Re: Cyclist rant: back in black



On Sat, 12 Mar 2005 14:50:06 -0000, "Clive George"
<[email protected]> wrote in message
<[email protected]>:

>> Should we say "the single person's tax threshold is 5000ukp, but you
>> won't start paying tax unless you earn over 6000ukp"? Do you think that
>> would add clarity to the situation?


>I think there's something about NI which works this way...


Slightly different: in the case of NI it's 9% of income unless you're
rich, in which case the percentage drops as your income rises.


Guy
--
http://www.chapmancentral.co.uk

"To every complex problem there is a solution which is
simple, neat and wrong" - HL Mencken
 
Tony Raven wrote:

> It was based on an average exertion cycle journey (c15mph)and the
> average emissions per mile of a typical small car


Is it comparing direct or indirect CO2 emissions? On direct,
the cyclist is zero because it's all from non-fossil fuels,
which are recycled from atmospheric CO2.

My car is small, and averages about 45mpg. A litre of petrol
is 35MJ of heat energy. 10 miles per litre, so 3.5MJ of heat
generated per mile. 833 kCals. When I'm exercising flat
out I couldn't do that in an hour, and 15mph is nowhere near
flat out, as you say.

http://www.exploratorium.edu/cycling/humanpower1.html

Suggests my back-of-envelope calculation to be reasonable.

Simon
 
Simon Proven wrote:
> Tony Raven wrote:
>
> > It was based on an average exertion cycle journey (c15mph)and the
> > average emissions per mile of a typical small car

>
> Is it comparing direct or indirect CO2 emissions? On direct,
> the cyclist is zero because it's all from non-fossil fuels,
> which are recycled from atmospheric CO2.


It would IMO be reasonable to include the indirect fossil fuel usage
that accompanies the (small) extra amount of food that the cyclist
consumes. IIRC that will actually be in the same ballpark as the
calorific content of the food itself (varying wildly with foodstuff).

Of course cyclists who only eat locally-grown, organic hand-knitted
tofu (or whatever equivalent grows in their locality - dandelion tea
and turnips, perhaps?) can feel as smug as they like.

James
 
James Annan wrote:
> Simon Proven wrote:
>
>>Tony Raven wrote:
>>
>>
>>>It was based on an average exertion cycle journey (c15mph)and the
>>>average emissions per mile of a typical small car

>>
>>Is it comparing direct or indirect CO2 emissions? On direct,
>>the cyclist is zero because it's all from non-fossil fuels,
>>which are recycled from atmospheric CO2.


> It would IMO be reasonable to include the indirect fossil fuel usage
> that accompanies the (small) extra amount of food that the cyclist
> consumes. IIRC that will actually be in the same ballpark as the
> calorific content of the food itself (varying wildly with foodstuff).


Agreed, as long as that's reciprocated by doing the same for
motorised transport too.

> Of course cyclists who only eat locally-grown, organic hand-knitted
> tofu (or whatever equivalent grows in their locality - dandelion tea
> and turnips, perhaps?) can feel as smug as they like.


The energy consumed driving to and from the supermarket is a
significant proportion of that used within the food energy
cycle, so if they cycle to wherever they get their food,
they can be more smug still.
 
Simon Proven wrote:
> James Annan wrote:
>
>> Simon Proven wrote:
>>
>>> Tony Raven wrote:
>>>
>>>
>>>> It was based on an average exertion cycle journey (c15mph)and the
>>>> average emissions per mile of a typical small car
>>>
>>>
>>> Is it comparing direct or indirect CO2 emissions? On direct,
>>> the cyclist is zero because it's all from non-fossil fuels,
>>> which are recycled from atmospheric CO2.

>
>
>> It would IMO be reasonable to include the indirect fossil fuel usage
>> that accompanies the (small) extra amount of food that the cyclist
>> consumes. IIRC that will actually be in the same ballpark as the
>> calorific content of the food itself (varying wildly with foodstuff).

>
>
> Agreed, as long as that's reciprocated by doing the same for
> motorised transport too.


