28 January 2009

The Most Efficient Machine Ever Invented

Swedish Bike Beauty
So I read an article in The Independent - a link sent by Claus - wherein it stated that "The energy efficiency of a bicycle has been estimated to be the equivalent of the average car doing 1,600 miles on a gallon of petrol."

For the roughly 6 billion of us who don't know what a gallon or a mile is, that is about 640 km per litre.

Lovely numbers. Does anyone know where this estimation originates? I'm curious.

The article has some cool quotes. I've seen them before, but repetition is sometimes nice:

Iris Murdoch: "The bicycle is the most civilised conveyance known to man. Other forms of transport grow daily more nightmarish. Only the bicycle remains pure in heart."

Elizabeth West: "When man invented the bicycle he reached the peak of his attainments. Here was a machine of precision and balance for the convenience of man. And (unlike subsequent inventions for man's convenience) the more he used it, the fitter his body became... Progress should have stopped when man invented the bicycle."

Jose Antonio Viera Gallo: "Socialism can only arrive by bicycle" [maybe not the wisest quote to chuck around Stateside... chuckle]

The journalist, despite clearly being a 'gear-dependent' type of cyclist tried to work out how much he saved by cycling:

"Let's take just one London commuter as a case study (that would be me). The cheapest way for me to travel the five miles from home to desk would be to buy a £1,208 annual travelcard. My bike was pretty pricey, at £700. Let's say it lasts seven years, so costs me £100 a year. I'm no good with a spanner so I get it serviced probably once every nine months. A basic service costs £55, so that's £83 a year for maintenance. My lights, lock, shoes and clothes don't come to more than £150. Let's divide that across two years – so £75. So cycling to work costs me about £258 a year (you could do it for less). Take off the £200 a year I spend on the days I'm forced on to public transport and I save £750 a year. That's enough for 266 pints of beer or a return flight to Sydney."

£55 for a service?! I pay about €13 down my local bike shop but nevermind that. And people could save even more cash by just buying a normal bike and using the clothes in the closet at home. [you KNEW I was going to say that, didn't you...] Nevertheless, it's a good indication of how people can save some money.

He also quote Cycling England's stats about the health benefits:
Cycling England estimates that every new cyclist saves the nation £382 a year in costs related to health, pollution and congestion. It says a 20 per cent increase in biking by 2012 would save £107m in premature deaths, £52m for the National Health Service and £87m in costs to employers through reduced sickness. A cut in pollution would save £71m a year, while reducing congestion would save £207m.

Here's the article from early January 2009.


Rob said...

This is a good source from HowStuffWorks - 952 miles per gallon.


allez1961 said...

The link Rob suggested is good but I might also add that food calories are renewable, gasoline not so much. Ironically, (in reference to yesterdays post) many folks over here in the USA use their Fun Spong...Dammit there I go again, I mean, they use their cycle computers to determine how many calories they are using on their bike rides so they can calculate how many doughnuts and beers they can have when they are done!

Malc said...

I think I read somewhere a long time ago that the bush roller chain (i.e. bike chain) is one of the most efficient methods of transferring energy from one place to another ever invented.

Anonymous said...

The source of the data may be here:


..which I believe also refers to a UN study a few years ago...

Kevin Love said...

The amounts saved by cycling seem to be too small.

Dr. David McKeown, Toronto's Medical Officer of Health, produced a report in 2007 in which he stated that traffic pollution in Toronto kills 440 people per year and injures 1,700 so seriously that they have to be hospitalized.

Cost: 2.2 billion dollars.

Source: http://www.toronto.ca/health/hphe/pdf/air_pollution_burden.pdf

2whls3spds said...

Numbers are going to vary depending on who calculated them and where they get their information. The favored "argument" against the efficiency of cycling is that; you should drive is because you would consume more calories because you are riding LOL...I have never seen too many car drivers worry about how many calories THEY consume.


Kris said...

The cost of your basic service around here is USD$40-$75, excluding parts. I own my own set of tools now and order my parts online. My bike used poor quality components that were damaged by the incredibly bad roads here, and those cost me a small fortune to replace as well after a recent crash involving roads destroyed by ice.

