Offset projects that capture and destroy methane from animal manure and organic food waste using anaerobic digesters may qualify for the award of CO2 emissions offset allowances under RGGI, provided they meet the requirements of below.
Eligibility
Eligible offset projects shall consist of the destruction of that portion of methane generated by an anaerobic digester that would have been generated in the absence of the offset project through the uncontrolled anaerobic storage of manure or organic food waste
Eligible offset projects shall employ only manure-based anaerobic digester systems using livestock manure as the majority of digester feedstock, defined as more than 50% of the mass input into the digester on an annual basis. Organic food waste used by an anaerobic digester shall only be that which would have been stored in anaerobic conditions in the absence of the offset project.
The provisions of paragraphs XX10.3(d)(2) and (3) of the RGGI Model Rule shall not apply to agricultural manure management offset projects provided either of the following requirements are met.
The offset project is located in a state that has a market penetration rate for anaerobic digester projects of 5% or less. The market penetration determination shall utilize the most recent market data available at the time of submission of the consistency application pursuant to section XX10.4 of the RGGI Model Rule and shall be determined as follows:
MP (%) = MGAD / MGSTATE
where:
MGAD = Average annual manure generation for the number of dairy cows and swine serving all anaerobic digester projects in the applicable state at the time of submission of a consistency application pursuant to section XX10.4 of the RGGI Model Rule.
MGSTATE = average annual manure production of all dairy cows and swine in the state at the time of submission of a consistency application pursuant to section XX10.4 of the RGGI Model Rule.
The offset project is located at a farm with 4,000 or less head of dairy cows, or a farm with equivalent animal units, assuming an average live weight for dairy cows (lbs./cow) of 1,400 lbs., or, if the project is a regional-type digester, total annual manure input to the digester is designed to be less than the average annual manure produced by a farm with 4,000 or less head of dairy cows, or a farm with equivalent animal units, assuming an average live weight for dairy cows (lbs./cow) of 1,400 lbs.
Offset Project Descriptions The offset project sponsor shall provide a detailed narrative of the offset project actions to be taken, including documentation that the offset project meets the eligibility requirements of paragraph (1) above. The offset project narrative shall include the following information.
Owner and operator of the offset project;
Location and specifications of the facility where the offset project will occur;
Owner and operator of the facility where the offset project will occur;
Specifications of the equipment to be installed and a technical schematic of the offset project; and
Location and specifications of the facilities from which anaerobic digester influent will be received, if different from the facility where the offset project will occur.
Emissions Baseline Determination The emissions baseline shall represent the potential emissions of the CH4 that would have been produced in a baseline scenario under uncontrolled anaerobic storage conditions and released directly to the atmosphere in the absence of the offset project.
Baseline CH4 emissions shall be calculated as follows:
CO2e (tons) = (Vm x M)/2000 x GWP
where:
CO2e = Potential CO2e emissions due to calculated CH4 production under site-specific anaerobic storage and weather conditions
MGSTATE = average annual manure production of all dairy cows and swine in the state at the time of submission of a consistency application pursuant to section XX10.4 of the RGGI Model Rule.
Vm = Volume of CH4 produced each month from degradation of volatile solids in a baseline uncontrolled anaerobic storage scenario under site-specific storage and weather conditions for the facility at which the manure or organic food waste is generated (ft3)
M = Mass of CH4 per cubic foot (0.04246 lb/ft³ default value at one atmosphere and 20°C)
GWP = Global warming potential of CH4 (23)
The estimated amount of volatile solids degraded each month under the uncontrolled anaerobic storage baseline scenario (kg) shall be calculated as follows:
VSdeg = VSavail x f
where:
VS = volatile solids as determined from the equation:
VS = Mm x TS% x VS%
where:
Mm = mass of manure or organic food waste produced per month (kg)
M = Mass of CH4 per cubic foot (0.04246 lb/ft³ default value at one atmosphere and 20°C)
TS% = concentration (percent) of total solids in manure or organic food
waste as determined through EPA 160.3 testing method (U.S.EPA Method Number 160.3, Methods for the Chemical Analysis of Water and Wastes (MCAWW) (EPA/600/479/020))
VS% = concentration (percent) of volatile solids in total solids as determined through EPA 160.4 testing method (U.S.EPA Method Number 160.4, Methods for the Chemical Analysis of Water and Wastes (MCAWW) (EPA/600/479/020))
VSavail = volatile solids available for degradation in manure or organic food waste storage each month as determined from the equation:
VSavail = VSp + ½ VSin – VSout
where:
VSp = volatile solids present in manure or organic food waste storage at beginning of month (left over from previous month) (kg)
VSin = volatile solids added to manure or organic food waste storage during the course of the month (kg). The factor of ½ is multiplied by this number to represent the average mass of volatile solids available for degradation for the entire duration of the month.
VSout = volatile solids removed from the manure or organic food waste storage for land application or export (assumed value based on standard farm practice)
f = van’t HoffArrhenius factor for the specific month as determined using the equation below. Using a base temperature of 30o C, the equation is as follows:
Tf = exp[E(T2 – T1)]/[(GC x T1 x T2)]
where:
f = conversion efficiency of VS to CH4 per month
E = activation energy constant (15,175 cal/mol)
T2 = average monthly ambient temperature for facility where manure or organic food waste is generated (converted from oCelsius to oKelvin) as determined from the nearest National Weather Service certified weather station (if reported temperature oC > 5 oC; if reported temperature oC < 5 oC, then F = 0.104)
T1 = 303.16 (30 oC converted to oK)
GC = ideal gas constant (1.987 cal/K mol)
The volume of CH4 produced (ft3) from degradation of volatile solids shall be calculated as follows:
Vm = (VSdeg x Bo) x 35.3147
where:
Vm = volume of CH4 (ft3)
VSdeg = volatile solids degraded (kg)
Bo = manure or organic food waste type-specific maximum methane generation constant (m3 CH4/kg VS degraded). For dairy cow manure, Bo = 0.24 m3 CH4/kg VS degraded. The methane generation constant for other types of manure shall be those cited at U.S. EPA, Inventory of U.S. Greenhouse Gas Emissions and Sinks: 19902004, Annex 3.10, Table 389 (U.S. EPA, April 2006), unless the project sponsor proposes an alternate methane generation constant. If the project sponsor proposes to use a methane generation constant other than the ones found in the above-cited reference, the project sponsor must provide justification and documentation to the REGULATORY AGENCY.
