Thermal, manure-to-energy systems have great potential to benefit both farms and the environment, but they are still relatively new. The technology comes with many variations, some of which are still in development. Existing commercial products have not been on the market for long, and long-term performance data from systems that have been in continuous operation in a farm-setting is currently not available.
Still, progressive farmers and manufacturers have found success with manure-to-energy systems that are well-matched to the farms they serve. Asking good questions early in the process is key to finding smart solutions for three important goals: manure management, financial savings, and environmental stewardship. Related: For information on other types of technologies, visit the manure treatment technologies home page.
Questions to Ask About Your Farm
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1. How much manure or poultry litter is available for use as fuel?
Many farms use manure and poultry litter nutrients as fertilizer. If your farm produces more manure or poultry litter than needed for use as a fertilizer, this surplus material may be available for use as a fuel.
The amount of fuel you’ll need to make the system cost-effective depends on your goals and the type of system you install — but the maximum size of the system will be defined in part by the amount of manure or poultry litter available to feed it.
2. How much energy do you want — or need — to produce?
The best way to get an accurate sense of your farm’s energy needs is to conduct an on-farm energy audit. An audit will outline your farm’s energy needs and identify low-cost opportunities to conserve energy. This will help you select an on-farm energy system that is truly matched to your farm’s needs.
On some farms, conserving energy may save more money than installing and operating a manure-to-energy system. If you decide to install a manure-to-energy system, conserving energy first can reduce the size the system and the start-up costs that go with it.
Contact your local office of the USDA Natural Resource Conservation Service to ask about cost-share funds that support on-farm energy audits.
3. Thermal systems work best with drier feedstocks. Is your farm’s manure or poultry litter dry enough for the system to work efficiently?
Most thermal technologies proposed for use at the farm scale perform best if the manure or poultry litter contains less than 35% moisture. Because of this, thermal systems are typically fed by drier manure from beef cattle feedlots and poultry litter.
The drier the manure, the better your thermal system will operate. Manure storage facilities can have a big impact on moisture content. Consider this issue yourself, and then follow up with vendors as you select a system. Ideally, the vendor will be able to test the proposed system using manure or poultry litter from your farm prior to purchase.
4. How will you handle the ash and bio-char co-products produced by the system?
Thermal processes that produce energy from manure and poultry litter also generate co-products that contain valuable plant nutrients. Combustion and gasification create ash, and pyrolysis creates biochar. In some cases, these materials can retain high temperatures when they exit thermal manure-to-energy systems and may need special storage facilities to protect farm staff and surrounding structures and allow the material to cool prior to transport.
Studies have taken place to determine how well plants can take up the nutrients in these co-products. The plant availability of phosphorus and potash ranges from 80 to almost 100%, depending on the type of technology that produces it.
It is important to consider the fate of the ash and biochar co-products, and ideally to have a market established for these materials in advance of installing the technology on your farm. Questions to consider include: How will you manage the co-product? Would you like to sell it yourself or through a partnership with the technology vendor? Is the potential revenue stream from the co-product needed to obtain a return on your investment?
5. For contract growers, is the integrator supportive?
Poultry growers who have contracts with integrators should confirm that the integrator is supportive of the project, especially if the project will provide heat to poultry houses. Give special attention to these questions:
- If the integrator pays all or some portion of the propane costs, are they willing to pass the cost savings onto the grower?
- Will an alternative heating system impact the settlement calculation (that is, the amount the grower gets paid for the birds)? In some cases, this payment is based on the farm’s production costs — including propane use — compared to other growers in the region.
6. Are you comfortable with the estimated, long-term costs for operation and maintenance?
On-farm thermal energy systems require significantly more time and maintenance than propane heating systems typically used in animal housing. According to the USDA Natural Resources Conservation Service technical standards, you should expect an equipment lifespan of approximately ten years.
Recognize that you will have operating and maintenance costs, and ask vendors to provide detailed estimates.
7. Are grants or loans available to support your start-up costs?
In some states, the USDA Natural Resources Conservation Service offers a cost-share program for on-farm thermal systems fueled by manure.
In the Chesapeake Bay region, the Environmental Finance Center at the University of Maryland has developed a guide that includes state and federal financing opportunities.
Questions to ask about: your farm | permitting | the technology
Questions to Ask About Permitting
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1. What is the general status of permitting requirements?
On-farm thermal systems may need to meet both federal and state permitting requirements related to air quality. The requirements for your project depend on the type of technology and size of the system. Keep in mind that these systems are new to permitting agencies as well as the farmers who want to use them — the rules vary and some are still being developed. Check on the specific rules that apply to your location and ask about the questions that are still being explored.
2. Will federal air quality permits apply to my system?
Federal air permitting rules for on-farm installations largely depend on whether manure or poultry litter proposed for fuel meets the EPA’s fuel legitimacy criteria.
Combustion of fuels in on-farm thermal systems using hot water to deliver heat usually falls under the EPA’s Boiler MACT rules. Depending on the size of the system, you may be required to notify the EPA and/or your state air permitting agency that the technology will be installed and submit biennial reports documenting that the equipment has been tuned-up at least once every two years.
