EPA 600/R-12/705 | October 2012 | www.epa.gov/ord
United States
Environmental Protection
Agency
State of Practice for Emerging Waste Conversion Technologies
Office of Research and Development
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EPA/600/R-12/684
October 2012
State of Practice for Emerging Waste
Conversion Technologies
Final Project Report
Prepared for
U.S. Environmental Protection Agency
Office of Research and Development
Research Triangle Park, NC 27709
Prepared by
RTI International
3040 Cornwallis Road
Research Triangle Park, NC 27709
BRTI
INTERNATIONAL
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Contents
Abbreviations and Acronyms List 3
Disclaimer 5
Executive Summary 6
Technology Types 6
Performance Summary 7
Future Outlook 9
Section 1: Introduction 11
1.1 Conversion Technology Development Stages 11
1.2 Conversion Technology Definitions 14
1.3 Challenges for Implementing Conversion Technologies 15
1.4 Report Structure 18
Section 2: Pyrolysis Technology 19
2.1 Existing Pyrolysis Technology Facilities and Vendors in North America 20
2.1.1 Agilyx:Tigard, Oregon 20
2.1.2 Envion: Derwood, MD (to be relocated to Florida in 2011/2012) 22
2.1.3 ClimaxGlobal Energy: South Carolina 24
2.1.4 JBI: Niagara Falls, New York 25
2.2 Environmental Data and LCA Results 26
Section 3: Gasification Technology 34
3.1 Existing Gasification Technology Facilities and Vendors in North America 35
3.1.1 Enerkem: Westbrook, PQ, Canada 38
3.1.2 Plasco: Ottawa, Ontario, Canada 40
3.1.4 Ze-gen: Attleboro, MA (Operations Suspended As Of September 2012) ..42
3.1.5 Geoplasma: St. Lucie, Florida [No longer in development at time of this
report] 43
3.2 Environmental Data and LCA Results 45
Section 4: Anaerobic Digestion Technology 54
4.1 Example Anaerobic Digestion Facilities 54
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4.1.1 County of Yolo Public Works Department: Yolo County, California 55
4.1.2 Quasar: Wooster, Ohio 57
4.1.3 Clean World/American River Packaging-Sacramento, CA 57
4.2 Environmental Data and LCA Results 58
Section 5: Findings and Recommendations 65
5.1 Key Findings 65
5.1.1 Significant Differences in Accepted Waste Materials 65
5.1.2 Considerable Variation among Technology Vendor Processes 66
5.1.3 Potential Environmental Benefits by Virtue of Energy and Materials
Recovery 66
5.1.4 Potential Cost Competitiveness with Conventional Waste Management
Technologies 67
5.1.5 High-level of Uncertainty Surrounding Existing Environmental and Cost
Performance Data for Environmental and Cost Information 68
5.2 Limitations and Recommendations for Future Research 68
Resources 70
Attachment A: LCA Scope, Data, and Key Assumptions 73
A.I Goals 73
A. 2 Scope and Boundaries 73
A.3 LCA Methodology, Assumptions, and Modules for Waste Conversion
Technologies 75
A.3.1 Treatment of Material and Energy Recovery 76
A.3.2 Items Excluded From the LCA 76
A.3.3 Para meters Tracked and Reported 77
A.4 Key Data and Assumptions Used in the Technology LCAs 79
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Abbreviations and Acronyms List
AD
BOD
BTU
C&D
COD
CRV
CT
D/F
DOE
DST
ECYWA
EIA
EIS
EOG
EPA
EPIC
FGD
FEMP
GHG
HAP
HOPE
HRSG
ICE
ICI
ISO
KWh
LCA
LCI
LCIA
Anaerobic Digestion
Biological Oxygen Demand
British Thermal Unit
Construction and Demolition
Chemical Oxygen Demand
Carbon Recovery Vessel
Conversion Technology
Dioxins and Furans
Department of Energy
Decision Support Tool
Department of Ecology Washington
Environmental Impact Analysis
Environmental Impact Statement
Envion Oil Generator
Environmental Protection Agency
Environment and Plastics Industry Council
Flue Gas Desulfurization
Federal Energy Management Program
Greenhouse Gas
Hazardous Air Pollutant
High Density Polyethylene
Heat Recovery Steam Generator
Internal Combustion Engine
Industrial Commercial and Institutional
International Organization for Standardization
Kilowatt hour
Life Cycle Analysis
Life Cycle Inventory
Life Cycle Impact Assessment
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LDPE
LHV
MMBtu
MBtu
MRF
MSW
MW
MWh
NA
NGO
OARDC
PAC
PET
PM
P20
PP
PS
PVC
RDF
Syngas
TCE
TNMOC
TPD
USDA
VE
VOC
Low Density Polyethylene
Lower Heating Value
Millions of British Thermal Units (BTUs)
Thousands of British Thermal Units (BTUs)
Materials Recycling Facility
Municipal Solid Waste
Megawatt
Megawatt hour
Not Applicable
Nongovernmental Organization
Ohio State University's Agricultural Research and
Development Center
Powered Activated Carbon
Polyethylene Terephthalate
Particulate Matter
Plastic20il
Polypropylene
Polystyrene
Polyvinyl Chloride
Refuse Derived Fuel
Synthetic gas or Synthesis gas
Tons of Carbon Equivalent
Total Nonmethane Organic Carbon
Tons per Day
U.S. Department of Agriculture
Visible Emissions
Volatile Organic Compound
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Disclaimer
This report includes a summary of available data and information for emerging waste
conversion technologies in North America. The U.S. EPA does not advocate or endorse any
particular technology or facility included in this report. The analysis and report were developed
from January 2011 to June 2012. Information and data were collected from interviews with
technology vendors, independent engineering analyses, vendor product information and
presentations, and literature/website reviews. The viability of available information or data
cannot be independently verified due to the lack of performance data or independent testing
being conducted to confirm vendor claims. Another difficulty in conducting a review of
emerging technologies for converting waste to fuels or energy is the dynamic nature of
emerging waste conversion technologies and markets.
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Executive Summary
RTI International (RTI) was contracted by the U.S. Environmental Protection Agency (EPA),
Office of Research and Development to conduct research to prepare a "State of Practice" report
to support State and local decision-makers on the subject of emerging waste conversion
technologies. Emerging technologies are defined as those in a commercial or advanced pre-
commercial development stage. While the application of these technologies to municipal solid
waste (MSW) feedstocks is only emerging in the United States (U.S.), these technologies have
been applied for the management of MSW in other parts of the world, such as Australia,
Canada, Europe, and Japan. A key aspect of international applications is that they are part of
waste systems with advanced segregation, such as source segregated organics collection.
Where conversion technologies have been most successful is in locations with already
established programs for waste segregation and collection, dedicated waste streams (e.g.,
plastic from industrial partners), and waste supply contracts so that potential plants can
operate economically.
For this study, focus was placed on the ability of these technologies to manage the currently
non-recycled fraction of municipal solid waste (MSW) in the U.S. The specific objectives for this
study and report were to develop:
• An overview of each waste conversion technology, identifying the types of feedstock
that have or can be used in each process and the air, water, and waste emissions.
• Information on energy and mass balance for each technology.
• Information on the economics of the technologies to help decision-makers
understand the key cost factors and economic feasibility.
• A listing and maps of proposed and operational facilities in the United States and
pertinent examples for each technology.
• A summary of key findings and considerations decision-makers should be aware of
when evaluating waste conversion technologies.
To address these objectives, RTI built upon research for plastics waste conversion technologies
conducted for the American Chemistry Council (see RTI, 2012). In that research, pyrolysis and
gasification technology vendors were identified and asked to provide process, environmental,
and cost information. Additionally, publicly available data sources were retrieved to
complement the data received from each vendor. This study for the EPA is specific to
technologies for non-recycled MSW and includes the additional technology category of anaerobic
digestion. In addition, data and information originally collected for technology vendors as part
of the 2012 study for the American Chemistry Council was updated in June 2012.
Technology Types
The technologies researched are identified in Table ES-1 along with information on the
feedstock, end products, conversion efficiency, and facility capacity. Different vendors and
facilities can have specific variations on the technology to enhance conversion efficiency and/or
tailor the end product to site-specific markets. The primary objective of the conversion
technologies is to convert waste into useful energy products that can include synthetic or
synthesis gas (syngas), biogas, petroleum, and/or commodity chemicals.
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Table ES-1. Overview of Conversion Technology Characteristics.1
Conversion
Technologies
Feedstock
Primary End
Product(s)
Conversion
Efficiency1
Facility Size
(Capacity)
Product
Energy Value
Pyrolysis
Plastics
Synthetic Oil,
Petroleum Wax
62-85%
10-30 tons per day
15,000-19,050 BTU/lb
Gasification
MSW2
Syngas, Electricity,
Ethanol
69-82%
75-3303 tons per day
11,5004-18,800 BTU/lb
Anaerobic
Digestion
Food, yard, and paper
wastes
Biogas, Electricity
60-75%
10-1005 tons per day
6,000-7,0005 BTU/lb
(estimated)
Conversion efficiency is defined as the percentage of feedstock energy value (e.g., btu/lb) that is transformed to and
contained in the end product (e.g., syngas, oil, biogas).
2 Only certain MSW fractions can be input to a gasifier. Glass, metals, aggregate, and other inerts are not desirable and may
cause damage to the reactor.
Total capacity permitted based on vendor communications. Geoplasma's St. Lucie, FL plasma gasification plant is permitted up
to 686 tons/day, but the vendor could not be reached for confirmation. [Note: as of September 2012, the St. Lucie facility is
no longer in development]
4LHVofethanol.
Estimated. AD facilities can span a wide range of sizes, input feedstocks, and designs.
The review of publicly available data and information revealed that most facilities reported to
be operating as commercial-scale are often operating in more of a demonstration mode and do
not have waste contracts and/or energy or product contracts in place. Because most facilities
are demonstration-stage plants, they are operating in batch-test rather than in a continuous-
mode that would be typical of commercial plants. Until there are commercially operating
facilities in North America, there will be a high level of uncertainty in the data to characterize
the performance, cost, and environmental aspects for these technologies.
Performance Summary
It is difficult to directly compare the cost and performance of pyrolysis, gasification, and AD
technologies directly due to differences in feedstocks and primary products (See Table ES-1).
Pyrolysis technologies typically process only plastics; gasification technologies typically process
plastics and biodegradable fractions of MSW but avoid inerts (e.g., glass, metals, aggregate);
and AD typically processes highly putrescible fractions of food, yard, and paper wastes. The
difference in suitable feedstocks creates differences in feedstock energy values as well as in
product energy value and related beneficial offsets. For pyrolysis, beneficial offsets are
primarily based on the conversion of plastics to oil. For gasification, beneficial offsets include
energy production and can also include recyclables (e.g., metals, glass, and other inorganics)
1 Plasma arc treatment and hydrolysis technologies are not included in this table. There is only one hydrolysis
facility and no plasma arc facilities in North America processing MSW and conversion technologies appear to be
moving in the direction of AD, gasification, and pyrolysis.
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removed in the up-front sorting process. This component, however, was not included in the
analysis since we assumed post-recycling MSW would be the input feedstock and any additional
recovery of recyclables would be minimal. For AD, the benefit offsets are primarily based on
the conversion of organic wastes to biogas, which is assumed to be used to produce electrical
energy.
Based on the available data2, life cycle environmental assessments constructed for pyrolysis
and gasification technologies were updated in 2012 by RTI. In addition, a comparable life cycle
environmental assessment for AD technology was constructed for this study. Because most
conversion technologies focus on feedstocks that are not suitable for conventional recycling,
comparisons were made only to landfills and waste-to-energy (WTE). Based on the
assessments and information gathered for conversion technologies, a qualitative evaluation
was performed as shown in Table ES-2. As shown in Table ES-2, conversion technologies may
offer environmental benefits as compared to landfill disposal. However, a clear environmental
benefit as compared to conventional WTE is more difficult to discern. Similar to landfills, WTE
can accept waste as is, are considered proven technologies, and can have large capacities.
Conversion technologies generally have smaller capacities and are more limited in the types of
materials that can be accepted. However, while the main product of WTE is electrical energy
(and possibly steam), conversion technologies produce synthetic or bio-based fuels that can be
either combusted to produce electrical energy, used as a transportation fuel, or sold as a
chemical commodity product based on regional markets.
Table ES-2. Evaluation of Conversion Technologies.
Pyrolysis
Gasification
Anaerobic
Digestion
Landfill
WTE
Landfill
Diversion
+ 1
++1
+ 1
-
+++
Net Energy
Recovery
+++2
++2
+ 2
+ 2
+++2
GHG
Emissions
Reduction
+
++
++
-
++
Commodity
Products
Potential
+++
+ 3,4
+ 3
na
+
Ability to
Accept Bulk
MS WAs Is
-
+
-
+++
+++
Commercial
Readiness
+
+
+
+++
+++
Cost
+
?
?
+++
+
-Worse, + Good, ++ Better, +++ Best, ? Indeterminate/not enough data, na Not applicable
''Relatively small facility capacity, may not significantly impact landfill diversion unless there are many facilities. For example,
pyrolysis accepts mainly plastic and AD mainly food and green waste.
Energy recovery creates beneficial offset of utility sector electricity production or petroleum fuel production.
3 May not be available markets or significant enough quantity to lead to marketable products.
4 Potential glass and metals recovery and associated recycling offsets (would only apply if the facility accepts bulk MSW).
The data used for this assessment were provided by industry vendors and were not independently validated. In
addition, the datasets used to characterize the technologies vary in the level of detail and the number of values
obtained for particular input parameters, with only one value obtained for certain parameters.
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As shown in Table ES-2, all conversion technologies can support landfill diversion and the exact
facility capacity and number of facilities will govern the significance of the diverted amount. At
present, none of the technologies can directly accept MSW, except for conventional WTE.
Rather, most conversion technologies can only utilize specific fractions of MSW (e.g., plastics,
organics) and thus must be paired with source segregation and separate collection or robust
materials separation up-front of the conversion process. This would require additional cost,
energy, and use of processes with additional environmental emissions. So for location specific
analysis, one most consider existing infrastructure and needs for enhanced segregation of
suitable materials and contractual arrangements for ensuring dedicated feedstocks.
From an environmental perspective, the conversion technologies showed potential benefits,
including reduced energy and carbon emissions. When compared to landfill disposal,
gasification of 100 tons of MSW per day and operating 300 days of the year may save energy
equivalent to the needs of about 1800-3600 households, or about 1500-3000 household
transportation energy needs according to EPA information3 about average household and
household transportation energy needs. This translates into a reduction of approximately
33,000-66,000 tons of carbon dioxide (C02) per year. Pyrolysis of 100 tons per day of non-
recycled plastics may save the amount of energy equivalent to the needs of about 550-1100
households, or about 460-910 household transportation energy needs and about 16,500-
27,500 tons of C02 emissions reduction per year. Treatment of 100 tons of organics waste in an
AD facility may save the amount of energy equivalent to the needs of about 170-690
households, or about 140-570 household transportation energy needs and approximately
12,000-14,000 tons of C02 emissions reduction per year.
Cost information for conversion technologies is limited and what is available from the literature
indicates that the net cost/ton for pyrolysis is comparable to landfilling, whereas the net
cost/ton for gasification and AD is higher. The estimated waste processing cost for pyrolysis is
approximately $50/ton of plastics, close to $90/ton of MSW for gasification, and close to
$115/ton of organics for AD. This cost is generally related to the capital and operating costs
required to run the process and dispose of any residuals. For comparison, U.S. landfill tipping
fees range from $15-96/ton of MSW, depending on the State or region, and average $44/ton
for the entire U.S. (Van Haaren et al., 2010). WTE tipping fees range from $25-98/ton of MSW,
depending on the State or region, and average $68/ton (Van Haaren et al., 2010).
Future Outlook
While conversion technologies present another option for managing non-recycled MSW, it will
be an estimated 5-10 years before the first-generation demonstration facilities transition to
stand-alone commercial operations (i.e., stand-alone operating facility not supported by
Federal grant funding or private capital investment capital) based on estimated times for siting,
permitting, construction, and contract development.
For the current suite of conversion technologies currently under development, plastics-to-oil
pyrolysis technologies are more mature than MSW and organics-based technologies (typically
gasification and AD), in part because of the decreased variability of the incoming feedstock—
3 http://www.epa.gov/dced/location efficiency BTU-chtl-graph.htm
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e.g., three facilities at a commercial stage were identified for plastics-to-oil pyrolysis, while
none at a commercial stage were identified for gasification and AD.
The capability of conversion technologies to meet landfill diversion and/or energy production
goals will likely depend heavily on the success of these first-generation facilities. Until these
facilities are operating commercially in North America, there will not be enough real-world data
to accurately characterize their environmental aspects and costs. While operating facilities exist
in Europe and Asia, they are often in unique settings. For example, a cursory review of facilities
in Europe indicated that they are typically located in regions where there is more separation of
recovered materials, which would help with the economics as well as the operation of the conversion
technology. In addition, facilities in other countries are not subject to the same State and local
permitting and regulatory processes as in the U.S. Thus, they may not provide comparable data
to accurately characterize environmental aspects or costs. In addition, waste sorting in Europe
is much more prevalent that in the U.S. which reduces the front end costs of conversion
technologies by not incurring additional costs associated with targeting specific materials.
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Section 1: Introduction
New technologies to convert municipal and other waste streams into fuels and chemical
commodities, termed conversion technologies, are rapidly developing. Conversion technologies
are garnering increasing interest and demand due primarily to alternative energy initiatives.
