United States National Risk Management

Environmental Protection Research Laboratory

Agency Research Triangle Park, NC 27711

Research and Development EPA/600/SR-95/089 July 1995

Methodologies for Quantifying

Pollution Prevention

Benefits from Landfill Gas

Control and Utilization

Project Summary

This report presents a methodology

and examples for developing air pollutant emission factors and emission estimates 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 necessary information to prepare uncontrolled and controlled landfill emission

inventories of carbon monoxide (CO),

nitrogen oxides (NOx), sulfur dioxide,

carbon dioxide, and methane. LFG flaring is the only control option addressed

in this report, while the utilization options include reciprocating internal

combustion (RIC) engines, steam and

gas turbines, and boilers.

The report includes examples of how

to use the data and methodology presented. The examples compare the air

pollutant emissions expected from control 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 distillate-oil-fired boiler. Annual emissions

are summarized from an uncontrolled

landfill and from a landfill following control or utilization with a flare, RIC engine, gas turbine, or boiler.

This Project Summary was developed

by EPA’s National Risk Management

Research Laboratory, Research Triangle

S.M. Roe, P.G. Fields, and R. Coad

Park, NC, to announce key findings of

the research project that is fully documented in a separate report of the same

title (see Project Report ordering information at back).

Introduction

Municipal solid waste landfills are required under the New Source Performance

Standards to install LFG collection and

control or utilization systems to reduce

emissions of non-methane organic compounds (NMOCs), hazardous air pollutants (HAPs), odorous substances, and

compounds with an explosion potential

(e.g., methane). LFG control systems refer 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 (IC) engines, 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 resulting from LFG control/utilization with other

forms of energy production. Also, greenhouse gas emissions from landfills are of

global concern, and therefore, a compari-
2

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 included. The emission factors developed

for comparison to other energy sources

are designated EFcol to represent that only

emissions associated with the combustion

of the collected LFG are included. These

emission factors will provide the best comparisons for alternative energy sources,

since the emissions associated with collecting those fuels (e.g., coal mining, petroleum extraction, and refining) are not

represented in published emission factors.

Methods to prepare uncontrolled and

controlled emission inventories are presented along with the discussion of developing emission factors for the collected

LFG. The controlled emission inventories,

however, include emissions from both the

control/utilization equipment and uncollected LFG.

Example LFG Control or

Utilization Assessment

An example assessment is included that

illustrates the use of the data and methods presented. The example provides

emission factors in pounds per kilowatthour for IC 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 natural gas turbine power plant. Also in the

example, emission factors are developed

for a LFG boiler and compared to emission factors from an industrial boiler fired

on either natural gas or distillate oil. Annual emission inventories were prepared

for each utilization option and comparison

energy source and presented along with

an annual inventory of emissions following flare control. The annual amount of

electricity produced for each power-generating utilization/comparison energy

source is also presented.

An annual emissions inventory of uncontrolled versus controlled landfill emissions (using a flare, IC engine, turbine, or

boiler) is also presented.

United States

Environmental Protection Agency

National Risk Management

Research Laboratory (G-72)

Cincinnati, OH 45268

BULK RATE

POSTAGE & FEES PAID

EPA

PERMIT No. G-35

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

Official Business

Penalty for Private Use

$300

EPA/600/SR-95/089