United States Air and Energy Engineering

Environmental Protection Research Laboratory

Agency Research Triangle Park, NC 27711

E AP Project Summary

Research and Development EPA/600/SR-95/035 May 1995

Clean Air Act (CAA) regulations for

new and existing municipal solid waste

landfills are expected to require approximately 500 to 700 sites to install

and maintain a landfill gas extraction

and control facility to reduce landfill

emissions, which include nonmethane

organic compounds, toxics, and greenhouse gases. The Air and Energy Engineering Research Laboratory (AEERL)

of the U.S. Environmental Protection

Agency (EPA) is conducting ongoing

research to provide information on energy conversion options for landfill gas

utilization as a means of assisting landfill owner/operators that may be affected

by the CAA regulations.

This report is a follow-on to a 1992

publication that provides information

on the different options for landfill gas

utilization that are illustrated by case

studies. The focus of this new report is

on technical and non-technical considerations associated with the development and operation of landfill gas to

energy projects. Much of the information used to generate this report is from

interviews and site visits with the major developers and operators of the

more than 110 projects in the U.S. This

report also provides the history and

trends of the landfill gas industry in

the U.S. Graphs illustrate how the influence of reciprocating internal combustion (RIC) engines, compared to

other utilization options, has steadily

increased over time.

Landfill gas is a medium heating

value fuel (approximately 500 Btu/scf

or 19 MJ/m3), and can contain corroLandfill Gas Energy Utilization

Experience: Discussion of

Technical and Non-Technical

Issues, Solutions, and Trends

sive compounds and particulates. The

gas may be used in direct heating applications (i.e., boilers or kilns), in reciprocating engines and turbines to produce electricity, or it may be purified to

pipeline quality gas, or for use in fuel

cells. This report identifies the potential difficulties that may be encountered

in developing a landfill gas to energy

project and presents possible solutions

that have been found through the experience of the landfill gas to energy

industry. Possible remedies to typical

technical landfill gas issues addressed

in this report are 1) material modifications, 2) condensate management, 3)

use of special oils (in RIC engines),

and 4) engine adjustments (in RIC engines).

Some of the non-technical problems

and solutions described in this report

are associated with the development

of energy utilization options including

project economics, barriers, and incentives. Two new programs that may provide incentives are described. The information presented on non-technical

barriers is primarily based on the experience of private U.S. landfill gas

project developers and operators and

is not intended to give a comprehensive overview of all perspectives on

landfill gas utilization.

Ongoing research by EPA and others is aimed at tracking and developing new options for landfill gas utilization. This report summarizes information on new landfill gas utilization technologies, including vehicular fuel systems and fuel cells. Overall results of

Michiel Doorn, John Pacey, and Don Augenstein
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programs to demonstrate the operational feasibility of innovative technologies appear quite promising. For example, the fuel cell technology for landfill gas has many potential advantages

over conventional technologies including its high energy efficiency, minimal

by-product emissions, and minimal labor and maintenance. The use of fuel

cells may be economically feasible before the turn of the century.

This Project Summary was developed

by EPA’s Air and Energy Engineering

Research Laboratory, Research Triangle 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).

Technical Considerations

This section discusses the technical issues associated with the use of landfill

gas compared to natural gas—which is

the primary fuel used for energy conversion equipment such as reciprocating engines, gas turbines, and fuel cells. This

section reviews these technical issues and

summarizes current field experience in

minimizing their effects. To obtain pragmatic and recent information, interviews

were conducted with five developers and/

or operators of landfill gas energy projects

and one engine manufacturer.

Technical issues arise as a result of the

relatively low heating value or from the

presence of chlorinated and toxic compounds, particulates, as well as the formation of condensates or deposits. [For

landfill gas the heating value is approximately 19 MJ/m3 and for natural gas it is

approximately 37 MJ/m3 (500 vs. 1,000

Btu/scf).] Possible remedies to typical technical landfill gas issues addressed in this

report are 1) material modifications, 2)

condensate management, 3) use of special oils (in RIC engines), and 4) engine

adjustments (in RIC engines).

The section presents four simplified process flow charts illustrating approaches to

landfill gas cleanup for utilization projects.

Non-Technical Considerations

This section discusses non-technical

barriers that are associated with landfill

gas recovery and utilization as encountered by the landfill gas utilization industry. Also, incentives and government initiatives to encourage landfill gas utilization are described. To obtain pragmatic

and recent information, interviews were

conducted with seven developers and/or

operators of landfill gas energy projects.

