1 

MEMORANDUM

TO: Hillary Ward, U.S. Environmental Protection Agency, OAQPS/Sector Policies and 

Programs Division, Fuel and Incineration Group 

FROM: Eastern Research Group, Inc. (ERG) 

DATE: April 2014 

SUBJECT: Methodology for Estimating Cost and Emission Impacts of MSW Landfill Regulations 

Introduction 

The EPA is reviewing the new source performance standards (NSPS) for municipal solid waste 

(MSW) landfills and issuing an Advanced Notice of Proposed Rulemaking (ANPRM) for a review of the 

emission guidelines (EG) for MSW landfills (40 CFR part 60, subpart WWW and 40 CFR part 60, 

subpart Cc, respectively). Currently, the regulations require any landfills of at least 2.5 million 

megagrams (Mg) and 2.5 cubic meters in design capacity with estimated nonmethane organic compounds 

(NMOC) emissions of at least 50 megagrams (Mg) per year to collect and control landfill gas (LFG). As 

part of the proposed revisions, a Microsoft® Access database was developed to calculate the cost and 

emission impacts associated with varying certain control parameters and applying these parameters to a 

dataset of existing and model future landfills. The development of the dataset is discussed in another 

memorandum.1

 The purpose of this memorandum is to summarize the methodology for the evaluations.

1. General Assumptions 

The emission reductions and costs associated with the requirements of the current rule are 

considered the baseline and each alternative was compared to this baseline. All existing landfills that 

accepted waste after November 19872

as well as future landfills that are predicted to open in the 5-year 

period of January 2014 through December 2018 are included in the analysis. Annual estimates of 

emission reductions and costs were estimated for each landfill and alternative control scenario over the 

10-year period (2014-2023) following the proposed revisions to the NSPS. Costs were estimated using a 

7 percent interest rate, which is consistent with EPA guidance for cost evaluations. 

The alternatives differ from the baseline by variations in the emission rate thresholds, the design 

capacity thresholds, the initial lag time to install gas collection and control systems (GCCS), and the 

expansion lag time for GCCS. A description of each variable is presented below: 

 The emission rate threshold in the current rule is 50 Mg per year NMOC. The alternatives 

include lower NMOC thresholds. 

 

1

 ERG. 2014. Summary of Landfill Dataset Used in the Cost and Emission Analysis of Landfill Regulations 2

 The designated facility under the EG is each existing MSW landfill that has accepted waste since November 8, 

1987. 
2 

 The design capacity threshold in the current rule is 2.5 million Mg and 2.5 cubic meters. Other 

landfill design capacity thresholds were evaluated as alternatives. 

 The initial lag time is the time period between when the landfill exceeds the emission threshold 

and when GCCS are required to be installed. The current rule allows a 30-month initial lag time, 

which was modeled as a 3-year lag time since the first-order decay equation used to model 

emissions is on an annual, instead of monthly, basis. Further, because the current rule requires 

annual NMOC emission reports to be submitted by 6 months into the following calendar year, the 

landfill would get 30 months after the submittal of its first NMOC emission report showing an 

exceedance to install the GCCS, which is approximately 36 months after the excess emissions 

occurred. Shorter initial lag times were examined among the alternatives. 

 The expansion lag time is the amount of time allotted for the landfill to expand the GCCS into 

waste being placed in new areas of the landfill. The current rule allows 2 years after initial waste 

placement in closed areas and 5 years after initial waste placement in active areas of the landfill; 

so the actual lag time varies by landfill depending how quickly expansion areas are filled and 

closed. Based on input received during public outreach, most modern large landfills do not reach 

final grade within 2 years and a majority of landfills are complying with the 5 year provision. 

Therefore, a 4-year expansion lag time was assumed to represent the baseline. A shorter lag time 

was examined as an alternative. 

2. Estimating Emission Impacts 

2.1 Waste Estimates 

First, the quantity of waste maintained in each landfill was estimated for each year of the analysis, 

based on one of two methods: 

1. When a landfill’s annual waste acceptance rate (WAR) and waste in place (WIP) values were 

available in the landfill dataset and associated with a particular year, those values were 

extrapolated to estimate the landfill’s WAR and WIP for each year. This estimation method was 

designated Option A in the database table of Calculated Inputs_Annual Waste 

 When a Landfill_WIP and Landfill_WIP_Year are reported, the WAR up until the 

Landfill_WIP_Year is estimated based on the following relationship: 

WAR = Landfill_WIP / (Landfill_WIP_Year - Landfill _Year_Open+1). 

