Agricultural Methane Recovery in Iowa

1
Agricultural Methane Recovery in Iowa

• Presentation to the Region 7 Pollution Fall
  Roundtable
• Presented by David Downing, Energy Data Analyst
• Energy and Waste Management Bureau,
• Iowa Department of Natural Resources
• October 2, 2002

2
Presentation Overview

• Define anaerobic digestion
• Current applications
• Energy potential
• Digester designs
• System cost/benefits
• Iowa Methane Energy Recovery Program
• Iowa projects
• Project incentives

3
Where Does Methane Gas Come From?

• Methane is the principal component of natural
  gas. It is also a major element of biogas, or
  gas produced during the decomposition of organic
  materials in the absence of oxygen.
• Anaerobic conditions occur in natural systems
  such as the bottom layers of wetlands and bogs,
  and in artificial systems like landfills,
  lagoons, and special designed tanks called
  anaerobic digesters.

4
What is a Methane Energy Recovery System?

• Methane energy recovery involves capturing and
  harnessing the methane generated from the
  breakdown of livestock, landfill, or municipal
  waste to produce a usable form of energy, such as
  heat or electricity.

5
Current Iowa Methane Recovery Systems by Sector

• Agriculture Iowa has 5 livestock confinement
  operations that have methane digesters and
  recovery systems installed.
• Landfills Iowa has three landfill-gas-to-energy
  projects with a total electric-generating
  capacity of 7.5 megawatts.
• Waste Water Treatment At least 19 Iowa municipal
  wastewater treatment plants capture methane for
  on-site use and electric generation.

6
Energy Potential From Agricultural Waste

• Each year Iowas livestock confinement operations
  produce 81 million tons of manure.
• This amount has the potential to generate 2.8
  billion kWh of electricity each year, equivalent
  to the energy consumed by 325,000 home annually.

7
Energy Potential From LFG

• Each pound of organic waste generates two to six
  cubic feet of landfill gas.
• Iowa has at least 12 candidate landfills,
  possessing an electricity generation potential of
  about 31 megawatts-the equivalent to powering
  27,000 homes.
• Emissions reductions equal removing 235,000 cars
  from Iowa roads.
  
  

8
Energy Potential From Iowa Wastewater

• 250,000 tons of municipal treated sludge is
  available each year for anaerobic digestion.
• This waste has the potential to produce three
  trillion BTUs of energy each year.
• Enough power to meet the electricity and heating
  needs of 24,000 Iowa homes annually.

9
Types of System Design

• Most livestock confinement operations in the U.S.
  that utilize a methane digester and methane
  recovery system currently employ one of three
  basic types of anaerobic digester technology
• covered lagoon
• plug flow
• complete mix

10
System Components

• A typical livestock waste anaerobic digestion
  system includes the following components
• Manure collection.
• Anaerobic digester.
• Gas handling.
• Effluent storage.
• Gas use.

11
Covered Lagoon System

• Methane gas is captured by placing an impermeable
  floating cover over the manure lagoon.
• The cover is sealed airtight by placing a
  weighted curtain on top of the cover material on
  the bank of the lagoon.
• The biogas is collected by pulling the gas
  through a perforated pipe that has been inserted
  under the sealed cover and then sent to the
  end-use application

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• System advantages
• Least expensive to build.
• Adaptable to a number of manure collection
  methods, including hydraulic flushing.
• Construction and management is simple and
  straightforward.
• System limitations
• Cannot be used in cold weather states because the
  digestion rate is dependent on temperature.
  Biogas production will vary by the season if the
  lagoon is not externally heated.
• Because the manure in a covered lagoon system is
  not completely digested, odor is often released
  when the manure is land applied.

13
Plug Flow System

• Usually rectangular in shape and built below
  ground level with an airtight cover.
• Manure flows to a mixing tank where the percent
  of total solids can be adjusted by adding water.
  In order for the digester to operate efficiently,
  the manure needs to have a total solids content
  of 11 to 13 percent.
• The contents of the mixing tank (the plug) are
  added daily, moving the older manure down the
  tank. The size of the tank is determined by
  number and size of daily plugs put into the
  digester, multiplied by the digester manure
  retention time of 15 to 20 days.

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• As manure is pushed through the system and the
  anaerobic process proceeds, biogas accumulates at
  the top of the digester tank. The biogas is
  pushed, by internal tank pressure or by pump,
  through a pipe located in the top 12'' of the
  tank to the end use area.
• How much biogas is produced and the quality of
  the gas (methane content) is determined in part
  by the level of heat available in the digester
  tank and the nutrient level of the manure
  entering the digester.

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• Mechanical mixers are expensive.
• The contents of the mixing tank (the plug) are
  added daily, moving the older manure down the
  tank. The size of the tank is determined by
  number and size of daily plugs put into the
  digester, multiplied by the digester manure
  retention time of 15 to 20 days.
• As manure is pushed through the system and the
  anaerobic process proceeds, biogas accumulates at
  the top of the digester tank. The biogas is
  pushed, by internal tank pressure or by pump,
  through a pipe located in the top 12'' of the
  tank to the end use area.

