Are bikes greener than cars? That was the question tackled in a recent post. Looking at the issue from the perspective purely of energy used to travel – the results were a little counter intuitive to most of us I think.
The big thing not in those calculations was the embodied energy and therefore carbon in both cars and bikes. Many people on this site argued it needs to be taken into account, and I don’t disagree with that. The inference was, I think, that taking this into account the bike would have a way lower impact – that bit I wasn’t so sure of. I’ve pulled together some figures now.
The original numbers looked at the energy expended by the rider and driver respectively of a bike and a wind powered car – it was only energy used for travel and surprisingly the wind powered car had a smaller carbon footprint. Far smaller.
But that ignores the ‘cost to build’ of each vehicle. Let’s add that in now.
The best estimates we could find for the ‘carbon cost’ of building an electric car are 6 Tonnes. The cost for a bike a miserly 63 kilos. The cost for a conventional gas burning car BTW is 4 Tonnes. So the wind powered car produces a lot more carbon on day one.
It’s hard to imagine that with a virtually 6 tonne headstart the bike is ever going to catch up to the wind powered car in a lifetimes use – but let’s see.
The tricky bit coming next is the number of miles and the number of years to assume each is used for. Cars drive many more miles than bikes pedal, it’s in the nature of the beast, as someone said here because you can do more miles easily, you do.
The average lifespan of a car in the UK is 14 years, the average annual mileage is 9,800.
It might be fair to assume a bike can also last 14 years, it might not. But even if the bike had to be totally replaced, it’s only 63 kilos which is negligible in the scheme of this – so it doesn’t matter if the bike can match the car for lifespan or not.
What about annual mileage? Not so clear. So here’s two scenarios:
10 miles a day (typical bike use?) and 9,800 miles a year (typical car use).
At 10 miles a day for 14 years:
The cyclist racks up 4.7 Tonnes of lifetime CO2. Or 0.09 kg per mile.
The wind car driver racks up nearly 6.4 Tonnes. Or 0.13 kg per mile.
(The petrol car is over 21 Tonnes BTW)
That’s if you use a car like you might use a bike.
How about if you use a bike like you might use a car?
At 9,800 miles a year for 14 years:
The cyclist racks up 12.7 Tonnes of lifetime CO2 . Or 0.09 kg per mile.
The wind car driver 7 Tonnes of lifetime CO2. Or 0.05 kg per mile.
(Petrol car 51 Tonnes…!)
The kg per mile figure for the cyclist doesn’t really change because the embedded carbon cost is so small, it’s lost in the rounding. For the wind car it drops significantly with mileage.
Two things I’d stress here. Cars and bikes are not apples and apples. We use them differently. Cars enable bigger distances and more travel – we take that opportunity. The Wind car wins easily based on the car use scenario of 9,800 miles a year and the Bike wins easily based on the biking scenario of some 3,000 miles a year.
Hang on a minute though, at 9,800 miles a year, that’s roughly 30 miles a day – is that a crazy bike use scenario? I don’t know, but it doesn’t look off the scale.
Second thing to stress – these figures are for energy used by rider/driver and vehicle – and they include carbon embedded in the making of each vehicle. They don’t include hospitals and roads and stuff… (And no, I’m not going there next… 🙂
The answer is not what you’d expect I think. On a low use basis (for a car) the cyclist has about two thirds the impact of the wind car driver – better for sure but not exactly as massive a difference as you might have assumed. But on a car use scenario the wind car wins by a bigger margin – the cyclist has almost double the impact of the wind car.
The reason, I’m sure, is that human bodies are not anywhere near as efficient as electric motors – which are some of the most efficient machines we make. Our talents lie not in doing the work of machines but elsewhere… 🙂
PS – Here’s a thought – If wind powered cars were made using wind energy rather than fossil fuels (more than feasible in the near future), we could slash the embedded carbon figure for a wind EV by a couple of tonnes perhaps… and it would beat the bike in either mileage scenario. Just a thought.
From the perspective of a sustainable transport planner (and ecotricity customer!), I think there is a fundamental issue that you need to think about with this – the NEED to travel. Post-war planning policy was all about opportunity and economic growth and “you’ve never had it so good!” stuff. Consequently because the car was king, land use planning was not very local-living friendly. Hence people have developed lifestyles where they drive 20+ miles to and from work each day – and they see this as normal!
I am keen to explore the extent to which people actually LIKE travelling that distance – and would they prefer not to have to? I think increasingly there is evidence that they would, if they could, like to turn the clock back a bit. If we drew a line under road-builidng – and stopped doing it, just hypothetically, how would that change the way we live?
