Dear Esther,
Any question on practical experience with biogas technology at schools you can forward to me by What´s App +25578486245

Dear Esther,

I just follow your thread as a farmer (who knows a little about biogas) and ecologist. And I think I understand the trouble your in when you say: you have to calculate the economic benefit of a biogas digester replacing firewood. Because you need to know the installation costs, you need to know the quality and amount of material you get (just feces or kitchen scraps as well?) and you have to care for good OM.

Mayor Kumar gave you energy equivalents for firewood an biogas. To me this answers roughly the question you asked.  To pick up more knowledge about biogasification just ask him or other enterprises in India (or elsewhere). And you will find plenty under the links Elisabeth sent to you.

Beside all that there would be an ecological benefit when you replace the need for firewood in most regions in the world. This benefit ist never shown in this plain economic calculations and this is part our the disaster in a fast growing population . But the true costs of firewood have to be mentioned and discussed in societies and companies as well. The great mindshift we need.

Wish you luck and success,

Heiner

Dear Elisabeth,

Thank you for sharing! Unfortunately I am not finding the volume of biogas that is being produced. Maybe my question is too specific. With the theoretical values I received from Mayor06 there is no business to replace firewood with biogas. Fortunately there appears to be an opportunity regarding replacing LPG gas with biogas. School use some of this gas for science practicals, so we would start to focus more on households since approximately 50% of the households in the area use LPG. Then hopefully in the future we can slowly replace firewood for biogas.

Kind regards,

Esther

Hi Esther,

I am wondering if you have seen some of the biogas Kenya publications we have in the SuSanA library? There are
actually quite a few about biogas projects in schools, due to a GIZ project that was carried out a few years ago.

From the library page: www.susana.org/en/knowledge-hub/resource...publications/library

You can either filter by biogas technology which gives these 129 results:
www.susana.org/en/knowledge-hub/resource...l_7%5B27%5D=27&test=

Or filter by Kenya in addition to the other filter which narrows it down to these 12 results:
www.susana.org/en/knowledge-hub/resource...&vbl_20%5B458%5D=458

(the filters are those black boxes on the left side of the library)

Is this useful?

Regards,
Elisabeth

Dear Mayor Kumar,

Thank you so much for your reply. This is at least something! Of course it is always difficult to work with theoretical value because the energy content of firewood is very much dependent on what kind of cooking systems they are using. But it is a start at least. 

Thank you

Esther

Hi ! Esther,

Though I have no experience of working on schools for the bio gas requirement, however considering the following you can arrive at a reasonable solution:-

•      energy content of firewood                                              = 12 MJ/kg (net calorific value)
•      energy content ( average calorific value) of bio gas  =  21  - 23.5 MJ/cum
• Hence 1 kg of firewood would correspond to                   = 12/22  = 0.54 cum of Bio Gas in terms of calorific value

Since you already know how much firewood is being consumed by the school, the adequacy of the proposed Bio Gas System can be worked out.
 Best regards,

Mayor Kumar
New Delhi
India.

Reference: "Potential of bio gas production to reduce firewood consumption in remote high elevation Himalayan Communities in Nepal" technical paper by Thomas Gross, Subodh Sharma et al www.rees-journal.org/articles/rees/full_html/2017/01/rees 170021s/rees170021s .html. 

Hi all,

I am working on a project to install a biodigester in Kenya that produces 56m3 of biogas per day. Since I am working for a commercial company I have to calculate the business case. The biogas we want to sell to schools that currently use firewood. I know the amount of firewood that the schools use and how much they pay for this. However I do not know how much biogas they would use, hence making it difficult for me to calculate the business case. I want to make a rough estimate of the biogas volume that schools would use. Therefore my question is;

'Is there somebody that could help me out with some rough numbers regarding the volume of biogas that is being used in school including the number of students, preferable in Kenya?'

Kind regards,

Esther