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Washington State Department of Agriculture Page 15 Washington Dairies and Digesters, October 2011 Washington Dairy Digestion Potential As of July 2011, manure from four percent of the cows on Washington’s commercial dairy farms was being processed at dairy digesters and, with the addition of other organic waste, was producing a steady output of up to 4,150 kilowatts of electricity, as well as a range of other valuable products and benefits described in this report. This dairy digester activity is just a fraction of what may be possible.
Expanding digester development in Washington taps into the potential to produce a significant amount of renewable energy and provide tools to manage dairy nutrients and protect water quality, while bringing economic benefits to dairies, digester owners, and a variety of related businesses.
Nationally, there is a major push to increase anaerobic digestion on the nation’s dairy farms.
• In May 2010, EPA and the U.S. Department of Agriculture signed an agreement to promote renewable energy generation and slash greenhouse gas emissions from livestock operations by expanding technical assistance and outreach to help overcome obstacles to digester development.
• In a December 2010 report, EPA AgSTAR estimated that opportunities for biogas capture and use exist at more than 2,600 dairy farms across the US, including 125 dairy farms in Washington.
• In May 2011, the national dairy industry announced a goal to have 1,300 anaerobic digesters operating across the country by 2020.
According to EPA AgSTAR, the potential for positive financial return appears to be most likely at dairy operations with milking herds of at least 500 cows and anaerobic lagoons or liquid slurry manure management systems. While herd size is an important factor in determining digester potential, many other factors come into play, including location, potential markets for electricity, heat or CNG, local utility interest, existing infrastructure, options for manure movement and management, and farmer interest. In particular, utility policies and low electricity pricing in Washington make project financing more difficult. Washington’s average retail electricity price of 6.6 cents/kWh in 2009 was well below the national average of 9.82 cents/kWh 9.
Regulatory Factors The regulatory environment has also been a factor as WSDA and other agencies consider how to carry out their responsibilities when presented with the growth of dairy AD systems in the state. Permitting requirements and other regulatory aspects related to digesters are in a state of evolution at both state and local levels. Regulations related to land use, zoning, water quality, air quality, solid waste management and dairy nutrient management may all come to be important factors during digester development. Regular communication among the agencies, the dairy industry, digester developers, and university researchers have helped in bringing issues and possible solutions to light and in working towards coordination of approval and permitting processes and regulatory consistency. For example, local health jurisdictions, conservation districts, the Department of Ecology and WSDA continue to work together on implementing the requirements surrounding the solid waste permit exemption that the six dairy digesters operate under.
Changes in technology or in digester operations – some digesters are looking to expand feedstocks beyond the limitations of the solid waste permit exemption – are likely to trigger further discussion and regulatory decisions about environmental and public health issues that will affect development.
Page 16 Washington State Department of Agriculture Washington Dairies and Digesters, October 2011 Dairy Size and Anaerobic Digestion Though EPA AgSTAR uses 500 cows as the threshold for digester potential, Washington’s experience indicates that a farm with less than 500 cows can successfully contribute to a centralized digester.
Figure 4 shows Washington’s 433 commercial dairies by size, with yellow diamonds indicating the size category for the eight dairies that currently contribute manure to the six digesters.
Potential Growth in Digesters by 2020 Washington’s experience with dairy digesters indicates a range of successful approaches. Based on the rate of development in Washington to date, an additional 6 to 9 dairy digesters could be expected to start operation by 2020. Of course, whether these digesters used manure from 100 cows or 5,000 cows would make a big difference in their impact.
This projected future growth may be a very conservative estimate. As the environmental benefits of digesters are realized, as financial, policy, and regulatory hurdles are overcome, and as technology and markets for co-products mature, dairy digester development may become more rapid in Washington.
In Development: Rainier Biogas
Rainier Biogas, the third digester project in Washington by Farm Power Northwest, is under development in King County, near Enumclaw. Construction has not started yet but, when finished, this digester is intended to take manure from at least three nearby dairies (about 1,500 cows) and to accept other pre-consumer waste feedstocks. The design is a GHD/Andgar hybrid plug flowcomplete mix with a 1 MW cogeneration system. The plans include a nutrient recovery system similar to the system recently installed at FPE Renewables.
