Is cycling really carbon-efficient?

This question, which I don't remember us discussing beyond the
presumption that it must be, is from Les Cargill, a regular over on
AGA. I thought it worth a thread of its own. -- AJ

******

You might be able to answer a question for me, though: when somebody
rides a bike for a mile, flat and level, just keeping an even pace
that's highly sustainable ( as in "for transportation purposes" type
pacing) what is the *total* carbon emitted? Counting
back all the way to the beef in the McDonalds he ate, the grain used
to feed the cow, the energy consumed growing that, the truck that
carried all that, all that.

I will bet that a little 100W to 500W gasoline motor that does pedal
assist emits less CO2 than the person pedalling, but it's a big
calculation, and I haven't done it. I thought maybe you had
seen somebody who has. And I will bet than an aircooled engine like
that, so long as the exhaust gas temperature is high enough, could
beat human muscle power for efficiency.

But somebody who grows their own potatoes might be able to beat that.

--
Les Cargill

On Fri, 27 Nov 2009 09:03:30 -0800 (PST), Andre Jute
wrote:

This question, which I don't remember us discussing beyond the
presumption that it must be, is from Les Cargill, a regular over on
AGA. I thought it worth a thread of its own. -- AJ

******

You might be able to answer a question for me, though: when somebody
rides a bike for a mile, flat and level, just keeping an even pace
that's highly sustainable ( as in "for transportation purposes" type
pacing) what is the *total* carbon emitted? Counting
back all the way to the beef in the McDonalds he ate, the grain used
to feed the cow, the energy consumed growing that, the truck that
carried all that, all that.

I will bet that a little 100W to 500W gasoline motor that does pedal
assist emits less CO2 than the person pedalling, but it's a big
calculation, and I haven't done it. I thought maybe you had
seen somebody who has. And I will bet than an aircooled engine like
that, so long as the exhaust gas temperature is high enough, could
beat human muscle power for efficiency.

But somebody who grows their own potatoes might be able to beat that.

Simple efficiency boost: Eat the drivers of foreign-made SUV's and
factor in future savings. Better yet, have welfare bums as an
appetizer and turn Algore into soup.

No there's a reduction in hot air!

On Nov 27, 11:03*am, Andre Jute wrote:
This question, which I don't remember us discussing beyond the
presumption that it must be, is from Les Cargill, a regular over on
AGA. I thought it worth a thread of its own. -- AJ

******

You might be able to answer a question for me, though: when somebody
rides a bike for a mile, flat and level, just keeping an even pace
that's highly sustainable ( as in "for transportation purposes" type
pacing) *what is the *total* carbon emitted? Counting
back all the way to the beef in the McDonalds he ate, the grain used
to feed the cow, the energy consumed growing that, the truck that
carried all that, all that.

I will bet that a little 100W to 500W gasoline motor that does pedal
assist emits less CO2 than the person pedalling, but it's a big
calculation, and I haven't done it. I thought maybe you had
seen somebody who has. And I will bet than an aircooled engine like
that, so long as the exhaust gas temperature is high enough, could
beat human muscle power for efficiency.

But somebody who grows their own potatoes might be able to beat that.

--
Les Cargill

You're assuming that CO2 is somehow a bad thing.

RickH wrote:
On Nov 27, 11:03 am, Andre Jute wrote:
This question, which I don't remember us discussing beyond the
presumption that it must be, is from Les Cargill, a regular over on
AGA. I thought it worth a thread of its own. -- AJ

******

You might be able to answer a question for me, though: when somebody
rides a bike for a mile, flat and level, just keeping an even pace
that's highly sustainable ( as in "for transportation purposes" type
pacing) what is the *total* carbon emitted? Counting
back all the way to the beef in the McDonalds he ate, the grain used
to feed the cow, the energy consumed growing that, the truck that
carried all that, all that.

I will bet that a little 100W to 500W gasoline motor that does pedal
assist emits less CO2 than the person pedalling, but it's a big
calculation, and I haven't done it. I thought maybe you had
seen somebody who has. And I will bet than an aircooled engine like
that, so long as the exhaust gas temperature is high enough, could
beat human muscle power for efficiency.

