[Stoves] K Smith Article in Energy for Sustainable Development

[Boston Nyer]

All,

In the column, Dr. Smith does not reference his $10 price-limit.  I have
heard this value several times and no one seems to know why $10 was deemed
appropriate.  I've been digging and cannot find the source of this
"decision".  Does anyone have further information?  In my opinion, its
extremely naive to cast a blanket price for all hh stoves around the world.

Cheers,
Boston Nyer




On Mon, Nov 29, 2010 at 9:55 AM, <rongretlarson at comcast.net> wrote:

> Richard (cc two lists)
>
> See some questions/notes below on your message today.  You said:
>
>     "*I would buy the one that burned some form of densified non wood
> biomass "cleanly" ......*
>
>     *[RWL1:  Those of us who are promoting char-producing stoves believe
> that they are much cleaner than those that only combust.  The usual low-cost
> stoves in developing countries almost universally use only wood (with some
> still-minor use of your  briquettes of course).  For those new to the
> subject, the difference is whether there is a single air supply or two.
> Does anyone reading this think that char-making stoves are not inherently
> cleaner?*
>      But I especially want to support your use of the term "densified
> non-wood" - which I think is also much needed in char-making stoves.  Nat
> Mulcahy of World Stoves always  emphasizes the use of "densified non-wood"
> as one of the main advantage of his Lucia stove (which could combust or
> gasify - but he chooses to operate in only a pyrolysis mode).  See his
> website for his rationales - which are (in part) similar to yours.
>    Several questions to you (as the person who probably knows the most on
> this densified non-wood cooking issue):
>        1a.  What are the relative advantages of making (not using) pellets
> vs briquettes?
>    It would seem that it should be much easier to "press" (I like your
> closing below) pellets than briquettes (especially the "holey" type).  Do
> you have any data on the relative power or energy and/ or cost requirements
> for production of pellets vs briquettes?
>
>        1b.  For those wanting char and not ash, the charred pellet is
> already in a wonderful form for application to soils.   Pellets mean some
> extra costs for the fuel supply in the front end of cooking - but could be a
> wonderful boon both in burning more cleanly and evenly and in later
> application of Biochar to the soil.  The same is possibly/probably true for
> briquettes - which I presume break up easily after being pyrolyzed.   Do you
> have any reason to think briquettes would be better than pellets in either
> pyrolysis or char-application terms?
>
>
> You concluded:]
>
> "....and would avoid both the wood supply and the char producing problems
> in one go."
>
>      [RWL:     2a.  Re the first issue of supply (with which I agree), I
> have recently read an article (author's name forgotten - I will try to find
> it) that showed a breakdown of the well known global net primary
> productivity (NPP) number of about 60 Gt C/yr.  They had about half going
> into wood and half into leaves -  a ratio I had not previously seen.  Since
> you are promoting the former (leaves) over the latter (wood) - and because
> almost all rural stove users are now using only wood (and even many
> briquettes and pellets seem to be made up of ground-up or chipped wood),
> have you seen this relative photosynthesis production ratio - which would
> seem to imply a huge wasted resource all over the world?
>
>      2b.  But I don't understand your term "char producing problems".  To
> me there are only benefits and advantages (at least with kitchen stoves).
> If you meant the horrible production of most charcoal out in the boondocks -
> with global warming and carcinogenic gases much worse than CO2 being
> produced - then I agree.   To prove that it is better for society to promote
> household production of Biochar (char placed in the ground) will be the
> subject of my next message.  Briefly it is that we need to make the economic
> argument that Biochar's two main advantages (carbon sequestration and soil
> improvements) outweigh the further combustion of the char for its energy
> value.  Two main reasons that I think we can make this argument (which I do
> not contend has already been proven).   First is the 2:1 advantage in the
> three-flows of money (which seem in the same ballpark).  But more important
> is that the first two monetary flows (climate and soils) are both
> investments - with good payback over long time periods.  The energy
> application of the char is only a single use - no out-year advantages at
> all.  More coming on the many out-year advantages of Biochar.
>
>    This is not to suggest that you do not believe in all this already - but
> others could interpret your sentence to favor burning of "densified
> non-woody biomass" rather than pyrolysis of the same.
>
> Ron]
>
> pressing on,
>
> Richard Stanley
> www.legacyfound.org
>
>
> On Nov 29, 2010, at 4:12 PM, Crispin Pemberton-Pigott wrote:
>
> [RWL:  I have snipped this to keep the responses separate - being different
> issues.]
>
> Dear Friends
>
> I agree with Ron that $10 is a believable figure for an improved stove with
> a dramatic (90%) reduction in emissions of PM. For the +$50 stove
>
> <snipped>
>
>
>
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-- 
Boston Nyer
Graduate Student
Department of Civil, Environmental, and Architectural Engineering
University of Colorado at Boulder
(585) 503-3459
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