I reckon over time people would re-adjust – they would seek jobs more locally, consider their quality of life more. I wonder if the side effect of the credit crunch and the house price crash is that people will be able to afford to live closer to where they work – and we should perhaps have policies that reinforce and respond to that aspiration.
I think we need to start planning for the outcomes that we want to see – not planning only for the worst case scenario. We need a better recognition that what we plan for, we usually get – plan for unsustainable trends to continue – in case they do, and they surely will!
Recently I’ve been working on some principles associated with trip purpose – why do people travel? I reckon it comes down to three things – there are “economic trips” – those are ones that we do at work, or lorries carrying goods, then there are “life affirming trips” – these are ones we have to do to function in society – go to work, go to school, buy food, that sort of thing. And then there are the third type – the “discretionary trips” – which are the ones we only make because we can afford to.
I reckon people – individuals, have an over-whelming desire to make their “life affirming trips” as brief, efficient and cheap as possible – and policy needs to catch up and provide the means for them to do so. Which would mean more people using the bike, or Shanks’ Pony, because they could.
Interesting points and as an engineer I’m always open to ‘doing the numbers’ to come closer to truth as rather than relying on supposition. However, good engineering relies on good assumptions and the right frame of reference. That’s where you have gone wrong here.
People do not eat food ‘efficiently’ (ie. eating more to do a daily bike commute as opposed to a basic calorie intake). Instead, in the developed world, we eat far more calories than we need (you only need to look at the obesity stats to know that) and thus convert food to work or waste with varying overall efficiency (witness the results of eating a large curry meal). Perhaps what you’re saying is that in a future carbon limited world we need to limit our food consumption, but I don’t think that rationing is anywhere near reality!
So, instead what you are actually doing when riding your bike as an average person is increasing efficiency by letting less food go to waste and getting more work out of a meal.
The other problem is that to look at this as a pure carbon problem leads to ignorance of broader sustainability issues in a similar way as has happened with 1st generation biofuels. We miss the incredible health benefits of cycling and its potential assistance with the obesity problem. We leave out the debilitating effect on the economy of road congestion caused by cars. We forget the environmental impact of loss of habitat from building roads.
Don’t get me wrong, I love what you are attempting with the wind car and I agree electrified transport and electric cars in particular are part of the solution. There are also other sustainability positives to the electric car – increased mobility is good for the economy. But you must recognise that sustainability means thinking in terms of horses for courses and your frame of reference needs to be right.
A bike is a great sustainable solution for a 10 mile return commute, but you are not going to go from London to Birmingham on a bike in a day for a meeting (your 30 miles per day scenario is definitely unrealistic for most people on bikes). You instead need to compare your car to realistic competitors (the train or the bus).
Finally I think the biggest problem with you presenting your numbers in this way is providing fodder for the Clarkson’s of this world who spout crap statistics to justify their recalcitrant world view. This in turn can damages progress towards sustainable solutions.
In the modern era there has been far too much spent on road infrastructure by governments at the expense of sustainable transport solutions. The chronic underinvestment in bike and public transport infrastructure for so many years has lead the UK to its current position where the infrastructure fails to cope with demand and provides no incentive for people to make the right choice. Instead people are lead towards the carbon intensive single occupancy car that dominates the country and gives us such a large part of our current carbon problem.
I agree with Will. It’s a good thing you are devoted to developing less harmful cars, but arguing that they are better than bikes is one step too far and undermines your credibility.
Much more important than substituting gasoline powered cars for electric cars is substituting the car alltogether, for the bike (short distances) and the train (long distance).
I’m not a car owner, and I’m not a petrol head, but there are occasions where the car is the right thing to use to get a legitimate job done, and in that case having a superior alternative to the ICE is a good thing.
For example, rural journeys with goods to carry where population density is of necessity too low for much public transport, especially train, to be viable for much or all of the journey. For example, what is my farmer aunt in the country a couple of miles from the nearest (poorly-served) bus stop meant to do when she gets ill or needs to get some substantial shopping? Or take produce to market?
Currently there are occasional journeys (such as an annual visit to my aunt!) where I hire an ICE. I’d much rather hire an EV and the range is doable. But my local car-hire companies don’t have any EVs presumably because they are currently too expensive and ‘weird’.
Cars continue to be a fantasticly liberating mode of transport for many people, so if we can ditch much of the environmental badness that currently goes with them, all to the good.
