[Stoves] MUST CHARCOAL BE A CAUSE FOR CONCERN?
Otto Formo
formo-o at online.no
Thu Oct 14 05:01:24 CDT 2010
Dear Kevin,
I very much agree with you, FAO is focusing on agriculture and forest issues, WHO on health, UNDP on environment and s.o.
They dont see the "whole" picture and one "action" might to an extend even harm another.
Iam not saying that charcoal is "bad" or useless.
Iam concerned the way its made out of traditional kilns, polluting and wasting a lot of energy.
The TLUD can reach even 750 C which should be hot enough for any type of cooking.
Any type of fuel need some kind of refinement or preparation, dont forgt that.
This goes for charcoal and fuel for the TLUD`s as well.
I would not say that cutting branches with a machete is "highly" prepared fuel.
If we call the TLUD, a gasifier or a pyrolytic gas stove, cant be the big difference to make an issue out of it.
Iam still conserned the way charcoal is produced and used in developing countries on behalf of the people living there , the forest, water, the local environmment and climate.
Otto
> From: Kevin [kchisholm at ca.inter.net]
> Sent: 2010-10-14 04:53:32 MEST
> To: Otto Formo [formo-o at online.no], Discussion of biomass cooking stoves [stoves at lists.bioenergylists.org]
> Subject: Re: [Stoves] MUST CHARCOAL BE A CAUSE FOR CONCERN?
>
> Dear Otto
> ----- Original Message -----
> From: Otto Formo
> Subject: SV: [Stoves] MUST CHARCOAL BE A CAUSE FOR CONCERN?
>
>
> Dear Kevin,
> what you actually are "saying" is that people in developing countries have no common sense and knowledge about polution from open fires.............
> # Not at all!! They work with what they have to accomplish what they want.My comments were directed more at the FAO who put prime focus on simply saving trees, rather than helping improving the lifestyle and health of the people.
>
> Why do they use open fires for cooking?
> The most ovious reason is that they have no choice or options.
> Secondly, this is how it has been done for centuries.
> It "works", why change?
> The women do the collecting of wood and the cooking, so why bather........
>
> # It is certainly misdirected to put the focus on saving trees at the expense of harming people. Hopefully, it will be a "win-win-win" situation where more efficient (less wood) and more effective (do a better job of cooking the way they want to cook) and cleaner (less harmful pollution) stoves can be configured.
>
> Best wishes,
>
> Kevin
> Inferring that "charcoal is bad" overlooks part of the function of some cooking systems. Some cooking styles must have the intense heat that charcoal can produce. The point of my posting was to address the whole problem, not just part of it.
>
> There is also no question about that even the best and most efficient charcoal stoves (without a chimmny) emitts far more CO than any TLUD gasifier stove.
>
> # Charcoal stoves permit a unique cooking capability that a TLUD cannot duplicate. There is probably a place for both stove systems. Much work has been done on TLUD stoves in the past few years, and they are working better now than ever. Less work has been done on charcoal stoves... no doubt that they can also be greatly improved also.
>
> # TLUD's are a neat stove for some applications, but they are far from being a cooking panacea. They require a highly prepared fuel, that they don't burn to completion, and they are basically a "batch stove". They are not really a "gasifier stove" but rather a "pyrolysis gas stove", that wants to leave charcoal behind. For some applications, the production of charcoal can be a disadvantage, while for others, it can be very advantageous.
> # So, getting back to my basic point... just what is the set of problems that need to be addressed? Why is charcoal a problem? What can be done to reduce the problems with charcoal? What other factors should be dealt with as part of the problem?
>
> The other fact is that CO also kills people in the "western" world as well by "missuse" of gas for heating and cooking, but it does not mean that we should stop using it!
> BUT we should be VERY carefull by using open flames indoors without good ventilation.
> This is something we learn in school at early age.
> If any positive progress should be "stoped" by missuse of just a few there is no way the "World" are going to move "forward", ever.
> Otto
>
>
> > From: Kevin [kchisholm at ca.inter.net]
> > Sent: 2010-10-13 16:33:52 MEST
> > To: Discussion of biomass cooking stoves [stoves at lists.bioenergylists.org]
> > Subject: Re: [Stoves] MUST CHARCOAL BE A CAUSE FOR CONCERN?
> >
> > Dear Rogerio
> >
> > I think that the wrong question is being asked. One can also ask the
> > question: "Must wood be a cause for concern?"
> >
> > 1: If the ultimate concern is simply availability of fuel, then both
> > primitive wood stoves and primitive charcoal systems are indeed a concern.
> >
> > 2: If health, as a result of products of combustion considerations is the
> > ultimate concern, then both primitive cooking systems are a concern.
> >
> > 3: The good thing about 3 stone wood fires is that they emit gross irritants
> > that minimize the potential for users to be killed during the cooking
> > session from CO poisoning. Good gharcoal stoves can be very efficient and
> > not emit apparent poisons, but if used in a confined space, the much more
> > efficient charcoal stove can kill the Family before the meal is finished.
> >
> > 4: Charcoal gives a quality of cooking that cannot be duplicated by a wood
> > fire.
> >
> > Obviously, a dreadfully inefficient "3 Stone Fire" can be much safer than an
> > "Improved Cooking Stove" that has much higher efficiency. There is so much
> > smoke and poisons coming off the 3 Stone Fire that people move upwind. An
> > "Improved Cooking Stove" might be improved just enough that people move it
> > inside a living space, and then they start dying from all sorts of
> > disorders. Charcoal stoves could end up being superior, in that there might
> > still be enough "residual irritants" emitted such that the Cook uses it in a
> > well ventilated space.
