[Digestion] 5000 dairy cow AD system

jonathan at bmpconsultants.com jonathan at bmpconsultants.com
Tue Jan 10 14:21:26 CST 2012


The issue here is that your looking for a commercially available system.
 Smaller systems are not commercially manufactured due to business models
proving the larger capital returns from the larger systems.  Their are many
 individuals that are "the garage inventors" that have successfully put
together these smaller systems.  Generally these systems have been created
using re-purposed material which has put the capital investment cost down
to near to nothing.   My suggestion would be to get a small team of
these ingenious individuals together and create your own solution.  Once
proven, simply market your solution as it appears to be an available niche
market.

On Tue, Jan 10, 2012 at 11:46 AM, David <david at h4c.org> wrote:

>
>
> On 1/9/2012 8:34 PM, Gould, Charles wrote:
>
> Mr. Harris,
>
>  I like your suggestion of smaller digesters. The problem is I have not
> been able to find a digester design robust enough yet cheap enough for a
> 100 cow dairy. Do you know where such a design exists? I have just about
> given up the notion that such a thing exists.
>
>
> This highlights a difficulty which may be partially fundamental (and to
> that degree absolute) but which seems largely conceptual, which is that
> because situations differ so much, and the need sufficiently moderate that
> there are few if any standard "replicable" designs for digesters, of the
> sort that would be used for, say, a large block of tract houses, where
> 1,000 houses might share four or five basic floor plans. And no doubt
> specifics in this area vary country-to-country...
>
> AgSTAR, of the US EPA, which could be said to be the primary
> government-based promoter of biogas in the US, is aimed strictly at
> manure-using digesters for farms with 500+ animals. For example, although
> it could hardly be said to be a digester at a modest scale (cost: $US10M+),
> the AgSTAR site deliberately (according to my conversation with a staffer)
> does not mention the Stahlbush Island Farms digester in Corvallis, OR,
> because it is fed plant matter exclusively-- therefore it is not a
> manure-based digester.
>
> It becomes a kind of self-fulfilling prophecy, because the system (in its
> academic support, among its industrial implementers and so on), becomes
> adapted to larger digesters, and therefore has that much more difficulty
> accommodating a different scale of thinking. But as well, it seems that the
> variability of energy prices in the US, where feed-in tariffs appear to be
> a political impossibility, has prevented the establishment of an industry
> that might work its way down to "smaller" digesters, after the larger
> digesters on the megafarms have been built, similar to what seems to be
> happening in Germany.
>
> I think there may well be a number of lower-cost building and process
> control technologies, perhaps along with energy crop co-digestion
> strategies, which could be put together in the proper circumstances to
> reduce the cost of digesters of a size below the AgSTAR limit in the US;
> but it would require a funder with vision to realize such an outcome.
>
> d.
> --
> David William House
>  "The Complete Biogas Handbook" www.completebiogas.com
> *Vahid Biogas*, an alternative energy consultancy www.vahidbiogas.com
>
>  "Make no search for water.       But find thirst,
> And water from the very ground will burst."
> (Rumi, a Persian mystic poet, quoted in *Delight of Hearts*, p. 77)
>
> http://bahai.us/
>
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>
>
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