These technologies have the potential to serve multiple functions, such as diverting waste from
landfills, reducing dependence on fossil fuels, and lowering the environmental footprint for
waste management. Conversion technologies are particularly difficult to define because their
market is in development and many of their design and operational features are not openly
communicated by vendors.
RTI was contracted by EPA's Office of Research and Development to conduct research to
evaluate and develop a "State of Practice" report for State and local decision-makers on the
suite of emerging waste conversion technologies in the United States. The technologies
information was collected throughout the 2011 time period and includes the general categories
of pyrolysis, gasification, and AD.
The objectives for this report were to develop:
• An overview of each waste conversion technology, including identifying the types of
feedstock that have or can be used in each process and the claimed and/or reported
air, water, and waste emissions.
• Information on energy and mass balance for each technology.
• Information on the economics of the technologies to help decision-makers
understand the key cost factors and economic feasibility.
• A listing and maps of proposed and operational facilities in the U.S. and pertinent
examples for each technology.
• A summary of key findings and considerations decision-makers should be aware of
when evaluating waste conversion technologies.
To address these objectives, this study evaluated real-world case examples and data and
information from the literature. This analysis provides a better understanding of the range of
emerging conversion technologies available that accept MSW or specific MSW fractions as
primary feedstock and identifies and profiles specific technology vendors. The study was also
designed to identify and quantify the potential cost and life cycle environmental
burdens/benefits of the technologies as compared to existing landfill disposal. Technology
categories are described in detail and potential benefits and impediments are reviewed.
Additionally, an LCA was performed for the general technology categories using data from
technology vendors in combination with data obtained from the literature.
1.1 Conversion Technology Development Stages
There are a number of ongoing efforts in North America to develop and commercialize waste
conversion technologies. The current situation is very dynamic, with new technology proposals,
new vendors, mergers and acquisitions, and redesigns or closings occurring almost weekly. It is
useful to consider the technology development stages as illustrated in Figure 1-1 when
discussing waste conversion technologies. There are technologies at every stage of the
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Idea Stage
Basic
Research
Patent
ctage
Pilot Scale
Field
Testing
Semi-
Commercial
Commercial Plant
Figure 1-1. Stages of Waste Conversion Technology Development.
Note: Most of the facilities investigated in this report are in the stages within the shaded area.
development cycle. At the time the facilities specific data used in this report were collected
(2011), there were only a few commercial-scale facilities operating.
Most facilities are at a pilot or semi-commercial stage. It was found that even facilities that are
commercial-scale are often operating in more of a demonstration mode and most do not have
waste contracts and/or energy or product contracts in place.
This study focused on technology vendors and facilities that were at the pilot to commercial
plant stages. Figure 1-2 illustrates the locations of existing North American waste conversion
facilities by main technology category of AD, concentrated acid hydrolysis, gasification, and
pyrolysis. Gasification and pyrolysis are the primary technology categories that can accept MSW
(or MSW fractions), whereas AD and concentrated acid hydrolysis primarily accept organics.
The current stages of technology development for pyrolysis, gasification, and AD facilities are
discussed in Sections 2-4, respectively.
12
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13
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Concentrated acid hydrolysis and plasma arc technology (direct plasma treatment as opposed
to plasma as part of gasification) were not included for further consideration in this report.
There is only one hydrolysis facility and no plasma arc facilities in North America processing
MSW and conversion technologies appear to be moving in the direction of AD, gasification, and
pyrolysis.
1.2 Conversion Technology Definitions
In this report, thermal and biochemical conversion technologies are described as pyrolysis,
gasification, or AD. Thermal conversion processes are characterized by higher temperatures
and conversion rates than biochemical processes. These technologies contain a continuum of
processes ranging from thermal decomposition in a primarily oxygen starved environment
(commonly referred to as pyrolysis/cracking processes) to partial oxidation in a sub-
stoichiometric environment (or gasification processes).
The definitions adopted in this report may not necessarily be the same as elsewhere or how
individual technology vendors categorize their process. Our main goal was to develop general
definition that would have value and meaning to State and local decision makers. With that in
mind, definitions for the technologies were constructed based on the strict engineering
definitions as well as the key accepted waste inputs and key outputs from the technologies.
It should be noted that vendor technologies are often difficult to fit under one technology
category and sometimes include characteristics common to more than one technology. For
example, in a two-stage (pyrolysis-gasification) fixed bed gasification process, some of the
oxygen injected into the system is used in reactions that produce heat, so that pyrolysis
(endothermic) gasification reactions can initiate, after which the exothermic reactions control
and cause the gasification process to be self-sustaining.
As described in Sections 2-3 thermal conversion processes such as pyrolysis and gasification are
characterized by higher temperatures and conversion rates than biochemical processes such as
AD as described in Section 4. As part of recent research for the American Chemistry Council
(RTI, 2012), RTI designed a questionnaire to collect life cycle energy and emissions data and
sent it to six facilities—Agilyx, Envion, Climax, JBI, Enerkem, and Ze-Gen. The data and
information collected from these questionnaires was supplemented with additional publicly
available data for each of these, and additional (e.g., AD), vendors. The data and information
from this American Chemistry Council project was updated for this project to capture the
current status and performance of facilities.
Since there were so few true commercial facilities in operation, it was difficult to present
reliable estimates for cost and life cycle environmental aspects. Most of the facilities covered in
this report were still in pilot and demonstration stages. As facilities transition to fully
operational commercial facilities, one would expect the process inputs/outputs to stabilize and
cost and environmental aspects to become more consistent and reliable. Given the emerging
nature of these technologies and the likelihood that most data corresponds to testing under
controlled batch tests, the uncertainty associated with the data should be considered high.
14
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Table 1-2. Overview of Conversion Technology Characteristics.
Conversion
Technologies
Feedstock
Primary End
Product(s)
Conversion
Efficiency1
Facility Size
(Capacity)
Product
Energy Value
Pyrolysis
Plastics
Synthetic Oil,
Petroleum Wax
62-85%
10-30 tons per day
15,000-19,050 BTU/lb
Gasification
MSW2
Syngas, Electricity,
Ethanol
69-82%
75-3303 tons per day
11,5004-18,800 BTU/lb
Anaerobic
Digestion
Food/yard wastes
Biogas, Electricity
60-75%
10-1005 tons per day
6,000-7,0005 BTU/lb
(estimated)
Conversion efficiency is defined as the percentage of feedstock energy value (e.g., btu/lb) that is extracted and contained in
the end product (e.g., syngas, oil, biogas).
2 Only certain MSW fractions can be input to a gasifier. Glass, metals, aggregate, and other inerts are not desirable and may
cause damage to the reactor.
3 Total capacity permitted based on vendor communications. Geoplasma's St. Lucie, FL plasma gasification plant is permitted up
to 686 tons/day, but the vendor could not be reached for confirmation. [Note: as of September 2012, the St. Lucie facility is
no longer in development]
4LHVof ethanol.
Estimated. AD facilities can span a wide range of sizes, input feedstocks, and designs.
Any data provided by the vendors have not been independently verified. While RTI vetted data
and information collected and contacted vendors for clarification where needed, very little
information was obtained about the tests and test conditions used to obtain the data.
Gathering this type of information, as well as performing an independent verification, is part of
the recommendations from this report.
1.3 Challenges for Implementing Conversion Technologies
As with any process, the operator must obtain appropriate federal, state, and local permits.
Several vendors noted difficulties with the state and local government permitting process
mainly because there aren't comparable facilities to draw a precedent from and it's not always
clear whether a conversion technology falls under the category of waste management or
renewable energy facility. Another key difference is that there is not long-term performance
data from conversion type facilities on which to establish regulatory limits and determine
potential impacts on local or regional air sheds.
The permitting process can take time and the facility owners may have difficulties that lead to
substantial delays in construction. Several vendors noted that they had encountered their
permits rejected several times. As with any new facility, construction operations may not begin
until permits are acquired. It may be necessary to obtain solid waste handling permits through
the appropriate local agency. It is also important for facilities to apply for and acquire air
permits in order to address any criteria pollutants and toxic air pollutants that may be emitted.
One such permit would be a Title V Permit, which sanctions construction of permitted
emissions units as well as initial operations (FL DEP, 2011). Emissions from startup, shutdown,
15
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and malfunction operations are also specified in air permits. Water quality permits are
necessary to regulate discharges to surface and ground water. The local or county planning
agency likely has requirements for the planned facility that encompass building, grading, water
system, shoreline, utility, site plan review, septic system, floodplain development, and any
zoning variance (ECY WA, 2011).
Before a facility is built, it may be necessary for an Environmental Impact Assessment (EIA) to
be prepared. The EIA is a comprehensive evaluation of the positive and negative impacts that
the proposed facility may have on the natural environment, as well as social and economic
consequences. After the assessment is completed, it is likely that an environmental impact
statement (EIS) will need to be written. An EIS is a decision-making tool that is required for
proposed projects that may significantly impact the environment. Included in this statement is
a discussion of the purpose and need for the project, alternatives, and environmental effects of
the proposed project.
After firms receive permits to operate, they must be able to secure contracts with waste
facilities in order to have a secure, continuous feedstock. Feedstocks are often one of the most
challenging aspects of successfully operating a conversion facility. The quantity of feedstock
needs to be relatively constant because the systems are optimized for a specific flow rate. It is
also necessary for quality and volume of feedstock to be taken into account. Brightstar
Environmental is an example of one company that encountered issues with feedstock supply.
Brightstar was a subsidiary of Energy Developments Limited and located in Australia's New
South Wales province in the city of Wollongong. The gasification facility was forced to close in
2004 due to feedstock contractual issues.
Most revenue from these processes comes from the sale of oil, gas, and/or electricity.
Therefore, if markets are not developed for recycled products from the pre-sorting process,
revenue that otherwise would have been generated is lost. Furthermore, if no market share
exists and clients are not found for the oil or gas products, the facilities will be forced to close
due to a lack of revenue.
Ash and other residual products from waste conversion technologies can be a regulated
hazardous waste or solid waste and will need to be assessed and approved by local or state
agencies to determine their potential use (e.g., as aggregate) and appropriate disposal (e.g.,
conventional versus hazardous waste landfill). Slag that may be produced is characterized by
technology vendors as non-leachable. However, it may require testing for compliance with
state and local regulations or standards and will likely need to be approved for reuse
applications. If a market is developed for slag and it is approved for reuse, it may be sold. If not,
the slag must be landfilled.
Another barrier can be the smell, noise, and visual aesthetics complaints from community
members after MSW facilities have been installed. The negative stigma has led to some
difficulty in locating sites for these plants. Some national nongovernmental organizations
(NGOs), such as the Sierra Club, believe facilities that use waste to convert to fuel lead to a
disincentive for individuals and communities to recycle or reduce their consumption. Global
Alliance for Incinerator Alternatives is a conglomeration of over 500 grassroots organizations
opposed to incinerators as well as other waste technologies. They argue that the emissions
16
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associated with these facilities, including gasification, pyrolysis, and plasma arc fuel climate
change, do not address the NGO's concern for overconsumption, and divert resources and
focus from recycling programs. Most easily accessible information that drives public opinion is
derived from these NGOs, which leads to a negative perception of these facilities. However,
communities that have installed waste conversion facilities in their communities tend to have a
more positive opinion of the technologies.
To reduce public resistance to these facilities, it would be helpful for companies to provide
outreach to the public to educate them about technological advances and other positive
aspects of these technologies. Some measures that may help include siting facilities at
brownfields (i.e., abandoned or underused industrial and commercial facilities available for re-
use), the use of dome designs to hide smokestack visibility, and integrated "utility campuses"
that consist of sewage treatment, electricity generation, and water reclamation facilities
(Lawrence, 2009). They may also need to control odors and noises emanating from operations
through such measures as enclosed tipping floors and biofilter systems.
Some legislative actions are designed to encourage the development of conversion
technologies. The federal government provides several grants and loans for feedstock
development, biofuels, and biobased product development for technologies such as these
conversion facilities. The Biomass Research and Development Initiative is one major source of
funding. The initiative is an interagency effort of senior decision-makers from various federal
agencies, including the U.S. Department of Agriculture (USDA) and U.S. Department of Energy
(DOE) as well as the White House. The USDA awards loans to companies that demonstrate the
potential benefits of their conversion technology processes. U.S. DOE provides funding for the
conversion of biomass to various fuels, such as those produced through the use of conversion
technologies. One company awarded a grant through this program is Enerkem. The company
was also awarded an $80 million loan through the Biorefinery Assistance Program.
Another federal program designed to assist energy efficiency projects is the DOE's Federal
Energy Management Program (FEMP). The objectives of FEMP are to lower government costs
by advancing energy efficiency and water conservation and increasing renewable resource use.
Agencies are guided by FEMP to use private sector financing for energy projects with the use of
Utility Energy Service Contracts or DOE's Super Energy Savings Performance Contracts. Other
federal assistance programs include EPA's Innovations Work Group, the National Center for
Environmental Research, and DOE's Office of Energy Efficiency and Renewable Energy.
State and local governments also provide incentives for the development of alternative waste
management approaches. For example, Iowa's Department of Natural Resources Land Quality
and Assistance Division offers a loan program that "encourages implementation of innovative
waste reduction and recycling techniques, develops markets for recyclable materials and
products, and encourages the adoption of the best waste management practices" (U.S. EPA,
2011). Other states, such as California, provide extensive research and development
opportunities for waste reduction. One such group is the California Energy Commission, which
recently announced a $4.5 million grant to aid the development of an AD plant in Perris,
California.
17
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1.4 Report Structure
Sections 2—4 of this report present technologies by main category: pyrolysis, gasification, and
AD, respectively. Each section contains a listing of known facilities in North America, profiles of
selected facilities, data ranges that were defined after considering all the data obtained on
these processes, and LCA results. It should be noted that we did not attempt to compare the
performance of the various technology vendors based on the life cycle modeling results in
Sections 2—4. Specific vendors were selected based on their relatively advanced stage of
technology development and/or availability of information. Inclusion in this report does not
signify endorsement by EPA. Section 5 presents the overall findings and recommendations.
Attachment A provides documentation for the scope, assumptions, and key data used to
complete the LCAs for conversion technologies and landfill and conventional WTE base cases.
18
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Section 2:
Pyrolysis Technology
Pyrolysis is defined as an endothermic process, also referred to as cracking, involving the use of
heat to thermally decompose carbon-based material in the absence of oxygen. Its main
products are a mixture of gaseous products, liquid products (typically oils of various kinds), and
solids (char and any metals or minerals that might have been components of the feedstock).
For its predominate use in North America on mixed plastics, liquid petroleum-type products
predominate, which generally require additional refining. Application of pyrolysis to mixed
MSW could potentially generate a gaseous mixture of carbon monoxide (CO) and hydrogen (H2)
called "syngas" that can be used for steam and electricity generation. Products of process are
commonly reported, but the list and proportion of each differs depending on reactor design,
reaction conditions, and feedstock.
Various technology vendors include different variations and names for pyrolysis processes in
their technology descriptions, which can be confusing to waste managers. Technologies that
are categorized as pyrolysis generally belong to one of the following process categories:
• Thermalpyrotysis/craching—The feedstock is heated at high temperatures (350-
900 degree Celsius) in the absence of a catalyst. Typically, thermal cracking uses
mixed plastics from industrial or municipal sources to yield low-octane liquid and gas
products. These products require refining to be upgraded to useable fuel products.
• Catalyticpyrolysis/cracking—The feedstock is processed using a catalyst. The
presence of a catalyst reduces the required reaction temperature and time
(compared to thermal pyrolysis). The catalysts used in this process can include acidic
materials (e.g., silica-alumina), zeolites (e.g., HY, HZSM-5, mordenite), or alkaline
compounds (e.g., zinc oxide). Research has shown that this method can be used to
process a variety of plastic feedstocks, including low density polyethylene (LDPE),
high density polyethylene (HOPE), polypropylene (PP), and polystyrene (PS). The
resulting products can include liquid and gas products.
• Hydrocracking (sometimes referred to as "hydrogenation")—The feedstock is
reacted with hydrogen and a catalyst. The process occurs under moderate
temperatures and pressures (e.g., 150-400 °C and 30-100 bar hydrogen). Most
research on this method has involved generating gasoline fuels from various waste
feedstocks, including MSW plastics, plastics mixed with coal, plastics mixed with
refinery oils, and scrap tires.
The process of pyrolysis creates residues including char, silica (sand), and ash. Some of these
residues may be reused (if approved by an environmental agency) while others must be
disposed of in a landfill. The amount of residual waste produced is about 15-20 percent of the
overall [plastics] feedstock used in the process. Litter, odor, traffic, noise, and dust must also be
assessed and will vary according to the differences in facility technology, size, and feedstock.
19
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2.1 Existing Pyrolysis Technology Facilities and Vendors in North America
Existing pyrolysis facilities identified in North America are listed in Table 2-1. As shown in the
table, the vendor name, status, accepted feedstock, location and main product output are
listed. At the time of this study, there were three commercial-scale pyrolysis facilities in the
U.S. including Agilyx, Intrinergy Coshocton, and JBI. Each of these facilities produces a
petroleum (crude oil) type product that is, or may be, sold as a chemical commodity rather than
used for producing energy.
2.1.1 Agilyx: Tigard, Oregon
Agilyx, formerly known as Plas2Fuel, was founded in 2004 and has an operating demonstration
facility in Oregon. Agilyx claims to be able to use waste plastics of any type as feedstock and
converts it into synthetic crude oil. According to the company, the plastic waste can be
commingled and no pre-sorting or pre-cleaning is needed. The company estimates that
approximately 10 tons of plastic may be converted to 60 barrels (or 2,400 gallons) of oil on a
daily basis through a pyrolysis process.