 The WAR after the Landfill_WIP_Year is based on the following relationship: 

WAR = (Landfill_Design_Cap_tons - Landfill_WIP) / (Landfill_Closure_Year - 

Landfill _WIP_Year+1). 

2. When WIP and WAR values were not available in the landfill dataset, the annual WAR was 

estimated using the landfill open and closure years and the landfill capacity and assuming a 

constant WAR over the lifetime of the landfill. This estimation method was designated Option D 

in the database table of Calculated Inputs_Annual Waste.

 WAR = Landfill_Design_Cap_tons / (Landfill_Closure_Year - Landfill _Year_Open+1)

Next, the annual WIP was calculated by summing the WAR over time. The EPA is aware of 

historical WAR data from GHGRP, and it plans to incorporate these data in a future iteration of 

the model. The EPA also noted that some respondents to the voluntary survey provided historical 

waste acceptance rates that will be considered in the next iteration of the analysis. 

2.
3 

2.2 Emission Equations 

After the annual quantity of waste was estimated for each landfill, a first order decay equation 

(Equation 1) was used estimate annual methane emissions from each landfill for each year during the 

period of 2014-2023. 

Eq. 1: kt

4t 0 CH k L M e    

Where: 

 CH4t = Methane, ft3

 in year t 

 k = Methane generation rate, year-1

 L0 = Potential methane generation capacity, ft3

 methane per ton 

 M = Mass of waste accepted in year t, tons 

 t = Analysis year (year 1 through 50), year 

The volume of LFG produced by a landfill was estimated using Equation 2. 

Eq. 2: LFGt = CH4t × 2 

Where: 

 LFGt = Landfill gas, ft3

 in year t 

CH4t = Methane, ft3

 in year t 

2 = Multiplier to convert methane to LFG (assuming that LFG is 50 percent 

methane), unitless 

The mass of NMOC emissions produced by each landfill was estimated based on the amount of 

LFG produced at the landfill, as shown in Equation 3. 

Eq. 3: NMOCt = LFGt ÷ 35.32 × 595 × 3.6E-9

Where: 

NMOCt = NMOC in year t, Mg in year t 

LFGt = Landfill gas, ft3

 in year t 

35.32 = Conversion, ft3

 per m3

595 = Concentration of NMOC in LFG, ppm NMOC by volume as hexane 

3.6E-9 = Conversion factor, Mg NMOC per m3

 LFG 

The mass of methane emissions produced by each landfill was estimated based on the volume of 

methane produced at the landfill, as shown in Equation 4a. 

Eq. 4a: Mg CH4 = CH4t × 0.0423 ÷ 2000 ÷ 0.90718 

Where: 

 Mg CH4 = Methane in year t, Mg in year t 

 CH4t = Methane, ft3

 in year t (From Equation 1) 

 0.0423 = Density of methane, lb per ft3

 2000 = Conversion, lb per short ton 

 0.90718 = Conversion, short ton per Mg 
4 

The mass of methane emissions, in terms of carbon dioxide equivalents, produced by each landfill 

was estimated using the Equation 4b. 

Eq. 4b: Mg CO2eq = Mg CH4 × GWPCH4

Where: 

 Mg CO2eqt = Methane emissions as carbon dioxide equivalents, Mg in year t 

 Mg CH4t = Methane, Mg in year t (From Equation 4a) 

 GWPCH4 = 25, Global Warming Potential of Methane 

2.3 NSPS/EG and AP-42 Default Values for Calculating Emissions3

The current NSPS requires the use of Tier 1 default value for the potential methane generation 

capacity (L0) and methane generation rate (k) to determine when the landfill exceeds the 50 Mg NMOC 

per year emission rate threshold. The NSPS L0 is equal to 5458 ft3

 methane per ton of waste and the NSPS 

k values are 0.05 per year for areas receiving 25 inches or more of rainfall per year and 0.02 per year for 

areas receiving less than 25 inches of rainfall. While the NSPS offers a conservatively high Tier 1 default 

NMOC concentration, the regulations allow the use of Tier 2 tests to determine NMOC concentration. 