If your manure or poultry litter does not meet the EPA’s legitimacy criteria, it will be considered waste instead of fuel. Combustion of waste is categorized as incineration. Federal permitting requirements for incinerators are not cost-effective or technically feasible for farm-scale systems. This makes it very important to ensure that your project meets the fuel legitimacy criteria before moving forward with installation.
Determining fuel legitimacy may be easier if you propose an on-farm thermal system that will capture energy only from manure or poultry litter produced on the farm. Under these conditions, you can make a fuel legitimacy determination through a “self-determination” process, without seeking federal or state approval. However, farmers using self-determination to meet fuel legitimacy standards should keep records justifying their decision.
The Farm Manure-to-Energy Initiative partners worked directly with the EPA and USDA Natural Resource Conservation Service to develop a checklist that can help determine whether your manure and poultry litter meets the EPA’s fuel legitimacy criteria. This is not an official EPA guidance document and should not be viewed as legal guidance, but it’s a good place to start. View the checklist….
Contact your state air permitting agency or your regional EPA non-hazardous secondary materials or air permitting office for more information about the fuel legitimacy process, farmer self-determination, and ensuring that your farm is in compliance with federal rules. Visit the EPA’s Boiler Compliance at Area Sources website for helpful information.
3. Will state or local permits apply to my system?
State and local governments may also require permits for on-farm thermal systems. These could address issues such as air emissions, fate of the ash or biochar, construction, or zoning.
The requirements may vary significantly from one place to another. Check on state and local permitting requirements early in your planning process.
Questions to ask about: your farm | permitting | the technology
Questions to Ask About the Technology
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1. Has the vendor’s technology actually been used on a farm using manure or poultry litter as a feedstock, operating at its full commercial size?
Farms are unique environments and technologies developed for other industries do not always perform well in farm settings. Vendors of wood-fired boilers may claim their systems can use manure or poultry litter as feedstock, but be wary of these claims. Ask if the system has actually been in operation, fueled by manure or poultry litter, over an extended period of time. If so, ask for a site visit to see the system in operation. Ask if you can speak to other farmers who are using the technology.
2. Is the amount and composition of manure or poultry litter from your farm compatible with the proposed system?
Ask the vendor to define the amount of manure or poultry that will be needed to run the proposed system on an annual basis. Be sure that the amount of excess litter from your farm can meet system requirements.
Manure and poultry litter also vary considerably from farm to farm. This variability can cause fuel handling and performance issues. For example, the Farm Manure-to-Energy Initiative has encountered differences between turkey and broiler chickens that impacted performance. Moisture content also plays a role.
To avoid surprises, ask the vendor to test your farm’s manure or poultry litter for compatibility with the proposed system. Some vendors routinely do this at their manufacturing facility. If this is not an option, take the time to locate existing installations that use manure or poultry litter as a fuel. Analyze differences between the manure or poultry litter from the sample sites and that from your own farm; ask the vendor to help evaluate whether or not those differences — such as particle size or moisture content — might impact system performance.
A company with a track record for on-farm deployment using manure and/or poultry litter from a variety of operations will have a much greater chance of success than a company with no on-farm experience or history using manure or poultry litter as a feedstock.
3. What infrastructure and space is required to install the system and any associated manure storage facilities?
Your manure-to-energy system will require a roofed shelter for the thermal equipment. The shelter can be completely enclosed or open on the sides, depending on the vendor’s requirements, the local weather, and the farmer’s preference. You will also need a power supply for the system and potentially running water.
The smallest footprint for broiler farms in the Manure-to-Energy Initiative is roughly 30 feet by 30 feet, while footprints for larger installations can be in the range of 60 feet by 60 feet. Much larger systems have been developed for other types of farms and cooperatives. Space requirements depend on the size of the equipment, which in turn depends on the output capacity, as well as whether the system is producing heat, electricity, or both.
You will also need covered storage for the manure or poultry litter to ensure that fuel fed to the thermal system is dry. Ideally, the storage structure should meet NRCS technical standards.
Locating the thermal equipment as close to the storage area as possible will reduce the time needed for hauling manure or poultry litter to the system. However, the location of the thermal system should also be balanced with the distance to the poultry houses so that installing plumbing duct work is not too costly. Thermal systems that deliver heat via hot water offer the most flexibility with respect to location, while thermal systems that deliver heat via hot air will need to be located as close to the heated buildings as possible.
Depending on the system and the farm layout, it may be possible to install the system in an existing manure or poultry litter storage facility. The technology vendor can help you determine if this is an option. However, if the poultry litter or manure storage facility was paid for with state or federal cost-share funds, it is important to confirm with your funding agency that locating manure-to-energy equipment in the facility does not violate terms of the contract.
If the thermal system structure is located a long distance from the farm’s main poultry litter or manure storage facility, expanding the structure’s footprint to allow for extra storage capacity can minimize time spent transporting fuel to the thermal system.
4. What kind of co-product does the system produce? Is there an established market for it?
Identify and learn about the type of co-product (ash or biochar) that the system will produce. Make sure that you discuss its fate with the vendor. Some vendors will offer to sell and distribute the co-product for you. In return, they expect to share some of the revenue. Others leave the sale of the ash or biochar co-product entirely to the farmer.
