Bioplex Home Background Info Project Research Links Acknowledgements Contact Us	Farm Digesters vs. Central Digesters It is possible to consider anaerobic digester applications for single farm units or combine wastes from different farms to benefit from economy of scale and where a single unit would not be economically justifiable. A single hog farm unit would need to have 10,000 hogs, a cattle farm about 200 milking cows and a poultry farm about 250,000 layers or broilers before they become efficient enough to make a reasonable return from selling the power and making fertilizer. Operations with fewer animals may consider on-farm anaerobic digesters for odor control or nutrient stabilization, but may not expect sufficient biogas yields to create profit from power generation. Attitudes are changing in regard to the incentives for using anaerobic digestion. The public is now expressing a positive attitude toward renewable energy and toward environmental sustainability and are willing to contribute toward those ends. The advantages of anaerobic digestion can be determined fiscally in such a way that the burden of owning and operating digesters can be spread over all of those who benefit from them, not just the livestock producers. Ownership structures that need to be evaluated include: Complete third-party ownership Joint ownership by the farmers and project developers Total ownership by the farmers Total ownership by a utility The ability to use EQIP funds from the U.S. Farm Program will also play a major role in determining the ideal ownership structure and financing alternatives. Theoretically, EQIP grants could fund up to 50% of the project, if the necessary conditions are met and the funds are available. The Farm Bill designates that 60% of the total EQIP monies be used for livestock waste projects, but, even so, demand for the funds will likely outstrip the supply. Active intervention by the state NRCS office could be decisive in determining the availability of such funding for this project. That fact illustrates the importance of having the non-dairy participants actively involved in the project. Potential EQIP funding is so important that its availability alone might dictate the recommended the ownership structure. The recently signed energy bill also provides financial incentives to build power-generating anaerobic digesters. The availability of Industrial Development Bonds (or similar bonds) would favor a different ownership structure, one in which at least one (and perhaps more) public or private non-farm entity would be required to "support" the bonds. Such bonds would carry a very low interest rate with the agency supporting them. Such an agency must justify such support by an offsetting benefit derived from the project. Digester Site Characteristics For the evaluated project, required and recommended site characteristics need to be delineated including minimum acreage required and infrastructure (roads, gas, water, power lines). Certain other minimum requirements will be dictated by characteristics of the selected digester plant. For example, export of nutrients from the farms to other uses may be a critical component of the project. It may be beneficial that the plant be located near a nutrient sink - a large user of water-borne nutrients. Zoning, proximity to neighbours, waste hauling miles, suitability for expansion are other considerations which are important. There will be trade-offs which must be considered and that can be assessed with the aid of a computer model. For example, if the only suitable site available was located far from the center of gravity of the affected farms, the computer model would tell, all other factors being equal, how many miles the material could be hauled while maintaining a specified minimum ROI. Power rate structures need to be determined, prospective locations for a collective digester, road mileages from each farm to those sites, certain capital items such as trucks and specialized trailers for hauling manure. Places where nutrients can be utilized in an agronomic manner without going back to the farm from which they came need assessing. The solids from a thermophilic digester are usable in certified organic food production and have been shown to have a premium market value at other locations. The project which best meets the tests of feasibility has the following characteristics: Waste is collected daily from the participating farms and trucked to a central digester location. The average hauling distance would need to be determined closely. At the digester site, the manure is converted biologically into biogas and a liquid effluent with suspended solids, which is essentially odor- and pathogen-free. The biogas is converted to electrical power and added to the grid. Digester effluent is separated into a solid component and a liquid component. The solid component is further processed and sold as organic fertilizer - bulk or bagged. The liquid portion may be further processed into a concentrated liquid (also organic) fertilizer. The liquid fertilizer is land applied on the land of participating farms or exported from the region for application on other cropland. Alternately, it could be further reduced and blended back into the solid component, eliminating the need for land application. The centralized waste conversion project would need to meet the tests for feasibility because: The technologies are proven and stable. Anaerobic digestion is used in many applications around the world. Technical advances in the past few years have brought the economics of downstream treatment into a range where it can be used successfully. It serves the needs of the participants: Farmers -- Removes completely the burden and costs of manure management. Manure is removed from their property and does not return. Liquid nutrients are applied to their land if/as they are needed. All of the mandated nutrient management compliance record keeping can be done at the central site and farmers are freed to manage their business, including expanding if the new facility enables them to do so. Utilities - Produces both renewable power and environmental incentives. The electricity is valued as generic power, but the incentives allow the utilities to meet their renewable/environmentally challenge. Incentives include a carbon credit (greenhouse emissions reduction), a renewable power component (Green Tags) and a Federal Production Tax Credit. Values for the utility partners are well defined and predictable. Public - Potential odor problems and surface water runoff concerns from land application of manure are completely eliminated. Raw manure is converted into a benign, discharge quality water which can re-enter the watershed without pollution concerns. The project may stimulate additional economic activities such as 1) blending and bagging of certified organic fertilizer, 2) organic and/or hydroponic vegetable production, 3) mushroom production and 4) other specialized organic/environmental business activities which utilize co-products of any centralized project. Bioplex Home  |  Background Info |  Project Research Links  |  Acknowledgements  |  Contact Us Copyright 2005 Bioplex Project - Site Designed and Developed by WV Designs