[Digestion] Costs of different household biodigesters

Tue Sep 28 19:48:18 CDT 2010

HI All,

We have reinforced polyethylene geomembrane digester in a variety of sizes
that come as a "kit" with all connections, biogas reservoir, geo-textil
ground liner, gas management systems with high pressure relief valve and
filter, and simpler burner.  The system can be installed in the ground or
above ground, and the material has a 20 year guarantee.  We service and
guarantee the systems for two years, and offer low cost service for the life
of the system (currently only in Mexico).  There may be additional costs
associated with a roof or greenhouse structure for the digester.  Note that
Jaime has also included the price of a greenhouse cover for the Bolivia
systems, which many others leave out.  Our intention is no use of concrete,
but sometimes there is a bit of work needed to make the pig-pen or stable
drain adequately to the digester.  Retail prices (all in) are below, and the
sizes refer to m3.  We have made systems of 1 and 2 m3 for test purposes,
but these are not much less expensive than that of 4 meters as the entrance
and exits cost the same and our asembly labor is nearly the same as well
(therefore larger systems are less expensive per m3).  From these prices we
offer discounts for good programs, low income families, and for higher
quantities purchased.

  Bolsa Sizes Costo (MXN) Costo (US$)  4 $9,292 $743  8 $12,802 $1,024  12
$16,312 $1,305  16 $19,823 $1,586  20 $20,515 $1,641  30 $28,813 $2,305

We also built a lot of regular plastic digesters in the style of Jaime
(Taiwanese or Preston Digester), and the costs in Mexico (same components,
double layer bag), were only about 10-20% lower.  This is higher than Jaime
has shown, which could be because of higher material prices in Mexico.

For SNV's program in Africa, their prices for the concrete dome digesters
were nearly identical for those I listed above.  We are quite a bit cheaper
overall as our system requires only a couple hours (one technician installs
3 per day) versus a week of construction.  Also, our materials prices are
much cheaper at higher volumes.

It is important to note that it can be very misleading to state "costs" for
these types of systems.  These sorts of speculations often seem to project
the idea that someone is building the system in their backyard, and
therefore it is appropriate to externalize many of the costs.  When
installing the "appropriate tech" style bag digester, there are a few days
of installation preparation, plus acquisition of materials, etc.  Just
pulling off the price tag of the materials often does not appropriately
encapsulate the full cost of the installation.  This tends to set up false
expectations to those who would like to promote the technology, or when a
government wants to spend to have them installed.  I beleive (please comment
Jaime) that the Bolivia program has a subsidy in place for installation,
transport, and labor, which is crucial to consider.  The families are also
required to supply certain materials and labor for the installation.

I also have a full study of Life Cycle Costs, which is arguably a better
measure of the cost of a system that you want to last a long time.  With a
longer projected life span (and repairability), geomembrane digesters were
about 40% less expensive over a 10 year span than lower quality plastic
systems.  Dome digester tend to hold their value longer in some cases, but
there is a higher abandonment rate due to slow gas leaks that reduce end
user satisfaction.

Saludos,

A

On Tue, Sep 28, 2010 at 6:03 PM, Jaime Marti Herrero <
tallerbiogas at hotmail.com> wrote:

>  Hi
> plugflow digester made of tubular polyethilene cost in Bolivia:
> -For cold climate : 230 us$ with 6.5m3 of liquid volume, green house, three
> biogas reservoirs, and one bunner
> -For valley climate: 185 us$ with 3,5m3 of liquid volume, 66% sun cover,
> two biogas reservoirs and one bunner
> -For tropical climate 168 us$ witk 3 m3 of  liquid volume, 66% sun cover,
> two biogas reservoirs and one bunner
> all of are load with 20kg of fresh cow manure and 60 liters of water per
> day, producing about 700 liters of biogas per day.
>
> We have done 1m3 tubular polyethilene digester for research considerations
> using 2m circunference plastic and 4,8 meters long. i dont have the cost
> because a plastic factory donate this material to our laboratory.
>
> i hope this helps
> keep in touch
> jaime
> -----
> *Jaime Martí Herrero*
>
> *Technical advisor of biogas for the GTZ-Bolivia*
>
> *CIMNE (*www.cimne.com <http://www.cimne.com/beegroup>)
>
> *Building Energy and Environment Group*
>
> *International research cooperation area*
>
> La Paz · Bolivia
>
> Tel. (+591)-73 090 621
>
>
>
>
> *BIOGAS AND BOLIVIA*
> -Taller Biogas Bolivia
> http://tallerbiogas.blogspot.com
> -Video: Biodigester installation in bolivian Altiplano
> http://es.youtube.com/watch?v=3Sl0XEN5Bgo
> http://www.youtube.com/watch?v=Vs0JuV8WD_c
>
> -Manual gratuito-Biodigestores familiares: Guía de diseño y manual de
> instalación
> http://www.upc.edu/grecdh/pdf/2008_JMH_Guia_biodigestores.pdf
>
>
>
>
> ------------------------------
> Date: Tue, 28 Sep 2010 10:50:06 -0700
> From: ivomdb at gmail.com
>
> To: digestion at lists.bioenergylists.org
> Subject: [Digestion] Costs of different household biodigesters
>
> Hi all,
>
> I would like to know if anyone knows or have a good estimate of the cost of
> the following small scale biodigesters:
>
> 1- Plug-flow polyethylene biodigester type (like the ones in Bolivia)
> (between 1-10 m3).... I don't know if it's possible to build one with such
> small size like 1m3
> 2- Chinese fixed-dome (between 1m3-10 m3)
> 3- ARTI type biodigester (1-2 m3)
>
> Thanks,
>
> Ivo Oliveira
>
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-- 
Alexander Eaton
Sistema Biobolsa
IRRI-Mexico

Mex cel: (55) 11522786
US cel: 970 275 4505

alex at sistemabiobolsa.com
alexanderb.eaton at gmail.com
sistemabiobolsa.com
www.irrimexico.org
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