Agilyx claims its system is able to handle any type of plastic feedstock and contamination level,
thus reducing time and cost of the process. Agilyx uses custom-designed cartridges to convey
feedstock to their processing equipment. Each system is modular and may be located at the
collection facility to reduce costs associated with feedstock transportation. These systems may
be scaled up or down, based on the amount of feedstock available.
Pre-processing of the plastic waste includes standard grinding and shredding to a density target
of 20-21 Ibs/ft3. The cartridges are filled with plastic feedstock and inserted into a large
processing vessel. A light industrial burner heats air to about 593.3 °C, and the air is circulated
around the exterior of the cartridge while the plastics are transformed from a solid to a liquid,
and finally a gas. In the gaseous form, the plastics have been broken down into oil-sized
molecules.
The heating system is closed loop in order to diminish heat loss. The gases are drawn from the
cartridge into a central condensing system. The gases are cooled in this system and condensed
into synthetic crude oil. Char is extracted from the stream, while lightweight gases that do not
condense continue downstream. The gases contain about 80 percent methane, propane, and
butane species. The gases are then either combusted for heat recovery or treated by an
environmental control device. The crude oil moves into a coalescing and settling process and is
eventually moved to an above-ground storage tank outside the facility for transport to a
refinery.
Agilyx's performance information includes a process energy ratio, which measures the British
thermal units (BTUs) received from the process (output) for each BTU input to the process.
According to the company's representatives, the process energy ratio (without including the
energy value found in char) is about 5:1. With the energy value of the char included, the ratio is
about 6:1. The BTU value of the crude oil produced is about 19,250 BTU/lb. The energy load
requirements are purchased from the local utility company. Agilyx has the ability to generate
both heat and electricity onsite (i.e., go off-grid), but their costs are lowered by purchasing
20
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Table 2-1. Pyrolysis Facilities in North America.
Vendor Name
Agilyx
Intrinergy
Coshocton, LLC
JBI
Envion
Climax Global
Energy
International
Environmental
Solutions
Vadxx
Agriplas
Green Power Inc
International
Environmental
Solutions
Oneida Tribe
Status
Commercial
Commercial
Commercial
Demo
(suspended)
Demo
Demo
Pilot Scale
Demo
Demo
Permitted
Pilot Scale
Feedstock
Plastics
Blends of crumb rubber,
shredded carpet fluff,
wood chips, and biomass
Plastics
PET, HOPE,
LDPE/LLDPE, PP, PE,
PS and PVC (less than
10%)
Plastics
MSW
Plastics, synthetic fibers,
used industrial solvents,
waste oils
Agricultural film, mixed
nursery and jug material,
food containers, and
other low- or zero-value
plastics
Plastics
MSW
MSW
Location
Tigard, OR
Coshocton, OH
Niagara Falls, NY
Derwood, MD
Fairfax, SC
Romoland,
California
Akron, OH
Kelso, WA
Pasco, WA
Riverside, CA
Green Bay, WI
Main Product
Crude Oil
Crude Oil
Diesel Fuel
Crude Oil
Crude Oil
Syngas
Crude Oil, natural
gas
Crude Oil
Crude Oil
Syngas
Syngas
Source (Sites accessed in June 2012)
http://www.sustainablebusinessoregon.com/articles/2010/06/plas2fuel opens sho
wcase facilitv changes name to a2ilvx.html
http://www.rdno.ca/services/swr/docs/swmpr/waste to energv.pdf
http://www.plastic2oil.com/site/home
http://inhabitat.com/new-envion-facilitv-turns-plastic-waste-into-10barrel-fuel/
http://www.envion.com/
http://blo2.cleantech.com/sector-insi2hts/waste/on-sta2e-in-new-vork-climax-
global-energy/
http://www.rdno.ca/services/swr/docs/swmpr/waste to energv.pdf
http://www.bioener2vproducers.or2/documents/ucr emissions report.pdf
http://www.wksu.or2/news/story/26888
http://www.2reen-ener2V-news.com/nwslnks/clips309/mar09019.html
http://www.cleanener2Vprojects.com/Summarv.html
http://dpw.lacountv. 2ov/pr2/pressroom/printview.aspx?ID=370&newstvpe=PRES
S
http://www. 2reenbavpress2azette.com/article/20101 102/GPG0101/1 1020584/One
ida-Seven-Generation- gasification-project-begins
21
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power. Natural gas is used as a supplemental fuel during startup and emergency situations.
Other fuels could be used as well.
According to data provided by Agilyx, (RTI, 2012), water requirements are minimal because it is
recycled and filtered for contaminants. Sorbent cartridges, or wastewater treatment filters, are
sent to a contractor to be cleaned and then are reused. No other inputs, such as catalysts, are
necessary for the process. The primary residual in the process is char, and the company is
attempting to find a commercial outlet for the product. About 8 percent of the feedstock
generally becomes char, but the values can range from 1-50 percent, depending on the type of
plastic used as feedstock.
Air emissions data reported by Agilyx (RTI, 2012) include permitted volatile organic compound
(VOC), nitrogen oxide (NOX), and carbon monoxide (CO) emissions. Particulate matter (PM) and
sulfur dioxide (S02) are considered de minimus and are unregulated. Approximately 1,500 short
tons per year of carbon dioxide (C02) are emitted from the light industrial burners. Agilyx is
permitted to emit 39 short tons per year of nitrogen oxides and 39 short tons per year of VOCs
but only discharge around 2.5 short tons of each pollutant. Agilyx is also allowed to emit 99
short tons per year of carbon monoxide, but actually emits about 1.5 short tons. Emissions of
hydrogen chloride (HCI), S02, NOX, and VOCs were stated by Agilyx to be based on a proposed
limit, not actual emissions levels (see RTI, 2012).
At the time of this report, Agilyx is the only pyrolysis facility known to have a refinery off-take
agreement within this industry. Currently, Agilyx is shipping crude oil from its facility in
Portland, Oregon, to the U.S. Oil and Refining Co., located in the Pacific Northwest. The impacts
of shipping and transportation costs in general were not researched in this study, but they
suggest additional burdens that should be considered when evaluating the financial viability of
the project.
2.1.2 Envion: Derwood, MD (to be relocated to Florida in 2011/2012)
Envion was founded in 2004 and focuses solely on the conversion of waste plastics to oil
through a low temperature thermal pyrolysis process. The vendor cites advantages of the
process to include relatively easy reactor construction and operation as well as the high
efficiency and high BTU value of output products. One reactor began running in a
demonstration capacity in 2009 at the Montgomery County Transfer Station (and appears to
have ceased operations due to lack of continued funding). In terms of design capacity, an
individual unit can process up to 10,000 tons of plastic waste annually. The company estimates
that each ton of plastic may be converted to about 4 barrels of refined petroleum through a
pyrolysis process. This technology can be scaled up or down through the addition of reactors.
General process information for Environ was obtained from an RW Beck (2010) study.
The Envion technology uses chipped plastics as feedstock for the pyrolysis process. An
illustration of the process is shown in Figure 2-1. The plastics must be chipped to less than 1.5
inches and melted. Approximately 1.22 tons of raw feedstock per hour is able to be processed.
About 1.8 tons per hour are processed after water and contaminants are purged. The feedstock
is composed of high-density polyethylene (HOPE), polypropylene (PP), low-density polyethylene
(LDPE) plastics, and polystyrene (PS), polyethylene terephthalate (PET), and polyvinyl chloride
22
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(PVC). PS, HOPE, LDPE, and PP are preferred because they provide the best oil yield. Only
restricted amounts of PET containers are used because they lead to much higher values of
waste product, mainly sludge. PVC plastics are also used in very small amounts due to the
chlorine compounds released in the cracking process. Data are not available to determine the
proportions of feedstock types but are thought to be comparable to typical MSW plastic
composition in the U.S.
Envion Plastic-to-Oil Technology
Block Flow Diagram of Plastic-to-Oil Process
Waste Plastic
I
Electricity
Electricity
Water to
Recovery
Non-Plastic
Screenings
udge Oil
Waste
Oil
Sludge Oil
Storage
Vent Gas
Electricity
Generation
Electricity
Figure 2-1. Envion Pyrolysis Process Flow Diagram.
(Source: www.envion.com)
In the pretreatment process, plastics move through a magnetic removal section and into the
melting and screening section where they are liquefied at 300 °C. The plastics then go through a
screen to filter nonplastic contaminants like glass and nonmagnetic metals. After the screening
process, the plastic feedstock is fed into a reactor vessel where the plastics are subjected to low
temperature thermal pyrolysis. Heat is introduced to the reactor vessel using far-infrared
heaters. The resultant gas from the reactor vessel is then passed through a packed tower to
remove contaminants. The gas is cooled and moved to tanks that separate reactor effluent into
three streams: process gas stream, product oil stream, and water stream. Light components in
the oil gas stream such as butane, propane, and methane exit the separation tank and are
moved to an internal combustion engine (ICE) to produce electricity for the process. The
efficiency of the ICE gen-set depends on the composition of the process gas. The product oil is
eventually transferred to primary oil tanks. Waste oil and water contaminants condense to
liquid form and are sent to the sludge tank.
23
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The sludge oil tank remains at an elevated temperature so contents do not solidify. To empty
the tank, some product oil is moved to the sludge oil tank to blend the oil so it may be moved
to a heated asphalt transfer truck.
Other inputs for this process include about 750 KW of electricity and up to 0.435 tons of water
per ton of raw plastic, depending on the amount of water needed for the cooling tower.
Material byproducts include process gas that is currently used to offset 10-25 percent of
electricity used in the process. The sludge byproduct accounts for about 15 percent of overall
feedstock. Currently, the sludge is stored in barrels since the BTU value of the sludge indicates
that it may have market potential as an energy source. Residuals include contaminants at a rate
of 2 TPD, or about 8 percent of the overall feedstock.
Environ claims to convert 1 short ton of plastic into about 4 barrels of oil with a value of about
18,300 BTU (RTI, 2012),. The parasitic load is about 480 KWh/ton of waste after process gas has
been combusted to generate electricity. The energy recovery efficiency of the Envion
technology can be highly variable depending on the feedstock, but is generally about 62
percent.
Estimates of emissions as reported by the vendor are listed in RTI (2012) and include methane,
sulfur dioxide, and nitrous oxide emissions. Mercury emissions are about 0.016 micrograms/ton
of waste. Lead emissions are 0.106 mg/L of oil. Envion did not provide any information on
water emissions. Sludge is currently considered a waste byproduct, although it has an energy
value.
The cost per design capacity is estimated by the vendor to be $7.6 million per unit or
$280,700/TPD. In terms of process cost per ton, estimates range from $17 to $60, assuming 80
percent of electricity use in the production process is from the grid. Costs would be lower if the
process relied solely on their own power generation. If a market niche is found for the sludge
byproduct it could possibly be sold, and this disposal costs would be reduced.
2.1.3 Climax Global Energy: South Carolina
Climax Global Energy is a company that exclusively uses plastics as their feedstock in order to
produce high-quality synthetic oil and wax. Climax currently operates a demonstration facility
and claims to be able to accept any type of plastic. Their source material comes from
municipalities and private companies within a 50-mile radius. The company claims that no pre-
cleaning or pre-sorting processes are necessary (although shredding is required); feedstocks are
fed directly into a pyrolysis chamber. In order to power this process, microwave energy or
diesel generators may be used. Vitrified solid residuals are one byproduct of this process.
Approximately 5-10 percent of the original mass of the feedstock is nontoxic ash that must be
landfilled.
Climax Global technology claims to be able to accept mixed, post-consumer plastics as
feedstock for their pyrolysis process. The plastics must be chipped a nd shredded prior to being
processed. Approximately 20 tons of raw feedstock per day is processed. Moisture content of
the feedstock ranges from 0 to 5 percent. One ton of waste plastic yields 5 barrels of synthetic
oil. The feedstock is converted using average bulk reactor temperatures of 400 °C. Inputs to the
process include a minimal amount of inert nitrogen and 1-3 gallons of water per minute. Three
24
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to 4 tons of light gases (e.g., methane, propane) are produced as byproducts. One to 3 tons of
solid carbonaceous residue and any inert materials from feedstock stream, such as rocks, dirt,
and glass, are removed as a part of the process.
Climax Global Energy claims an energy recovery efficiency of approximately 75 percent. The
commodity wax has approximately 6 million BTUs per barrel. The internal parasitic power
requirement is expected to be about 18,000 KWh per day. No external fuel use is required in
order for the facility to begin operations.
According to data reported by the RTI (2012), the facility emits PM, C02 and hydrocarbons, S02,
N20, VOCs, NOX, and CO. Byproducts of the process include inorganic residue and ash.
Additionally, less than 1 gallon of water effluent per hour is produced during the process.
The cost per design capacity is estimated to be $250,000/TPD, including materials, handling,
and other plant costs. Similar to the other pyrolysis operations profiled, Climax claims it is able
to create many different products out of its plastic feedstock. For example, commodity wax is
one product that has a variety of uses such as cosmetics, adhesives, and coatings. The company
can also produce oils that can be refined into ultra-low sulfur diesel and high-grade synthetic
lubricants such as automobile motor fuels.
2.1.4 JBI: Niagara Falls, New York
JBI uses a proprietary pyrolysis process, Plastic20il (P20), to convert mixed, nonrecyclable
plastic waste to fuel oil and naphtha. JBI receives feedstock from a variety of sources, including
commercial and industrial partners, and is currently seeking a permit to use MSW-based
feedstock. JBI has been operating at a commercial status in Niagara Falls, New York, since 2010
and anticipates one jointly-operated site in Canada and several in Florida. The P20 processor is
highly automated and runs continuously, as long as feedstock is loaded into the hopper.
Approximately 1,800 pounds of feedstock can be converted per hour. The process currently
converts up to 20 tons of plastics per day. However, 30-ton-per-day units are in development.
The footprint for the processing equipment is less than 1,000 square feet.
Feedstock is first shredded or pre-melted and conveyed to the reactor via a hopper and
conveyor system. The reactor cracks the plastics into shorter hydrocarbons that are gaseous at
the operating temperature of the reactor. After cracking, the heavy fraction gases are
condensed and stored in fuel tanks and the light fraction gases are compressed and used to
internally power the P20 process or are sold separately. Inputs include natural gas for start-up,
proprietary catalysts, water and electricity. P20 is permitted to generate electricity onsite using
process gases as fuel. Since the process can convert approximately 8 percent of the plastic
feedstock into these light-fraction process gases, the grid electricity requirement averages
around 67 KWh per ton of plastics processed.
According to data reported to RTI by JBI (RTI, 2012), for every ton of plastic processed,
approximately 5 pounds of nonhazardous solids, 136 pounds of char (characterized by JBI as
carbon black or pet coke), and spent catalysts are produced in addition to the naphtha, diesel,
and light-fraction gases. Residues are removed automatically.
The Plastic20il process claims a recovery efficiency rate of approximately 92 percent (RTI, 2012).
Each ton of plastic produces approximately 1,700 pounds of gasoline and diesel. Additional
25
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byproducts include residuals, which have been found to have a heating value of 10,600 BTU,
and syngas. These products and byproducts may then be blended with other fuels and
additives, depending on the market and/or needs of the purchaser. JBI also relies on the off-
gases generated internally, reducing the operating costs and offsetting electricity grid mix
emissions.
According to the RTI report (2012), primary air emissions from the P20 process include
particulate matter, carbon dioxide, nitrogen oxides, hydrocarbons, and VOCs. However, JBI
claims it is not required to monitor emissions or install emissions control technologies. In terms
of GHG emissions, converting 1 ton of plastic using the P20 process is claimed by JBI to yield
approximately 0.29 pounds of carbon equivalent emissions. The vendor also reports 2.41
pounds of NOX emitted for every ton of waste plastics. JBI reports that the atmospheric
emissions are less than those of a natural gas furnace. JBI claims water is used for gas cooling
and wastewater from this step is reused, but no water effluent is generated.
The estimate for cost per design capacity is $587,000 for the entire machine. Operational costs
to cold start and power the processing equipment average about $7 per hour. Plastics are
generally provided to JBI at no cost.
In addition to receiving permits to begin commercial operations in New York, JBI recently
announced a joint venture with OxyVinyl Canada to produce oil onsite using the waste plastics
generated by OxyVinyl. JBI is currently focusing on creating additional partnerships with
organizations that have existing permits and high-volume waste plastic streams to maximize
consistent feedstock volume while minimizing the permitting processes.
2.2 Environmental Data and LCA Results
For the American Chemistry Council, RTI developed ranges for energy and emissions data for
the pyrolysis technology category as a whole (see RTI, 2012). The data are shown in Table 2-2
and include ranges developed from a combination of vendor-supplied estimates, company web-
pages, publicly available permit applications, and publicly available literature. Specific data
provided by technology vendors is available in RTI's (2012) report.
The LCA methodology was used to guide the environmental and cost assessment. Using a life
cycle perspective encourages planners and decision-makers to consider the environmental
aspects of the entire waste management system. These include activities that occur outside of
the traditional framework of activities, from the point-of-waste collection to final disposal. For
example, anyone evaluating options for recycling should consider the net environmental
benefits (or additional burdens), including any potential displacement of raw materials or
energy. Similarly, when energy is recovered through waste combustion, conversion
technologies, or landfill gas-to-energy, the production of fuels and the generation of electricity
from the utility sector is displaced. For the pyrolysis technologies, commodity oils/waxes are
the main product and thus we assumed that the commodity oils/waxes displace petroleum-
based crude oil.
26
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Table 2-2. Pyrolysis Process Data Ranges.
Parameters
Units
Value
Process Inputs and Outputs
CO
"13
Q.