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• System advantages
• Medium cost range.
• Simple design.
• Less labor intensive to operate.
• System limitations
• Manure must have at least 6 percent solids
  content, with an optimal solids content of 11
  percent.
• This type of digester is compatible only with
  dairy scrape manure.
• Requires a pre-mix tank.

17
Complete Mix Digester

• Complete mix digester systems consist of an
  engineered tank, round or square, that is located
  above or below ground. The digester tank is
  covered with a fixed lid, most often made from
  poured concrete.
• The process begins with manure being collected in
  the mixing pit either by a gravity-flow or a
  mechanical pump system.

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• A benefit of the complete mix system is that the
  digester can handle high manure volumes and use
  manure with solid contents ranging from 3 to 10
  percent.
• The manure is then sent to the reactor digester
  tank to be mixed, where a mechanical prop or
  blade system is used to keep the manure solids in
  suspension in the digester. This creates a
  homogenous substrate that prevents the formation
  of a crust on the surface. Retention time in the
  digester is usually between 10 to 20 days.

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• As the biogas builds at the top of the digester
  tank during the anaerobic process, the methane is
  removed from the digester by pipe and transported
  to the end use application.
• Complete mix systems operate at either the
  mesophilic (20 degrees C to 45 degrees C) or
  thermophilic (45 degrees C to 60 degrees C)
  temperature ranges. The warmer the manure is in
  the mixing pit and digester, the shorter the
  retention time will be and the greater the biogas
  production.

20

• System advantages
• Can use slurry manure with a solid content of 3
  to 10 percent.
• Mechanical mixers keep solids from collecting on
  the bottom of the digester tank, delaying
  cleaning.
• System limitations
• System requires additional maintenance.

21
System Cost

• One of the barriers to expanding the use of
  anaerobic digesters and methane recovery systems
  is the overall cost of the system and subsequent
  slow rate of return on investment.
• System costs have averaged 350,000 for a 700 cow
  dairy and 500,000 for a 5,000 head
  farrow-to-wean operation.
• Engineering and design work has averaged 31,000
  per system.

22

• The cost of design and construction is often
  higher than other forms of construction because
  these systems are relatively new and have a
  number of unknowns. Few contractors or farm
  managers have practical experience in the design
  or construction of these systems. This often
  leads to cost overruns due to a trial-by-error
  approach.

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• Reasons for Cost Overruns
• Owners and general contractors often hire the
  firms they trust and are familiar with, not the
  lowest bid.
• Construction costs in rural areas vary greatly,
  particularly for material costs, such as lumber
  and concrete.
• When contractors have to travel great distances
  to perform repeated tasks, costs for services
  escalate. This is particularly true for heavy
  equipment functions.

24
Benefits From a Methane Recovery System

• Waste stream becomes a value added product.
• Environmental benefits from reduced emissions.
• Cost savings from generation agreement, possible
  future carbon credits.
• Reduced odor levels. Odor abatement studies at
  livestock confinement facilities that operate
  anaerobic digesters and methane recovery systems
  have confirmed that odor levels are lower when
  compared to similar sized facilities with open
  lagoon systems.

25
Iowa Methane Energy Recovery Program

• In 1998, the Department of Natural Resources
  formed an advisory committee to support the
  development of a Methane Energy Recovery Program.
  This committee of state and federal agencies,
  agricultural organizations, utilities and
  environmental groups recognizes the increasing
  importance of controlling odor, reducing the risk
  of pollution and offsetting fossil fuel
  consumption.
• The goal of the program is to demonstrate and
  promote methane recovery at livestock
  confinements and other appropriate operations in
  Iowa.

26
Iowa Projects

• Top Deck Dairy
• Located near Westgate, in Fayette County.
• 700 cow dairy utilizes the 17,000 gallons of
  manure they produce daily to generate
  electricity.
• A plug-flow digester.
• 150 hp engine with a 100kW generator and a 30kW
  Capstone microturbine to create 130 kilowatts of
  electricity.
• Enough to power 20 homes daily.

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• The Top Deck dairy manure digester is the first
  in Iowa to put power on Iowas electrical grid,
  and is one of just 20 operating systems in the
  country. Power is available 24 hours each day for
  energy customers.
• The final report for the Top Deck Dairy project
  is available on the Iowa Department of Natural
  Resources web site at www.state.ia.us/dnr/energy/
  programs/index.htm

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• Northeast Iowa Community College
• 150-cow Dairy Education and Applied Research Plug
  flow digester
• Manure from the freestall barn is mechanically
  scraped to a reception pit.
• Retention time is approximately 20 days.
• Methane gas from the digester is used in a nearby
  boiler, with the hot water used to maintain the
  digester temperature and heat portions of the
  milking facilities during cold months.
• Heat generation has been approximately 2.7
  million Btu per day.
• A solids separator has been installed and is
  being studied.