But somebody who grows their own potatoes might be able to beat that.

--
Les Cargill

You're assuming that CO2 is somehow a bad thing.


Consider it a working assumption. What I'd like to know is: does
cycling always beat driving a car so far as oil use goes?

Kinda figgered maybe cyclist would have found some work
somebody else has done that would say yea or nay.

I remember a thing James Burke did where he accounted for the
energy used by a Tour de France cyclist, and 90% of the energy went into
bucking the wind.

Don't make me ask Mythbusters.

--
Les Cargill

In article
,
RickH wrote:

On Nov 27, 11:03*am, Andre Jute wrote:
This question, which I don't remember us discussing beyond the
presumption that it must be, is from Les Cargill, a regular over on
AGA. I thought it worth a thread of its own. -- AJ

******

You might be able to answer a question for me, though: when
somebody rides a bike for a mile, flat and level, just keeping an
even pace that's highly sustainable ( as in "for transportation
purposes" type pacing) *what is the *total* carbon emitted?
Counting back all the way to the beef in the McDonalds he ate, the
grain used to feed the cow, the energy consumed growing that, the
truck that carried all that, all that.

I will bet that a little 100W to 500W gasoline motor that does
pedal assist emits less CO2 than the person pedalling, but it's a
big calculation, and I haven't done it. I thought maybe you had
seen somebody who has. And I will bet than an aircooled engine like
that, so long as the exhaust gas temperature is high enough, could
beat human muscle power for efficiency.

But somebody who grows their own potatoes might be able to beat
that.

-- Les Cargill

You're assuming that CO2 is somehow a bad thing.

And that the laws of thermodynamics have been repealed. Jeez, Andre the
Troll is slipping. We've already had this discussion a few dozen times.
What an idiot.

In article
,
Norman wrote:

On Nov 27, 2:17*pm, RickH wrote:
On Nov 27, 11:03*am, Andre Jute wrote:





This question, which I don't remember us discussing beyond the
presumption that it must be, is from Les Cargill, a regular over
on AGA. I thought it worth a thread of its own. -- AJ

******

You might be able to answer a question for me, though: when
somebody rides a bike for a mile, flat and level, just keeping an
even pace that's highly sustainable ( as in "for transportation
purposes" type pacing) *what is the *total* carbon emitted?
Counting back all the way to the beef in the McDonalds he ate,
the grain used to feed the cow, the energy consumed growing that,
the truck that carried all that, all that.

I will bet that a little 100W to 500W gasoline motor that does
pedal assist emits less CO2 than the person pedalling, but it's a
big calculation, and I haven't done it. I thought maybe you had
seen somebody who has. And I will bet than an aircooled engine
like that, so long as the exhaust gas temperature is high enough,
could beat human muscle power for efficiency.

But somebody who grows their own potatoes might be able to beat
that.

-- Les Cargill

You're assuming that CO2 is somehow a bad thing.

Actually, I think it's a decent proxy for energy efficiency. Except
that automobiles also emit H2O as a combustion byproduct. & lots more
CO, and Nitrogen-based irritants. & soot*. So I guess what I'm
trying to say is that it's a pretty ****ty proxy for energy
efficiency. Actually.

Waste heat is a much better proxy for efficiency. An engine in a
typical car probably produces more waste heat in a mile than a cyclist
does in 50.

On 2009-11-27, Les Cargill wrote:
[...]
Consider it a working assumption. What I'd like to know is: does
cycling always beat driving a car so far as oil use goes?

For energy use, I'd be surprised if cycling ever used more. The human
body considered as an engine is about 25% efficient, cars are maybe 30%.
But a car is so much bigger and heavier and has much squishier tyres,
you use much more energy to go anywhere in it.

As for oil use, well it depends, but a cyclist doesn't have to use any
oil at all except a few drops on the chain.

On the other hand if you ride less than about 5 miles to work and then
take a hot shower lasting more than about 5 minutes that you wouldn't
otherwise have, you're probably using more energy than if you'd driven
in the car.