Um... was "(small) extra amount of food" not clear enough for you?

>
>
> The energy consumed driving to and from the supermarket is a
> significant proportion of that used within the food energy
> cycle


I find that very hard to believe. Figures?

James
 
On 12 Mar 2005 16:51:59 -0800, "James Annan"
<[email protected]> wrote in message
<[email protected]>:

>It would IMO be reasonable to include the indirect fossil fuel usage
>that accompanies the (small) extra amount of food that the cyclist
>consumes. IIRC that will actually be in the same ballpark as the
>calorific content of the food itself (varying wildly with foodstuff).


Heh! You think there's an oil well and refinery under every filling
station?


Guy
--
http://www.chapmancentral.co.uk

"To every complex problem there is a solution which is
simple, neat and wrong" - HL Mencken
 
Just zis Guy, you know? wrote:

> On 12 Mar 2005 16:51:59 -0800, "James Annan"
> <[email protected]> wrote in message
> <[email protected]>:
>
>
>>It would IMO be reasonable to include the indirect fossil fuel usage
>>that accompanies the (small) extra amount of food that the cyclist
>>consumes. IIRC that will actually be in the same ballpark as the
>>calorific content of the food itself (varying wildly with foodstuff).

>
>
> Heh! You think there's an oil well and refinery under every filling
> station?


Um....no. Why?

James
 
On Sun, 13 Mar 2005 09:47:56 +0000, "Just zis Guy, you know?"
<[email protected]> wrote in message
<[email protected]>:

>>It would IMO be reasonable to include the indirect fossil fuel usage
>>that accompanies the (small) extra amount of food that the cyclist
>>consumes. IIRC that will actually be in the same ballpark as the
>>calorific content of the food itself (varying wildly with foodstuff).


>Heh! You think there's an oil well and refinery under every filling
>station?


It read as if you were counting the cost of growing, processing and
transporting the food, but not that of the fuel used by the cars. Not
that you would make such an error, it just looked funny.


Guy
--
http://www.chapmancentral.co.uk

"To every complex problem there is a solution which is
simple, neat and wrong" - HL Mencken
 
James Annan wrote:
> Just zis Guy, you know? wrote:
>
>> On 12 Mar 2005 16:51:59 -0800, "James Annan"
>> <[email protected]> wrote in message
>> <[email protected]>:
>>
>>
>>> It would IMO be reasonable to include the indirect fossil fuel usage
>>> that accompanies the (small) extra amount of food that the cyclist
>>> consumes. IIRC that will actually be in the same ballpark as the
>>> calorific content of the food itself (varying wildly with foodstuff).

>>
>>
>>
>> Heh! You think there's an oil well and refinery under every filling
>> station?

>
>
> Um....no. Why?
>
> James


Well, it means that you have to scale the energy use from the
car by the cost of getting the oil out of the ground, into a
form that can be used by the car, and getting it to the car.
And, getting the car to the petrol station (unless one happens
to be stopping en route). ISTR that it adds something like
20% to the effective CO2 emissions, BICBW.
 
IIRC, the "energy returned on energy invested" for the most easily
extracted oil in the world (KSA) is about 30 to 1. IOW, to get 30
barrels of oil from ground to petrol tank you'll burn 1 barrel.
 
James Annan wrote:
> Just zis Guy, you know? wrote:
>
>> On Sun, 13 Mar 2005 09:47:56 +0000, "Just zis Guy, you know?"
>> <[email protected]> wrote in message
>> <[email protected]>:
>>
>>
>>>> It would IMO be reasonable to include the indirect fossil fuel
>>>> usage that accompanies the (small) extra amount of food that the
>>>> cyclist consumes. IIRC that will actually be in the same ballpark
>>>> as the calorific content of the food itself (varying wildly with
>>>> foodstuff).

>>
>>
>>> Heh! You think there's an oil well and refinery under every filling
>>> station?

>>
>>
>> It read as if you were counting the cost of growing, processing and
>> transporting the food, but not that of the fuel used by the cars. Not
>> that you would make such an error, it just looked funny.

