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48 responses to “Are cars greener than bikes?”

    • steveintex

      the three hundred pound couch potato climbing into her electric car to go greet at the walmart may use less carbon than the svelte blogger commuting to work on her bicycle. but the society will spend far more carbon enabling her sedentary existence than it does for the active one.

    • MechaZilla

      This is sophistry of the highest degree.

    • Damon Hart-Davis

      Thanks for that Dale: it’s closer than I thought it might be…

      Any idea of the amortised embedded manufacture of car + supporting infrastructure vs bike and its?



    • Energy Saving

      I concur with you on all of the points that you have written.

      I agree also that the embedded carbon will also have an impact, and that is where I believe the flaw lies in this carbon impact assessment.

      We don’t know the amount of carbon emitted to produce a car, but I know that it is substantial, I even would go as far to say that in it’s lifetime the car may through use, produce less CO2 than it did to produce the car. Added with the other issues with waste streams for vehicles.

      You also have the infrastructure issue to deal with, would we have required or would we need much of the existing network of roads if cars were not owned by the majority. Would we need to build as many bridges, roads, and motorways. Would shopping centres be out of town, requiring us to drive to get there.

      As steveintex mentioned, would we be so obese, would we fuel that obesity, and put such a strain on the environment and medical institutions. Would we have so many deaths on the roads or road works, that ultimately emit copious amounts of CO2 from engines left idle or detours of many miles.

      I completely agree we need to find solutions to problems and the wind ev is a concept that I wholeheartedly believe is a viable solution to reducing transport emissions, but biking still has far greater benefits socially and environmentally than driving when looking at the greater picture.

      Keep up the valiant work at Ecotricity, I just wish there wasn’t an energy monopoly in Northern Ireland so that you could supply my home 😀 with New Energy!

    • Nick Maynard


      Have you run the numbers if you take into account the construction carbon cost of an average electric car, average bike, and the appropriate proportion of the turbine?

      I’d venture that would give a more balanced view of the overall cost…


    • Rob

      You are, of course, assuming a 1-to-1 additional food consumption for ‘work done’ by your cyclist… Many a ‘fat bastard’ is already consuming 5000+ calories per day which is just turning into fat in a ‘slow’ metabolism. With regular exercise an improved metabolic rate often leads to a lower total calory consumption even though ‘work’ is being done.
      I’m looking forward to seeing a row of these ‘wind cars’ parked outside the local gym. Now if only you could get those exercise machines hooked up to the grid and pumping power out too….

    • Nick Maynard


      … silly me. I really should read all of the article before writing!


    • Rob

      Hey Dale,
      Where do we sign up for the free electricity after six months?

    • James

      LOL! Great post, and the comments it has generated, love it!

    • Neil Montgomery

      Hello again Dale,
      Thanks for your letter 14 October and for pointing out this ‘blog’ to me.
      Despite your logical response to my letter and your rational article above, I still think that there is something in ‘pedal power’ (especially if linked through a geared system to mini windmills which would then continually turn no matter what the weather conditions were).
      Looking around our local community, it strikes me that most people could give 4 (or 8 or 12)hours per week ‘pedalling for the grid’ without the need to increase their calorie intake – and what benefits we would see in (expenditure on) the nation’s health!!
      Even though I’m rather fit and lean myself, I don’t believe that I eat more when I exercise – I exercise to stay fit and lean – if I didn’t exercise, I’d probably consume the same calories and get bigger!!
      Anyway, no point in me banging on as I’m obviously not a scientist and more ‘power’ to your elbow whichever route you take.

    • Thomas Lankester


      You are not comparing like with like.
      What happens when you do the figures for an electric car vs. an electric bike?

      I am also a bit suspicious of ding the car figures at 30mph as drag hoses mpg (equivalent) at high speeds. Are you rally going to hop in your wind powered sporty car and do 30mph?