That being said, if I factor in time saved by not having to look for parking, taking shortcuts possible only on a bicycle, so on and so forth, the savings are in my favour again. All of this completely ignores the obvious health benefits of cycling too, for which there is no amount of money that can represent the quality of life attained by riding my bicycle.

That's not the best thing though. When all the roads are snowed in and they don't plow the roads, the lighter the vehicle the less trouble it has getting around. There's not a lot that's lighter than a bicycle :)

William said...

It's a difficult thing to calculate, because the farther you go into details, the more you have to cherrypick the numbers.
First off, the human body is not an efficient machine, so the calories eaten do no equal the calories put into work.
Then there's also the question of the energy put into the food. (discounting the sunlight, of course). What kind of fertilizer has been used? If you spread pig-urine on the fields for fertilizer, you have something near to a zero-sum equation.
The matter is very different if you use synthetic fertilizer, because that's actually made out of oil. (not just with the energy from oil - you can't assume that windmills can replace oil here - it's the actual oil that's converted into fertilizer. Check wikipedia for details)

There's no doubt, though, that even the clunkiest cargobike is more energyefficient than any car.
(WV conest - Of all the coneheads, Mr. Frederick was the conest)

Adrienne Johnson said...

While I can not quote the source of this info, I have heard that 8 hours of sleeping takes more energy than 8 hours of watching television. Save energy, quit sleeping! :)

Karl McCracken (twitter: @karlonsea) said...

You need to be careful with things like "gallons" as well, because there are gallons and gallons. An Imperial Gallon is 1.2 US Gallons. One of the few things that's bigger over here than over there . . .

I'm curious about 'normal' bikes, and I wonder if you can help me out. My Sturdy Commuting Bike needs replacing this spring (not so sturdy, it turned out), and I'm seriously tempted to go for something like a Pashley Roadster Sovereign. My standard commuting trips are about 8-10 miles (13-16km) each way, but up to 15 miles (24km) is within my comfortable range.

When I've mentioned the sort of bike that I want and how far I ride, I've got definite raised eyebrows from even those that I'd consider the most broad-church cyclists in the UK.

So my question is, do people use such 'normal' bikes over such daily-ish distances?

George said...

The better measurement in metric litres/100km.

The most efficient cars on the road - tiny diesel Volkswagens - consume 3.2litres/100km.

1600mpg is 0.147litres/100km. 21x the most efficient cars.

Denis said...

Bike is efficient in all aspects. This is obvious.
As for saving some money, this is absolutely real!
Maintenance is done by my bike mechanic friend at home - for lower prices *_*: Seasonal general things UAH120 per year (UAH8.00=USD1.00), teflon chain & fork oils - UAH40.00 (per year), seems that`s all...
But what is most important - I feel good, I do all my city routine things in time and get a great amount of pleasure for my vaio.

allez1961 said...

Have you noticed that the scientific hair splitting about just how much gas, calories, blah, blah, blah takes the fun out of the discussion just like like a cycle computer takes the fun out of the ride. I don't need all the data to know the benefits of the bike ride. It is evident by observation that riding a bike is beneficial in a lot of ways. I save money, I get fitter, I have fun. My brain appears to be the only instrumentation I need!

Kevin Love said...

Karl asked:
"So my question is, do people use such 'normal' bikes over such daily-ish distances?"

Kevin's answer:
I own a Pashley Roadster Sovereign. Pricy, but when you consider that it will last for the rest of my life it's worth it.

Most of my trips here in downtown Toronto are for much shorter distances. To work is 1.2 km. There is a grocery store within 100 metres of my front door (I don't bike!). Church is 6 km. I went 500 metres to the dentist yesterday. Post office is 350 metres.

My longer trips tend to be visiting relatives and friends. Any more than 10 km and I'll go multi-modal on the subway or regional rail network, both of which allow bicycles on the trains.

The 10 km mark is because
I've kitted my Pashley with a Nine Continent's electric assist, which has a practical range in City traffic of a little over 20 km.

I highly recommend my set-up. If you wanted to use an electric assist for your distances you should get a spare battery to have a 40 kn range.

Adrienne Johnson said...