Ben C wrote:
On 2009-11-27, Les Cargill wrote:
[...]
Consider it a working assumption. What I'd like to know is: does
cycling always beat driving a car so far as oil use goes?

For energy use, I'd be surprised if cycling ever used more. The human
body considered as an engine is about 25% efficient, cars are maybe 30%.
But a car is so much bigger and heavier and has much squishier tyres,
you use much more energy to go anywhere in it.


Right. I couldn't agree more. Now, what about the cost ( ostensibly in
units of energy ) of the muscle power to power the bicycle. IOW,
how many "miles per gallon" (of milk) to propel a bicycle, and what's
the to-the-metal cost of that in oil?

Suppose a ride costs exactly one McDonald's Quarter Pounder ( 420
calories ) . What is the total oil energy input into one Quarter
Pounder?

As for oil use, well it depends, but a cyclist doesn't have to use any
oil at all except a few drops on the chain.


The cyclist consumes other things to ride that bike. In our culture,
those things consume oil.

On the other hand if you ride less than about 5 miles to work and then
take a hot shower lasting more than about 5 minutes that you wouldn't
otherwise have, you're probably using more energy than if you'd driven
in the car.

Odd, because my electric bill when I don't run the A/C or heat
for a month is roughly about that of a a tank of gas for the car - call
it $30 US.

I figure a shower costs a buck, IOW. under current cost structure,
that's about .4 of a gallon of gas, or 8+ miles for a 20 MPG car.

Because the parameters for the "fuel" for bicycles are much, much
more narrow and the quality must be so much better, I will bet
on scant evidence that a mile driven costs less in greenhouse gas than
does a mile in a car.

And please note that someone living in Bejing or Mumbai will have
a totally different set of parameters here - a "bike's ride" worth of
rice grown in a traditional paddy consumes little more than sunlight.

But that is a really excellent point. I hadn't even considered
peripheral things like that.

--
Les Cargill

On Nov 27, 11:03*am, Andre Jute wrote:
This question, which I don't remember us discussing beyond the
presumption that it must be, is from Les Cargill, a regular over on
AGA. I thought it worth a thread of its own. -- AJ

******

You might be able to answer a question for me, though: when somebody
rides a bike for a mile, flat and level, just keeping an even pace
that's highly sustainable ( as in "for transportation purposes" type
pacing) *what is the *total* carbon emitted? Counting
back all the way to the beef in the McDonalds he ate, the grain used
to feed the cow, the energy consumed growing that, the truck that
carried all that, all that.

I will bet that a little 100W to 500W gasoline motor that does pedal
assist emits less CO2 than the person pedalling, but it's a big
calculation, and I haven't done it. I thought maybe you had
seen somebody who has. And I will bet than an aircooled engine like
that, so long as the exhaust gas temperature is high enough, could
beat human muscle power for efficiency.

But somebody who grows their own potatoes might be able to beat that.

--
Les Cargill

A gallon of vegetable oil contains 35,000 dietary calories or can be
burned in a diesel engine.
If a cyclist is riding at 10 MPH and consuming 175 calories an hour,
he can ride for 200 hours over 2,000 miles.

An automotive diesel might get 25-50 mpg.

On Nov 27, 2:34 pm, Les Cargill wrote:

Consider it a working assumption. What I'd like to know is: does
cycling always beat driving a car so far as oil use goes?

The answer is yes, by a longshot.

Drivers still have to eat. Bicycling doesn't require that much extra
food energy.

Both the human engine and the internal combustion engine are pretty
inefficient. But in terms of kilocalories burned per unit distance a
bicyclist is easily 20 times more efficient than a 'fuel-efficient'
car, even if the car putters around at the speed of a slow
transportational cyclist. The figure is likely to be much higher.

The primary reason is the weight of the machine. A compact car weighs
around 3000 pounds. The mechanical advantage supplied by the bicycle
comes at very small cost in weight, and the driver and engine are
combined into one entity.

Nothing beats the bike for efficiency. Not even walking or the train.
Liquid petroleum fuel and internal combustion engines are superior in
other aspects.