(Many landfills have conducted Tier 2 tests and gotten values that are consistent with the AP-42 average 

NMOC concentration of 595 ppmv.) Therefore, the combination of the Tier 1 defaults for k and L0 and 

the NMOC concentration of 595 ppmv were used to represent how landfills currently calculate NMOC 

emissions to determine if they have to install controls under the NSPS. Because the use of these values 

result in estimates of LFG and NMOC that are in accordance with the current NSPS; in this evaluation 

these estimates were called LFGNSPS/EG and NMOCNSPS/EG. NSPS defaults tend to overestimate actual 

emissions at most landfills (due to the conservatively high L0 and k values). 

EPA has collected and compiled available emission factor data for landfills in the report 

Compilation of Air Pollutant Emission Factors (AP-42).4

 The AP-42 L0 is equal to 3210 ft3 methane per 

ton of waste. The AP-42 k values are 0.04 per year for areas receiving 25 inches or more of rainfall per 

year and 0.02 per year for areas receiving less than 25 inches of rainfall. The use of these values, in 

combination with the NMOC concentration of 595 ppmv, result in estimates of LFG and NMOC that are 

in accordance with the AP-42; in this evaluation these estimates were called LFGAP-42 and NMOCAP-42. 

As previously mentioned, for this evaluation, LFGNSPS/EG and NMOCNSPS/EG were used to 

determine when landfills would install controls. To determine when landfills may remove controls, the 

current rules allow landfills to measure the actual collected gas flow rate as well as the concentration 

(instead of relying on Tier 1 default L0 and k defaults). Because the AP-42 values for L0 and k produce 

results that more closely match actual gas flow rates and emissions, LFGAP-42 and NMOCAP-42 were used 

in this analysis to determine when landfills would remove controls. 

Landfill-Specific k Factors 

As noted above, the k values depend on the amount of precipitation at the landfill. For this 

evaluation, precipitation data by climate division from the National Oceanic and Atmospheric 

Administration (NOAA) were obtained and averaged over the period of 2000 to 2009.5

 These average 

 

3

 The modeling requirements for existing sources under the state and federal plans implementing the EG are similar 

to those for new sources under the current NSPS. 

4

 USEPA AP-42, Fifth Edition, Volume I Chapter 2: Solid Waste Disposal. 

http://www.epa.gov/ttn/chief/ap42/ch02/index.html 5

 NOAA climate division data are available online at: http://www7.ncdc.noaa.gov/CDO/CDODivisionalSelect.jsp#

and are available for download at ftp://ftp.ncdc.noaa.gov/pub/data/cirs. 
5 

precipitation factors of each climate division were matched to the county-level location of each landfill. 

The k factors were assigned to each landfill based on the resulting amount of precipitation at each landfill. 

2.4 Emission Reductions

To estimate emission reductions, the amount of LFG, methane and NMOC emitted at each 

landfill was estimated using the equations in Section 2.1. After the emissions at each landfill exceed the 

NMOC emission rate threshold of each control scenario, the model assumed that the collection equipment 

was installed and operational at the landfill after the initial lag time of the control scenario. For example, 

if the landfill exceeded the NMOC emission threshold in year 1, and the initial lag time was 3 years, the 

landfill would begin collecting gas in year 4. As the landfill was filled over time, the model assumed the 

landfill would expand the GCCS into new areas of waste placement in accordance with the expansion lag 

time of the control scenario. If the landfill was not expanding the gas collection system (i.e., by installing 

wells in new areas of waste placement) every year, the landfill may have produced more emissions than 

could be collected until the gas collection system was expanded. 

Once the landfill reached the maximum gas production and the gas production started to decrease, 

the analysis assumed that the GCCS would collect all of the emitted gas. To determine the amount of 

LFG, methane and NMOC collected, the analysis used the LFGAP-42 and NMOCAP-42, estimates with the 

appropriate lag times. This was the best estimate of actual gas collected. See Table 1 for an example of 

the collected gas estimate at a landfill where the initial lag time was 3 years and the expansion lag time 

was 4 years. 