      PS I also concur with the fundamental ‘elephants in the room’ of healthcare carbon costs and the whopping embedded energy difference between car and bike.

    • Chris

      Ha! This is all very amusing to me…

      Especially as I remember joking to friends once that we should put all our criminals on tredmills, hook them up to the national grid, and make them serve their sentences in miles instead of years!! … Whilst also generating electricity renewably for wider society! A sort of 2 birds with 1 stone attempt!! .. Well I liked it anyway!

      But it seems you have fatally quashed my dream whipping this society into shape through forced exercise!!! Ha! … Unless we figure out how to ‘carbon capture’ the inmates exhaled breath!


    • Chris

      … Oh and limit their diet! … Hmm this idea is getting somewhat less ethical.

    • Baboonboy

      Like to see the figures when the embedded energy of a bike and car is taken into account.

      I bet the figures aren’t that close then.

      Perhaps a more interesting argument comes from this…

      According to a paper authored by professor Karl T. Ulrich of The Wharton School at the University of Pennsylvania, there are immediate energy savings by bicycle riding, since a cyclist is between six and nine times more energy efficient than a single occupant automobile. But Ulrich calculates that cyclists increase their longevity by 10.6 days for every year of cycling. And by living longer, they also stand to consume more energy over their lifetimes.

      Always worth remembering that statistics can be used to prove alomost any viewpoint…

    • Seb


      nice article. I like the way you’ve presented the argument, but I think it’s straying into the realm of the dodgy.

      “And if you up your activity level you up your need to eat – it’s that simple.”

      But it’s not that simple. A person doesn’t work like a car with the exact fuel input being translated into a proportionate output. Ultimately there will be days when we overeat or skip breakfast and they won’t correspond to our physical activity that day. We’ll store our excess “fuel” or burn our stores when immediate fuel sources are insufficient with other complicated energy losses and efficiencies intertwined into that equation. Our metabolism and fitness will affect our ability to do the work of riding a bike as mentioned above and for those of us that cycle more, we’ll have more efficient “engines” so will need to eat less.

      But I suppose the real point is that cycling provides a useful way to keep fit. I’m assuming this article relies on the argument that if you are less active you need to eat less. But most people don’t think like that and if they were to switch from cycling to an electric car they would maintain their habitual diets.

      If they then noticed that they were putting on the pounds, they’d probably up their exercise again and hit the gym, take up running, etc. and, as mentioned above, unless you’re planning to hook exercise bikes up to the grid then that’s just wasted energy.

      Like I say, I enjoyed the article, it’s a fun argument but ultimately grounded in a reality that doesn’t exist.

    • Damon Hart-Davis

      Ultimately Dale is right: doing more work has to use more energy from fuel (eg food), else you’ve invented a perpetual motion machine.

      The laws of thermodynamics are not optional, even if not always immediately obvious!



    • Rob

      In a pure fuel vs work done calculation I would agree.
      The human engine doesn’t work that way and adjusts calorie rate of burn subject to exercise and training. A ‘fat bastard’ eating 5000 calories a day and hardly moving will be ‘badly tuned’ compared to a ‘daily jogger’ who may well find he has a smaller appetite despite doing ‘more work’.
      If you’re looking for a mathematical reason beyone the ‘training’ one factor will be the lower resting heart rate for the guy doing the regular exercise leading to a more efficient ‘idle state’.

    • Justin Noe

      I guess we could add to this argument that a push bike will partialy harness energy already consumed whereas a car will simply require extra energy.
      It’s also worth noting that if the numbers are correct you’ll still release 9 extra Kilos of CO2 per year (if we’re splitting hairs!)
      I still think a electric car is better than a fossil fuel car. It’s certainly more fun than cycling but the choice is not over fuel effeciency.

    • Stuart

      Actually the the brownest form of travel is running. I costed out a new pair of Nikes every 1,000 miles (flown in from China?) before thinking of all the huff & puff.

