ASERTTI Digester Performance Partnership
Phase Two Digester Program: Pilot Performance and Cost Database for
Anaerobic Digester Systems for Livestock Manures
Through a grant from the Blue Moon Fund, ASERTTI embarked on Phase Two of
the digester program and completed a study titled "Pilot Performance and
Cost Database for Anaerobic Digestion Systems for Livestock Manures" to
better understand how the protocol was being used, and to find ways to
increase the volume and quality of performance data available to the public.
The Energy Center of Wisconsin, an ASERTTI member, was the lead on this
Purpose: The purpose of Phase Two of the digester program work was
to help overcome the challenges of collecting new data and analyzing
existing ASERTTI/AgSTAR protocol driven data, promote greater levels of
testing, create recommendations for digester operation improvement, and
provide public access to the protocol information.
Background: Several years ago, ASERTTI members determined that the
relatively high failure rates among anaerobic digesters in agricultural
settings were an impediment to realizing the potential value of livestock
manures as a renewable source of energy as well as the associated
environmental, energy efficiency, and energy cost benefits. Thus,
ASERTTI undertook the first phase of a
protocol program as a means to identify successful design, feedstock,
and operation combinations and promote the growth of this important
technology. Through Phase One funding, ASERTTI, in
partnership with USDA Rural Development and EPA's AgStar Program, developed
a detailed set of protocols to assess digester options, designs, and
performance. However, it quickly became evident that the
challenges to encourage testing and analysis were considerable.
Phase Two of the digester program was developed to address the
significant outreach required for investment and the considerable analytical
time necessary to fully understand the data.
Results: An MS Access database populated with data on installed
farm anaerobic digester systems and pre-made reports summarizing performance
data for Web posting were developed. The final report for the ASERTTI
project, Pilot Performance and Cost Database for Anaerobic Digestion Systems
for Livestock Manures, describes the results from the examination of the
early attempts at using the protocol with a primary focus on the means
by which barriers could be removed or reduced to expand the protocol's
use and increase its utility. Attempts to use the
protocol have been sparse, and the successful gathering and reporting of
protocol adherent data even rarer. This is due to a number of factors that
have deterred researchers from using the protocol, and others that prevented
successful completion of monitoring efforts once the decision to use the
protocol was made. Some of these issues and complications are further
discussed in the Findings section of this report.
Next Steps: The ASERTTI/USDA Rural Development/AgSTAR
protocol serves an important function in providing a standard means of
characterizing and evaluating farm-based anaerobic digester systems as well
as monitoring their performance. The early applications of the protocol
described in this report provide valuable information on barriers to its
use. The new international protocol will take an important step in
encouraging more widespread use of standardized characterizations by
offering tiered options of varying cost rather than "all-or-nothing"
adherence. It appears, however, that funding for full protocol use will
continue to be an issue, and that any efforts to develop more farm system
data using the protocol will need to be funded by some entity other than the
farm, the digester designer, or the involved utility. None of these groups
alone will likely be motivated enough to bear the expense.