Table 1. Example of Collected NMOC Estimate at a Landfill with an Initial Lag Time of 3 Years 

and an Expansion Lag Time of 4 Years 

Year NMOCNSPS/EG NMOCAP-42 Collected NMOC 

1 50.2 27.7 0.0 

2 50.4 27.9 0.0 

3 50.6 28.0 0.0 

4 50.8 28.2 28.2 

5 51.0 28.3 28.2 

6 51.1 28.5 28.2 

7 51.3 28.6 28.2 

8 51.5 28.7 28.7 

9 51.6 28.9 28.7 

10 51.7 29.0 28.7 

11 51.9 29.1 28.7 

12 52.0 29.2 29.2 

13 52.1 29.3 29.2 

14 52.2 29.4 29.2 

15 52.3 29.5 29.2 

The emission reductions are equal to the amount of collected NMOC and methane that is 

combusted. The amount of collected NMOC and methane destroyed by combustion controls was 

estimated by multiplying the amount of collected gas by a destruction efficiency of 98 percent. The 

98 percent destruction efficiency accounts for the fact that combustion is not 100 percent efficient. 

3. Cost Equations 

The cost equations used in this regulatory evaluation were derived from EPA’s Landfill Gas 

Energy Cost Model (LFGcost), version 2.3, which was developed by EPA’s Landfill Methane Outreach 

Program (LMOP). LFGcost estimates costs for gas collection, flare and energy recovery systems and was 
6 

developed based on cost data obtained from equipment vendors and consulting firms that have installed 

and operated numerous gas collection and control systems. LFGcost encompasses the types of costs 

included in the EPA Office of Air Quality Planning and Standards (OAQPS) control cost manual 

including capital costs, annual costs, and recovery credits. Total capital costs include purchased 

equipment costs, installation costs, engineering and design costs, costs for site preparation and buildings, 

costs of permits and fees, and working capital. Total annual costs include direct costs, indirect costs, and 

recovery credits. Direct annual costs are those that are proportional to a facility-specific metrics such as 

the facility’s productive output or size. Indirect annual costs are independent of facility-specific metrics 

and may include categories such as administrative charges, taxes, or insurance. Recovery credits are for 

materials or energy recovered by the control system.

For this evaluation, all costs are presented in 2012$. The costs included in LFGcost are in 2008$ 

and were escalated to 2012$ using an escalation factor of 1 percent for capital costs and 2.5 percent for 

O&M costs. 

The analysis presents the annualized capital cost of flares, wells, wellheads (including piping to 

collect gas) and engines over the lifetime of the equipment. It was assumed that the equipment would be 

replaced when its lifetime was over, so the annualized capital costs were incurred as long as the landfill 

still had controls in place. In order to calculate the annualization factors, it was assumed that flares, wells, 

well heads, and engines had a 15-year lifetime. In addition, there was a mobilization/installation charge to 

bring well drilling equipment on site each time the gas collection system was expanded. Because the 

landfill would be drilling wells to expand the control system during the expansion lag year, it was 

assumed that this capital installation cost had a lifetime equal to the expansion lag time. 

A number of the capital costs equations depend on the number of wells at each landfill. In order 

to estimate the number of wells at each landfill, the number of acres that have been filled with waste for 

each landfill for each year were estimated. It was assumed that the percent of design area filled (acres) 

would track the ratio of waste in place/design capacity (e.g., if a landfill had a waste-in-place amount 

equivalent to 40 percent of design capacity, then 40 percent of the planned acreage would be filled). In 

addition, it was assumed that each landfill would install one well per acre, consistent with the guidelines 

provided in the LFGcost model, and that the number of wells would increase periodically based on 

expansion lag time. See Table 2 for an example of the number of wells estimated annually at a landfill 

where the initial lag time is 3 years and the expansion lag time is 4 years. 

Table 2. Example of Number of Wells at a Landfill with an Initial Lag Time of 3 Years and an 

Expansion Lag Time Equal to 4 Years (and the landfill reaches the emission rate threshold in year 

1) 

Year Acreage Number of Wells 

1 98.2 0 

2 102.9 0 

3 107.5 0 

4 112.1 112 

5 116.8 112 

6 121.4 112 

7 126.1 112 

8 130.7 131 

9 135.4 131 

10 140 131 

11 140 131 

12 140 140 

13 140 140 
7 

Year Acreage Number of Wells 

14 140 140 

15 140 140 

3.1 Capital Costs 

The equations used in this evaluation to calculate capital costs for flares, wells, wellheads 

(including gas collection piping), mobilization/installation, and engines are presented below. All costs 

equations are shown on an individual landfill and year basis. 