      But it is a bit shortsighted to think of the energy/co2 emitted by the vehicle/cyclist/runner. One uses an extensive, costly infrastructure that needs constant renewal. The others don’t. And on this thesis all gyms should be shut, pathways closed and a free subsidised remote control given to the poor to avoid unnecessary movement.

      Indeed the NHS should be required to provide that complete cradle to grave care. Preferably in the same bed, fed on a minimal drip.

      Aha there we have it – the real co2 polluters are people – not cars, boats & planes. Tax ’em out of existance! Oh, I think the government is already trying 😉

    • John Morse-Brown

      Nice article Dale, but shouldn’t we be thinking more holistically here? What about the health benefits of cycling versus driving? What about road congestion? What about the space required to park a car?


    • Chris

      I know public transport has lots of support amongst ‘greenies’ for very good reasons. But I came across these figures on page 295 of ‘The Self Sufficient-ish Bible’ that you may be interested in.

      Figures are based on CO2/passenger for a 650k/400mile trip from London to Edinburgh. The flights are calculated using an RFI multiplier of 2. And I presume from these figures, they’ve only put one individual in the cars!

      Express Coach = 53Kg
      Hybrid (or small) Car = 68Kg
      Intercity Train = 73Kg
      Medium Car (2 Litre) = 129Kg
      Large Car (4.8 Litre) = 215Kg
      Plane = 339Kg

      Obviously that doesn’t take into account the damage of vehicle and infrastructure manufacture or disposal.

    • Jonny Holt

      Green-ness is not just a dry arithmetical calculation of calorific inputs. It is also a less easily accounted balance of benefits and encumberances, and their impact on health, culture and community.

      In these theoretical circumstances the food consumed by the bicyclist can be produced by the bicyclist. The power consumed by the electric (wind-powered) car is perhaps less likely to be the result of such a direct connection between producer and user. Control is surrendered to a corporation and responsibility is diluted. There is a lessened nobility in being dependant.

      Travelling by bicycle is healthy, self-reliant and generally is likely to foster more connection with the locality. The bicyclist might be more vulnerable but probably has a greater awareness of other road users as a result. Driving a car is a practical means of covering greater distances, can be more relaxing and allows an increased opportunity to be less parochial – meeting people from communities up and down the country. On the other hand the cocoon of a vehicle inhibits normal human interaction between travellers, who all become depersonalised in the minds of other road users.

      In the end it is horses for courses. I’m sorry – I have inadvertently introduced another, possibly greener, mode of transport into the debate ….

    • Adam Brown

      Hi Dale,

      This is all very interesting, but I don’t think that the comparison is complete enough. Suppose that I own both a bike and a car (as most people with bikes probably do). Then I get embedded carbon costs from both, which is clearly less green.

      Suppose instead that I don’t own a car. Then, it is very likely that the vast majority of the replacement of the mileage that I used to do in the car comes not from the bike, but from other forms of transport (public transport, taxis etc…). Furthermore, owning a car encourages discretionary driving. For instance, suppose that I want to buy lots of drinks. I live very near a small supermarket that I can walk to. But if I own a car, I will probably drive to the big out-of-town Tesco. Or suppose that I decide to have a picnic with my girlfriend. If I own a car, I will be less inclined to keep the event local, because the time costs of getting to other places are vastly reduced with respect to either using public transport or riding a bike to the picnic spot.

      The point is that it isn’t really fair to compare a bike mile-for-mile with a car, because the thing that really counts is the change in transport usage patterns that come with the decision to own or not to own a car. It is literally not a real-world scenario to say “all else being equal”, because it never would be.

