that if you truly believe that we’re doomed no matter what we do (because there’s no way we’re getting India or China to stop fucking), you have to deal with the reality that nobody wants to think about population control.

    In all honesty, if we’re doomed anyway, fuck the planet. Leave it uninhabitable by any species until it gets swallowed by the sun eventually. If we go down, we’re taking the Earth with us! Now there’s a policy I can get behind.

  • DJB

    @ Limit

    Batteries may be a better solution. Honestly, it’s not my area of expertise. I’m just trying to make sure people understand that there are solutions to the intermittancy problem, since intermittancy is often used as an excuse to dismiss wind and solar altogether.

  • Joel Kopitz

    As a start to reducing overpopulation, line up the people who even considered using BTUs for the calculations.

  • angle

    Two words: Soylent Green.

  • walker o

    There are some inconvenient truths in what lies ahead. We pull back now or we pay a lot more later. We’re willing to pretend that we can easily get off the oil fix (we’re still screwed if no one ever turned their automobiles on again… damn numbers).

    It is tougher because our parents didn’t take care of this.

    As for starvation of the elderly, that’s over the top and makes it clear that you realize that you have to realign your ideological filter to meet reality.

    Policies could change that push back the retirement age of the baby boomers (you know they did that already to gen x… you know that?), and they could apply means testing. I have a multi-millionaire uncle who pulls in nice more than I do in salary and still collects SS. Reduction in the level of benefits might also have to occur. It is a bloody reality.

    If wishing were all it took to have a clean and strong economy…



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