5. What is the scope of the proposed system?
Thermal technology is just one component of the energy system. For the project to function properly, the entire system must be integrated. The thermal technology must be designed to meet specifications of the heat delivery or electricity-generating equipment, and this whole system has to be designed to meet the energy requirements of the farm. The best vendors will install a whole system, not just a single component.
To do this successfully, the vendor should be knowledgeable not only about producing energy but converting and delivering it to its end use. This might mean distributing heat to animal housing or connecting electricity projects to the regional distribution grid. Connecting on-farm energy systems to the grid can be extremely challenging and expensive, so vendors who have worked with the farm’s utility provider in the past have a better chance of avoiding cost overruns and delays.
6. Is the vendor familiar with permitting requirements for the proposed system?
Nothing replaces your direct, independent research on permitting requirements for your project. However, an informed, proactive vendor may be a big help along the way. The vendor may have already gathered contacts and information about the local, state, and federal permits that may or may not apply to a specific manure-to-energy system.
7. Can the vendor provide emissions data (if necessary) to secure state permits?
Some states require emissions data to issue air quality permits for on-farm manure-to-energy systems. Technology vendors should be able to provide this data.
For technologies demonstrated with funding from the Farm Manure-to-Energy Initiative, comprehensive emissions data is available to support the permitting process.
8. How much will it cost to install?
Thermal technologies that use manure and poultry litter as feedstock are still in the early phases of commercialization or in the research and development phase. This means that manufacturers are testing the market and are not yet producing their equipment in large numbers. This in turns leads to variation in costs and, generally, higher costs per unit.
You will need to research customized options for your farm, and its costs, with individual vendors.
Prices for farms participating in the Farm Manure-to-Energy Initiative were quoted in the range of $0.40 to $0.63 per Btu/hour for thermal, manure-to-energy technologies using poultry litter as a feedstock to produce heat for poultry houses.
Differences in cost related to the type of technology, material handling, and heat delivery system. Heat output capacity for various technologies currently on the market that have demonstrated capability to use poultry litter as a fuel ranges from 500,000 Btu/hour to nearly 5 million Btu/hour.
At this time, for most farms, reducing the use and cost of propane will not by itself justify the cost of the system. However, some benefits for poultry production have not yet been studied and quantified, which could affect the overall return-on-investment. This is also true for potential income from sales of co-products like ash and biochar. Examples of questions being studied include:
- Does drier heat from thermal technologies improve air quality in the poultry house and in turn improve bird health, feed conversion, and production?
- Do lower fuel costs and more abundant heat in the winter improve house air quality and overall production?
- Where will the market settle on the value of phosphorus and potash in the ash and bio-char co-products?
9. What are the estimated, long-term costs for operation and maintenance?
On-farm thermal energy systems require significantly more time and maintenance than propane heating systems typically used in animal housing. According to the USDA Natural Resources Conservation Service technical standards, you should expect an equipment lifespan of approximately ten years.
No third-party, performance-based data is available for long-term operating and maintenance costs. To get a realistic sense of the commitment you are considering, talk with vendors and — ideally — with farmers who use similar technologies.
Ask about labor requirements by day, month, and year. What training and support is provided? What long-term maintenance costs are projected for the proposed system?
10. Is the vendor willing to provide a warranty and if so, what does it cover?
The USDA Natural Resources Conservation Service establishes an expected lifetime for thermal technologies of 10 years. This means that the system should operate as designed for approximately 10 years if operation and maintenance guidelines are followed.
A warranty is the period of time for which the equipment is guaranteed not to fail. A vendor’s warranty may be for less than the 10 years of expected lifetime. A large difference between the warranty and the expected lifetime of the equipment, combined with the lack of information about the long-term performance of these technologies and high capital costs, raises the risk for your investment.
11. Does this technology qualify for nutrient or carbon credits or trading?
Some states offer nutrient credits for technologies that reduce pollution loading to surface waters. Contact your state environmental protection agency to determine whether nutrient trading is available in your state and, if so, whether farm-scale thermal technologies are eligible.
Thermal technologies that produce heat and electricity may also be eligible for renewable energy credits. These may be offered by third-party credit purchasers, utility companies that purchase renewable energy, or state programs designed to incentivize renewable energy. Contact your state energy administration to find out more information.
Questions to ask about: your farm | permitting | the technology
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Development of this information was funded by the National Fish and Wildlife Foundation (NFWF), the USDA, U.S. EPA, and Chesapeake Bay Funders Network. The views and conclusions contained in materials related to the Farm Manure-to-Energy Initiative are those of the authors and should not be interpreted as representing the opinions or policies of NFWF, the USDA, U.S. EPA, or Chesapeake Bay Funders Network. Mention of trade names or commercial products does not constitute endorsement by project funders.
This case study was funded by the National Fish and Wildlife Foundation (NFWF), the USDA, U.S. EPA, and Chesapeake Bay Funders Network. The views and conclusions contained in materials related to the 