      There are, of course, externalities that aren’t accounted for in this picture either. For example, by not owning a car, maybe I avoid spending a few grand on buying it, and then maybe a few thousand in running costs, insurance, tax and servicing every year. The money saved this way is likely (given human nature) to be spent on other goods and services. So I now find that I CAN afford that holiday in Bermuda after all…

      Added to which, any car that is bought ultimately contributes to the economic support of the car industry, and reduces the demand on public transport, thereby reducing the political pressure for its adequate provision. And buying a car and then NOT using it, your net carbon per mile becomes vastly greater, because the offsetting of the carbon costs inherent in its manufacture happens less quickly.

      In fact, you could almost go so far as to say that the contribution to carbon costs from buying anything is pretty much determined by the economic activity that the purchase creates. The only real way around this is a slow yet firm commitment to decouple economic activity from carbon emission, and not any personal decision that one person is liable to make.

    • Frosty

      Hello, Just found your site from a link posted on a peak oil forum.

      I was thinking about this topic myself a while ago.. In the end though it boils down to this. If cars (petrol / diesel) were to be replaced by electric or wind versions we would still have the social problems that are associated with private car transport now, i.e. road injuries, road infrastructure upkeep (as mentioned in an earlier comment), and living arrangements designed around cars as opposed to being ‘human scale’ again. I don’t know many people who would do a like for like commute on a bike as a car to get to work (although I once had to do a 35 mile round daily commute which was knackering to say the least!) and we’d have a better intergration of residential, work and leisure ‘zones’ if people were walking and cycling and unable to drive long distances any more. I know that all this is well without the realms of the argument but like other people have said, a full accounting aproach would need to be made in the comparision. For example, what are the current carbon costs on the health service due to people being unfit due to lack of excercise or from being hit by moving cars? What are the carbon costs of the renewal of road surfaces and potential new road building projects? What are the carbon costs of not having places of work near where people live thus forcing car usage or bike usage for a lot of people as opposed to being able to walk it? What’s the carbon costs of large scale supermarkets *still* having customers who can drive to their centralised shops putting other local producers at a disadvantage (so still enouraging the needless shipment of food over great distances). I am not sure all of this could be accurately measured or if anyone has the time for it but it’s a complicated afair, however, probably not what you’d intended for the comparison 🙂

      On the supermarket point, the bike would be far less of a carbon contributor if people were builing local organic fruit and veg over supermarket imported versions as the ratio of calories used in production and transport is far less for, say a local organic carrot than one thats been grown in a way that degrades the soil and then shipped through 300 miles of distribution channels 🙂 I know people are quoting the 10:1 calorie ratio for food in the US at the moment, so 100 calories of food used on a bike is actually 1000 (depending on your shopping habits) and a lot of that 1000 has come from fossil fuels. That’s why I get irritated by the greener than thou cyclists who still buy their food from Tesco 🙂



    • Gareth

      Many thanks for the update Dale.

      The paltry renewables obligation target for NI is upsetting, and there is no competition or green alternative to choose from, it’s good to hear that you are planning to enter the market now the door is open.

      This is very exciting news, not just for me, but I’m sure for many other people in NI. It will certainly garner media coverage in NI as you will be opening up the market, especially if you get in before SSE. You won’t be competing on price most likely, but a real alternative. Why buy just electricity, when you could buy new energy. I’d be glad to be the first domestic customer to sign on the dotted line.

      Good luck, with the application, I have no doubt you will easily get the licence, feel free to keep me informed about your progress.

    • Duncan

      This is a really silly argument although it’s always good to try and look at things from a different angle. You did make me think about food as fuel and the stats are interesting but you should probably concede defeat on the rest because your central point is way off. Never mind the carbon produced to make the raw materials for the car and the wind turbines, to ship them around the world and put them together, what about the man (and therefore fuel/food) hours required to build and maintain them? The people running the grid, mainting the roads, fixing the engines, attending to road accidents, printing speeding tickets. It’s not going to be even close to an extra 400 calories a day. It’s a nice thought experiment but for God’s sake don’t go round using this as a proper argument 🙂 Keep up the good work though, it’s much appreciated…

