Is cycling anywhere near as green as it could be ?

[SkipdiverJohn]

Cycling can be very green, or not green at all, depending how you do it.. My sort of cyclling, using old secondhand steel bikes, salvaged spare parts, and quite often, even secondhand tyres and tubes is as green as any activity involving manufactured products can be.
On the other hand the upgrade-obsessed carbon fibre brigade who keep chopping and changing their bikes and components every five minutes, often renew cycling-specific clothing, run flimsy road tyres then bin them after a few hundred miles because there's a cut in the outer casing, aren't in any way green at all. Their resources footprint might even be worse overall than someone who buys an old secondhand banger of a car, keeps it for years, and doesn't replace it until it stops working.
One of the most bizarre things is the concept of getting on an aeroplane, with a bike, then flying hundreds if not thousands of miles just so they can ride that bike in a foreign country, then getting on another plane and travelling several hundreds or thousands more miles back. And some of these clowns who fly abroad for their cycling jollies will be the same people moaning about motorists at home causing pollution!

 

[Illaveago]

You don't have to buy a bike every several years just because it isn't the latest model . A couple of my bikes are at least 70 years old , they were 2nd hand. A couple of my other bikes would have ended up being put out for the dustmen if I hadn't taken them , another one was found dumped in some brambles. They have been put back into use with the minimum of new parts . A new inner tube, cables, some loose bearings and grease. They don't have the latest equipment but they can be repaired easily and a lot of the components are interchangeable and can be found 2nd hand.
I suppose it stems from being brought up in the 50's and 60's from the make do and mend era.

 

[Drago]

In terms of miles travelled for energy / calories expended, cycling is far more efficient.


Even taking into account the embodied energy of the bicycle.

That oft quoted tidbit is tosh.

A typical, workaday, moderaltely lightweight bicycle frame weighs 2kg. 2kg of aluminium requires 15,000 Wh of electricity per Kg.

Petrol is 454Wh per gallon.

A typical petrol car will easily achieve 50MPG.

So in terms of energy expensiture, that 15,000 Wh to create 1Kg of alumiunium is equivalent to 22,000 miles of car travel. So the energy required to manufacture a 2Kg frame would power a car for 44,000 miles, and thats to just for the basic raw material, never mind drawing into tubes, hydroforming, welding, etc.

44,000 miles equivalent of energy, just to make the raw billet metal required to manufacture a frame.

Chuck in the energy required to manufacturer everything else required to make a bicycle, transport them from elsewhere across the globe to the bike factory, and you're looking at an energy expenditure that would power a car for the thick end of one hundred thusand miles. And thats before the bike has even travelled a single metre with a rider on it.

So when people trot out this stuff about cycling being mpre energy efficient than walking, even when accounting for the energy required in its manufacture, theyre talking out of their behind. The maths don't lie.

 

[SkipdiverJohn]

@Drago, also consider most bikes will only transport one rider, whereas most cars are capable of carrying four or five people. The bottom line is it all depends how many miles a particular mode of transport can cover during it's total life cycle, and how fully utilised it is during those miles.

 

[Lovacott]

Not many people buy a new car, drive it only 10 miles, then take it to the tip a few years later, when it's taking up space in the garage.

My local tip sells the bikes on so they end up doing more than ten miles.

Probably the worst offender is the latest fitness device as seen on the shopping channel. Most get to spend many years tucked under the bed before being chucked out with the household waste on Tuesday.

 

[mudsticks]

That oft quoted tidbit is tosh.

A typical, workaday, moderaltely lightweight bicycle frame weighs 2kg. 2kg of aluminium requires 15,000 Wh of electricity.

Petrol is 454Wh per gallon.

A typical petrol car will easily achieve 50MPG.

So in terms of energy expensiture, that 15,000 Wh to create 1Kg of alumiunium is equivalent to 22,000 miles of car travel. So the energy required to manufacture a 2Kg frame would power a car for 44,000 miles, and thats to just for the basic raw material, never mind drawing into tubes, hydroforming, welding, etc.

44,000 miles equivalent of energy, just to make the raw billet metal required to manufacture a frame.

Chuck in the energy required to manufacturer everything else required to make a bicycle, transport them from elsewhere across the globe to the bike factory, and you're looking at an energy expenditure that would power a car for the thick end of one hundred thusand miles. And thats before the bike has even travelled a single metre with a rider on it.