>
> Well, the total energy cost of extracting, processing and transporting
> the fuel is probably a fairly small proportion of its energy content
> anyway, otherwise it wouldn't be worth the bother...


The general figure given by the biodiesel industry is that of about an 83%
yield in petrodiesel. i.e. 17% of the energy is used in extraction,
transport and refining the fuel. (The yield with biodiesel is approximately
the same, as well). It should be easy enough to find sources for this.

Ambrose
 
James Annan wrote:

>
> Well, the total energy cost of extracting, processing and transporting
> the fuel is probably a fairly small proportion of its energy content
> anyway, otherwise it wouldn't be worth the bother...


That just does not follow. Whatever it costs and however much energy is
used in the process it is worth it to the companies involved if the
product can be sold at a profit that gives an acceptable return on capital.

Just the amount of gas flared from oil fields is astounding. This is
some data for 1998 for the UK
http://www.dbd-data.co.uk/bb1999/append9.htm
The total is 5.49 million standard cubic metres per day (i.e. gas at 20C
and 1 bar).

This world bank report
http://rru.worldbank.org/Documents/279-Gerner-Svensson-Djumena.pdf
states in its first page
"Every year oil producers flare and vent gas equivalent to the
combined gas consumption of Central and South America. Africa flares
and vents gas equivalent to half its power consumption."
The graph on page 2 illustrates who flared what in 2003.

It's not quite so much as it used to be around the world because it's
getting more attractive to do something with the gas and governments are
getting a little more twitchy about such blatant waste, but for a long
time gas was treated as a waste product in most oil production areas.

Then there's the energy consumed by production facilities. A decent
sized North Sea platform will have perhaps two RB211 duel-fuel gas
turbines driving generating sets running 24 hours a day. Such turbines
can put out maybe 20MW each at a thermal efficiency less than 40%. The
DTI estimates that the total offshore power generating capacity (output)
is 4GW from gas turbines and 250MW from diesels.
http://www.og.dti.gov.uk/regulation/guidance/environment/ippc/ippc_app3.htm

This is a short report by UKOOA (UK Offshore Operators Association) on
the atmospheric emissions due to the UK offshore oil & gas industry
http://www.oilandgas.org.uk/issues/1998report/v0000914.htm

Here's a Rolls Royce page explaining some of the reasons why oil
production needs hefty power generation facilities
http://www.rolls-royce.com/energy/overview/oilgas/appsintro.jsp

--
Joe * If I cannot be free I'll be cheap
 
Simon Proven wrote:

> James Annan wrote:
>
>> Simon Proven wrote:
>>
>>> James Annan wrote:
>>>
>>>> Simon Proven wrote:
>>>>
>>>>> Tony Raven wrote:
>>>>>
>>>>>
>>>>>> It was based on an average exertion cycle journey (c15mph)and the
>>>>>> average emissions per mile of a typical small car
>>>>>
>>>>>
>>>>>
>>>>>
>>>>> Is it comparing direct or indirect CO2 emissions? On direct,
>>>>> the cyclist is zero because it's all from non-fossil fuels,
>>>>> which are recycled from atmospheric CO2.
>>>
>>>
>>>
>>>
>>>> It would IMO be reasonable to include the indirect fossil fuel usage
>>>> that accompanies the (small) extra amount of food that the cyclist
>>>> consumes. IIRC that will actually be in the same ballpark as the
>>>> calorific content of the food itself (varying wildly with foodstuff).
>>>
>>>
>>>
>>>
>>> Agreed, as long as that's reciprocated by doing the same for
>>> motorised transport too.

>>
>>
>>
>> Um... was "(small) extra amount of food" not clear enough for you?

>
>
> It depends if the fossil energy used in food production and
> transport is significantly more than the energy contained
> in the food itself. For certain types of food, fossil energy
> can be 50-100x the energy contained in the food, iirc.
>
>>> The energy consumed driving to and from the supermarket is a
>>> significant proportion of that used within the food energy
>>> cycle

>>
>>
>>
>> I find that very hard to believe. Figures?