U.S. barriers that were identified from

the interviews conducted for this report

include:

• Unfavorable economics due to low

energy prices and high debt service

rates for landfill gas-to-energy projects

that generate electricity or pipeline

quality gas;

• Limited or unstable marketplace;

• Obtaining third party project financing

at reasonable cost, because it is difficult, time consuming, and proportionately more costly for small projects

than for large projects;

• Difficulties in obtaining air permits,

especially for projects located in

ozone, nitrogen oxide (NOx

), and carbon monoxide (CO) nonattainment areas, because air boards and utilities

often have lengthy permit processes

and contract negotiations;

• Difficulties in negotiating power contracts with local utilities because they

are primarily interested in purchasing

low-cost power without considering

environmental externalities (e.g., offsets from power plants using fossil

fuel). [However, the environment has

changed somewhat as a consequence

of State Public Utility Commissions

(PUCs) who mandate that utilities pay

only avoided cost for electricity purchases];

• Unforeseen costs resulting from compliance with new air quality rules and

regulations, and declining energy revenues that cannot be adjusted to offset new costs;

• Taxation by some states (e.g., California) on landfill gas extraction and

energy conversion facilities; and

• Difficulties in understanding federal

and state energy policies and environmental regulations that may affect

these projects.

U.S. incentives for undertaking landfill

gas projects include:

• Purchase of electricity at avoided cost

of between 2.5 and 3.0 cents/kWh,

except where a utility offers a special

incentive program, consisting of a

levelized higher price, and/or capacity entitlement,

• Production Tax Credits (PTCs),

• Favorable utility contracts for electricity projects,

• Tax exemptions for landfill gas extraction and energy conversion facilities,

• Technical assistance from EPA’s Control Technology Center, and

• New initiatives such as the Department of Energy’s research, development, and demonstration program

(RD&D Program) targeted at the technical barriers to landfill methane (CH4

)

energy recovery and EPA’s Landfill

CH4

 Outreach Program that is designed to remove regulatory, information, and other barriers.

Emerging Technologies

Emerging technologies are discussed

in this report:

• Landfill gas utilization as vehicular fuel

(demonstration project),

• Conversion of landfill gas to methanol (demonstration plant under construction),

• Landfill gas utilization in fuel cells

(demonstration project),

• Rankine cycle converters (field tests

have been conducted to recover

waste heat from landfill gas flares),

and

• Stirling engines (no landfill gas experience to date).

Most experience to date has been on

fuel cell applications to landfill gas. The

EPA initiated a research and development

project in 1991 to evaluate the use of

commercially available fuel cells for landfill gas applications, because of the potential environmental and energy efficiency

characteristics, which include a higher energy efficiency (to 40%), minimal by-product emissions, and minimal labor and maintenance requirements.

The major technical consideration associated with the application of fuel cells

to landfill gas projects is the gas cleanup

system. Testing of EPA’s cleanup system

has just been completed, resulting in over

200 hours of successful operation. The

gas cleanup system is designed to clean

the gas to 3 ppmv of chlorides and 3

ppmv of sulfur. Next, a 1-year demonstration is planned to study the performance

of fuel cells for landfill gas energy conversion applications. The major non-techni-
3

cal consideration associated with fuel cells

has been the capital cost.

Appendices and Other

Information

The report includes other material that

is geared to the landfill gas industry. Various appendices provide information on:

• International landfill gas experience,

• Attributes of various proven technologies for generating electricity while

utilizing landfill gas as a fuel,

• Landfill gas turbines,

• A demonstration project to convert

landfill gas into vehicle fuel,

• An EPA memo dated July 1994 providing the EPA’s New Source Review

policy that regards landfill gas to energy projects as potential pollution prevention sources, and

• Non-technical issues such as the sale

of electricity from landfill gas projects

and alternative energy regulatory policies.
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Michiel Doorn is with E. H. Pechan and Assoc., Inc., Durham, NC 27707; John Pacey

is with F.H.C., Inc., Pebble Beach, CA 93953; and Don Augenstein is with I.E.M.,

Palo Alto, CA 94306.

Susan A. Thorneloe is the EPA Project Officer (see below).

The complete report, entitled “Landfill Gas Energy Utilization Experience: Discussion of Technical and Non-Technical Issues, Solutions, and Trends,” (Order No.

PB95-188108; Cost: $36.50, 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:

Air and Energy Engineering Research Laboratory

U.S. Environmental Protection Agency

Research Triangle Park, NC 27711

• •

United States

Environmental Protection Agency

Center for Environmental Research Information

Cincinnati, OH 45268

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