@Karl- I have what is, here, so quaintly termed a 'normal' bike. I ride daily, up to 20 miles/ 30 kilometers a day. I average about 12 miles a day. My bike and I handle it quite well.

peteathome said...

Numbers I've seen, based on fuel consumption for vehicles and calorie consumption for people ( with fuel translated into calories as 1 gallon gasoline contains roughly 35,825 KCalories ( food calories) or 41 KWH.

per passenger mile:
single occupant auto(25 miles/gal): 1433 cal
train: 885
bus: 920
walking: 100
bicycle: 35

Going backwards, the calorie consumption of the bicyclist translates into 1023 miles/gallon.

To be fair, I'm not taking into account the energy required to produce, transport and process the food, which can easily drop this mileage in half.

Anonymous said...

"Participatory democracy demands low-energy technology, and free people must travel the road to productive social relations at the speed of a bicycle."

Ivan Illich, Energy and Equity 1970

Illich has an entire chapter on how the bicycle facilitates social justice. Energy and Equity is available online:

It is a quick read, just a couple of hours, but some of the ideas have stuck with me for a very long time.


Anonymous said...

"Man on a bicycle can go three or four times faster than the pedestrian, but uses five times less energy in the process. He carries one gram of his weight over a kilometer of flat road at an expense of only 0.15 calories. The bicycle is the perfect transducer to match man's metabolic energy to the impedance of locomotion. Equipped with this tool, man outstrips the efficiency of not only all machines but all other animals as well."

Ivan Illich, Energy and Equity

Sorry for the bandwith, I could not help myself.


marks said...

Quick calculation of the total costs for my bike pr. year:

Flat tire: 2 or 3 x 100 kr. (20 USD).

That's it.

Oh, and my bike was 2000 kr. (350 USD).

Just get a bike and start using it - there's nothing more to it, people.

Anonymous said...

William > First off, the human body is not an efficient machine, so the calories eaten do no equal the calories put into work.

The car is no more efficient at converting chemical energy to physical work; the internal combustion engine is about on par with mammalian metabolism. There are limits to this efficiency that follow from the laws of thermodynamics. The trouble with the car, though, is that it is very big, heavy, unaerodynamic and has large mechanical inefficiencies beyond the engine (shafts, rolling resistance of the tires etc.). Only a couple of percent of the calories in the tank go to moving the people (more likely, a person) inside from A to B. Of course, you can argue that the big unaerodynamic chassis keeps the passengers dry and comfortable and therefore the energy spent on it is not waste.

The other point I was wondering about is that do cyclists actually eat more? Most of the energy people get from food is spent on basic metabolism and homeostasis, that is maintaining the body. I suspect the energy spent on cycling would otherwise be accumulated around the waist in a lot of cases. The amount I eat has nothing to do with how much I ride my bicycle and my weight has fluctuated a few kilos up and down regardless of the amount of cycling.

Anonymous said...

Anonymous above has a good point. I also thought that you can't compare a car and a bike directly, as bike has no motor in it - the motor is the cyclist. Therefore one should compare the efficiency of a car and and a bike/cyclist combination:

Which part of the energy eaten by the cyclist, can be get out from the rear wheel of a bike? Then you get the efficiency for a bike.

I assume that the most of the energy eaten, is spent to maintain normal body functions (body heat, digestion, blood flow etc.).

However - this is just a one point of view. I share your opinion, that the bike is the ultimate machine eg. for commuting, as co2 (and other) emissions are way lower when compared to cars.

David Hembrow said...

Karl said: "So my question is, do people use such 'normal' bikes over such daily-ish distances?"

Quite a lot of children here cycle 20 km each way daily to get to secondary school. That's a daily 40 km / 25 mile round trip. They all have "normal" bikes.

I usually pick something else for longer rides, but after another bike broke down I rode my dilapidated old 3 speed for several days of about 60 miles a day and it was fine.

Anonymous said...

Why don't they know what a mile is? I know what a km is!

Kiashu said...

These sorts of comparisons, like so many trees planted being equivalent to so many cars off the road, it's just silly.

You don't need any petrol at all to ride a bicycle, just as you don't need any food to run a car. It makes as much sense to talk about a bicycle in "miles per gallon" as it does to talk about a car in "loaves of bread per mile".

