[Stoves] Jatropha and its future

rongretlarson at comcast.net rongretlarson at comcast.net
Fri Aug 12 17:52:17 CDT 2011


Jan - 1. This is to hope you can add a little more data so we can more accurately figure out a payback time for a charcoal-making (Pyrolyzing) stove in Tanzania (with extensions presumably to other countries). For ease of comparison, I will convert using 1617 Tsh to $1. 

2. Your two hour cook time costs $0.155 for 1 kg of Jatropha seeds, $.62 for maybe 1.2 kg (or $.50/kg??- lower energy density) wood, and more ?? for charcoal (guess at $.80?? for maybe 0.8kg of (higher energy density) char valued at $1/kg ??). Asking you to correct these guestimates based on your description below. 

3. Assuming you can get back from the first two about 25% char then the return value for Jatropha is 0.25kg*$1/kg, so the cook made $0.10 per meal using Jatropha seeds. For wood, about 0.3kg *$1.00/kg - so he/she saves about half of the $0.62. Much better buy to go with Jatropha seeds (as you have been saying - but maybe not true in India - but who still may see an ag value per the folowing and may have an equally good alternative waste ag fuel). 

4. Assuming there are two periods in the day for using the 1 kg of jatropha seed, making $0.20 per day, then a one year pay back can occur on a stove costing $73.00. (I think you are aiming lower) 

5. What the Biochar folk want is to not sell the char back, but to place it in the stove-user's garden. Each year there would be in this example about 1/2 kg per day of char or 180 kg in a year. At 10 tons per hectare loading (same as 1 kg/sqm), this stove would cover180 sqm, if used twice a day. So assume a 1/2 meter strip, we can get a linear 0.36 km. If garden producing at 2 tons per hectare sees a doubling to 4 tons per hectare, then the 180 sq meters gets an increase of 200 gm/sqm (100 gm/linear meter) - or new added annual garden output of 36 kg (onions, carrots, squash, etc). Nothing in Colorado is less than $2/kg - so maybe the extra first year value (halving the $value for high value Tanzanian market crops) is near $36. If the initial cost could be taken from savings, then we are up to $110 per year in return (rounding $113 down). If no more char is placed in the ground, and the stove lasts 5 years, then the total stove income is $550. 

6. But the Biochar keeps coming and giving, so at the end of five years of putting char in new ground, we are not deaing with a linear .36 km, but 5 times that or 1.8 km of vegetable row, and the number of row-years is up to 1+2+3+4+5 = 15 row-years (10 more than the previous 5) . If one row year gave a new annual garden income of $36. and the 5 year total income was $550, then the new total would be $550+10*36 = $910. 

7. But, the Biochar is still working after 5 years, so, now using a discount factor, maybe we can convince the potential stove buyer that there is another $100 available should the land (now up to (a postulated) loaded 900 sq m, [or 0.09 hectare - approaching a quarter of an acre] be sold. In total over $1000 profit on a $73 investment on a stove - within the first 5-years No environmental cost that I can see and the fuel-seeds were bought - not picked (not very likely). It gets better when you factor in inflation and devaluation of the Tsh. A return on investment around a factor of 15. 

8. Should the investment in a char-using stove be preferred, the 5-year outgo in dollars for a "Thrifty" $5 jiko would be 5 yrs*365 days/yr*2 meals a day*$0.80/meal =8*365>$2600. The difference is over $3400 on the $68 price difference - a factor greater than 20. It doubles for those picking their own seeds. 

9. This is considerably low-balled in some cases, since Nat Mulcahy of World Stoves says his stoves (with a 5-year guarantee) are seeing a large use (factor of 3 or more??) for boiling water and other income-generating activities. But 20 is a good round return number to start with. 

10. Jan - Did I do the fudging somewhere near correctly? I am assuming 18 MJ/kg for wood and about 30 MJ/kg for char, with Jatropha seeds in between somewhere. Here's hoping you (& others) can sharpen the computation a bit (for other combinations of charcoal-making vs charcoal-using and a more healthy, less time-consuming kitchen to boot. Health based $ statistics for lost work days should be figured in) 

Ron 


----- Original Message -----
From: "Jan Bianchi" <janbianchi at comcast.net> 
To: "Discussion of biomass cooking stoves" <stoves at lists.bioenergylists.org> 
Sent: Friday, August 12, 2011 1:47:42 PM 
Subject: Re: [Stoves] Jatropha and its future 

A.D 

Sounds like you've got a good market for jatropha in India. In Tanzania 
Africa, where much of what has been planted is going unharvested, it sells 
for about $250 Tsh per kg which has a burn time of more than two hours, 
whereas a bundle of wood with a two hour burns time costs $1,000 Tsh. 
Charcoal costs even more 

So its all about location. 

Jan 



-----Original Message----- 
From: stoves-bounces at lists.bioenergylists.org 
[mailto:stoves-bounces at lists.bioenergylists.org] On Behalf Of Anand Karve 
Sent: Thursday, August 11, 2011 8:44 PM 
To: Discussion of biomass cooking stoves 
Subject: Re: [Stoves] Jatropha and its future 

Dear Ron and stovers, 
there is a good market for Jatropha seeds in India. Itinerant 
merchants go from village to village and buy Jatropha seed from 
anybody who wants to sell it. Since this commodity has a value, the 
seed of Jatropha planted as hedges along the boundary of one's 
property usually gets harvested by somebody else, The property owner 
may harvest only the seed on the internal side of the hedge. Jatropha 
was planted as a hedge plant long before there was any talk of 
biodiesel. If one plucks a leaf of Jatropha, latex oozes out of the 
wound. This latex foams like soap. In some rural households there are 
a few Jatropha plants right next to the latrine. After defacation, the 
user of the latrine plucks a couple of leaves, crushes them in his 
hands and uses them to wash his hands. Nobody really bothered to find 
out what was done with Jatropha oil. Most of the non-edible oils in 
India, like Pongamia, Callophyllum, neem, etc. are bitter and brown in 
colour. Jatropha oil is colourless and it does not have any strong 
taste or smell. Even the fatty acid composition is similar to most of 
our edible oils. Therefore I am quite sure that it is used, even 
today, as an adulterant in edible oil. At its present price, nobody 
would use whole Jatropha seed as stove fuel in India. 
Yours 
A.D.Karve 
On Thu, Aug 11, 2011 at 7:33 AM, <rongretlarson at comcast.net> wrote: 
> Jan and list: 
> 
> Thanks for the detailed responses. I hope you can continue to supply 
good 
> photos like those we have seen. Very helpful in figuring out how to make 
> pyrolysis stoves move faster. I think the central secondary air post has 
a 
> lot of promise. I believe a combination pot and stove combination could 
> give high efficiency with where you are heading, since you already have a 
> convective shield geometry. As said earlier, I think a control over 
> primary air is important and will prove valuable in more than the shutdown 
> operation 
> The use of the full jatropha seed seems to be a good solution where 
rural 
> folk need propety boundaries. In reading about jatropha, I see there are 
> big gains to be made in seed production through proper pruning (same as 
for 
> almonds) - so your stove system could have a bigger supply than now being 
> planned for and can maybe get to more urban folk as well. 
> 
> Ron 

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