Anaerobic digesters convert the energy stored in organic materials present in manure into biogas.  Biogas can be fed directly into a gas-fired combustion turbine.  The type of turbine most often used for small-scale electricity production is the microturbine.  Combustion of biogas converts the energy stored in the bonds of the molecules of the methane contained in the biogas into mechanical energy as it spins a turbine.  The mechanical energy produced by biogas combustion in an engine or microturbine spins a turbine that produces a stream of electrons, or, electricity.  In addition, waste heat from these engines can provide heating or hot water for use on farm.

As a fuel, biogas composed of 65% methane yields about 650 Btu per cubic foot.  Often used when designing systems for the anaerobic digestion of manure, these energy estimates can predict the amount of power production per animal.  General estimates predict one kilowatt of electricity production requires five to eight dairy cows.

The MREC and the WI DATCP -- Department of Ag., Trade and Consumer Projection -- Wisconsin Biogas Development Group have assembled the following list of current resources on the topic of anaerobic digestion. Choose from the menu below or scroll manually.  If you have other links, or if you have articles that would be of interest to our readers, please forward them to the editor.

Anaerobic Digester Basics

• Fundamentals of Biogas Production from Dairy Manure
• Dairy Waste Handbook
• Facts on Methane Production from Animal Manure
• Definition & Demo Sites of Anaerobic Digestion
•  Digester Self Evaluation and Checklist
• Creating Fuel from Manure is a Hot Topic -- Again!
• Farm Energy from Manure
• National Food & Energy Council, NFEC Agricultural Methane Recovery
• Anaerobic Digestion -- of farm and food processing residues.  This publication provides information on the planning and development of a sustainable industry.
• Overcoming the Limitations in Anaerobic Digestion of Dairy Wastes
• Anaerobic Digestion and Farm Odors

 

Uses for Biogas other than Electricity Production

• Biogas as a Vehicle Fuel -- a European Overview (Oct. 2003)

 

Financial Assistance & Economics of Using Anaerobic Digesters

• Farmers Need to Check out Funding for Renewable Energy Ventures, says (WI) DATCP Secretary (June 28, 2002)
• The Economics and Feasibility of using Anaerobic Digesters on Small and Mid-size Dairy Farms

 

Farmers' Digester Experience

• Midwestern Farmers Convert Livestock Manure into Electricity (Nov. 4, 2002)
• Temperature Phased Anaerobic Digestion System Monitoring Project at Tinedale Farm, Final Report
• Habenschilds Farm Anaerobic Digestor -- Final Report, in Princeton, MN
• Jamaican Poultry Farms
• Langerwerf Dairy in Durham, CA
• Tinedale Farm in Wrightstown, WI. [Note: This is a study funded through the Energy Center of Wisconsin.]

 

Anaerobic Digester Studies

• The Potential of Thermophilic Anaerobic Fermentation for Biological Methane Production and Odor Control Using Swine Manure as a Substrate
• Paper: Generating Methane Gas From Manure (Version #1, 1993)
• Methane Recovery from Animal Manures -- The Current Opportunities Casebook, National Renewable Energy Lab
• Anaerobic Digester Methane to Energy, a [WI] Statewide Technological and Economical Feasibility assessment of considering A.D. to produce electricity.
  • National Agricultural Library - Topical Bibliographies of Agricola Database (USDA)
    • Dairy Farm Manure Management - 1 (129 Citations: January 1988 - November 1994)
    • Dairy Farm Manure Management - 2 (80 Citations: January 1995 - September 1997)
• Agricultural Biogas Casebook -- 2004 Update, Great Lakes Regional Biomass Energy Program, Council of Great Lakes Governors
• Anaerobic Digester Electrical Technologies, Mark Moser, RCM Digesters
• ABEN-97: Evaluation of Anaerobic Digestion Options for Groups of Dairy Farms in Upstate New York. [Note: This180-page publication is available for a fee of $18.00 (includes shipping and handling).]
• Anaerobic Digestion in Rural China, City Farmer, Canada's Office of Urban Agriculture
• Northern Ireland - Farm Waste Anaerobic Digesters

 

Organizations that Support Anaerobic Digestion Endeavors

• AGSTAR: U.S. Environmental Protection Agency (EPA), the U.S. Department of Agriculture, and the U.S. Department of Energy program to encourage the use of biogas.
• Minnesota Project
• Minnesota Institute for Sustainable Agriculture
• Focus on Energy (promotes energy efficiency technology in Wisconsin)
• National Renewable Energy Laboratory (a national laboratory of the US Dept. of Energy)
• Biomass Research & Development Initiative
• US Department of Energy Office of Energy Efficiency and Renewable Energy
• Iowa Energy Center
• Natural Resources, Agriculture, and Engineering Service (NRAES)
• Western United Resource Development, Inc

 

• International
  • Anaerobic Digestion Network, AD-NETT is a network of professionals working in anaerobic digestion of agro-industrial wastes in Europe and Canada. Its prime motive is to enable exchange of information and experience, and to disseminate this information to relevant organisations, such as potential users and developers.  [Note: Their Web site previous had URL to the following reports:
    • Economics of anaerobic digestion of agricultural waste
    • Environmental Aspects of Biogas Technology
    • Legislation in different European countries regarding implementation of anaerobic digestion
    • Hygienic and sanitation requirements in biogas plants treating animal manures or mixtures of manures and other organic wastes
    • Process Design of Agricultural Digestors
    • 13 Country Reports of Status of Anaerobic Digestion Activities ]
  • Renewable Energy Association , British BioGen has merged with the Renewable Energy Association. BioGen was the trade association to the United Kingdom's bioenergy industry, and now as the REA, programs for other renewable energy resources are available. The REA’s main objective is to secure the best legislative and regulatory framework for expanding renewable energy production in the UK. The site also has a number of "Resource Groups", some looking at individual renewable energy technologies, others focussed on sub-sectors of the industry.
  • ManureNet Canada
  • Swiss Biogas Forum - Homepage

 

• Private Companies
  • Anergen Corp. (Division of Commercial Engineering Corp.)
  • Environmental Engineering Company -- transforming waste into beneficial components
    • Dairy Waste Anaerobic Digestion Handbook
    • Overcoming the Limitations in Anaerobic Digestion of Dairy Wastes
    • Anaerobic Digestion and Farm Odors
  • Environomics - a designer of manure biogas digestion systems.
  • GHD, Inc.
  • Microgy, Inc.
  • Resource Conservation Management, Inc. - a designer of manure biogas digestion systems.

The Wisconsin Biogas Development Group was formed to bring focus to the
concept of the utilization of manure, particularly from Wisconsin's dairy
farms, for the production of methane to produce electricity or heat.
Potentially, electricity from manure could add to the financial bottom line
for farmers or at least offset manure management expenses. It could also
become a factor contributing to the State's reduction in our reliance on
imported energy. The group, while spearheaded by representatives of several
state agencies, has benefited immeasurably from routine participation by
dairy farmers, engineers, electric utility representatives, communications
professionals, consultants and others.

The Wisconsin Department of Agriculture, Trade and Consumer Protection
(DATCP) currently hosts the group. If you would like to be added to the
distribution list of this group, please contact Roger Kasper.

WBDG Meeting Presentations

460 Henry Mall University of Wisconsin-Madison Madison, WI 53706 608-262-1228 (fax) email: mrec@uwex.edu