Rgds
Damon
I have not read a piece that I agree with more on this blog than Will’s comment, above. Far too much emphasis is placed on individual modes of transport rather than communal methods. For example the whole of the South East runs on electrified railways- think of the decrease in carbon kg/mile/person if these were powered by renewable sources. Similarly London Underground (who I believe do currently use a “green” tariif – whether it is a true green tariff or a greenwash tariff I’m not sure)provide a remarkably environmentally sound method of transport if measured using the carbon kg/mile/person comparison.
Essentially my point is that sustainability lies in co-operation and community and that economies of scale are true in terms of energy efficiency as well as finance, so I think that the practical application for an electric 2 person (small adults too, if the original Lotus Elise is anything to go by) sports car is limited.
Well this topic certainly seems to create much discussion. I am one of those cyclists who endures morning rush hour and wished he could one day sit in the warm comfort of his EV during winter months.
Yes sustainability is an issue but I do worry that too much socialist rhetoric may lead on to a “Logan’s run” style population control discussion!
Cars are fun and sportcars are a child’s dream so I guess what I’m saying is we should push for evermore eco friendly ways of realising those dreams.
I hope that this is just the beginning and that future EVs may actually become good for the environment. Keep up the good work Dale but don’t pick on us poor cyclists too much! We can’t help breathing out all that horrible CO2.
Not a petrolhead, a naturehead. I’ve got a bike but need the car, living in a very remote area of countryside. As Will said – chronic lack of infrastructure and any proper planning for bike users – that’s the problem. When a city dweller the bike was fine!
I’m waiting for electric cars to get longer range – And it would be charged on Ecotricity of course!
On the farm I work at we’ve got electric buggies already doing this – the battery technology is what lets us down. Ever seen the film – “Who Killed the Electric Car?” ?
Finally – calm down, cyclists – Zero’s obviously NOT arguing against bikes. He’s just shown us some useful arithmetic!
Well, now I’m ashamed, even during high school I never did more than 19 miles per day, and that was just some 50 minutes worth of driving.
But anyway, I found these numbers very interesting, certainly surprising, specially in a way that, if you carpool the number goes way up in the favor of the car. But we’re also talking air powered and electric cars, i.e. vehicles which will require new infrastructure, refitting of factories, advanced technology. Bikes on the other hand are unlikely to get any better, nor do they have to.
Also, (and this is just an observation, not an accusation), you keep referring to this problem as ‘being greener’ than something else. That should account for way more than just carbon I think. What about the titanium compounds that end up on the side of the road from catalytic converters, the size (and number) of the tires one has to go through during those 14 years. All the other fumes we endure in the cities because its ram packed with cars. The very size of the cars, for which (at least in my city) there are already seldom places one can park, and none of them are unobtrusive for pedestrians, and cyclists. Add to that the infrastructure of new garages and parking lots, pavements, the damage done after car accidents which also has to be sanitized plus injury treatments and petrochemical byproducts in medication that are used and….I’ve gone way off, but my point is:
interesting as it may be to see how inefficient our bodies are compared to the marvels of technology we produced, I hardly think that anything human powered, weighing less than a decent computer case, can be considered less green.
But that’s just me, and don’t take it as I said, as an accusation, it’s merely an observation, from a student of design who is terribly worried what the hell he should do in his working life…
Nice. Dale thank you for doing these calculations. What if all workers and projects have a waste footprint too? Have you factored the per worker and per vehicle waste unit into your building process? Here is some of my thinking about this from a few years ago.
………
Social Sustainability Factoring
Carbon Footprint (Home) + Waste Footprint (H)
+
Carbon Footprint (Work) + Waste Footprint (W)
= PSQ (Personal Sustainability Quotient)
LEED Building Rating + PSQ(x)
= TSQ (Total Sustainability Quotient)
x=number of people in your business
There are many issues regarding electric cars that people do not realize. A great site covering these is http://www.ElectricCarSociety.com which also tell you how to build your own electric car.
Thanks Will. The idea behind the stats was a simple ‘laws of physics’ look at what it takes to get around in cars and on bikes – really just to highlight that biking is not free to the planet, work has to be done and paid for (in food and carbon).
The simple figures are the bare bones. if you cycle once now and then you won’t probably feel any hungrier or notice a different diet, but if you did it every day you would – it’s inescapable. I’m saying a mass switch to biking would trigger a rise in food consumption and carbon – that’s inescapable too. Likewise there would be a rise in fitness, health and happiness – and that may well outweigh the adverse impacts.
I am for sure, as Naturehead says – not arguing against bikes. I think they make sense.