_c
CO
3
CL
3
O
Power consumption/ parasitic load
Other inputs (e.g., water, oxygen,
etc.)
Supplemental fuel use
Energy product (e.g., syngas,
ethanol, hydrogen, electricity,
steam)
Residuals (e.g., ash, char, slag, etc.)
Water losses
Water
Natural Gas
Syngas
Crude oil
Light fraction (liquid)
Gas fraction
Gasoline
Diesel
Char
Solid residues
Inorganic sludge
Nonhazardous solid waste
KWh/dryton
gal/dry ton
MMBtu/dry ton
MMBtu/dry ton
Ib/dry ton
Ib/dry ton
Ib/dry ton
Ib/dry ton
Ib/dry ton
Ib/dry ton
Ib/dry ton
Ib/dry ton
Ib/dry ton
gal/dry ton
0.3
30
967
300
200
136
-
-
-
-
-
-
430
216
0.03
0.2
1362
400
500
23
1,711
160
160
300
5
25
Air Emissions Data
PM
Fossil Carbon Dioxide (CO2Fossil)
Methane (CH4)
HCI
Hydrocarbons
Nitrous Oxide (N2O)
NOx expressed as NO2
Carbon Monoxide (CO)
Lead
VOC
Ib/dry ton
Ib/dry ton
Ib/dry ton
Ib/dry ton
Ib/dry ton
Ib/dry ton
Ib/dry ton
Ib/dry ton
Ib/dry ton
Ib/dry ton
0.04
500
26
0.01
0.3
2.E-04
3.E-04
-
-
-
-
-
-
-
-
15
962
65
3.E-04
8
2
91
9
0.02
2
Cost Data
Cost per to n of design capacity
$/dtpd
29,350
-
280,699
LCA can be a valuable tool to ensure that a given technology creates actual environmental
improvements rather than just transfers environmental burdens from one life cycle stage to
another or from one environmental media to another. This analysis is also useful for screening
systems to identify the key drivers behind their environmental performance.
The approach for constructing the LCA was to develop inventories of energy, emissions, and
cost for the conversion technology system and to utilize the Municipal Solid Waste Decision
Support Tool4 (MSW DST), a tool developed under a cooperative agreement between RTI and
EPA, to capture the other life cycle components (e.g., materials pre-processing [separation],
landfill disposal, energy production, transportation, and materials production activities). The
data and models in the MSW DST have been developed for the U.S. EPA and has gone through a
series of reviews including external peer, quality assurance, administrative, and stakeholder
reviews. Conversion technology results were then compared to results for base case landfill
and conventional WTE scenarios. The landfill and WTE results are presented as a range. For
https://mswd st.rti.org/index. htm
27
-------
landfills, the lower end of the range represents disposal in a landfill with a gas collection and
flaring system and the upper end of the range represents disposal in a landfill with a gas-to-
energy type management system. For WTE, the lower end of the range represents facility with
an efficiency of 18,000 btu/kwh and the upper end of the range represents facility with an
efficiency of 14,000 btu/kwh. It is assumed that the electricity produced from WTE displaces
electricity from utilities based on the U.S. average electricity grid mix of fuels.
The LCA results do not represent any one specific facility or vendor. Rather, data collected for
selected technology vendors as profiled in Section 2.1 were supplemented with data collected
from the literature and lower-upper bound ranges were developed for the technology. Results
include the transportation and disposal of residuals. Thus, the cost and LCA results include the
burdens associated with the pyrolysis facility as well as with transportation and disposal of
residuals. The benefits are those associated with fuels recovery.
The scope, assumptions, and key data are described in Attachment A. Results are presented in
this section as net total burdens minus benefits. Therefore, negative energy results mean that
more energy is recovered than that needed to run the processes; negative GHG emissions
mean that there are more emissions savings as a result of energy and fuels production using the
waste material relative to using virgin material; and negative cost results mean that the
revenues are higher than the costs.
Energy
For pyrolysis, energy is consumed to power the process and ancillary systems and transport and
dispose of residuals in a landfill. Energy in the form of petroleum products (e.g., fuel oil and
petroleum wax) is the main output from the pyrolysis process. Typically this product is
transported off-site for use.
The results for energy consumption for pyrolysis are shown in Figure 2-2 on a per-ton basis and
in Figure 2-3 per MMBtu of energy produced. According to these figures, the petroleum
product output generates large energy offsets. The pyrolysis process can be considered an
energy producer (i.e., the energy produced exceeds the energy consumed), with some variation
in the amount of energy produced, according to the data obtained from the vendors and the
literature.
GHG Emissions
Consistent with the energy results, Figures 2-4 and 2-5 show that pyrolysis of plastics results in
GHG emissions savings, which are mostly due to emissions savings from the replacement of
conventional energy (petroleum) products. The emissions data obtained for pyrolysis exhibits a
wide range of variation, as illustrated by the minimum and the maximum bars.
28
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I -5
J -10
I -15
4-1
Q.
f -20
V)
O
~25
01
£ -30
-35
HMin Values
El Max Values
Pyrolysis Process Fuel offsets
Disposal
NET TOTAL
Figure 2-2. Net Energy Consumption Per Ton for Pyrolysis of Plastics.
1.00
O.E
£ =5- 0.00
ll
w T3
r- O
| - -0.50
li
§ OJ
c £ -i.oo
^ -1.50
LLJ
-2.00
Pyrolysis Process Fuel offsets
Disposal
NET TOTAL
Figure 2-3. Net Energy Consumption Per MMBtu for Pyrolysis of Plastics.
29
-------
0.40
HMin Values
ElMax Values
-0.20
Pyrolysis Process
Fuel offsets
Disposal
NET TOTAL
Figure 2-4. Net Carbon Equivalents Per Ton for Pyrolysis of Plastics.
0.020
oj 0.015
01
1 0.010
T3
01
c
_OJ
ro
cr
LU
O
0.005
0.000
-0.005
-0.010
HMin Values
SMax Values
Pyrolysis Process Fuel offsets
Disposal
NET TOTAL
Figure 2-5. Net Carbon Equivalents Per MMBtu for Pyrolysis of Plastics.
Cost
The net cost (expenses minus revenues) per ton for pyrolysis of plastics is shown in Figures 2-6
and 2-7. As shown in these figures, the net cost range is negative, signifying a net revenue
stream that results from the market value of the petroleum product being greater than the cost
to process the plastics into petroleum via the pyrolysis process.
30
-------
100
50
_ -50
o
>-100
•c
—-150
o
5 -200
-250
-300
-350
HMin Values
El Max Values
Pyrolysis Process
Fuel offsets
Disposal
NET TOTAL
Figure 2-6. Net Cost Per Ton for Pyrolysis of Plastics.
T3
01
U
3
T3
O
L_
Q.
g
w
4-J
t/1
O
0
-2
-4
-6
-8
-10
-12
-14
Min Values
ESMax Values
Pyrolysis Process Fuel offsets
Disposal
NET TOTAL
Figure 2-7. Net Cost Per MMBtu for Pyrolysis of Plastics.
The conversion efficiency (e.g., number of barrels of oil per ton of plastics) and contracted
market price for the recovered petroleum product are highly significant to the net cost.
Facilities will likely align their specific technology to obtain the specific petroleum product (e.g.,
diesel and petroleum wax) that yields the highest market price.
Comparison to Landfill and WTE Base Cases
In this section, the results for pyrolysis of plastics are compared to results for a landfill and WTE
base case for plastics. A low-high range was developed for the landfill base case using a landfill
31
-------
with gas collection and flaring for the "low" end of the range and a landfill with gas collection
and energy recovery for the "high" end of the range. However, since plastics waste isn't
expected to produce any gas, this distinction is not relevant and only done to be consistent with
the gasification results. Again, the landfill base case was modeled using RTI's MSW DST and is
representative of a U.S. average. Similarly, a low-high range was developed for WTE using a
plant efficiency of 14,000 btu/kwh as the "low" end of the range and a plant efficiency of
18,000 btu/kwh as the "high" end of the range.
Figure 2-8 shows the results for net energy consumption (i.e., energy consumed minus energy
produced). According to this figure, the net energy saved using the pyrolysis technology versus
landfill disposal is approximately 22-32 MMBtu per dry ton of plastics. These savings are mostly
associated with the fuels produced by the pyrolysis facility and the fact that there is no energy
recovery potential (i.e., there is no methane generation) from landfill disposal of plastics.
When compared to WTE, pyrolysis appears to be in a similar range to WTE.
<; n
"c"
o
+2 n n
>
^ -50
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V)
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^-300
aj 3u.u
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LLJ
or n
-:-:•
~-~-
~-~-
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I~I~
—
_ _
Low
Landfill (
High
Plastics)
Low
WTE(P
High
lastics)
Low
Pyrolysis
High
(Plastics)
Figure 2-8. Net Energy Consumption for Landfill, WTE and Pyrolysis of Plastics.
Figure 2-9 shows the results for net carbon emissions (i.e., carbon emissions minus savings).
According to this figure, the pyrolysis technology results in a net positive emission of carbon of
approximately 0.03-0.26 TCE per dry ton of plastics processed when compared to landfills. This
positive value is mostly associated with the crude oil produced by the pyrolysis facility and the
fact that no carbon emissions are generated from landfill disposal of plastics. In the case of
pyrolysis, the crude oil product may be combusted or used as a chemical feedstock to a
manufacturing process. If used as a chemical feedstock, the carbon may be released to the
32
-------
c
jj U.ZD
£•
u
t
c U.lb
O
1
^ 0 10
c
o
.a
u
n nn
Low
Landfill (
High
Plastics)
~-~
— —
::::
~-~-
in
Low High Low High
WTE (Plastics) Pyrolysis (Plastics)
Figure 2-9. Net Carbon Equivalents for Landfill, WTE and Pyrolysis of Plastics.
atmosphere or possibly incorporated into the product. These results assume the carbon
content of the crude oil ultimately is released to the atmosphere.
Figure 2-10 shows the results for net cost (i.e., costs minus revenues). According to this figure,
the pyrolysis technology results in a net reduction of approximately $250-300 per dry ton of
plastics processed when compared to landfills and WTE. Consistent with the energy and GHG
emissions results, this reduction is mostly associated with the fuels produced by the pyrolysis
facility. For example, the pyrolysis facility will obtain revenues from sale of the crude oil.
150
100
50
0
c
O
£• -50
•a
J2-100
«
3 -150
-200
-250
-300
Low
High
Landfill (Plastics)
Low High
WTE (Plastics)
Low High
Pyrolysis (Plastics)
Figure 2-10. Net Cost for Landfill, WTE and Pyrolysis of Plastics.
33
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Section 3:
Gasification Technology
Gasification is the partial oxidation of carbon-based feedstock to generate syngas. The process
is similar to pyrolysis, except that oxygen (as air, concentrated oxygen, or steam) is added to
maintain a reducing atmosphere, where the quantity of oxygen available is less than the
stoichiometric ratio for complete combustion. Gasification forms primarily carbon monoxide
and hydrogen, but potentially other constituents such as methane particularly when operating
at lower gasification temperatures. Gasification is an endothermic process and requires a heat
source, such as syngas combustion, char combustion, or steam. The primary product of
gasification, syngas, can be converted into heat, power, fuels, fertilizers or chemical products,
or used in fuel cells. The current main types of gasification processes for MSW include the
following:
• High temperature gasification—High temperature gasification reactors, as
described in ARI (2007), can reach up to 1,200 °C and produce an inert byproduct, or
slag, that does not need further processing to be stabilized. The syngas is typically
combusted to generate steam which can be used for power and/or heat generation;
however, the resultant sysngas may also be used for other applications such as
chemicals production. Typically, this technology processes a mix of carbonaceous
waste including paper, plastics, and other organics with a moisture content of up to
30 percent, which avoids the need for drying. In general, there are no water
emissions because conventional water treatment systems are used to convert
process discharges to useable process and/or cooling water. Treatment systems
include settling and precipitation to capture and remove solids, which are returned
to the high-temperature reactor.
• Low temperature gasification—Low temperature gasification reactors, as
described in ARI (2007) and RTI (2005), operate at temperatures between 600 and
875 °C and produce ash that could be sent to a vitrification process to make it inert
and available for other uses. Syngas is the main product from this process and is
typically used for electricity generation using an Internal Combustion Engine (ICE).
This process can also recover steam energy. Separate estimates of energy from
syngas and steam are obtained. This technology is assumed to require a feedstock
with a moisture content of 5 percent or less and includes a drying pre-processing. A
mix of gases and aerosols are produced from low temperature gasification and are
sent to be quenched. The resulting liquid is cooled and water is recovered and sent
to a solids mixing tank. Char, brine, and bio-oils may also be recovered. Bio-oils are
typically recycled back to the process, but may be useful as fuel intermediates, and
char and brine are included as water and solid waste emissions.
• Plasma gasification—Plasma gasification converts selected waste streams
including paper, plastics, and other organics, hazardous waste, and chemicals to
syngas, steam, and slag. In this technology, the gasification reactor uses a plasma
torch where a high-voltage current is passed between two electrodes to create a
34
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high-intensity arc, which in turn rips electrons from the air and converts the gas into
plasma or a field of intense and radiant energy with temperatures of thousands of
degrees Celsius. The heated and ionized plasma gas is then used to treat the
feedstock. Material such as petroleum coke is sometimes added to the reactor to
support reduction reactions and to stabilize the slag. No drying pre-processing of the
feedstock is required and the feedstock is assumed to have up to 30 percent
moisture content. Syngas and steam are then typically used for power generation,
included in the estimate of total electricity offsets. The slag, also produced in this
process, is quenched prior to any use or disposal.
As with pyrolysis, residues such as slag and ash that are produced in the gasification process
may need to be disposed of at a landfill. Another potential issue that may need to be assessed
is the level of pre-sorting necessary. Some pre-processing will be needed for many of these
facilities. For some gasification technologies, however, a significant presorting process will be
required, including the removal of recyclables, sorting, shredding, and drying. The pre-sorting
process is necessary to make the feedstock more homogenous and to increase efficiency of the
overall process. The amount of material removed depends on the feedstock composition and
the specific process requirements. Pre-processing, such as grinding, size classification, drying,
or slurring, may be required to facilitate feeding of the feedstock into the particular conversion
process being utilized.
3.1 Existing Gasification Technology Facilities and Vendors in North
America
Existing gasification facilities identified in North America are listed in Table 3-1. As shown in the
table, the vendor name, status, accepted feedstock, location and main product output are
listed. At the time of this study, there were not any commercially operating gasification
facilities accepting MSW in the U.S., however, there are a number of MSW-based facilities
under development and testing. Each of these facilities produces syngas as the main product
which is typically used for producing electrical energy. Liquid fuels, and other commodity
chemicals are potential byproducts from gasification technology that may be marketable.
35
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Table 3-1. Existing Gasification Facilities in North America.
Vendor
Name
Blue Fire Ethanol
Nexterra
RangeFuels
Cirque Energy LLC
Alter NRG
Taylor Biomass
Primenergy
Westinghouse/
Coronal (subsidiary
of AlterNRG)
Westinghouse/
Coskata subsidiary of
AlterNRG)
Enerkem
Westing-
house/Coskata
Status
Permitted
Commercial
Commercial
Commissioned
Field Testing
Commissioned
Commissioned
Semi-commercial
Demo
Demo
Demo
Feedstock
Wood chips, forest
residuals, urban wood
waste
Wood residues
Non-food biomass, such
as woody biomass and
grasses
Wood chips
MSW
paper, fiber, food
residuals, leather, some
textiles and wood
products from MSW
Carpet Residues
MSW, WWT biosolids,
and tires
Non-food based
feedstocks, forest/ag
waste and construction
waste
MSW, wood chips,
treated wood, sludge,
petcoke, spent plastics,
wheat straw
Building waste, forest
waste
Location
Fulton, Mississippi
Heffley Creek, BC
Soperton, GA
Midland MI; Dow
Coming
Milwaukee, WI
Montgomery, NY
Dalton, Georgia
International Falls,
Minnesota
Madison,
Pennsylvania
Sherbrooke, Quebec,
Canada
Warrenville, IL
Main Product
Ethanol
Syngas
Syngas
Syngas
Syngas
Syngas
Syngas
Syngas
Ethanol
syngas, methanol,
acetates, second
generation ethanol
Source (Sites accessed in June 2012)
http://www.eere.energv.gov/golden/PDFs/ReadingRoom/NEPA/l%20Blue
Fire%20DOE%20Final%20EA%206-4-10.pdf
http://www.nexterra.ca/PDF/Project Profile Tolko 20100118.pdf
http://www.rangefuels.com/range-fuels-produces-cellulosic-methanol-
from-first-commercial-cellulosic-biofuels-plant.html
http://www.dowcorning.com/content/news/midland biomass_plant dow c
orning.aspx?bhcp=l
http://www.wisbusiness.com/index.iml?Article=209527
http://www.tavlorbiomassenergv.com/tavlorbiomass04 mont mn.html
http://www.shawfloors.com/pv obi cache/pv obi id D731E1B2C5B45E
CE98332FBBClFB427478F32AOO/filename/Enviro Brochure2009.pdf
http://alternrg.com/press release 94443
http://www.westinghouse-plasma.com/technologv/demonstration-facilitv
http://www.enerkem.com/en/our-locations/overview.html
http://www.coskata.com/facilities/?source=C3C8A85B-7736-4D64-87F8-
9E4FBD45D1BO
36
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Vendor
Name
InEnTech, LLC
Fiasco Energy
Ze-gen
(operations have
suspended as of
September 2012)
Enerkem
Fulcrum, InEnTech,
LLC
Ineos
Nexterra
InEnTech AVM
Entech Renewable
Energy
Ineos
Fulcrum, InEnTech,
LLC
Enerkem
Enerkem
Status
Demo
Demo
Demo
Demo
Demo
Demo
Demo
Permitted
Permitted
Permitted
Permitted
Permitted
Permitted
Feedstock
MSW
MSW
MSW- wood wastes,
non-recyclable plastics,
carpet, and glycol (anti-
freeze)
MSW/used electricity
and telephone poles
Post-recycled MSW
Pre-processed MSW
Sawmill residues
MSW
MSW
Yard, wood, agricultural
and vegetative wastes
MSW
MSW
MSW
Location
Richland, WA
Ottawa, Canada
New Bedford, MA
Westbury, Quebec,
Canada
Pleas anton,
California
Fayetteville,
Arkansas
Vancouver, BC
Columbia Ridge, OR
Huntington Beach,
CA
Vero Beach, FL
Reno, Nevada
Edmonton, Canada
Pontotoc, MS
Main Product
Syngas
Syngas
Syngas
Ethanol
Ethanol
Syngas
Syngas
Syngas
Ethanol
Ethanol
Ethanol (as well as
Syngas, Methanol,
Acetates)
Ethanol (as well as
Syngas, Methanol,
Acetates)
Source (Sites accessed in June 2012)
http://www.inentec.com/pem-facilities.html
http://www.bioenergvproducers.org/documents/ucr emissions report.pdf
http://attleboroproject.com/qa.html
http://www.rdno.ca/services/swr/docs/swmpr/waste to energv.pdf
http://www.bioenergvproducers.org/documents/ucr emissions report.pdf
http://www.ge mcanadawaste. com/52901. html?*session*id*kev*=*session
http://fulcrum-bioenergv.com/documents/IEReport-032610-FINAL.pdf
http://www.dep.state.fl.us/Air/emission/bioenergv/indian river/INEOS tec
hnical evaluation.pdf
http://www.unbc.ca/releases/2010/ll 25biomass ignition.html
http://www.inentec.com/images/stories/documents/PressReleases/releases-
-s4%20or%20announceme nt-march-2010_final.pdf
http ://www. socalconversion. org/ne ws . html
http://www.ineosbio.com/76-Press releases-13.htm
http ://fulcrum-bioenergy. com/biofuel-plants . html
http://www.enerkem.com/en/our-locations/plants/edmonton-alberta.html
http://www.enerkem.com/en/our-locations/plants/pontotoc-
mississippi.html
37
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3.1.1 Enerkem: Westbrook, PQ, Canada
Enerkem's process is designed to convert waste materials to syngas as an intermediate product.