    • Randy

      Consideration of the lifetime carbon cost per mile is a good start. One could also factor in the health benefit of a given mode of transport. I bicycle because it’s fun and as noted by Baboonboy, bicycling has a health benefit. Could exposure to EMF’s from an electric car motors be unhealthy? Maybe a car could be made out of wood or recycled materials. The embodied energy of virgin aluminum it’s 191.0 and for recycled aluminum it’s 8.1

    • Paul

      A person driving a car is going to eat similar amounts of food to someone that cycles or maybe slightly less, plus they are going to be using electricity to power the car.

      eg. the cyclist world probably burn up the calories and stay slim, thus only requiring slightly more food intake. Where as the car driver would burn less calories and burn fuel or use stored energy in the car. In order to stay slim the car driver may go on extra journeys to the gym and use electric exercise machines, to get slim.

      Basically the calculations are not complete unless the food intake for both transport methods are included.
      There are significant consequences to using the car that have impacts on many things, this includes the closeness people live to their work place, the support cars give to the super market/ retail park system etc.

      The other point is that people that don’t have a car may very well not make a journey because it is less convenient or the weather looks bad etc.
      The convenience of a car can result (and actually does result) in unnecessary journeys being made.

    • Rob

      Randy – the AA did air quality survey work a few years back. The level of gaseous pollutants were 3 times greater IN cars than in the ambient air where a pedestrian or cyclist would be.
      Good job the ‘Wind Car’ is topless!!!

    • nommo

      Hmm.. shame Dale couldn’t get hold of a second hand Lotus Eco Elise to rip the ICE and power by wind.

      What if the car and the bike was made of mostly hemp and other low energy, carbon neutral materials. Wouldn’t the car then be storing more CO2 than the bike..?

      I like this thought experiment.

    • nommo

      Hehe – Rob – I do want a bike but not a cardboard one! 😉

    • Jeffrey Lam

      I really think we need to stop talking about eating food. It’s the CO2 emissions we are concerned with, not the food consumed, perhaps apart from the CO2 emissions caused in the manufacture, transport and preparation of the food. The CO2 is emitted at the point of use, so when you get on the bike and pedal (or whatever) that’s when the CO2 is emitted. How much (or how much more) you eat is then not that relevant, except for it’s effect on the rider’s weight.

    • Paul

      I think I misunderstood the original calculations made by Dale.

      But my other comments remain.
      IMO a (electric) car owner would have a bigger carbon footprint because the vehicle would offer greater conveniences and opportunities to use more energy.

      People commute long distances today because the technology enables them to.

      Really many of these statistics ignore human behaviour and desire. The carbon footprint of a car can look good if it is full of passengers, but appalling with just a driver.

      So the determining factor will be the use of the technology. If you fill a car up with passengers every time you drive it, you are running a bus service!

    • Ben

      A dizzying display of statistics and arguments aimed in the same rough area.

      I agree with most above, and think Paul (above) has a good point that are we talking about behaviour of our friends of a strange average of the population?

      People differ greatly and you may find people who drive their car to work (be it a wind car or not) may still go to the gym or ride a bike for fitness afterwards making the food element in the argument almost redundant unless you compare it to a mean average of the nations activities.

      The localisation of foods would obviously help still this problem and help greatly generally, but this is obviously a whole different kettle of fish which i won’t delve into now.

      I found the stats in ‘are cars greener than bikes?’ extremely interesting. If change is to take hold i still feel more media has to embrace the green issues and make a bigger effort to make statistics largely available, so we all can start making a lfestyle change, not just a shopping one.

