United States
Environmental Protection
Agency
National Risk Management
Research Laboratory
Research Triangle Park, NC 27711
Research and Development
EPA/600/SR-95/089 July 1995
4>EPA Project Summary
Methodologies for Quantifying
Pollution Prevention
Benefits from Landfill Gas
Control and Utilization
S.M. Roe, P.G. Fields, and R. Goad
This report presents a methodology
and examples for developing air pollut-
ant emission factors and emission es-
timates for comparing air quality
impacts associated with landfill gas
(LFG) control and utilization equipment
and other energy sources (e.g., coal,
natural gas) on a common basis. The
methodology also provides the neces-
sary information to prepare uncon-
trolled and controlled landfill emission
inventories of carbon monoxide (CO),
nitrogen oxides (NOX), sulfur dioxide,
carbon dioxide, and methane. LFG flar-
ing is the only control option addressed
in this report, while the utilization op-
tions include reciprocating internal
combustion (RIC) engines, steam and
gas turbines, and boilers.
The report includes examples of how
to use the data and methodology pre-
sented. The examples compare the air
pollutant emissions expected from con-
trol or utilization of the LFG from an
example landfill using a flare, a RIC
engine, a gas turbine, and a boiler. The
example assessment also compares the
LFG utilization options to emissions
expected from an equivalent amount of
energy input to a coal-fired steam
power plant, a natural gas turbine plant,
a natural-gas-fired boiler, and a distil-
late-oil-fired boiler. Annual emissions
are summarized from an uncontrolled
landfill and from a landfill following con-
trol or utilization with a flare, RIC en-
gine, gas turbine, or boiler.
This Project Summary was developed
by EPA's National Risk Management
Research Laboratory, Research Triangle
Park, NC, to announce key findings of
the research project that is fully docu-
mented in a separate report of the same
title (see Project Report ordering infor-
mation at back).
Introduction
Municipal solid waste landfills are re-
quired under the New Source Performance
Standards to install LFG collection and
control or utilization systems to reduce
emissions of non-methane organic com-
pounds (NMOCs), hazardous air pollut-
ants (HAPs), odorous substances, and
compounds with an explosion potential
(e.g., methane). LFG control systems re-
fer to flares, where there is no recovery of
the associated energy. On the other hand,
LFG utilization refers to the recovery of
LFG energy either as primary heat (e.g.,
industrial boiler or space heater) or as a
fuel source to drive electricity generating
equipment. Currently, these are the most
common utilization options.
Primary emissions from municipal solid
waste landfills, such as methane (CH4)
and NMOCs, can be combusted in either
a control or utilization device. However,
systems used to control or utilize LFG
(e.g., flares, internal combustion (1C) en-
gines, gas turbines, and boilers) produce
emissions of NOX and CO, often referred
to as secondary emissions. Since CO and
NOX emissions are of concern in
nonattainment areas, methods are needed
to comparatively assess emissions result-
ing from LFG control/utilization with other
forms of energy production. Also, green-
house gas emissions from landfills are of
global concern, and therefore, a compari-
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son of the net benefits associated with
LFG control or utilization and other forms
of energy production is often of interest.
Methods to Develop Emission
Factors and Emission
Inventories
Methods to develop emission factors
from each control/utilization option are in-
cluded. The emission factors developed
for comparison to other energy sources
are designated EFCO| to represent that only
emissions associated with the combustion
of the collected LFG are included. These
emission factors will provide the best com-
parisons for alternative energy sources,
since the emissions associated with col-
lecting those fuels (e.g., coal mining, pe-
troleum extraction, and refining) are not
represented in published emission factors.
Methods to prepare uncontrolled and
controlled emission inventories are pre-
sented along with the discussion of devel-
oping emission factors for the collected
LFG. The controlled emission inventories,
however, include emissions from both the
control/utilization equipment and uncol-
lected LFG.
Example LFG Control or
Utilization Assessment
An example assessment is included that
illustrates the use of the data and meth-
ods presented. The example provides
emission factors in pounds per kilowatt-
hour for 1C engines and gas turbines fired
on LFG compared to emissions from an
equivalent amount of energy input to a
coal-fired steam power plant and a natu-
ral gas turbine power plant. Also in the
example, emission factors are developed
for a LFG boiler and compared to emis-
sion factors from an industrial boiler fired
on either natural gas or distillate oil. An-
nual emission inventories were prepared
for each utilization option and comparison
energy source and presented along with
an annual inventory of emissions follow-
ing flare control. The annual amount of
electricity produced for each power-gen-
erating utilization/comparison energy
source is also presented.
An annual emissions inventory of un-
controlled versus controlled landfill emis-
sions (using a flare, 1C engine, turbine, or
boiler) is also presented.
S.M. Roe, P.G. Fields, and R. Coad are with E.H. Pechan and Associates, Inc.,
Rancho Cordova, CA 95742.
Susan A. Thorneloe is the EPA Project Officer (see below).
The complete report, entitled "Methodologies for Quantifying Pollution Prevention
Benefits from Landfill Gas Control and Utilization," (Order No. PB95-243176,
Cost: $17.50, subject to change) will be available only from
National Technical Information Service
5285 Port Royal Road
Springfield, VA 22161
Telephone: 703-487-4650
The EPA Project Officer can be contacted at
National Risk Management Research Laboratory
(formerly Air and Energy Engineering Research Laboratory)
U.S. Environmental Protection Agency
Research Triangle Park, NC 27711
United States
Environmental Protection Agency
National Risk Management
Research Laboratory (G-72)
Cincinnati, OH 45268
Official Business
Penalty for Private Use
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