Sources of feedstock include MSW, refuse-derived fuel (RDF) from sorted MSW, woody wastes
from construction and demolition, used telephone poles, and other wastes from industrial,
commercial, and institutional (ICI) processes. Electricity, ethanol, and other green chemicals are
options for final products.
The company currently has two operational facilities including a pilot-scale demonstration plant
in Sherbrooke, QC, Canada; and an operating commercial-scale demonstration plant in
Westbury, QC, Canada. Enerkem also has begun construction on two additional facilities: one in
Pontotoc, MS, and one in Edmonton, AB, Canada. According to Enerkem's website, the
Pontotoc facility is currently finalizing permits required to build and operate the facility. The
Edmonton facility is anticipated to begin full operations in 2013. Information regarding the
status of the operations can be found on the City of Edmonton's and the company's websites.
Another Enerkem facility is being proposed in Varennes, QC, Canada. All information about the
anticipated Pontotoc, MS, plant was obtained from the Environmental Assessment (U.S. DOE,
2010). Information about the Canadian facilities was obtained from a combination of personal
communications and literature search.
The commercial-scale demonstration facility has been in operation since 2009 and, in its
demonstration stage, has managed approximately 39 tons per day of feedstock on a dry basis.
[Source]Commercial-scale demonstration signifies that the facility is in the next-to-final stage of
the technology development cycle and is a commercial-scale facility running smaller "batches"
of waste to refine the process. The planned commercial facilities will have a capacity of
approximately 330 dry tons per day.
The Enerkem gasification process is illustrated in Figure 3-1. The first steps in the process are to
dry, sort, and shred the waste. Three types of feedstock are used: (a) refuse-derived fuel (RDF)
that has been sorted from MSW, (b) construction and demolition (C&D) waste, and (c)
institutional, commercial, and small industry (ICI) waste. The pre-sorting of RDF waste includes
sorting and biological treatment followed by processing to a "fluff." The facility can also accept
more traditional pelletized RDF. C&D wood is shredded and ICI is sorted and also shredded. All
pre-processing occurs at the facility. The inorganic matter content of each type of feedstock is
generally 15 percent of total weight for RDF and ICI, while C&D wood is less than 5 percent.
The shredded "fluff from MSW, C&D, and ICI waste is fed into a bubbling fluidized gasifier. The
waste is converted into syngas. Inert residues are removed and can be used as aggregate for
construction (if approved). Next, the syngas goes through a series of steps that clean and
condition the syngas. These systems include cyclones, a cooling system, water treatment, and a
washing tower. Wastewater is a main byproduct of this portion of the process, but is reused.
Enerkem claims the heating value of syngas is between 6 and 12 megajoules per standard cubic
meter, depending on the process specifics. Electricity can be produced with the use of syngas in
an internal combustion engine (ICE) generator-set. Alternatively, the syngas can enter catalytic
reactors where it is converted into liquid fuel including ethanol, advanced biofuels, and/or
green chemicals. Conversion to ethanol requires oxygen and steam inputs for this step of the
38
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Wide variety
of raw materials
Urban Biomass
• Sorted Municipal
Solid Waste
• Institutional,
Commercial and
Industrial Waste
• Renovation, Construction
& Demolition Waste
• Treated Wood (railway ties,
power poles)
Agricultural Residues
e.g. bagasse,
corn stover,
wheat straw
and rice hulls
Forest Residues
e.g. wood chips,
sawdust, bark,
thinnings, limbs,
tops, needles
Step 1:
Feedstock
pre-treatment
Drying, sorting
and shredding
Step 2:
Gasification
Conversion of
carbon-rich residues
into synthetic gas
Step 3:
Synthetic gas
conditioning
Cleaning and
conditioning process
Step 4:
Conversion into
liquid fuel
Catalytic conversion
of syngas
Catalytic
material
Air/Oxygen
Recovery of inert
material as aggregate
for construction materials
Second generation
ethanol, other advanced
biofuels and
green chemicals
Figure 3-1. Enerkem Gasification Process Flow Diagram.
(Source: http://enerkem.com/en/our-solution/technology/process.html)
process. The exact process configuration and end product(s) will be tailored to the markets and
contractual arrangements.
Performance information provided by the vendor includes the efficiency of the process in terms
of efficiency of conversion into final products on a calorific basis, as well as the reliability of the
technology in commercial operating conditions. Enerkem states that 72% of the lower heating
value (LHV) of the feedstock is converted to syngas. In addition, high- or low-grade heat
recovery is an option that Enerkem states can provide 5-10 percent of additional conversion
efficiency. The internal parasitic power requirement to operate the gasification process is
approximately 600 KWh per dry ton when electricity is the end product and 490 KWh per dry
ton when ethanol is the end product. In addition, natural gas is required (15.72 Ibs per ton of
MSW) for facility start-up, but is not used as a co-fuel for normal process operation.
Since Enerkem is operating as a demonstration facility, information about the reliability of the
process at commercial operating conditions is not available at this time.
In general, the data quality for emissions estimates is low since the facility is still in the
demonstration stage. As the facility transitions to a fully operational commercial stage, one
would expect the process inputs/outputs to stabilize and emissions to be more consistent for
measurement.
Primary air emissions from the Enerkem process include C02 and NOX as well as traces of
methane, HCI, hydrocarbons, S02, and CO. The vendor indicated to RTI that mercury, cadmium,
lead, ammonia, dioxin, and furan emissions are all below Canadian and U.S. (and EU) regulatory
limits. Ammonia is also an emission that must be controlled using a scrubber system. The
ammonia then must be removed from the circulating scrubbing water. The recovered ammonia
(NH3) can be sold or reintroduced in the gasifier, where it is converted into nitrogen (N2) and
39
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hydrogen (H2). A steady state level of NH3 is thus achieved and the syngas maintains a
concentration below the regulations.
In terms of GHG emissions, Enerkem estimates (American Chemistry Council, 2012) that
approximately 40 percent of the carbon in the feed is turned into C02, but approximately 75
percent of the produced C02 is recovered and reused. The ratio of biogenic to fossil carbon in
C02 depends on the ratio of biogenic to fossil material in the RDF feed stream. Enerkem also
indicated (see RTI, 2012) that the biogenic to fossil carbon fraction is typically 3- 4 to 1 for the
RDF since it contains about 20 percent plastics and 60 to 70 percent biomass.
Water is used for gas cooling and wastewater from this step is reused. The process itself is a net
water producer. Enerkem estimates that it purges 1 ton of process water per ton of feed (dry
basis). The facility cleans this water and returns about 80 percent of the purged water to the
process. The remaining excess water generated is evaporated in a cooling tower or discharged
as wastewater. Enerkem data provide a range of 544 to 1,270 pounds of water generated per
ton of waste processed, depending on the moisture content removed in the drying/dehydrating
step.
Residual wastes produced by the process include primarily char and spent or residual catalysts
from the catalytic synthesis stage. No estimate for char production was provided, but the char
would require disposal. If the process is tailored to produce alcohol fuels as the main product,
then residual catalysts would be produced and also require disposal.
Estimates for capital and operating costs were collected through publicly available sources as
well as from the American Chemistry Council (2012). Similar to emissions, reliable cost
estimates are difficult to present since the facility is still in the demonstration stage. As the
facility transitions to a fully operational commercial facility, one would expect the process
inputs/outputs to stabilize and costs to be more consistent and reliable.
Estimates for cost per design capacity for the Enerkem Pontotoc, MS, facility is $424,000 per
dry ton. For their 330 dry ton per day facility, the total capital cost would be approximately
$140 million. Additionally, an external source presentation indicates Enerkem receives
feedstock at no cost or at a gain of approximately $45 per ton of waste for the Quebec facility.
Electricity, ethanol, and other green chemicals are options for final products for the planned
facilities. The exact process configuration and operation specifics will be tailored to the markets
and contractual arrangements.
3.1.2 Fiasco: Ottawa, Ontario, Canada
Fiasco Energy Group operates a commercial-scale demonstration facility working closely with
the city of Ottawa. The partnership began in April 2006 and the facility was constructed at the
site of the operating Trail Road Landfill. Currently, the facility is permitted to process 93 ton per
day of solid waste and is designed to generate 4 MW of electricity. Fiasco Energy Group
provided RTI with an independent comparative analysis of Fiasco and other waste-to-energy
(WTE) facilities as well as with a process brochure (Pembina, 2009; Fiasco, 2011). Additionally,
general process information and semi-annual emissions reports were obtained from the
company's website (Fiasco, 2010).
40
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Fiasco Energy Group's Ottawa Trail Road Facility is a WTE facility that utilizes non-recycled
MSW. MSW is first shredded and then goes into the conversion chamber, which converts waste
into crude syngas with the use of recycled heat. A plasma torch is used to heat and stabilize
residual solids liberates any remaining volatile compounds and fixed carbon into crude syngas,
which then flows back to the conversion chamber.
The crude syngas moves to the refinement chamber and plasma torches are utilized to clean
and refine the gas. At this point, the syngas is passed through several unit operations designed
to remove heavy metals, particulate matter (PM), and acid gases. After cleaning, the Syngas is
routed to either a flare, or an ICE to generate electricity. A percentage of the process water
must be disposed of through a licensed carrier, or permitted for treatment at a POTW.
However, Plasco will be a net producer of water because the excess moisture in the waste is
removed at high temperatures. The water is then filtered and cleaned to sewer water
standards.
The process flow diagram for Plasco is Figure 3-2.
Recyclables
Processing
Recyclables
Processing
Municipal
Waste
flecyclatles
Residual MSW
Plasco
Conversion Process
Recovered
Metals
Shredding/
Metals
Recovery
Retined Gas
Power Generator
(Steam Turbine)
Conversion
Chamber
ynsortedMSW
MSW
tat
, (Sttam)
Gas Cleaning/
HRSG
Quality
Water
0.1% DISPOSE
(HEAVY METALS)
mat
(Stem)
Plasco Syngas
Product
Storage
Power
Generation
(1C Engines)
Engine
Exhaust
of Recycled
Materials
Maximum Technical Advantage
Figure 3-2. Plasco Gasification Process Flow Diagram.
(Source: www.plascoenergygroup.com)
No data were obtained for the energy conversion efficiency of the process. However, Plasco
reports that 98 percent of the waste processed is converted to marketable products.
Additionally, a 2009 study comparing Plasco to standard waste-to-energy processes indicates
that each ton of waste produces between 2,000 and 3,000 cubic meters of syngas with an
41
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energy content of 3 to 5 megajoules per cubic meter, depending on the feedstock content.
Higher energy content in feedstock yields higher energy content and higher volumes of syngas.
If accurate, syngas would yield approximately 3,200 to 7,900 BTUs per pound of waste. This
estimate is significantly less than what other gasification vendors are claiming. However, the
study estimates that when used to generate electricity, the Fiasco process produces more
energy per ton of input, than mass burn WTE or landfill gas to energy.
Slag is one residual from the Fiasco process. Fiasco claim the slag is transformed to pellets,
which are inert vitrified, or glass, residues. Converter ash is a byproduct that is also produced
when the carbon recovery vessel (CRV) is not running. The ash is then landfilled. Baghouse ash
is sent offsite as hazardous waste.
No cost information for the Fiasco technology was provided; however, the website indicates
that approximately $270 million in capital has been raised and invested in Fiasco since 2005.
Additionally, an external source presentation5 indicates that capital costs are approximately
US$86/ton of waste.
Since the Fiasco facility is still in a demonstration phase, details of the facility's operations may
not necessarily be representative of the actual levels of efficiency and waste outputs that will
occur under a commercial facility. Although the demonstration facility may not perform as well
as the planned commercial-scale one, a technical review conducted in 2009 displayed results in
favor of Fiasco's operations (see Pembina, 2009). An independent research organization
conducted an analysis of the commercial version of the current demonstration facility in
comparison with incineration, AD, and landfill gas with gas capture facilities located around the
world (Pembina, 2009). The life cycle analysis results showed that air emissions were lower or
about the same for Fiasco when compared to other systems, with the exception of heavy
metals and PM. Fiasco had a heightened ability to generate a greater energy value per waste
unit. The company was also capable of generating more marketable products from a given
waste stream, and was also able to remove more sulfur, heavy metals, and PM before
combustion than the other companies. The results of the study lead to a favorable conclusion
of Fiasco's planned commercial-scale facility in terms of environmental effects and efficiency
levels.
3.1.4 Ze-gen: Attleboro, MA (Operations Suspended As Of September 2012)
Ze-gen was founded in 2004. The company was expected to complete construction and begin
operations in 2012 of the Attleboro Clean Energy Project, located within the Attleboro
Corporate Campus in Massachusetts.. However, declines in natural gas prices and difficulties
obtaining permits led to the cancellation of the project. The city council banned any gasification
plant on account of potential "toxic dust." The facility was going to be co-located with an
industrial wastewater treatment facility. The design capacity was expected to be between 75
and 150 tons per day. The energy products were expected to be steam and synthesis gas
(syngas) with one-quarter the energy density of natural gas and expected to replace natural
gas. The company also has a demonstration facility, mainly for research and development,
located in New Bedford, MA, that opened in 2007.
5 http://www.seas.columbia.edu/earth/wtert/meet2010/Proceedings/presentations/CASTALDI.pdf.
42
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Ze-gen will construct a liquid metal gasification facility that utilizes post-recycled, processed
waste material. The facility will accept the following feedstocks: creosote treated railroad ties,
nonrecyclable plastics, and clean wood waste. Pre-processing of the feedstock will be necessary
and will occur through a contracted processer off-site. After pre-processing is complete, the
moisture content of the feedstock will be less than 20 percent and the inorganic matter content
will be less than 5 percent. Other inputs are required in order to achieve air emissions control,
such as sodium hydroxide, calcium hydroxide, aqueous ammonia, and activated carbon.
Synthesis gas (syngas) will be created through a thermo-chemical process with the use of liquid
copper. The temperature of the gasifier will be about 1,204 °C. The process of gasification will
divide organic and inorganic components. The organic components will be reformulated to
produce syngas, while inorganic components will be removed. The syngas will be used in a
boiler that will produce steam and power a generator to yield electricity.
The Attleboro Clean Energy Project is expected to have an energy recovery efficiency of
approximately 48 percent. The internal parasitic power requirement is expected to be less than
one MW. The regional electricity grid mix displaced by delivered electricity is 9 percent coal, 38
percent natural gas, 25 percent oil, and 14 percent hydroelectric power and renewable. In
order for the facility to begin operations, supplemental fuel use will be necessary at a rate of
approximately 1,500 MMBtu of natural gas per startup.
Ze-Gen's process emissions will be regulated by the Massachusetts Department of
Environmental Protection and will include PM, C02, CH4, HCI, NOX, VOCs, CO, NH3, mercury
(Hg), cadmium (Cd), and lead (Pb). Massachusetts does not treat biogenic carbon emissions as
neutral, unlike most other states. In their report, Ze-gen computes carbon contributions in
three ways: avoided emissions, total carbon + biogenic, and carbon without including biogenic
emissions. Ze-gen provided a range of emissions, and for this report the upper bounds of
emissions levels were used. Wastewater will be another byproduct of the gasification process,
and will occur at a rate of about 45 gallons per minute. Residuals will also be present from
those inorganic components that have been removed from liquid metal. The components will
be made into vitreous glass-like slag. About 1.5 tons of slag is expected to be generated per
day.