Calculating Emissions Reductions Emissions reductions shall be determined based on the potential emissions (in tons of CO2e) of the CH4 that would have been produced in the absence of the offset project under a baseline scenario that represents uncontrolled anaerobic storage conditions, as calculated pursuant to subparagraphs (3)(i) through (iii) of this subdivision, and released directly to the atmosphere. Emissions reductions may not exceed the potential emissions of the anaerobic digester, as represented by the annual volume of CH4 produced by the anaerobic digester, as monitored pursuant to paragraph (5) of this subdivision. If the project is a regional-type digester, CO2 emissions due to transportation of manure and organic food waste from the site where the manure and organic food waste was generated to the anaerobic digester shall be subtracted from the emissions reduction calculated pursuant to subparagraphs (3)(i) through (iii) of this subdivision. Transport CO2 emissions shall be determined through one of the following methods.
Documentation of transport fuel use for all shipments of manure and organic food waste from offsite to the anaerobic digester during each reporting year and a log of transport miles for each shipment. CO2 emissions shall be determined through the application of an emissions factor for the fuel type used. If this option is chosen, the following emissions factors shall be applied as appropriate.
Diesel fuel: 22.912 lbs. CO2/gallon.
Gasoline: 19.878 lbs. CO2/gallon.
Other fuel: submitted emissions factor approved by the REGULATORY AGENCY.
Documentation of total tons of manure and organic food waste transported from offsite for input into the anaerobic digester during each reporting year, as monitored pursuant to subparagraph (5)(i) of this subdivision, and a log of transport miles and fuel type used for each shipment. CO2 emissions shall be determined through the application of a ton-mile transport emission factor for the fuel type used. If this option is chosen, the following emissions factors shall be applied as appropriate for each ton of manure delivered, and multiplied by the number of miles transported.
Diesel fuel: 0.131 lbs. CO2 per ton-mile
Gasoline: 0.133 lbs. CO2 per ton-mile.
Other fuel: submitted emissions factor approved by the REGULATORY AGENCY.
Monitoring and Verification Requirements Offset projects shall employ a system that provides metering of biogas volumetric flow rate and determination of CH4 concentration. Annual monitoring and verification reports shall include monthly biogas volumetric flow rate and CH4 concentration determination. Monitoring and verification shall also meet the following requirements.
If the offset project is a regional-type digester, manure and organic food waste from each distinct source supplying to the anaerobic digester shall be sampled monthly to determine the amount of volatile solids present. Any emissions reduction will be calculated according to mass of manure and organic food waste (kg) being digested and percentage of volatile solids present before digestion, consistent with the requirements at paragraph (3) and subparagraph (5)(iii) of this subdivision, and apportioned accordingly among sources. The project sponsor shall provide supporting material and receipts tracking the monthly receipt of manure and organic food waste (kg) used to supply the anaerobic digester from each supplier.
If the offset project includes the digestion of organic food waste eligible pursuant to subparagraph (1)(ii) of this subdivision, organic food waste shall be sampled monthly to determine the amount of volatile solids present before digestion, consistent with the requirements at paragraph (3) and subparagraph (5)(iii) of this subdivision, and apportioned accordingly.
The project sponsor shall submit a monitoring and verification plan as part of the consistency application that includes a quality assurance and quality control program associated with equipment used to determine biogas volumetric flow rate and CH4 composition. The monitoring and verification plan shall be specified in accordance with the applicable monitoring requirements listed in Table 1 below. The monitoring and verification plan shall also include provisions for ensuring that measuring and monitoring equipment is maintained, operated, and calibrated based on manufacturer’s recommendations, as well as provisions for the retention of maintenance records for audit purposes.
The monitoring and verification plan shall be certified by an independent verifier accredited pursuant to section XX10.6 of the RGGI Model Rule.
Input Parameter
Measurement Unit
Frequency of Sampling
Sampling Method(s)
Influent flow (mass_ into the digester
Kilograms (kg) per month (wet weight)
Monthly total into the digester
a) Recorded Weight
b) Digester Influent pump flow
c) Livestock population and application of American Society of Agriculture and Biological Engineers (ASABE) standard (ASAE D384.2, March 2005)
Influent total solids concentration (TS)
Percent (of sample)
Monthly, depending upon recorded variations
U.S. EPA Method Number 160.3, Methods for Chemical Analysis of Water and Wastes (MCAWW) (EPA/600/4-79/020)
Influent volatile solids (VS) concentration
Percent of (TS)
Monthly, depending upon recorded variations
USEPA Method Number 160.4, Methods for Chemical Analysis of Water and Wastes (MCAWW) (EPA/600/4-79/020)
Average monthly ambient temperature
Temperature oC
Monthly (based on farm averages)
Closest National Weather Service- certified weather station
The project sponsor shall verify biogas CH4 composition quarterly through gas sampling and third party laboratory analysis using applicable U.S. EPA test methods.