Flare Capital Costs 

 

Flares are the primary control device used at landfills. All landfills required to comply with the 

control scenario were assumed to install flares; even landfills using engines would have flares as the backup control device for periods when the engines are not operating. The capital flare costs were estimated 

using the equation below, which was based on the installed cost of the knockout, blower, and flare system 

as determined in LFGcost. The flares were sized based on the maximum LFG flow rate over the 15-year 

flare lifetime, which could be as late as 2037 for projects that were expected to begin operation in 2023. 

Eq. 5: 4

0.61

15yr max

capital 15,y 4,100 (1.01) 525,600

LFG

Flare z   













  

Where: 

Flare capital = Installed annualized cost of knockout, blower, and flare system, 2012$ 

z 15,y = Annualization factor where x=15 yrs and y=interest rate (0.07), unitless 

LFG15yrmax = Maximum LFG collected for 15 year project period, ft3

 per year 

525,600 = Conversion factor, minutes per year 

$4,100 = Installed capital cost of knockout, blower, and flare system, 2008$ per 

ft3

/min LFG 

(1.01)4

 = Adjustment from 2008$ to 2012$, unitless6

Well Capital Costs 

The well capital costs were based on a dollar per foot of well depth installed estimate from 

LFGcost. As shown in the equation below, wells were assumed to have a depth of 10 feet less than the 

landfill depth. The method used to estimate the number of wells at the landfill each year is described 

above. 

Eq. 6: Well capital = z 15,y × (Depth – 10) × 90 × Wells annual × (1.01)4

Where: 

Well capital = Installed annualized cost of wells, 2012$ 

z 15,y = Annualization factor where x=15 yrs and y=interest rate (0.07), unitless 

Depth = Landfill waste depth, feet 

10 = feet 

$90 = Installed capital cost of one well, 2008$ per foot of well depth 

 

6

 Escalation equation uses a formula of (1+escalation/100)t, where capital cost escalation is assumed to be 1 percent 

and t is equal to 4 years 
8 

Wells annual = Number of wells operated each year 

(1.01)4

 = Adjustment from 2008$ to 2012$, unitless 

Wellhead Capital Costs 

The capital wellhead cost covered the equipment associated with each well, including the 

wellhead and gathering lines (and associated sumps) connecting the wells, and was dependent on the 

number of wells. The capital wellhead costs at each landfill were estimated using a dollar per wellhead 

installed cost from LFGcost and the number of wells at each landfill. 

Eq. 7: Wellhead capital = z 15,y × 15,000 × Wells annual × (1.01)4

Where: 

Wellhead capital = Installed annualized cost of wellheads, 2012$ 

z 15,y = Annualization factor where x=15 yrs and y=interest rate (0.07), unitless 

$15,000 = Installed capital cost of one wellhead, 2008$ per well 

Wells annual = Number of wells operated each year 

(1.01)4

 = Adjustment from 2008$ to 2012$, unitless 

Mobilization/ Installation Costs for Wellfield Expansion 

The cost occurs each time the gas collection system (i.e., wellfield) was expanded into new areas 

of the landfill, so the frequency was dependent on the expansion lag time. This cost was independent of 

the number of wells being added. It included costs such as planning and set-up, mobilization costs to get 

the well drilling rig on site, and limited engineering/management costs. This cost was estimated using the 

following equation: 

Eq. 8: Installation capital = z x,y × 25,000 × (1.01)4

Where: 

Installation capital= Mobilization/installation annualized cost, 2012$ 

z x,y = Annualization factor where x=expansion lag time in yrs and y=interest 

rate (0.07), unitless 

$25,000 = Mobilization/Installation costs, per occurrence, 2008$ 

(1.01)4

 = Adjustment from 2008$ to 2012$, unitless 

Engine Capital Costs 

Engines were assumed to be installed only at landfills that produced enough LFG to power the 

engine and only when the electricity buyback rates allowed the operation of the engine to be profitable. 