So when people trot out this stuff about cycling being mpre energy efficient than walking, even when accounting for the energy required in its manufacture, theyre talking out of their behind. The maths don't lie.

Interesting figures, thanks.
There is also of course time efficiency to factor in as well..

I wouldn't have got to the shops in time to get trifle ingredients this avo, if I'd walked rather than ridden, and then I would have been in trouble...

And of course theres the amount of food we require to pedal, rather than walk a given number of miles.

Certainly we need to keep using our bicycles pretty much forever, and then recycle all the materials at the end, as far as is possible .

Apparently aluminium is endlessly recyclable.

And we need to stop buying new ones, or new 'stuff' all the time.

Of course your figures vis s vis running a car over a certain number of miles with X amount of fossil fuel energy, don't take into account the embodied energy of making that car either.

Nor the energy required to extract those fossil fuels in the first place.

Stats can be slippery things, depending on what you count in, or out..

 

[Lovacott]

And of course theres the amount of food we require to pedal, rather than walk a given number of miles.

It's the amount of food we throw away which is of greater concern.

6.7 million tonnes of perfectly edible food goes to waste in the UK every year because people buy more than they can eat. This is in spite of the fact that we now all have fridges and freezers to help us prolong food life.

 

[presta]

Cycle
Energy use cycling at 12mph: 7 METs = 490 kcal/hr (70kg rider) = 41 kcal/mile (Ref. 1)
CO2 Emissions from food production: 2.63 g/kcal (Ref. 2)
CO2 Emissions producing cyclist’s food: 107 g/mile

Car
Average CO2 emissions of a new car: 200 g/mile (Ref. 3)
Alternative fuel vehicles are typically 45% lower emissions: 110 g/mile
Energy use driving: 2 METs = 140 kcal/hr (70kg driver) = 4.7 kcal/mile at 30mph
CO2 Emissions producing driver’s food: 12 g/mile
Total emissions: 122 g/mile

Ratio of cycling emissions to greenest car emissions: 107/122 = 88%

References
1. Biometric data, University of South Carolina
http://prevention.sph.sc.edu/tools/docs/documents_compendium.pdf
2. Agricultural Emissions
http://shrinkthatfootprint.com/food-carbon-footprint-diet
3. Vehicle emissions SMMT
http://www.smmt.co.uk/co2report/

 

[mudsticks]

It's the amount of food we throw away which is of greater concern.

6.7 million tonnes of perfectly edible food goes to waste in the UK every year because people buy more than they can eat. This is in spite of the fact that we now all have fridges and freezers to help us prolong food life.

Yup.

And don't get me started on the tonnes of food that doesn't even make it to the 'super' market, because it's deemed unsightly in some way..

 

[Edwardoka]

That oft quoted tidbit is tosh.

A typical, workaday, moderaltely lightweight bicycle frame weighs 2kg. 2kg of aluminium requires 15,000 Wh of electricity per Kg.

Petrol is 454Wh per gallon.

A typical petrol car will easily achieve 50MPG.

So in terms of energy expensiture, that 15,000 Wh to create 1Kg of alumiunium is equivalent to 22,000 miles of car travel. So the energy required to manufacture a 2Kg frame would power a car for 44,000 miles, and thats to just for the basic raw material, never mind drawing into tubes, hydroforming, welding, etc.

44,000 miles equivalent of energy, just to make the raw billet metal required to manufacture a frame.

Chuck in the energy required to manufacturer everything else required to make a bicycle, transport them from elsewhere across the globe to the bike factory, and you're looking at an energy expenditure that would power a car for the thick end of one hundred thusand miles. And thats before the bike has even travelled a single metre with a rider on it.

So when people trot out this stuff about cycling being mpre energy efficient than walking, even when accounting for the energy required in its manufacture, theyre talking out of their behind. The maths don't lie.

Gonna need some sources for those numbers, because being a worthless nerd with nothing going on in my life I had to check, because the numbers did not ring true at all.

My sources suggest that petroleum has 1.3*10^8 joules per gallon which, when converted to watt hours, is ... 36111.1r Wh, and not, for instance, 454Wh. Indeed, those USians with their weird units like cups and sticks also have a unit called the Gallon of Gasoline Equivalent, where 1 GGE = 37kWh.