Information for Future Digester Operators Here are some insights, from WSDA conversations and work with current dairy digester operators, that may be useful for future projects.
• Careful planning and organization are key to success.
• Negotiating the different permitting processes can be a major challenge during development.
• Failure to apply for required permits can seriously delay the completion and operation of a project.
• A good relationship with a cooperative power utility is essential to negotiating power purchase agreements (both duration and price), intertie agreements, and potential transfers to another utility.
• Plan ample time for dairy nutrient management plans to be updated. No non-manure feedstock can be used in the digester until the updated DNMPs are approved.
• Manure handling systems (especially pumps) are the most prone to failure. Build in redundancy to minimize the effect if these systems fail.
• Minimize costs by doing your own maintenance as much as possible.
• To be successful you have to rely on a variety of revenue streams. Flexibility in marketing different products allows operators to weather changes in feedstock availability or low power prices.
Other Types of Anaerobic Digestion in Washington Anaerobic digestion can be used to produce energy from a wide range of biodegradable materials, including municipal biosolids, a wide range of food wastes, and even municipal solid waste. This report focuses on anaerobic digestion at dairies, but AD also takes place at municipal and industrial wastewater treatment facilities in Washington.
Municipal Wastewater Treatment: The state’s largest wastewater treatment facilities have anaerobic digestion systems, although not all of them are using biogas for electricity or heat production.
Anaerobic digestion with energy generation is taking place at both the King County South and West Point plants and at LOTT in Olympia. These plants use the biogas for electricity production, plant heating, or both; the biosolids are land applied as a soil amendment, or used to produce compost or potting mixes.
Industrial Wastewater Treatment: According to a company news release, the J.R. Simplot potato processing facility in Moses Lake installed a 20 million gallon digester in 2007 that treats wastewater on site. The biogas produced is used to heat process water, reducing the plant’s natural gas use.
Municipal Organics Treatment: There are two digesters for post-consumer organics currently in the planning stage in Washington: one at the Cedar Grove composting facility in Snohomish County, and the other at Barr Regional Bio-Industrial Park in Lincoln County.
References and Endnotes
Information used in this report is from the following sources:
Dr. Keith Bowers, Multiform Harvest Digester operators at FPE Renewables, George DeRuyter & Sons Dairy, Qualco Energy, Farm Power Northwest, and Van Dyk-S Holsteins Environmental Protection Agency, AgSTAR Program Professor Craig Frear, Washington State University United States Department of Agriculture, National Agricultural Statistics Service Washington State University, CSANR Research Report 2010-001, 2010 Washington State Department of Agriculture, Dairy Nutrient Management Program Endnotes ASAE Standard D384.2, Manure Production and Characteristics, American Society of Agricultural Engineers, March 2005.
2The three size categories correspond with the U.S. Environmental Protection Agency categories for dairies under the federal Concentrated Animal Feeding Operation (CAFO) rules.
AgSTAR is a collaborative program between EPA, the U.S. Department of Agriculture, and the U.S.
Department of Energy with the objective of supporting anaerobic digestion systems for livestock manure management. http://www.epa.gov/agstar/ SSB 5797 was enacted as Chapter 178, Laws of 2009. The specifics of the regulatory framework are codified in RCW 70.95.330. The Department of Ecology and local health departments have regulatory oversight for AD co-digestion facilities under the state’s solid waste law. The guidelines for digesters operating under the exemption are available at http://www.ecy.wa.gov/pubs/0907029.pdf.
5 USDA Natural Resources Conservation Service (NRCS) Conservation Practice Standard 366, Anaerobic Digester C. Frear, W. Liao, T. Ewing, and S. Chen. 2011. Evaluation of Co-Digestion at a Commercial Dairy Anaerobic Digester, Clean – Soil, Air, Water, 39(7): 697-704.
F. Alatriste-Mondragón, P. Samar, H. H. J. Cox, B. K. Ahring, and R. Iranpour, R. 2006. Anaerobic Codigestion of Municipal, Farm, and Industrial Organic Wastes: A Survey of Recent Literature, Water Environment Research 78(6): 607-636.
R. Braun, E. Brachtl, and M. Grasmug. 2003. Codigestion of Proteinaceous Industrial Waste, Applied Biochemistry and Biotechnology 109: 139-153.
United States Energy Information Administration, State Electricity Profiles 2009