We need a true common unit, which is energy. All motion requires energy, but where we get that energy from is important.

For example, if I hang my clothes out to dry instead of putting them in an electric dryer, it still takes energy to dry them - but one energy resource is extremely large, the other not so much. I don't deplete the sun by hanging my washing out; I do deplete coal or copper for transmission lines by using electricity.

We can't really compare these very different things on some imaginary common basis. We need to compare like with like.

For example, as I explained in why I hate cars, if you include the time you have to work to pay for running a car and road taxes and so on, and compare with the costs of walking or biking or training etc (with all their associated costs) cars turn out to be the slowest form of transport.

Anonymous said...

"Why don't they know what a mile is? I know what a km is!"

Expecting the whole world to know what a mile and a gallon is only because they are still used in some countries is quite arrogant.

George said...

"Why don't they know what a mile is? I know what a km is!"

This is because only two countries still use the imperial system. The USA, and Myanmar (Burma).

Every other one uses metric. Well, the British still use miles for distance, but they're British.

William said...

The whole 'mile' thing is difficult. Our swedish neighbours also have a mile - theirs is 10 kilometers long. You can imagine my horror, when I read that the speed on US interstates where 60mph.

njh said...

These energy calculations are of course bunk. It is quite possible for a cyclist to use no more food energy than metabolism simply by riding slowly - if you ride as slowly as you walk your energy consumption drops, compared to walking, by a factor of 5. In fact it drops to the same as a resting metabolism. Combine this with the fact that a cyclist can be fitter (and hence more energy efficient) than a car driver and it is possible that a bike has effectively infinite energy efficiency over a sedentary worker. This could be the case for Copenhagen's slow cyclists. Of course a slow cyclist doesn't get very fit.

On the other hand, if you assume the cyclist rides at peak output, eat feedlot beef (yuck!) for all their energy needs, flown from the other side of the plant, eating corn produced in the highly oil intensive manner of the US, rides a carbon fiber bike no old than a year and that all their additional energy use is directly provided by their food intake, then you find that a cyclist is half the energy efficiency of an SUV with flat tyres.

Furthermore, a car driver will think nothing of driving 40 miles to do some shopping, a cyclist will probably consider 2 miles to have the same utility. This results in a 20 times energy efficiency saving. (Then there are more subtle issues like the energy of maintaining the vast areas of asphalt for cars, increased health costs for sedentary workforces, particulates and smog, car accident injuries and deaths etc - when you factor these in the car's fuel economy drops further.)

Regarding fertilizer having to come from oil. This is nonsense. The only fertiliser element that requires energy to make is Nitrogen (the others are all available to all plants in oxidised forms and are merely mined or collected). This energy is in the form of oxidation potential and can be provided by electricity, or directly from the sun (you can 'unburn' nitrogen at high temperatures - which is what causes smog, yep smog is fertiliser!). I designed a fertiliser plant based on algae for a town in australia, which produces nitrogen fertiliser from algae.

My suspicion is that people who state such efficiency numbers will always pick the numbers to suit their argument.

And be warned that the most efficient lifestyle is to be dead as soon as possible, so be careful what you wish for.

João Lacerda said...

Excelent post!

Inspiring to see the efficiency of the bicycle in terms of "fuel consuption"

But google's calculator tells me it is even more efficient.

Doing 680 km/l

Mikael said...

the swedes, like the rest of the planet, use metric. they do, however, use swedish miles, when talking to other swedes.

just like the brits still use 'stones' to calculate their weight and fractions of a 'gill' to measure alcohol.

Anonymous said...

me llamó la atención la enorme cantidad de comentarios y quiero mencionar el excelente libro de Iván Ilich Energía y Equidad, del que ya hay varios comentarios en inglés, para los que lo quieran leer en español también lo pueden hallar en internet. Ilich vivió en México varios años, y aquí escribió varias de sus obras.

Anonymous said...

aquí en méxico estamos atrasados en lo que se refiere a caminos para bicicletas y las facilidades que se encuentran en otros países,esperemos que eso cambie en los próximos años (quisiera que fueran meses, pero con estos gobiernos ....)