>
>
> New Scientist, 5 Match had an article about the environmental
> costs, these being broken down by source. These are the
> costs (in paying for the damage done) rather than energy
> use per se.
>
> Environmental costs:
>
> Domestic road transport (farm to shop): 29.2%
> Agriculture: 18.8%
> Shopping transport: 15.8%
> International transport and waste disposal: <0.02%
> Govt subsidies: 36.2%
>


For starters, it is not clear what that 16% refers to.

But more importantly, you are double-counting the cycling, cos either
this journey to the shops is the one whose benefits you are trying to
calculate in the first place, or it is another journey in which case you
are attributing its benefits to the first journey...

James
 
Alan Braggins wrote:

[...]

> Assuming you aren't talking about Raspberry Leaf Spot Virus, what are
> you talking about?


AIUI's a Real Life Stripy Vehicle.

HTH, HAND etc...



A

--
Trade Oil in €
 
JLB wrote:

> James Annan wrote:
>
>>
>> Well, the total energy cost of extracting, processing and transporting
>> the fuel is probably a fairly small proportion of its energy content
>> anyway, otherwise it wouldn't be worth the bother...

>
>
> That just does not follow.


Not as a logical proof, no. Nevertheless, it is true.

James
 
James Annan wrote:

> But more importantly, you are double-counting the cycling, cos either
> this journey to the shops is the one whose benefits you are trying to
> calculate in the first place, or it is another journey in which case you
> are attributing its benefits to the first journey...


The benefit of cycling to the shops applies to both journeys.

Simon
 
Just zis Guy, you know? wrote:
> Maybe. I'd be faintly surprised if more than 1/4 of the energy
> content of a barrel of crude actually made it as far as tractive
> effort, but I can't find figures at the moment.


Thermodynamics limit it to something around 50% anyway, the only way to use
oil more efficiently is to use it for heating or combined heat and power.

Better aerodynamics, less wasteful acceleration, lighter cars and
regenerative braking could of course make cars go a lot further per joule.


--
Andy Morris

AndyAtJinkasDotFreeserve.Co.UK

Love this:
Put an end to Outlook Express's messy quotes
http://home.in.tum.de/~jain/software/oe-quotefix/
 
Simon Proven wrote:
> James Annan wrote:
>
> > But more importantly, you are double-counting the cycling, cos

either
> > this journey to the shops is the one whose benefits you are trying

to
> > calculate in the first place, or it is another journey in which

case you
> > are attributing its benefits to the first journey...

>
> The benefit of cycling to the shops applies to both journeys.


The subject was emissions per mile, so it doesn't matter how many
journeys are counted so long as they are counted once!

James
 
Tony Raven wrote:
> Ambrose Nankivell wrote:
>
>>
>> Of course, there's no reason modern speedometers should be inaccurate.
>> Perhaps optical reading of the road rather than rotation speed of the
>> tyres would give the requisite accuracy at the required price.
>>

>
> You can get a radar based one for bicycles so no reason you couldn't
> have one for cars. I've checked my speedos against a GPS unit and found
> a variation between reading 10% over (Ford) to spot on (Mercedes).


Of course, GPS positioning varies according to the electron/ion density
in the lower ionosphere. How exact do you want to be? :)

R.
 
Richard wrote:
> Tony Raven wrote:
>
>> Ambrose Nankivell wrote:
>>
>>>
>>> Of course, there's no reason modern speedometers should be
>>> inaccurate. Perhaps optical reading of the road rather than rotation
>>> speed of the tyres would give the requisite accuracy at the required
>>> price.
>>>

>>
>> You can get a radar based one for bicycles so no reason you couldn't
>> have one for cars. I've checked my speedos against a GPS unit and
>> found a variation between reading 10% over (Ford) to spot on (Mercedes).

>
>
> Of course, GPS positioning varies according to the electron/ion density
> in the lower ionosphere. How exact do you want to be? :)
>


Enough to measure relatavistic effects? ;-)

Tony