Standard engines used at landfills have approximately 1 MW capacity, which equates to 195 million ft3

per year of collected LFG (at 50 percent methane). Therefore, engines were assumed to be installed at 

landfills that had at least 195 million ft3

 per year of collected LFG for at least 15 years, which could be as 

late as 2037 for engines there were installed in 2023. 

The engine capital and operation and maintenance (O&M) equations were calculated and 

summed to determine at what electricity buyback rate an engine would be profitable. The profitable 

electricity buyback rate was greater than $0.0457 per kWh at 7 percent interest. It was assumed engines 

were only installed in states with buyback rates exceeding those values. 
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Multiple engines may be present at a landfill when there is sufficient gas flow to support 

additional engines. As noted above, one engine required 195 million ft3

 per year of collected LFG. To 

have two engines on site, the landfill must have had double that amount of LFG (390 million ft3

 per year) 

for at least 15 years after the project start date, which could be as late as 2037 for projects starting in 

2023. 

The capital costs for engines were based on the capital costs for standard reciprocating enginegenerator sets in LFGcost. These costs included gas compression and treatment to remove particulates 

and moisture (e.g., a chiller), reciprocating engine and generator, electrical interconnect equipment, and 

site work including housings, utilities, and total facility engineering, design, and permitting. 

Eq. 9: Engine capital = z 15,y × 1,850,000 × (1.01)4

 × Engine multiplier

Where: 

Engine capital = Installed annualized cost of engines, 2012$ 

z 15,y = Annualization factor where x=15 yrs and y=interest rate (0.07), unitless 

$1,850,000 = Installed capital cost of one reciprocating engine-generator set, 2008$ per 

engine 

(1.01)4

 = Adjustment from 2008$ to 2012$, unitless 

Engine multiplier = Number of engines needed 

3.2 Operation and Maintenance (O&M) Costs 

The equations used in this evaluation to calculate O&M costs for flares, wells, electricity, and 

engines are presented below. All cost equations are shown on an individual landfill and year basis. These 

costs for all landfills were summed by year and the resulting annual sums were used to estimate NPV 

costs. 

To accurately estimate annual electricity costs and engine revenue from the generation and sale of 

electricity, two electricity prices were needed. Landfills must purchase electricity to operate the blowers 

used to collect LFG. EPA used commercial average retail electricity prices by State from the U.S. Energy 

Information Administration to estimate electricity purchase prices at the landfill. 

Landfills utilizing engines generate revenue from the sale of the LFG-produced electricity. The 

amount of revenue generated depends primarily on the buyback rate negotiated between the landfill (or 

third party developer) and the electric company purchasing the LFG-generated power. Average (mean) 

wholesale prices for each state from the U.S. Energy Information Administration (EIA) were used to 

estimate electricity buyback rates7

. These wholesale prices generally fit in the range of typical buyback 

prices for LFG of $0.025 - $0.07/kWh, as discussed in LMOP’s Project Development Handbook. 

Additionally, LFGcost uses a default buyback rate of $0.06/kWh and the U.S. average of the wholesale 

prices used is $0.058/kWh. 

EIA wholesale data were not available for three States (HI, RI & WV). For these States, 

electricity purchase price data from EIA were used to estimate buyback rates.8

 The buyback rates were 

estimated by first determining the ratio of each State’s purchase price to the overall average U.S. 

purchase. This ratio was then multiplied by the calculated average U.S. whole price to estimate a buyback 

 

7

 U.S. DOE/EIA. Form EIA-861 Database. Final Data File for 2009 (File 1.xls). 

http://www.eia.doe.gov/cneaf/electricity/page/eia861.html

8

 U.S. DOE/EIA. Electric Sales, Revenue, and Average Price 2009. Table 4. Average Retail Price for Bundled and 

Unbundled Consumers by Sector, Census Division, and State, 2009. Nov 2010. 

http://www.eia.doe.gov/electricity/esr/table4.html 
10 

rate. Electricity price data for the U.S. territories of Guam, Puerto Rico, and the Virgin Islands were not 

found. Therefore, an LFGcost scenario was created using economic inputs expected on an island to 

estimate a buyback rate of $0.12/kWh utilized by all three territories.