No cost information for the Ze-gen technology was provided or found through literature and
Web searches. Currently, Ze-gen is testing the viability of using various feedstocks, including its
ability to use marine debris plastic floating along the surface of the ocean. If successful, the
company could remove some of the waste that is detrimental to the overall ecosystem health
of the ocean while converting waste to usable fuel.
3.1.5 Geoplasma: St. Lucie, Florida [No longer in developmental time of this report]
Jacoby Development, Inc. formed Geoplasma, LLC in 2003 in order to work on research and
development for conversion technologies. Geoplasma is a planned facility that has received its
final air permit from the Florida Department of Environmental Protection. The facility is set to
produce 22 MW of power with the use of 600 tons of waste on a daily basis. Geoplasma, St.
Lucie will be constructed at the St. Lucie County Solid Waste Facility. All information about the
anticipated St. Lucie plant was obtained from the Environmental Assessment (U.S. DOE, 2010).
43
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The facility will use Class I waste, which in Florida includes solid waste that is not hazardous and
waste not banned from disposal in a lined landfill. It will also process construction and
demolition (C&D) waste, tires, and yard waste. Geoplasma will reduce monetary and time costs
associated with transport of waste to the facility because they will be co-located with the waste
facility. The feedstocks will be received in the existing receiving and baling recycling building.
Supplementary storage will be constructed similar to the existing one. A conveyer system will
transport waste fuel to the initial processing location to reduce the size of the material. The
moisture content of the feedstock value is assumed to be 30 percent. In order to minimize
fugitive emissions and odors, air for the gasifier will be pulled from the waste processing area
and conveyer system.
The waste will also be mixed with coke and limestone. Coke will be necessary to mix with MSW
and tire fuel to have a porous bed at the bottom of the gasifier. Limestone will be used in the
flue gas desulfurization (FGD). The mixed feedstock will be fed into the plasma heat gasifier.
The organic constituents will undergo a conversion process into a syngas, which will then be
combusted in a multi-stage thermal oxidizer, and then a heat recovery steam generator (HRSG)
to produce high-pressure and high-temperature steam. The steam will power a steam turbine
electrical generator that will supply electricity to the grid. Exhaust gas from the HRSG will be
filtered through an emissions control system before it is discharged to reduce harmful
pollutants.
No information on the energy performance of Geoplasma's anticipated facility was supplied by
the vendor; however, the Florida Department of Environmental Protection (FL DEP, 2011) cites
that the facility is anticipated to produce approximately 22 MW of power from approximately
600 tons per day of waste.
According to a Florida Department of Environmental Protection construction permit application
(FL DEP, 2011), Geoplasma is considered a source of hazardous air pollutant (HAP) emissions
and is in accordance with Title V a major source category. No water emissions data were
available. Since the facility is not yet functioning, the potential to emit value was used instead
of actual emissions levels. The facility was also assumed to be operating 312 days a year on a
24-hour basis. Emissions that have limits include NOX, CO, S02, VOC, HCI, PM, Lead, Hg, Cd,
dioxins and furans (D/F), visible emissions (VE), and NH3. Limestone is used in air pollution
control equipment to minimize S02 emissions. Another input is powered activated carbon
(PAC) delivery, which will be used to manage Hg, trace metals, and complex organic
compounds.
Byproducts of the plasma gasification process include vitrified inorganic residue. The bottom of
the gasifier will also discharge some residue metals into water. Sand-like aggregate and metal
nodules will be produced from this mixture at a rate of 13,200 Ib/hr. The two byproducts are
planned to be separated, stored, and loaded into trucks to be sold offsite. Spent PAC will be
accumulated in the system baghouse and moved to a storage silo at a rate of 900 Ib/hour. In
order to reduce PM emissions, the PAC will be transferred through an enclosed conveyer to the
silo. Gypsum is another process byproduct, and is expected to be produced by the FGD system
at a rate of 900 Ib/hour.
44
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The Geoplasma data collected was not analyzed during this analysis for several reasons. Most
importantly, the Geoplasma process data were the only data we were able to collect for the
plasma arc process. Additionally, we were not able to obtain all of the process information
needed for the LCA.
No cost information was provided by the company and was not available at the time of this
report. According to the public's comments on the draft permit, support for the facility is
widespread. One potential issue that may need to be addressed in the future is that excess
emissions are allowed during startup, shutdown, or malfunction. The Blue Ridge Environmental
Defense League specifically cited that this flexibility in emissions levels is unacceptable. If there
are issues during Geoplasma's operations that lead to significantly higher emissions, it is
possible that this issue may come up again.
3.2 Environmental Data and LCA Results
For the American Chemistry Council, RTI developed ranges for energy and emissions data for
MSW gasification technology category as a whole (see RTI, 2012). The data are shown in Table
3-2 and include ranges developed from a combination of vendor-supplied estimates, company
web-pages, publicly available permit applications, and the open literature. Specific data
provided by technology vendors is available in RTI report.
LCA results for energy consumption and GHG emissions (as carbon equivalents), as well as cost
are presented and discussed in this section of the report. The key data and assumptions for the
LCA and those specific to gasification are included in Attachment A. Results are presented as
net total burdens minus benefits. LCA results are also presented on a per dry ton basis as well
as per unit of energy produced (1 MMBTU) basis.
The cost and LCA results for energy and GHG emissions for gasification of MSW are presented
in this section. Since gasification technologies typically accept MSW that must be pre-
processed, recyclables are recovered and residual unwanted wastes must be disposed. Thus
the cost and LCA results include burdens associated with the pre-processing of MSW, as well as
the transportation and disposal of residuals. The primary driver of the difference in gasification
emissions per ton of MSW is driven by feedstock differences and has less to do with the process, unless
plastics are removed. The benefits include not only the electricity recovered. Since we assumed
the facilities would accept post-recycling MSW, potential recovery of additional recycles was
assumed to be minimal and therefore not included. However, if a facility accepted MSW that
contained a significant amount of recyclable material, it could potentially be recovered for
recycling and create additional benefits.
45
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Table 3-2. Gasification Process Data Per Dry Ton.
Parameters
Units
Value
Process Inputs and Outputs
CO
•5
a.
_c
1
Q.
•5
0
Power consumption/ parasitic load
Other inputs (e.g., water, oxygen, etc.)
Supplemental fuel use
Energy product (e.g., syngas, ethanol,
hydrogen, electricity, steam)
Material byproducts
Residuals (e.g., ash, char, slag, etc.)
Oxygen
Catalysts and chemicals
Diesel for preprocessing
Caustic for gas cleaning and cooling
Activated Carbon for gas cleaning and
cooling
Feldspar for gas cleaning and cooling
Water
Natural Gas
Electricity
Residual gas
Sulfur
Salt
Slag
Char
Slag
Gasifier solid residues
Spent catalysts and chemicals
Inorganic sludge
Nonhazardous solid waste
KWh
Ib
Ib
gal
Ib
gal
gal
gal
Ib
KWh
Ib
Ib
Ib
Ib
Ib
Ib
Ib
Ib
Ib
Ib
200
540
16
925
2.6
9
24
25
-
-
-
-
-
-
-
-
490
1,446
107
0.05
10
0.2
0.1
1,622
87
1,302
428
2.7
13
424
297
75
120
3
45
13
Air Emissions Data
PM
PM10
Biogenic Carbon Dioxide (CO2bio)
Fossil Carbon Dioxide (CO2fossil)
Methane (CH4)
HCI
Sulfur Dioxide (SO2)
Sulfur Oxide
Nitrous Oxide (N2O)
NOx expressed as NO2
Carbon Monoxide (CO)
Mercury (Hg)
Cadmium (Cd)
Lead
VOC
HAP
Acetaldehyde
Total non-methane organic carbon (TNMOC)
Dioxins and Furans
Ib
Ib
Ib
Ib
Ib
Ib
Ib
Ib
Ib
Ib
Ib
Ib
Ib
Ib
Ib
Ib
Ib
Ib
Ib
0.01
Ib
Ib
2.E-04
0
0
0.001
0.2
0.1
1
0
-
-
-
-
-
-
-
-
-
-
0.35
0.001
1,048
2
0.03
0.4
5.E-05
0.40
1
1
6.E-07
8.E-06
1.E-05
0.04
0.1
0.1
0.2
0
Water Emissions Data
Water Effluent
gal
600
-
1,400
Cost Data
Cost per design capacity
$/dtpd
499,109
46
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Energy
For gasification, energy is consumed to pre-process the incoming MSW, power the gasifier and
ancillary systems, transport residuals, and dispose of residuals in a landfill. Energy in the form
of syngas is the main output from the gasification process. Typically this syngas is combusted
onsite in an internal combustion engine (ICE) generator set (gen-set) to produce electricity.
This is the process modeled in the LCA. The syngas can be directly used or converted to liquid
fuel, but these options were not modeled because they are less common.
The net energy consumption results for gasification are shown in Figure 3-3 on a per-ton basis
and in Figure 3-4 per MMBtu of energy produced. As shown in the figures, the energy (in the
form of electrical energy) produced from the gasification process generate significant energy
offsets. The gasification process itself is a net electricity producer (i.e., the energy produced
exceeds the energy consumed) with some variation (according to the data obtained from the
different vendors and the literature) in the amount of energy produced in the range of 6-
12MMBtu per ton of MSW input or approximately .6-.9 MMBtu per MMBtu of energy
produced.
o
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Q Max Values
Gasification
process
Electricity offset
Disposal
NET TOTAL
Figure 3-3. Net Energy Consumption Per Ton for Gasification of MSW.
47
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Figure 3-4. Net Energy Consumption Per MMBtu for Gasification of MSW.
GHG Emissions
Figures 3-5 and 3-6 show the gasification process producing a net GHG emissions savings at the
lower end of emissions generation from the process, which results from the displacement of
conventional electricity production (assuming displacement of fossil fuels in the U.S. average
grid mix of fuels for electricity production). The emissions data obtained for the gasification
piece of the LCA exhibits a wide range of variation from a net savings of approximately 0.28
TCE/dry ton (~0.02TCE/MMBtu energy produced) to a burden of 0.05 TCE/dry ton (~0.005
TCE/MMBtu energy produced) as illustrated by the minimum and the maximum bars.
Cost
Cost data were only available for one of the gasification technology vendors. Figures 3-7 and 3-
8 show the cost (or revenue) by process as well as the total net cost of approximately ($48) to
($12) per ton of MSW or ($3) to ($2) per MMBtu of energy produced. This signifies that the
revenues received from the sale of electricity are greater than the costs to process the MSW via
the gasification technology. In Figures 3-7 and 3-8, the process cost/revenue is per vendor-
supplied values and the remaining residuals disposal costs are per RTI's MSW DST.
48
-------
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Figure 3-5. Net Carbon Equivalents Per Ton for Gasification of MSW.
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Figure 3-6. Net Carbon Equivalents Per MMBtu for Gasification of MSW.
49
-------
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with an efficiency of 14,000 btu/kwh. It is assumed that the electricity produced from WTE
displaces electricity from utilities based on the U.S. average electricity grid mix of fuels.
Figure 3-9 shows the results for net energy consumption (i.e., energy consumed minus energy
produced). According to this figure, the net energy saved using the gasification technology
versus landfill disposal is approximately 6.5-13 MMBtu per dry ton of MSW. These savings are
mostly associated with the energy produced by the gasification facility. For example, when
compared to a landfill with energy recovery (i.e., the low landfill energy consumption bar in
Figure 3-9), these savings indicate that the gasification facility is much more efficient at
producing energy than the landfill facility. WTE also results in a net energy savings that appears
to be at the high-end of the gasification savings. Gasification in general has the potential for
energy savings on a per ton basis than WTE because it is designed to be a more efficient
conversion process.
"c"
S n -
c
^ -)
1 4
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s.
1
£ 12
c
LU
•_-_-
."_"_
-_-_
Low
Landfill
High Low High
(MSW) WTE (MSW)
Low High
Gasification (MSW)
Figure 3-9. Net Energy Consumption for Landfill, WTE and Gasification of MSW.
Figure 3-10 shows the results for net carbon emissions (i.e., carbon emissions minus savings).
According to this figure, the gasification technology results in a net reduction of approximately
0.3-0.6 TCE per dry ton of MSW processed when compared to landfills. This reduction is mostly
associated with the energy produced by the gasification facility. For example, Figure 3-9
indicates that the gasification facility is more efficient at energy production than the landfill
with energy recovery, so the emissions savings associated with energy production using waste
versus virgin materials are also greater for gasification facilities. Again, the WTE alternative also
51
-------
0/in
o
+j
>• n -)n
•a
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ii n 1 n
•— -
10
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tg
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11 11 liii!
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1 1 1 1 1
Low High Low High Low High
Landfill (MSW) WTE (MSW) Gasification (MSW)
Figure 3-10. Net Carbon Equivalents for Landfill, WTE and Gasification of MSW.
results in a net carbon emissions savings that is in-range with gasification but potentially not as
great due to the expected energy conversion efficiency of gasification.
Figure 3-11 shows the results for net cost (i.e., cost minus revenues). According to this figure,
the gasification technology results appear to result in a net reduction of approximately $50-115
per dry ton of MSW processed when compared to landfills and will depend upon power pricing
as well as the cost to build, finance, and operate. By having larger energy savings, as illustrated
in Figure 3-9, the gasification facility will also get more revenues from energy sales than the
landfill with energy recovery. Consistent with the energy and GHG emissions results, this
reduction is mostly associated with the energy produced by the gasification facility and the
stated cost of operation by technology vendors. WTE by contrast has a significantly higher cost
than gasification, based on the available data. In general, higher quality data from gasification
technologies is needed to better characterize costs. It's not clear if currently available cost
estimates include all costs and are accurate, as there are no currently stand-alone commercially
operating facilities that were found.
52
-------
1 nn
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Landfill (MSW) WTE (MSW) Gasification (MSW)
Figure 3-11. Net Cost for Landfill, WTE and Gasification of MSW.
53
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Section 4:
Anaerobic Digestion Technology
AD is a biochemical conversion process that decomposes organic material in the absence of
oxygen (02). Organic waste materials such as manure, agricultural wastes, and biodegradable
fractions of industrial, commercial, and MSW (or fractions of MSW) can be used as feedstocks
for anaerobic digesters. The main product of AD is a methane-rich biogas, which can be
combusted to generate heat and/or electricity, converted to pipeline quality gas, or further
refined to create biomethane, a transportation fuel. Byproducts of AD include C02 and
undigested solids. Depending on the type of feedstock used, the undigested solids may have
economic value when refined and used as a fertilizer soil amendment.
There are several types of anaerobic digesters. Digesters can be classified into "wet" or "dry"
systems, depending on the feedstock; into single- or multiple-stage systems, depending on their
complexity; and batch or continuous flow systems, depending on the feedstock input method.
• "Wet"or "dry"systems—Wet systems generally process feedstocks with a total
solid content of less than 15 percent, whereas dry systems process feedstocks with
greater than 15 percent total solid content. Wet systems are most appropriate for
wastewater AD. Dry systems are preferred for MSW because bacteria have a higher
survival rate and less pre-handling is required.
• Single-stage or multiple-stage systems— M ulti-stage systems are more
expensive than single-stage systems to construct and operate; however, they have
higher loading rates and greater feedstock flexibility. For MSW, the majority of AD
systems are single-stage due to the complexity and cost barriers of multi-stage
systems, but the prevalence may change as technology becomes more affordable
and standardized.
• Batch or continuous flow systems—Batch systems process waste within a single
sealed reactor or holding tank, whereas continuous systems use a series of reactors.
Batch systems require less precision and have lower construction costs than
continuous systems, but may result in inconsistent biogas production and
incomplete degradations. Comparatively, continuous systems increase process
efficiency due to increased control over bacterial reactions taking place within the
reactors.
Some pre-sorting and pretreatment is necessary to limit the clogging of the pumps and to
reduce inert material(s) located in the reactor. Also, it is necessary to remove metals and
plastics prior to adding the stream into the AD. Otherwise, the stream may contaminate the
process. Generally, the material handling systems include extensive receiving, particle size
reduction, and separation processes before the feedstock may be fed into the digester.
4.1 Example Anaerobic Digestion Facilities
Existing AD facilities identified in North America are listed in Table 4-1. As shown in the table,
the vendor name, status, accepted feedstock, location and main product output are listed. AD
54
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for MSW is being used in Europe6. However, few commercial AD facilities that process MSW are
in operation in the United States. A pilot facility, East Bay Municipal Utility District, is currently
operating in California. It co-digests food scraps from restaurants within the San Francisco Bay
area at its wastewater treatment plant in order to generate biogasthat is used to produce
electricity. The study has found that converting 100 tons per day (TPD) for five days per week
offers enough power for 800-1,400 homes annually. Another private AD facility built by Clean
World recently opened at American River Packaging. As shown in Table 4-1, there are a
number of AD facilities currently under development. Each of these facilities produces biogas as
the main product which is typically used for producing electrical energy. Peat is a byproduct
from AD technology that may be marketable as compost.
4.1.1 County of Yolo Public Works Department: Yolo County, California
This project is not a conventional AD project in that the digester unit was constructed as a cell
on top of an existing landfill cell as it will be described in detail under the Process Details
section. The California Department of Resources Recycling and Recovery (CalRecycle)
commissioned the design and construction of this pilot-scale anaerobic digester. The system is
co-located at Yolo County Central Landfill and has been in operation since 2007. This system
takes advantage of the facility's landfill gas-to-energy infrastructure to increase the energy
recovery efficiency of the digester and also allows for the recovery of the residual material to
be used as compost. Due to the innovations in the project, this AD approach has the potential
to be more cost-effective at a larger scale than many other AD systems (CalRecycle, 2010) when
compared with landfill disposal and other waste management techniques.