> >
> > The "problem", whatever it is, must be clearly defined before one can arrive
> > at a meaningful answer to the "problem." A better question might be along
> > the lines of: "What is the best way for people to accomplish their desired
> > cooking task, with a given quantity of wood fuel, while improving the health
> > of the people using a particular "cooking system?"
> >
> > Perhaps someone else can formulate a better question that is more relevant
> > to whatever issue is of concern. There is no point in promoting an "improved
> > stove system" that cuts wood usage in half, but doesn't cook the food the
> > way the people want it, and then kills them afterward.
> >
> > Best wishes,
> >
> > Kevin
> >
> > ----- Original Message -----
> > From: "rogerio carneiro de miranda" <carneirodemiranda at gmail.com>
> > To: "Discussion of biomass cooking stoves" <stoves at lists.bioenergylists.org>
> > Sent: Wednesday, October 13, 2010 9:01 AM
> > Subject: Re: [Stoves] MUST CHARCOAL BE A CAUSE FOR CONCERN?
> >
> >
> > Dear Crispin and others who has responded.
> >
> > Making a simple calculation (see table below), I found the following
> > numbers based on 1 kg of Eucalyptus grandis, with 4650 kcal/kg as
> > fuelwood, or 7600 kcal/kg as charcoal.
> >
> > Considering the worst case scenarios, with woodstoves efficiency of 10
> > to 15% one would get 450 to 698 kcal of energy into the pot, and to
> > have the same amount of energy from charcoal into the pot, one would
> > need to have either a relative medium charcoaling efficiency of 20%
> > but with a charcoal stove with 30% efficiency, or charcoal stoves of
> > normal efficiency around 20% but with higher charcoaling efficiencies
> > of 30 or 40-%.
> >
> > Based on that, shouldn't be logical to assume that under "primitive"
> > existing general conditions as seeing in the field today, that
> > cooking with wood is more energy efficient than cooking with charcoal?
> >
> > Assuming that woodstoves can easily achieve 20% efficiency which
> > delivers 900 kcal into the pot, and to do the same job with charcol
> > one would need a 30% energy efficiency charcoal stove using charcoal
> > produced at 40% charcoaling process, what is nearly impossible to
> > achieve.
> >
> > Unless charcoal stoves of 40% are possible, so to use with charcoaling
> > kilns of high 30% efficiency?
> >
> > Rogerio
> >
> >
> >
> > cooking with charcoal
> > efficiency(%) 10%-20%-30%
> > (kcal)
> > charcoaling 10% (760) (76) (152) (22)
> > 20% (1520) (152) (304) (456)
> > 30% (2280) (228) (456) (684)
> > 40% (3040) (304) (608) (912)
> >
> > cooking with fuelwood
> > efficiency(%) 10% 15% 20% 30%
> > (Kcal) (450) (698) (900) (1350)
> >
> >
> >
> >
> > 2010/10/12 Crispin Pemberton-Pigott <crispinpigott at gmail.com>:
> > > Dear Rogerio
> > >
> > > We discussed this a while back and I forwarded some example of the energy
> > > balance.
> > >
> > > Yes, the fact is there is nearly no difference between the amount of food
> > > cooked with wood or that same wood turned into charcoal. The caveats are
> > > that I depends on the wood stove, the charcoaling method and the charcoal
> > > stove.
> > >
> > > Those are three huge variables, but for 'medium quality' on all three
> > > counts, the answers are about the same.
> > >
> > > The overall difference that one might be inclined to ponder is the amount
> > > of
> > > energy that is used to being the fuel to the cook. In the case of
> > > charcoal,
> > > say in Mozambique, the distance that one can profitably transport charcoal
> > > is far greater than that for wood because it is so much more energy dense.
> > > It is even better than coal because coal usually has a lot of ash in it.
> > >
> > > So, when considering what to criticise, replace and promote, one has to
> > > look
> > > at the three main variables, what one could do to change them, and what
> > > the
> > > transport implications are. It is pretty tempting to think of charcoal
> > > making vehicles using wood gas for locomotion, delivering charcoal to the
> > > cities. They would start off heavily loaded and get lighter as they got
> > > closer to town!
> > >
> > > I recall Cecil Cook and I having fun with this equation some time ago.
> > >
> > > What is always good (as Richard Stanley recently point out) is to make
> > > sure
> > > that all the chips and dust from the charcoal business end up in
> > > briquettes
> > > of some form. Usually the review of charcoal is made by a hostile agent
> > > and
> > > the 'waste' involved is emphasized, not the methods by which it can easily
> > > be made very efficient, all things considered.
> > >
> > > There is still a lot of this story to be told by someone with a talent for
> > > integrating technologies and stove ideas.
> > >
> > > Regards
> > > Crispin
> > >
> > >
> > > +++++++++++++++
> > >
> > >>I found the following quote on a FAO publication
> > > (http://www.fao.org/docrep/005/y4450e/y4450e10.htm), and I wonder if this
> > > is
> > > a correct statement responding to the question :
> > >
> > > "Must charcoal be a cause for concern?
> > >
> > > The shift from fuelwood to charcoal, even if it lasts only a few decades,
> > > could have major ecological consequences if it is not kept under control.
> > > However, since charcoal stoves are more efficient than wood stoves, the
> > > ratio of primary energy to usable energy is almost the same as with
> > > fuelwood. Thus with adequate supervision, management and support, the
> > > shift
> > > does not need to disrupt present levels of resource use."
> > >
> > > What do you think? Can at the end, with actual stoves and charcoaling
> > > efficiencies, be the wood consumption the same?
> > >
> > > Rogerio
> > >
> > >
> > >
> > > _______________________________________________
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> > >
> >
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