Just trying to show a more whole picture, which I think becomes relevant when discussing or envisioning a mass switch from cars to cycling. Cycling 25 miles costs 1,000 calories (just to use round numbers), if we all did that once a day (assuming it was over and above what we all normally do), the nations calorie consumption would rise maybe 25%. And one of the big issues we will face in the near future is having enough food to feed ourselves. A mass switch to cycling would exacerbate that problem. Just a perspective.
I read this book once, Sci-Fi, can’t remember the title, but it was set in a world where energy was scarce to the extent that people had to control how fast they moved around – to conserve energy (calories). It was a compelling story.
Cheers.
Thanks Justin, you’ve a good point there if I read it right – we need solutions for the future that will be fun, that’s what we’re trying to do/show with our car (which is what lead me to talk ‘cars v bikes’). My message with regards bikes though may have been slightly lost in the translation, I’m so def not against cyclists – all power to your pedals… 🙂 Cheers.
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Thanks Naturehead. I think the city/country split in terms of how useful (or essential) cars/bikes/public transport are, might well explain some of the different views expressed here. I live in the country and without thinking about it or saying it, my views are based very much on my experience of transport, it’s about where I live and how transport works here. That’s def a factor in why I see the need for cars. Cheers.
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Thanks Igor, all taken in the best possible way… 🙂 And appreciated. Cheers.
Thanks for this Randy. We only used the calories of the driver and rider and typical carbon contents based on typical diets – no deeper down the chain than that. It’s really to illustrate that there are ‘hidden costs’ things we often overlook or assume are free – in this case cycling. Cheers.
“It’s really to illustrate that there are ‘hidden costs’ things we often overlook or assume are free – in this case cycling.”
hmmm… Actually Dale, me think thou dost protest too much. When I first read this and looked at the dodgy maths I was amazed and had to check the date, thinking this was an April fools joke. On realising it isn’t I sat perplexed as to why someone such as yourself would be persisted with this line of BS…. Then it occured to me why… You are copping flak over the car building thing, aren’t you?
All your green chums (the vegan type rather than we somewhat more pragmatic treehuggers) have turned therir heads in shame at you and you have felt the need to defend your electric car for tools…
Its OK, Dale, most of us forgive you 🙂
Hi Gavin, close but not quite. The spark for this post was actually Peter Pannier (he used to post here, where did he go…?) telling me I
shouldn’t be supporting the car industry as bikes were the answer.
That’s where this grew from. Really it is just a simple point being made, there’s no free lunch.
Not sure what you mean by dodgy maths, I’d be happy to have some elaboration from you on that, the maths is (as I understand it) spot on.
Cheers.
You keep calling it a wind powered car and it’s not really.
I have an idea for a wind powered car but looking at the progress you have made it would be impossible to implement into the design that you have already developed.
Your car looks great though. Hope it proves as efficient as you desire and that it gets into production.
I guess it’s technically not powered by the wind itself… but it’s a shorter name than “electric vehicle charged from a house that uses electricity produced by wind turbines”
;o)
Hiya Tom.
Ah yes – we do get that a lot. People expect ‘wind-powered’ to mean a ‘normal’ car, but directly powered by a vehicle mounted wind turbine… sadly that is not possible with our current understanding of physics… 🙁
‘Wind power’ generally involves converting the rotational energy from the wind blown blades into electricity, which is regulated, then either stored in a battery and inverted before being sent to power a device, or is sent direct to the grid for distribution. It is still wind power though.
If you want to see a literal example of a wind powered car (as in – no electrical storage, conversion, transmission shenanigans between the wind and the power to drive) then check out one of Ecotricity’s other projects – the record breaking Greenbird, which still pushes the laws of physics to the limits…
Thanks for dropping by,
Cheers
Paul
Hi Guys, quick thought from me on this one – I believe it is right to call this a wind powered car. Electricity after all is not a ‘source’ of power it is a ‘medium’ And it’s not enough for us all to switch to electric vehicles – that of itself is only a partial answer, the electricity has to come from somewhere – it can’t continue to come from fossil fuels.
Calling this car wind powered is about skipping to the end of the debate – where the power actually has to come from, electricity is a way to carry the power, wind is the source of it.
Cheers.
Yeah!!! Hopefully the Nemesis is the start of the future!
And the matt black paint job is seriously cool :o)
Is it true that Nemesis is going to be re-painted?
I think the idea is to paint it in the green union jack colours eventually (suck on that EDF). But for now its in the traditional matt black of top secret concept cars!