    • Justin Noe

      This is a snippet from a recent New Scientist article:
      “Does switching from bus to bike really have any effect? After all, cycling isn’t completely carbon neutral because I’ve got to eat to fuel my legs.”
      “You are much better off cycling. A 12 kilometre round commute on a bus or subway train is reckoned to generate 164 kilograms of carbon per commuter per year. Somebody cycling that distance would burn about 50,000 calories a year – roughly the amount of energy in 22 kilograms of brown bread. A kilo of brown bread has a carbon footprint of about 1.1 kilograms, so switching from public transport to a bike saves about 140 kilograms of carbon emissions per year. Although this only really works if enough people cycle to allow public transport providers to reduce the number of buses and trains they run.”
      I realise the analogy is different to one one on this blog but there are parallels. Dale’s car will not be carbon neutral until the grid is mainly supplied by renewables. This could take a long time and a lot of tonnes of carbon.
      I still say bring on the electric supercar. Great blog Dale.

    • Sarah

      I was reading your blog with interest and intelligence, when I was suddenly struck by a blonde moment and thought you were discussing garages as in personal garages attached to houses. My thought was of course there will still be garages, where will everyone put those cast off plastic toys that our children must have and break in two minutes.

      More seriously, surely the point is, we must all do as much as we can and only public demand will drive forward change and change will take time, because the majority of people will either pretend that nothing’s wrong. The analogy of a traffic diversion springs to mind where people bowl along in the outside lane, pretending that they have failed to notice the signs and even if they have they could possibly apply to them and then try to barge in front to avoid waiting in the queue. Or, hope that others will do the right thing so that they wont have to. How many loaves of bread does it take to manufacture an electric car?

    • James

      You seem to be forgetting that food is biofuel. The precise carbon footprint would depend on exactly what you are eating and the agricultural production methods. A diet of vegetables, grains and fruit would be close to carbon neutral.

      Besides if you really want to compare, you would need to consider the environmental benefits and disadvantages of exercise and related longer life-expectancy (not guaranteed in cycling in London!) and perhaps fewer health care treatments and drugs, all of which have their own environmental impact.

      What this really demonstrates is the fallacy of reducing everything to carbon footprints. Both cycling and wind-powered cars are to be encouraged, but for the foreseeable future, cycling remains a more realistic prospect.

    • Paul

      Hi Dale:

      The Gym has replaced natural physical activities.
      People live less active lives, they drive cars, work in an office, stuff food they don’t need down their throats and then use a gym to compensate.

      The other point of course is that this all uses energy and costs money. The energy footprint and resource use is much bigger as a result of modern living. It is IMO pointless isolating one issue with cars, because there is a huge number of issues that have cascading negative impacts on other environmental issues. You only have to look at the way the US has developed as the result of the car, to see why there are problems.

      On the issue of food intake. Sure in theory people need more food to cycle etc.
      But in practice people eat just as much when they drive a car.
      I don’t see people buying less than me at the checkout just because they have a car.

    • Neil Law

      This is really interesting stuff.

      Re: diet.
      Until health played a hand and stopped me, I was a very active cyclist,and regularly used it for journeys (both for the pleasure of cycling AND to get to places) upwards of 80 miles. I found that I ate less than I did on non-cycling days. This was partly because I had less time spent on sedentary activities,when I would be more likely to snack just because I could, or maybe for something to do with my hands..I don’t know..but when cycling I tended to eat smaller amounts, because I wanted to get back in the saddle before my muscles cooled down too much. Also, when cycling regularly I think I was just more tuned in to my body ,so I was less likely to eat when my body didn’t need it. I would be more aware of feeling bloated if I over-ate. I still keep myself averagely fit as far as I can, but it doesn’t foster the same bodily awareness as the prolonged and regular activity of a cyclist who uses their bike both for pleasure and transport.

    • Robin Smith

      The efficiency of the human vehicle increases with use. The sedentary vehicle acquires a lot of baggage (fat). This baggage means that additional calories have to be consumed to support it. The active vehicle has a much superior heating system to the sedentary vehicle that is often kept indoors in front of an electric fire and 42″ television set. The 20st sedentary vehicle will generally consume more calories than the 12st cyclist. Therefore cycling is carbon negative because of savings made through increase in efficiency and outdoor use.