29

• Bell Farms (formerly SWIne USA)
• Located in Union County
• 5,000 head farrow-to-wean swine operation
• Complete mix anaerobic digester
• Engine generator that produces 60 kilowatts of
  electricity for use at the operation, 60 percent
  of the energy needed by the farm.
• Waste heat from the engine generator is captured
  and used to heat the digester.
• A detailed final report and contact information
  for the Bell Farms (SWIne USA) project can be
  found on the Iowa Department of Natural Resources
  Web site at www.state.ia.us/dnr/energy/programs/i
  ndex.htm

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• Iowa Waste Characterization Study
• Provides county level data on the amount of
  livestock waste in Iowa by animal type, numbers,
  and the energy potential of the entire waste
  stream.
• Overview of the economics involved in the capture
  and use of methane from animal waste to generate
  electricity.
• The study is available on the Iowa Department of
  Natural Resources web site at www.state.ia.us/dnr
  /energy/programs/index.htm

31
Iowa Methane Recovery Permit Requirements

• Regulations for livestock confinement facilities
  vary, depending on the size of the facility,
  animal type and the number of animals housed.
• Some operations may also require a manure
  management plan.
• Jurisdiction for regulatory enforcement often
  falls under a combination of local and state
  governments.
• If the methane recovery system involves putting
  electric generation into the local grid, a
  utility agreement will be necessary with the
  local utility.

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Methane Energy Recovery Incentives

• AgSTAR
• Directed to show dairy and pork producers "how to
• manage manure profitably while protecting the
• environment.
• For funding amount and application contact
• AgSTAR.
• 1-800-95-AgSTAR
• http//www.epa.gov/outreach/agstar/iondex.htm
• Department of Energy
• Focused on biomass biorefinery for production of
  polymers and fuel.
• Approximately 7.3 million will be awarded over
  the next 3-5 years.
• For an application contact
• Chris Kielich

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• Department of Energy
• Focused on biomass biorefinery for production of
• polymers and fuel.
• Approximately 7.3 million will be awarded over
  the
• next 3-5 years.
• For an application contact
• Chris Kielich
• 202-586-5806

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• Great Lakes Regional Biomass Energy Program
• Projects include the area of liquid biofuels and
• biomass power.
• Funding amounts vary and usually require matching
• funds.
• Applications are due in the spring.
• Contact Fred Kuzel, Director
• 35 East Wacker Drive, Suite 1850
• Chicago, IL 60601
• 312-407-0177
• E-mail fkuzel_at_cglg.org

35

• USDA Rural Business Cooperative Program
• Seeks to assist entities in rural areas to obtain
  loans
• for the purpose of improving the economic and
• environmental climate in rural communities,
• including initiatives for pollution abatement and
• control.
• Funding ranges from 35,000 to 10 million for a
• total of 50 million.
• Contact http//www.rurdev.usda.gov/rbs/busp/bpdir
  .htm
•  

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• Alternative Energy Revolving Loan Program Iowa
• Energy Center
• The program provides low-interest loans to
• individuals and organizations who wish to build
• alternative energy production facilities in Iowa.
• Application deadlinesOctober 31 and March 31 of
• each year.
• Contact Keith Kutz
• Iowa Energy Center
• 2521 Elwood, Suite 124
• Ames, IA 50010-8263
• 515-294-8819
• http//www.energy.iastate.edu/AERLP/loans.html

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• Iowa Department of Natural Resources
• Methane Gas Conversion Property Tax Exemption
• Eligible technologies include alternative fuels.
• Loan amount - 100 of the project. Applications
• shall be filed with the assessing authority not
  later
• than February 1 of each year for which the
• exemption is requested on forms provided by the
• Department of Revenue and Finance.
• Contact David Downing
• [phone]
• david.downing_at_dnr.state.ia.us
•  

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• Solid Waste Alternatives Program (SWAP)
• The Solid Waste Alternatives Program (SWAP)
• funds the statewide development and expansion of
• waste reduction and recycling projects.
• Pre-proposals are accepted year round and
• reviewed quarterly.
• Contact Valerie Drew
• Iowa DNR - Waste Managementewwwww
• Assistance Division
• [phone]
• valerie.drew_at_dnr.state.ia.us
• http//www.state.ia.us/dnr/organiza/wmad/wmabure
• u/solidwaste/swap/index.htm

39

• Value-Added Agricultural Products and
• Processes Financial Assistance Program
• (VAAPFAP) - Iowa Renewable Fuel Fund
• The State Loan Program offers a combination
• of forgivable and traditional loans, with the
  interest
• rate typically the prime rate. Research and
• development projects are not eligible for this
• program. Funding amount is combination of
• forgivable and traditional loans, with a maximum
  of
• 525,000.
• Contact Joe Jones, Iowa Department of Economic
• Development - Bureau of Business Finance
• [phone]
• http//www.smart.state.ia.us/financial.htmvaap
• ap

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• Iowa Department of Natural Resources
• Methane Energy Replacement Generation Tax
• Exemption.
• This statute exempts electricity generated by
• methane gas conversion property from the
• replacement generation tax, which is six
• hundredths of a cent per kilowatt-hour.
• Contact David Downing
• [phone]
• david.downing_at_dnr.state.ia.us
•