The digester was constructed on top of an existing landfill cell. The digester cell was lined and
then layered with 1,894 tons of green waste, 34 tons of wood chips, 130 tons of aged horse
manure, and 25 pounds of limestone and capped with a liner cover. Pipes that are distributed
between the waste layers transfer the gas to the energy facility located onsite. Leachate and
water are re-circulated to promote anaerobic degradation.
The process has demonstrated the ability to produce 1,680 cubic feet of methane per dry ton of
waste. Due to these results, it was suggested that further pilot projects be initialized in order to
understand the technological barriers such as high moisture waste and odor issues associated
with food waste. It is also recommended that a better quantification of emissions associated
with composting be assessed. Overall, the study found that California would greatly benefit
from a wider implementation of waste diversion to produce methane gas and electricity.
6 See http://www.seas.columbia.edu/earth/vermathesis.pdffor a listing of AD facilities in Europe.
55
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Table 4-1. AD Technology Facilities in North America.
Vendor
Name
Clean World
City of Riverside
Quasar Energy
Group
Quasar Energy
Group
Central Marin
Sanitation
Humboldt Co. Waste
Authority
Terrabon
B & D Geerts
East Bay Municipal
Utility District
Sacramento Co.
Regional WWTP
Arrow Ecological
Status
Commercial
Commercial
Commercial
Commercial
Commissioned
Commissioned
Demo
Demo
Demo
Demo
Permitted
Feedstock
Food, paper and
agricultural residue
grease from
restaurants
MSW components,
crop waste, grass,
and manure
MSW components
MSW components
grease from
restaurants
MSW, sewage
sludge, forest/ag
residues
Food waste, green
material, and mixed
solid waste
MSW components
MSW components
MSW components
Location
Sacramento, CA
City of Riverside
Wooster, OH
Columbus, OH
City of San Rafael
Humboldt Co. Waste
Authority
Bryan, TX
Yolo County, CA
East Bay Municipal
Utility District
Elk Grove, CA
Ferris, CA
Main Product
Bio gas
Bio gas
Electricity
Electricity, biogas,
and CNG
Biogas
Biogas
Gasoline
Biogas
Biogas
Biogas
Electricity
Source (Sites accessed in June 2012)
httDV/www.cleanworldDartners.com/technolo cries/
http://www.riversideca.2ov/sewer/proiect-2rease.asp
http://www.schmackbioener2V.com/pa2es/wooster.html
http://www.schmackbioener2V.com/pa2es/columbus.html
http://www.citvofsanrafael.org/ Assets/Methane +Gas+Studv.pdf
http://www. hwma. net/HRF WDFS.pdf
http://www.terrabon.com/mixalco semiworksplant.php
http://www.epa.2ov/re2ion9/or2anics/svmposium/2010/Pors9-15-10.pdf
http://www.epa.2ov/re2ion9/or2anics/svmposium/2010/Pors9-15-10.pdf
http://www.biomassma2azine.com/articles/3376/buildin2-on-its--biomass-
base/
http://dpw.lacountv. 2ov/pr2/pressroom/printview.aspx?ID=370&newstvpe=
PRESS
56
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4.1.2 Quasar: Wooster, Ohio
Quasar joined Ohio State University's Agricultural Research and Development Center (OARDC)
to build an AD system called the ecoFARMsystemSSO (F550) system in the BioHio Research Park
located in Wooster, Ohio. The F550 system uses regional food and crop waste as well as grass
and manure from the university's farm operations in order to produce renewable energy and
other byproducts.
In the Quasar process, a receiving hopper is filled with biomass within the plant building to
control odors. Live bottom hopper augers move the waste toward the middle of the hopper.
Biomass is discharged and passes through a grinder to the process lines. Fresh biomass mixes
with heated recycled biomass and moves into the biomass equalization tank. The liquid waste
passes through a strainer in order to remove any leftover solid materials. Liquid biomass is then
added to the equalization tank, which may store biomass for up to six days. A pipe connects
the head space in the equalization tank with the digester tank and dual purpose tank in order to
sustain equalized pressure. The space also provides an area for displaced gas from filling or
discharging or temperature expansion.
After digestion is complete, the biomass is pasteurized in order to remove pathogens. Energy
recovery is completed through a biomass to biomass heat exchanger as it is pumped to a
holding tank. Energy recovered is transferred and temperature elevated through a heat
exchanger. Suspended solids in the digested material are mechanically separated in a
dewatering process. The resulting cake biomass is about 25 percent dry solids.
The system capacity is 550,000 gallons, and biomass may be stored for about 3 days, while the
average digestion time is about 28 days. The system can handle 19,382 wet tons of waste
annually, and produces 5,256 MWh of electricity. The digester is currently operational and is
able to offset half of OARDC's electricity demand.
4.1.3 Clean World/American River Packaging-Sacramento, CA
Clean World Partners recently opened a commercial high-solids AD system at American River
Packaging's Sacramento headquarters. The Clean World AD system is based on AD technology
developed at the University of California, Davis and is designed to convert food waste,
agricultural residue, and other organic waste into renewable energy, fertilizer and soil
enhancements. Clean World anticipates that its AD technology installed at American River
Packaging will convert 7.5 tons of food waste from Campbell Soup and other regional food
producers along with .5 tons of unrecyclable corrugated material into biogas. Clean World
claims the biogas produced will generate approximately 1,300 kWh of renewable electricity per
day, supplying about 37 percent of American River's internal electricity needs.
Clean World's process can be classified as "dry" and multi-stage. The vendor materials claim
organic solid waste with up to 50 percent solid content can be accepted without adding water.
With relatively homogeneous organics coming from industrial/commercial partners, additional
preprocessing of the organics is said to be minimized. Clean World claims that the high-solids
technology is more efficient and flexible than other existing AD systems and rapid waste
throughput will require less water for processing, reduce tank size and manufacturing costs.
57
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The Clean World system installed at American River Packaging resulted from a public-private
partnership. Research and feasibility studies were provided by DC Davis, CalRecycle and the
California Energy Commission. Private investment funded the facility's construction and
installation. Being privately owned and operated, it appears that the facility accept organics
only from contracted industrial/commercial partners. The vendor estimates that more than
2,900 tons of organic waste will be diverted annually from landfills, and that the AD technology
will produce 1,000 tons of organic soil amendment per year for application at regional
agricultural sites. According to Clean World, the solid byproduct is considered to be
wastewater by California regulations and it's treated via a membrane separation system to
create a higher-value product that is currently sold for agricultural application. It's unclear at
this time whether this product will offset the use of fertilizers or other products at the
application site.
No emissions or cost information was found for the Clean World facility at American River
Packaging. A report from the California Energy Commission with this type of information is
expected to be released in mid- to late-2012. Clean World is also constructing a planned 100-
ton per day AD system in south Sacramento which is expected to open in late spring 2013.
4.2 Environmental Data and LCA Results
For this study, RTI developed ranges for energy and emissions data for the AD technology
category as a whole, as shown in Table 4-2. We were not able to identify data available for
stand-alone commercial AD facilities, and therefore data was developed from existing studies in
the open literature. An assessment report is planned for release for the Clean World AD facility
at American River Packaging but it was not available at the time of this report.
LCA results for energy consumption and GHG emissions (as carbon equivalent emissions), as
well as cost are presented and discussed in this section of the report. Results are presented as
net total burdens minus benefits. Therefore, negative energy results mean that more energy is
recovered than that needed to run the processes; negative GHG emissions mean that there are
more emissions savings as a result of energy and fuels production using the waste material
relative to using virgin material; and negative cost results mean that the revenues are higher
than the costs.
The cost and LCA results for energy and GHG emissions for AD of organics (namely, food and
yard wastes) are presented in this section. AD results include transportation and disposal of
residuals. Thus the cost and LCA results include the burdens associated with the AD facility as
well as with transportation and disposal of residuals. The benefits are those associated with
energy recovery. With AD technology, the resulting peat/compost byproduct may also be used
as a soil amendment but it is difficult at this time to know what, if any, other products (e.g.,
fertilizers) may be displaced. For purposes of the LCA, it was assumed that the peat/compost
byproduct would not offset other products.
The key data and assumptions for the LCA and those specific to AD are included in Attachment
A. Consistent with the LCA results for pyrolysis and gasification, the LCA results for AD are
presented as net totals, burdens minus benefits.
58
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Table 4-2. AD Process Data Per Dry Ton of Input Material.
Parameters
Units
Value
Data Sources
Process Characteristics
Power consumption/parasitic load
Total Solids
Volatile Solids
Biodegradable Volatile
Solids
Conversion Efficiency
waste to methane
Conversion Efficiency
methane to electricity
% energy produced
%
%
%
%
%
22
60
33
-
"
~
30
70
70
75
75
39
RTI (2005) and ARI
(2007)
RTI (2005)
RTI (2005)
RTI (2005)
RTI (2005) and ARI
(2007)
RTI (2005) and ARI
(2007)
Air Emissions Data
PM
HCI
Nitrogen Oxides
Sulfur Oxides
Carbon Monoxide (CO)
Carbon Dioxide (biomass)
Ib
Ib
Ib
Ib
Ib
Ib
0.12
0.02
0.61
0.03
1.15
137
RTI (2005)
RTI (2005)
RTI (2005)
RTI (2005)
RTI (2005)
RTI (2005)
Cost Data
Cost per design capacity
$/dtpd
82
ARI (2007)
Energy
For AD, energy is consumed in feedstock pre-processing, digestate post processing, ancillary
systems, and transport and dispose of residuals in a landfill. Energy in the form of methane-rich
biogas, which can be combusted to generate heat and/or electricity or further refined to create
biomethane, a transportation fuel, is the main output from the AD process. For this analysis we
assumed the biomethane will be used to generate electricity.
The LCA results for energy consumption for AD are shown in Figures 4-1 and 4-2. According to
Figure 4-1, the electricity output generates energy offsets. The AD process can be considered
an energy producer (i.e., the energy produced exceeds the energy consumed), with some
variation in the amount of energy produced, according to the data obtained from the literature.
59
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2.0
1.0
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-1.0
-2.0
-4.0
-5.0
HMin Values
0 Max Values
AD Process Electricity Offsets
Disposal
NET TOTAL
Figure 4-1. Net Energy Consumption Per Ton for AD of Organics.
i.o
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£ =5" 0.0
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NET TOTAL
Figure 4-2. Net Energy Consumption Per MMBtu for AD of Organics.
GHG Emissions
Consistent with the energy results, Figures 4-3 and 4-4 show that the AD of organics results in
GHG emissions savings, which results from the displacement of conventional electricity
production (assuming displacement of fossil fuels in the U.S. average grid mix of fuels for
electricity production).
60
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0.04
~ 0.02
o
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-0.04
c
o
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ro
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HMin Values
QMax Values
AD Process Electricity Offsets Disposal
NET TOTAL
Figure 4-3. Net Carbon Equivalents Per Ton for AD of Organics.
O
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HMin Values
QMax Values
AD Process Electricity Offsets
Disposal
NET TOTAL
Figure 4-4. Net Carbon Equivalents Per MMBtu for AD of Organics.
Cost
The net (expenses-revenue) cost per ton for the AD of organics is shown in Figures 4-5 and 4-6.
As shown in these figures, the net cost range is positive, signifying a net cost stream that results
61
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AD Process Electricity Offsets Disposal
NET TOTAL
HMin Values
HMax Values
Figure 4-5. Net Cost Per Ton for AD of Organics.
•c
8
01
3
£
o
u
AD Process
Electricity Offsets
Disposal
NET TOTAL
HMin Values
0Max Values
Figure 4-6. Net Cost Per MMBtu for AD of Organics.
from the capital and operating costs of AD being greater than the revenues brought by
electricity sale.
Comparison to Landfill and WTE Base Cases
In this section, the results for the AD of organics are compared to results for a landfill and WTE
base cases for organics. A low-high range was developed for the landfill base case using a
landfill with gas collection and flaring for the low end of the range and a landfill with gas
62
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collection and energy recovery for the high end of the range. The landfill base case was
modeled using RTI's MSW DST and is representative of a U.S. average. For WTE, the lower end
of the range represents facility with an efficiency of 18,000 btu/kwh and the upper end of the
range represents facility with an efficiency of 14,000 btu/kwh. It is assumed that the electricity
produced from WTE displaces electricity from utilities based on the U.S. average electricity grid
mix of fuels
Figure 4-7 shows the results for net energy consumption (i.e., energy consumed minus energy
produced). According to this figure, the net energy saved using the AD technology versus
landfill disposal is approximately 0.6-2.5 MMBtu per dry ton of organics. These savings are
mostly associated with the energy produced by the AD facility. For example, when compared to
a landfill with energy recovery (i.e., the low landfill energy consumption bar in Figure 4-7),
these savings indicate that the AD facility is more efficient at producing energy than the landfill
facility. However, when compared to WTE the AD technology does not appear to be as efficient
in converting organics to energy.
*c"
+j U.b
>
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CQ -U.b
i
7 -i.o -
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3 ^
in
SSSs
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in
-~-~-
-~-~-
_ _ _
~-~-
~-~-
•:•:•:•:•:•:•
Low High
Landfill (Organics)
Low High
WTE (Organics)
Low High
AD (Organics)
Figure 4-7. Net Energy Consumption for Landfill, WTE and AD of Organics.
Figure 4-8 shows the results for net carbon emissions (i.e., carbon emissions minus savings).
According to this figure, the AD technology results in a net reduction of approximately 0.11-
0.13 TCE per dry ton of organics managed via AD as compared to landfill disposal. This
reduction is mostly associated with the energy produced by the AD facility. For example, Figure
4-7 indicates that the AD facility is more efficient at energy production than the landfill with
energy recovery, so the emissions savings associated with energy production using waste
63
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n 1 n
5
4_i
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u, 0'02
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— — — — nnnnnnii :=:=:
~-~- "_~_~ iiiiiiiiiiiii! iiiiiiiiiiiii
~-~- "_~_~ jijijijijijij: iiiiiiiiiiiii
— yiiy
Low High Low High Low High
Landfill (Organics) WTE (Organics) AD(Organics)
Figure 4-8. Net Carbon Equivalents for Landfill, WTE and AD of Organics.
versus virgin materials are also greater for AD facilities. WTE appears to result in the same level
of net carbon emission reduction as AD.
Figure 4-9 shows the results for net costs (i.e., costs minus revenues). According to this figure,
the AD technology results in a net reduction of approximately $75 per dry ton of organics
processed when compared to landfills. Consistent with the energy and GHG emissions results,
this reduction is mostly associated with the energy produced by the AD facility. For example,
by having larger energy savings, as illustrated in Figure 4-7, the AD facility will also get more
revenues from energy sales than the landfill with energy recovery. AD also appears to be
slightly higher in net cost as compared to WTE.
100
*^" on
s
c
vv
3 40
20
0_
^333S
•
1
Low
Landfill ((
i
High
Drganics)
-_-_-
_-_-_
_-_-_
~-~-!
~-~-|
Low High
WTE (Organics)
Low
AD (Or
High
ganics)
Figure 4-9. Net Cost for Landfill, WTE and AD of Organics.
64
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Section 5: Findings and Recommendations
Emerging waste conversion technologies may present alternatives to landfill disposal for
managing non-recycled MSW; however, there are currently very few commercially operating
facilities in the U.S. At the time of this study, we estimated there were 9 pyrolysis, 7
gasification, and 10 AD demonstration and commercially operating facilities in North America7
that process municipal wastes. In general, we found that plastics-to-oil pyrolysis facilities were
at a more mature commercially operating stage in the U.S., while bulk MSW (typically
gasification) and organics (typically AD) technologies were still largely in the demonstration
phase at the time of this report.
Anecdotal evidence suggests that project viability may in part be affected by difficulties
encountered scaling up facilities from demonstration to commercial scale (especially MSW-
based plants), financial backing/economic conditions, and the highly variable permitting
classifications. In addition, having a [contractually and compositionally] dedicated and/or
segregated feedstock is another challenge to successful commercialization.
5.1 Key Findings
The following sections highlight our key findings from this study including current waste
conversion facilities in the U.S. exhibit:
• Significant differences in accepted waste materials.
• Considerable variation among technology vendor processes.
• Potential environmental benefits by virtue of energy and materials recovery.
• Potential cost competitiveness with conventional waste management technology.
• High-level of uncertainty surrounding existing environmental and cost performance
data.
Each of these findings is expanded on in the following sections.
5.1.1 Significant Differences in Accepted Waste Materials
Ultimately, the findings from this research show that the different categories of waste
conversion technologies are designed to handle very different types of waste feedstock. In
general, pyrolysis technologies utilize only plastics, gasification technologies utilize MSW, and
AD utilizes food, yard, and paper waste. Pyrolysis facilities were reported to receive plastics
from both materials recycling facilities and, more so, from industrial partnerships. Gasification
can received bulk MSW (pre- or post-recycling) but requires up-front sorting and processing to
remove undesirable materials. Alternatively, a gasification facility could partner with a MRF to
receive positive-sort materials that are desirable. For AD, the food, yard, and residual paper
fractions of MSW will need to separated out, either at the source or up-front of the AD facility.
Similar to pyrolysis, it may be advantageous for AD facilities to secure industrial/commercial
partners for feedstock (as is being done with the Clean World/American River Packaging
facility).