If you've got that wrong, what else have you got wrong?

Further, the energy conversion efficiency between chemical and kinetic energy of a petrol car is somewhere between 18% and 35%.

0/10 see me after class.

 

[BoldonLad]

There are a lot of claims of efficiency / greenness (is that a word?), with an absence of links to sources, and/or "in my opinion" disclaimers, in this thread.

 

[Ming the Merciless]

That oft quoted tidbit is tosh.

A typical, workaday, moderaltely lightweight bicycle frame weighs 2kg. 2kg of aluminium requires 15,000 Wh of electricity per Kg.

Petrol is 454Wh per gallon.

A typical petrol car will easily achieve 50MPG.

How many kg of aluminium in a car?

 

[Edwardoka]

There are a lot of claims of efficiency / greenness (is that a word?), with an absence of links to sources, and/or "in my opinion" disclaimers, in this thread.

My sources:
https://www.ocean.washington.edu/courses/envir215/energynumbers.pdf
https://en.wikipedia.org/wiki/Gasoline_gallon_equivalent
https://x-engineer.org/automotive-e...gines/performance/fuel-conversion-efficiency/

 

[Ming the Merciless]

Cycle
Energy use cycling at 12mph: 7 METs = 490 kcal/hr (70kg rider) = 41 kcal/mile (Ref. 1)
CO2 Emissions from food production: 2.63 g/kcal (Ref. 2)
CO2 Emissions producing cyclist’s food: 107 g/mile

Car
Average CO2 emissions of a new car: 200 g/mile (Ref. 3)
Alternative fuel vehicles are typically 45% lower emissions: 110 g/mile
Energy use driving: 2 METs = 140 kcal/hr (70kg driver) = 4.7 kcal/mile at 30mph
CO2 Emissions producing driver’s food: 12 g/mile
Total emissions: 122 g/mile

Ratio of cycling emissions to greenest car emissions: 107/122 = 88%

References
1. Biometric data, University of South Carolina
http://prevention.sph.sc.edu/tools/docs/documents_compendium.pdf
2. Agricultural Emissions
http://shrinkthatfootprint.com/food-carbon-footprint-diet
3. Vehicle emissions SMMT
http://www.smmt.co.uk/co2report/

Now the problem I have with this is that it assumes those who chose to mostly cycle eat more than those who mostly drive. In my view this isn’t true, they broadly consume the same amount of calories. It’s just that one burns the calories whilst one lays them down as fat.

One essentially shifts their body weight plus between 10-15kg extra. One moves themselves and around 1,700kg extra. Guess which one is more energy efficient and therefore somewhat greener.

 

[Edwardoka]

Cycle
Energy use cycling at 12mph: 7 METs = 490 kcal/hr (70kg rider) = 41 kcal/mile (Ref. 1)
CO2 Emissions from food production: 2.63 g/kcal (Ref. 2)
CO2 Emissions producing cyclist’s food: 107 g/mile

Car
Average CO2 emissions of a new car: 200 g/mile (Ref. 3)
Alternative fuel vehicles are typically 45% lower emissions: 110 g/mile
Energy use driving: 2 METs = 140 kcal/hr (70kg driver) = 4.7 kcal/mile at 30mph
CO2 Emissions producing driver’s food: 12 g/mile
Total emissions: 122 g/mile

Ratio of cycling emissions to greenest car emissions: 107/122 = 88%

References
1. Biometric data, University of South Carolina
http://prevention.sph.sc.edu/tools/docs/documents_compendium.pdf
2. Agricultural Emissions
http://shrinkthatfootprint.com/food-carbon-footprint-diet
3. Vehicle emissions SMMT
http://www.smmt.co.uk/co2report/

Something irked me about this and it took me a while to realise what it was. You can use this methodology to state that:
a) someone who doesn't move emits infinity grams of CO2 per mile (or rather, undefined grams)
b) someone on the ISS (also burning 140 kcal/hr) burns 0.00817279626 kcal/mile and thus the CO2 emissions from producing their food is 0.02149445416 g/mile

The answer to a) is meaningless and the answer to b) while technically correct, ignores the vast number of externalities involved in putting a 70kg human and their food into low earth orbit.