Flare O&M Costs 

An estimate of the flare O&M costs from LFGcost was used to estimate the flare annual costs, as 

shown in the equation below: 

Eq. 10: Flare O&M = 4,500 × (1.025)4

Where: 

Flare O&Ml = Flare annual O&M costs, 2012$ 

$4,500 = Annual O&M flare cost, 2008$ 

(1.025)4 = Adjustment from 2008$ to 2012$, unitless9

Well O&M Costs 

An estimate of the well O&M costs from LFGcost was used to estimate the well annual costs, as 

shown in the equation below: 

Eq. 11: Well O&M = 2,250 × Wells annual × (1.025)4

Where: 

Well O&Ml = Well annual O&M costs, 2012$ 

$2,250 = Annual O&M well costs, 2008$ per well 

Wells annual = Number of wells operating each year 

(1.025)4

 = Adjustment from 2008$ to 2012$, unitless 

Electricity O&M Costs 

The electricity cost of operating the blowers was calculated using the electricity usage of blowers 

and the electricity purchase price. 

Eq. 12: Electricity O&M = 0.002 × Electricitypurchase × LFG collected 

Where: 

Electricity O&M = Electricity annual O&M costs, 2012$ 

0.002 = Electricity usage by blowers, kWh per ft3

 LFG 

Electricity purchase = Electricity purchase price, 2012$ per kWh 

LFG collected = Amount of LFG collected, ft3

 per year 

Engine O&M Costs 

For landfills with engines installed, the O&M costs of the engine were estimated using the annual 

costs for standard reciprocating engine-generator sets from LFGcost, and taking into account the amount 

of time that the engine was operating each year and the number of engines on site. 

 

9

 Escalation equation uses a formula of (1+escalation/100)t, where O&M cost escalation is assumed to be 2.5 

percent and t is equal to 4 years. 
11 

Eq. 13: Engine O&M = 0.02 × 1,000 × 8,760 × 0.93 × (1.025)4 × Engine multiplier

Where: 

Engine O&M = Engine annual O&M costs, 2012$ 

0.02 = Annual O&M engine cost, 2008$ per kWh 

1,000 = Amount of electricity as kW produced by a 1 MW engine, kW per engine 

8,760 = Conversion factor, hours per year 

0.93 = Fraction of time that the engine is online, unitless 

(1.025)4

 = Adjustment from 2008$ to 2012$, unitless 

Engine multiplier = Number of engines 

Engine Revenue Costs 

For landfills with engines installed, the revenue of the electricity produced by the engines was 

calculated using the equation below. This equation assumed that all electricity generated was sold to the 

grid (instead of some of the electricity generated being used to power the GCCS). 

Eq. 14: Engine revenue = 1,000 × 8,760 × 0.93 × Electricity buyback × Engine multiplier

Where: 

Engine revenue = Engine annual revenue, 2012$ 

1,000 = Amount of electricity as kW produced by a 1 MW engine, kW per engine 

8,760 = Conversion factor, hours per year 

0.93 = Fraction of time that the engine is online, unitless 

Electricity buyback = Electricity buyback rate, 2012$ per KWh 

Engine multiplier = Number of engines 

4. Summary 

This memorandum summarizes the emission reduction and cost equations used to evaluate the 

cost and emission impacts of various control scenarios considered under the review of the NSPS and EG. 

The EPA determined which landfills met the design capacity and emission rate thresholds for each 

regulatory option, then calculated the emission reductions and costs for each landfill for each year from 

2014 through 2023 under each control scenario using the equations described in this memorandum. The 

results of applying this methodology to the landfills dataset are discussed in other memoranda and are 

detailed in the database.10, 11, 12, 13 

 

10 ERG. 2014. Cost and Emissions Impacts Resulting from the Landfills NSPS Review. 

11 ERG. 2014. Modeling Database Containing Inputs and Results of Proposed Revisions to MSW Landfill NSPS. 

12 ERG. 2014. Preliminary Cost and Emissions Impacts Analysis for Review of the MSW Landfills Emission 

Guidelines. 

13 ERG. 2014. Modeling Database Containing Inputs and Preliminary Impacts for Review of the MSW Landfill 

Emission Guidelines.