By Erik Ramberg
What is the most efficient way to transport a person a given distance? The unit to compare is the amount of energy (MegaJoules) required per person per kilometer. The numbers below are fuel efficiencies copied or calculated from information in the Wikipedia entry for "Fuel efficiency in transportation", which contains 40 interesting references. I've assumed 80% occupancy in each of the multi-passenger cases, including the automobile. Also, the energy needed to deliver the fuel to the vehicle, and to manufacture the vehicle, is not included in these efficiencies.
1. Bicycle 0.12
2. Train 0.1-0.3
3. Walking 0.33
4. Transit bus 0.38
5. Automobile (4 people) 0.9
6. Jet airplane 1.4
7. Ocean liner 7.7
There are many lessons to be learned from this ultra-simple tabulation. First of all, it is hard to beat a person peddling a bicycle - perhaps the most efficient mode of transportation by any animal on planet Earth. Secondly, the only thing worse than driving your car with just yourself as a passenger, is if you decided to take an ocean liner to work every day. Intercity travel can be up to 10 times more efficient by train than by airplane. Once you are in a city, don't hesitate taking a bus for a few blocks - you expend about the same amount of energy (and carbon dioxide) as walking.
One question for policy makers: for a city of 1 million people, why don't we just buy 100,000 bicycles for free use by the population? The expenditure is only on the order of $10 million, and the savings in energy would be incredible.
4. Transit bus 0.38
5. Automobile (4 people) 0.9
6. Jet airplane 1.4
7. Ocean liner 7.7
There are many lessons to be learned from this ultra-simple tabulation. First of all, it is hard to beat a person peddling a bicycle - perhaps the most efficient mode of transportation by any animal on planet Earth. Secondly, the only thing worse than driving your car with just yourself as a passenger, is if you decided to take an ocean liner to work every day. Intercity travel can be up to 10 times more efficient by train than by airplane. Once you are in a city, don't hesitate taking a bus for a few blocks - you expend about the same amount of energy (and carbon dioxide) as walking.
One question for policy makers: for a city of 1 million people, why don't we just buy 100,000 bicycles for free use by the population? The expenditure is only on the order of $10 million, and the savings in energy would be incredible.
Bicycles may be even a bigger winner than your numbers show. I found a bike energy calculator at http://www.mne.psu.edu/lamancusa/ProdDiss/Bicycle/bikecalc.htm that claims that at 15mph I would be burning about 88 Watts on a nice bike. This translates to about 0.013 MJ/km. Maybe someone missed a decimal point. Also, while cars aren't too bad if all the seats are full, the measured occupancy of cars on the road works out to be about 1.1 passengers per car.
ReplyDeleteSo, bicycles are clear high performance winners when we look at energy. They of course are not the perfect answer for all situations. Winters, rainy days and the like are all a problem. Your idea of public bikes has been tried in some locations with success. There is nothing that can be done that will do more good for the buck.
Then there are electric bikes. I get excited by these because I have about a 12 mile commute and that makes for a long ride on a hot day. I will save this topic for another entry.
Several references indicate you might be right and that bicycling is 5-10 times more efficient than I had written. That is pretty amazing - almost hard to believe. Since 1 kiloJoule = .25 Calories, then that means riding a bicycle for a kilometer only burns up 4 Calories. That sounds low. I burn up 4 Calories tying my shoelaces.
ReplyDeleteI agree with bchase, bikes are unreliable when combined with poor weather. Also, bchase has pointed out that the commute may be uncomfortably far; how many of the 1 million are within agreeable riding distance? On top of that, Americans are notoriously lazy/unfit. How many of the 1 million would ride even one mile to work?
ReplyDeleteOne thing I love about America is our freedom to do whatever we want, within reason. Unfortunately, this includes driving large 5mpg vehicles, alone, over any distance traveled greater than a quarter mile while abusing one's health from lack of exercise. Many people would find any deviation from this pattern quite undesirable. Ride a bike? Pffft.
I'll conclude with an interesting link I found on Slashdot:
http://www.bixisystem.com/home/
This is about a system similar to what you propose being implemented in Montreal. Seems cool.
Mark
I agree that Bicyclist are the true Green Power Savers right now when it comes to transportation, but realistically I would opt for good public transportation like the mass transit system they have in big cities.
ReplyDeleteCar pooling may also work if there is enough interest for it, but you need consistency with
the drivers knowing that they will be there day in day out.
Unfortunately the roads in the US are not made for bicycles. Sharing the road with the cars is surely dangerous and many people who would love to bicycle to work are deterred from doing so by the risk. In addition to spending 10 millions to by bicycles cities would need to spend much more making their roads safe for the most efficient users.
ReplyDelete