7 This includes demonstration and commercial scale facilities only. Proposed and planned facilities were not
included.
65
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It is also difficult to compare the cost and performance of pyrolysis, gasification, and AD
technologies directly due to differences in feedstock. Differences in accepted feedstock means
there will create differences in feedstock energy value as well differences in beneficial offsets.
For pyrolysis, beneficial offsets are primarily based on the conversion of plastics to oil. For
gasification, beneficial offsets include energy production and can also include the recyclables
(e.g., remove metals, glass, and other inorganics) in the up-front sorting process but this
component was not included in this analysis since we assumed non-recycled waste would be
the input feedstock and little recyclables available. For AD, the benefit offsets are primarily
based on the conversion of organic wastes to biogas which is assumed to be used to produce
electrical energy.
5.1.2 Considerable Variation among Technology Vendor Processes
Within the main technology categories of pyrolysis, gasification and AD, different technology
vendors/facilities have specific variations on the process to enhance conversion efficiency
and/or tailor the end product to their respective site-specific markets. The primary objective of
the conversion technologies is to convert waste into useful energy products that can include
syngas or biogas, petroleum, and/or commodity chemicals. Syngas and biogas can be used
directly in industrial boilers or in an ICE gen-set to produce electrical energy. Petroleum and
commodity chemicals are typically tailored to specific end-users (e.g., petroleum wax for
cosmetics manufacturers). Each end product has different life-cycle offsets which may affect
the overall environmental impact of the process.
While studies and analyses can be done on waste conversion technologies in general (as done
in this report), specific analyses also need to be done for individual technologies located in
specific regions. In this regard, all technologies have their benefits (and burdens) and decisions
about their adoption will likely be done on a site- or region-specific basis and depend on
characteristics such as waste composition, contracts for assuring steady waste feedstock
supply, State and local permitting conditions, market prices for electricity and fuels, availability
of markets for products, and distance to those markets.
5.1.3 Potential Environmental Benefits by Virtue of Energy and Materials Recovery
Using the currently available data, a high-level LCA conducted for the conversion technologies
indicates that the technologies may offer environmental benefits as compared to landfill
disposal. Specifically, we estimated that gasification (excluding energy production and
materials recycling offsets) of MSW saves between 6.5—13 MMBtu per ton as compared to
landfill disposal. Pyrolysis of waste plastics saves between 22—32 MMBtu per ton as compared
to landfill disposal. Likewise, our results show that gasification of MSW saves between 0.3—0.6
TCE emissions per ton of MSW treated as compared to landfill disposal. Pyrolysis of waste
plastics saves between 0.03 and 0.26 TCE emissions per ton as compared to landfill disposal.
AD of organics waste saves between 0.11—0.13 TCE per ton compared to landfill disposal.
Given the developmental stage and the current capacities of technologies, our preliminary
estimates suggest that conversion technologies would offset significantly less than 1 percent of
total annual U.S. oil consumption. For example, the average size of a plastics-to-oil facility is in
the range of 10-30 tons per day. If there were 100 plastics-to-oil facilities in the U.S. by 2015,
conversion production could offset approximately 6,000-18,000 barrels of oil per day, assuming
66
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1 ton of plastic is equivalent to 6 barrels of oil. Total consumption of oil in the U.S. is forecast to
be 21.57 million barrels per day in 2015.8 Therefore, according to these estimates, 100
commercial-scale plants would supply, at most, a tenth of 1 percent of U.S. oil consumption.
While MSW-based conversion facilities are anticipated to convert 7-10 times more waste to
energy, estimates still indicate significantly less than 1 percent of annual U.S. oil consumption.
From a local perspective, conversion technologies may show more pronounced benefits,
including reduced energy and carbon emissions. When compared to landfill disposal,
gasification of 100 tons of MSW per day and operating 300 days of the year may save energy
equivalent to the needs of about 1805-3610 households, or 1480-2950 household
transportation energy needs according to EPA information9 about average household and
household transportation energy needs. This translates into a reduction of approximately
33,000-66,000 tons of C02 emissions per year. Pyrolysis of 100 tons per day of non-recycled
plastics may save the amount of energy equivalent to the needs of 555-1110 households, or
455-910 household transportation energy needs and about 16,500-27,500 tons of C02
emissions reduction per year. Treatment of 100 tons of organics waste in an AD facility may
save the amount of energy equivalent to the needs of 167-694 households, or!36-568
household transportation energy needs and approximately 12,100-14,300 tons of C02
emissions reduction per year.
5.1.4 Potential Cost Competitiveness with Conventional Waste Management
Technologies
Estimates of cost provided by technology vendors indicate cost/ton may be comparable to
other MSW options, such as recycling and landfilling. Vendors estimate that the cost to process
the waste is approximately $50/ton for pyrolysis and gasification technologies, and
approximately $100/ton for AD. This cost is generally related to the capital and operating costs
required to run the process and the market price for products. For comparison, the U.S.
average tipping fee is $44/ton for landfills and approximately $68/ton for mass burn WTE.10
The limited cost information available from the literature indicates that the cost/ton for
pyrolysis is comparable to MSW options, such as recycling and landfilling, and that the cost/ton
for gasification and AD is higher. The estimated waste processing cost for pyrolysis is
approximately $50/ton of plastics, close to $90/ton of MSW for gasification, and close to
$115/ton of organics for AD. This cost is generally related to the capital and operating costs
required to run the process and dispose of any residuals. For comparison, U.S. landfill tipping
fees range from $15-96/ton of MSW and WTE tipping fees range from $25-98/ton of MSW,
depending on the State or region (Van Haaren et al., 2010).
The economic sustainability of conversion facilities will depend on the markets for energy and
commodity products. Each facility will likely tailor its process to match site-specific market
conditions and contractual arrangements. For example, according to common behavior if the
price of crude oil continues to increase, technologies that convert plastics and MSW to
http://www.researchandmarkets.com/research/96a49e/united states oil and gas report ql 2011.
9 http://www.epa.gov/dced/location efficiency BTU-chtl-graph.htm
10 http://www.seas.columbia.edu/earth/wtert/sofos/SOG2010.pdf
67
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synthetic petroleum and/or liquid transportation fuels will be able to generate more revenue
from the sale of products and become more cost competitive.
5.1.5 High-Level of Uncertainty Surrounding Existing Environmental and Cost
Performance Data for Environmental and Cost Information
There is a high level of uncertainty associated with the current environmental and cost data
associated with waste conversion technologies. Because most conversion facilities are
demonstration plants, they are operating in batch-test mode and not as a continuous-mode
commercial plant. Until there are commercially operating facilities in North America, there will
not be good real-world data to characterize the environmental aspects and costs for these
technologies. It was found that even facilities that are commercial-scale are often operating in
more of a demonstration mode and do not have waste contracts and/or energy or product
contracts in place.
5.2 Limitations and Recommendations for Future Research
Real-world cost and environmental information is difficult to obtain, due primarily to the
current stage of development of conversion technologies in the U.S. As more commercial-scale
facilities are built and operating, it would be beneficial to reassess the cost and environmental
performance of conversion technologies as compared to competing waste management
alternatives. There is a general need for longer term operating data on plants to determine any
by-product emissions and verify energy efficiency claims. Also, with the appropriate caveats,
data from facilities outside North America (e.g., in Europe and Japan), may be useful for filling
gaps in the North America dataset or for comparison purposes if adjusted appropriately.
Additional research that could be done in the near term to advance the understanding of
conversion technologies might include examining sensitivities and "break-even" points relative
to cost and environmental aspects for key parameters such as:
• Feedstock composition (e.g., high vs. low BTU value feedstock)
• Plant energy conversion efficiency
• Recovery of materials for recycling (for MSW technologies)
• Beneficial offsets for different end product alternatives
• Distance to market for liquid fuels
• Market prices for energy products
• Market prices for recyclable and other byproduct streams.
The costs considered in this study were scarce (i.e., one data point for gasification, three data
points for pyrolysis, and one data point for AD) and based on facilities that are not operating at
a commercial stage. Therefore, there is inherent uncertainty in these data. For example, at the
waste processing cost estimated for pyrolysis of plastics (approximately $50/ton of plastics) full-
scale commercial plants should be fairly common in areas with high-cost landfill disposal.
For AD, we assumed the facilities would be stand-alone and not excess wastewater treatment
digester capacity. This assumption was made to simplify the cost and life cycle environmental
assessments. However, it is expected that AD economics would be favorable for utilizing
unused wastewater treatment capacity. For example, according to CalRecycle (2009), the
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estimates for the state of California indicate that if 75 percent of the capacity comes from
existing wastewater treatment facilities and 25 percent from stand-alone facilities, the total
annual costs are almost six times higher than when all the capacity comes from existing
facilities.
Information about the financing mechanisms proposed or in place for the facilities identified in
this report was not collected. Information such as existing or planned government subsidies
and private sector off-take agreements, in addition to the net cost estimates provided in this
study, would give a better picture of the financial viability of these technologies.
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Beck, R.W., 2010. Independent Engineer's Report, Envion Plastic-to-Oil Technology. Prepared
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Goco, Pio (2010). Telephone Conversation regarding Envion processes and environmental
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Attachment A: LCA Scope, Data, and Key Assumptions
For the LCA, we adopted the methodologies used to develop life cycle inventories (LCIs) as part
of a life cycle assessment (LCA). LCA is a technique for assessing the environmental aspects and
potential impacts of a system from raw materials acquisition through production, use, and
disposal. According to the internationally accepted ISO 14040 standard, conducting an LCA
includes compiling an inventory (called an LCI - life cycle inventory) of relevant inputs and
outputs of a system, evaluating the potential environmental and health impacts of those inputs
and outputs (called an LCIA - life cycle impact assessment), and interpreting the results in
relation to the objectives of the study. In this study, we developed high-level11 LCIs aiming to
identify and evaluate the general environmental performance and cost of the conversion
technologies and to compare them to a reference waste management option (landfill).
A.I Goals
The overall goal of the analysis is to estimate the impacts that MSW-based conversion
technologies have on the environment and public health. In general, the analysis will seek to
quantify the life cycle environmental burdens/benefits of conversion technologies and to
compare these burdens/benefits to the baseline practice of landfill disposal.
The goal of the LCA is not necessarily to make definitive conclusions about conversion
technologies or the environmental preference of conversion technologies compared to the
existing landfill base case. Rather, the goal is to better understand the potential environmental
benefits that may result from the commercialization of conversion technologies, the tradeoffs
of employing conversion technologies as alternatives to existing MSW management practices,
and the variables that influence the potential environmental impacts of conversion
technologies.
A. 2 Scope and Boundaries
Since pyrolysis, gasification, and AD have different functional units with respect to the type of
feedstock accepted, we did not directly compare the three systems. The function of the
gasification technology system is to transform the mixed waste fraction of non-recycled waste
(i.e., residual waste after recycling and composting) into energy and useful products. The
functional unit is then a mass unit (e.g., a ton of MSW) of mixed waste. The pyrolysis
technology system manages plastic waste. Therefore, the functional unit is a mass unit of
plastics waste (e.g., a ton of plastics). AD accepts organics, mostly food waste, so the functional
unit is then a mass unit of organic waste (e.g., a ton of organics).
Figure A-l illustrates the system boundaries defined for a conversion technology (CT) in this
assessment. In the figure, the boundaries include not only the conversion technology and other
MSW management operations, but also the processes that supply inputs to those operations,
such as fuels, electricity, and materials production. Likewise, any useful energy or materials
11 The data used for this assessment were provided by industry vendors and were not independently validated. In
addition, the datasets used to characterize the technologies vary in the level of detail and the number of values
obtained for particular input parameters, with only one value obtained for certain parameters.
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produced from the conversion technology system are included in the study boundaries as
offsets. An offset is the displacement of energy or materials produced from primary (virgin)
resources that result from using secondary (recycled) energy or materials.
RTI used a gate-to-grave approach for this assessment and assumed that all waste is fed to the
conversion technologies after collection and separation for recycling or composting. Some
technologies will require additional screening of the feedstock prior to the conversion process
and this is included as part of the conversion technology subsystem. Therefore, the boundaries
of this assessment were defined by the red box in Figure A-l.
Energy and
Materials
Energy and
Materials
i
Collection
Materials
Separation
?r/o/ and Energy Balance
Conversion Technology
(e.g., gasification)
Land
Disposal
Emissions
Energy
By-
products
Residues
Figure A-l. General Life Cycle Boundaries for a Conversion Technology System.
Once the specific conversion technology designs were identified based on the technical
evaluation of technology vendors, detailed process descriptions and process flow diagrams
were prepared to identify mass flows, energy consumption, environmental releases, and other
significant waste production and resource utilization parameters. An important aspect of this
step was identifying the key aspects (for example, facility construction and operation
parameters) of each process that needed to be considered and ensuring that all conversion
technology systems were defined in a consistent manner. For example, if one conversion
technology system included the production of materials used for pollution control, then all
conversion technology systems should include this aspect.
In comparing conversion technologies to existing landfill disposal practices, we needed to have
consistent data for each burden (for example, dioxin/furan emissions) across all unit processes
in the waste management system. Therefore, if data for any given burden was not consistently
available across all processes included in the system, then the burden was not included in the
comparative results of conversion technologies to existing management practices. However, we
did consider all burdens in this report when describing specific conversion technologies
(Sections 2-4). In general, the main categories of inputs and outputs that are reported for each
conversion technology system are consistent with those reported in the MSW DST. These
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include annual estimates for energy consumption, air emissions, water pollutants, and solid
waste. In deciding upon which LCI burdens to present in this report, we chose energy and
greenhouse gas (GHG) emissions since the input data used to estimate these results were
consistently available for the various processes included in the LCIs.
A.3 LCA Methodology, Assumptions, and Modules for Waste Conversion
Technologies
As part of the LCA, data was collected to quantify the relevant inputs and outputs for each
conversion technology system. We collected, reviewed, and compiled data based on the
conversion technology system boundaries (Figure A-l). We worked with the internal and
external contacts to identify available data for each of the conversion technologies. Data were
collected from the following sources:
• Technology vendors.
• Publicly available literature.
• Federal reports.
• State and municipal governments.
• Industry reports.
• Trade associations.
• Waste collection, processing, and disposal facility records and reports.
The scope and boundaries for each major conversion technology category are based on the
technology class definitions and vendor-specific process flow diagrams presented in Sections 2-
4 of this report as well as other information collected from the literature. Each process flow
diagram shows the major process steps that occur in processing and converting waste input. In
addition, the diagrams show the main material and energy inputs and outputs for each
conversion technology.
As shown by the process flow diagrams, the processes for which data are presented are not
cradle-to-grave, but rather gate-to-gate. This is because the conversion technologies by
themselves are just one process step within the system. Only after all of the pieces of life cycle
inventory data from each process step within the system boundaries are assembled can the
inventory module for each conversion technology be completed. These inventory modules rely
on the material and energy data provided by the vendors and/or obtained from the literature
as a starting point and then add the inventory information for upstream and downstream steps.
In general, the construction of the LCA module for each conversion technology is depicted as
follows:
LC input/output burdens - Offsets = Net LCI Coefficients
For example, gasification may use natural gas as a supplemental fuel. The amount of natural gas
consumed for a given tonnage of waste processed is calculated in the material and energy
model. This amount is multiplied by the environmental burdens associated with producing the
natural gas and added to the inventory for the technology. Similarly, the gasification process
generates some residual waste and char that is landfilled. The environmental burden associated
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with the transportation and landfill disposal of these residuals was added to the inventory for
the technology.
Material and energy offsets are netted out of the LCI. In the case of pyrolysis, the main products
are waxes and liquid fuels, each having a number of possible end uses. For this study, we
assumed that it would be used as a replacement for fuel oil. The quantity of commodity oil that
is produced by the process (as given by the material and energy model) is converted to an
equivalent function amount of fuel oil. That amount of fuel oil offset is then multiplied by the
inventory burdens associated with fuel oil production, and these burdens are netted out of the
inventory for the technology.
A. 3.1 Treatment of Material and Energy Recovery
Only energy recovery was included within the conversion technologies' boundaries. Some
gasification vendors report material recovery from pre-processing of the mixed waste arriving
at their facilities. However, because we assumed non-recycled waste would be the input
feedstock, there would likely be only small amounts of available recyclables. In addition, the
current test/demonstration nature of the facilities means they do not yet have contracts in
place and/or data for materials recovery and available markets. For these reasons, as well as
maintaining consistent treatment across the technologies, materials recycling related benefits
were not included in the assessment.
For energy-related offsets, we assumed that electrical energy produced from landfill gas-to-
energy and conversion technology systems displaces electrical energy produced from fossil
sources. The exact mix of fossil fuels displaced is based on the U.S. average grid mix. Electrical
energy is produced mainly from the gasification and AD technologies.
For the pyrolysis/cracking technologies, commodity oils/waxes are the main product. We
assumed that the commodity oils/waxes displace petroleum-based crude oil.
A. 3.2 Items Excluded From the LCA
A number of items have been excluded from the LCA because they are typically found to be
negligible in terms of the inventory totals. These items are described below.
The energy and environmental burdens associated with the manufacture of capital equipment
is not included in the life cycle profiles. This includes equipment to manufacture buildings,
motor vehicles, and industrial machinery. The life cycle burdens associated with such capital
equipment generally, for a ton of materials, becomes negligible when averaged over the
millions of tons of product that the capital equipment manufactures compared to the burdens
associated with the processing steps.
The fuels and power consumed to heat, cool, and light manufacturing establishments are
omitted from the calculations. For most industries, space conditioning energy is quite low
compared to process energy. Energy consumed for space conditioning is usually less than 1
percent of the total energy consumption for the manufacturing process. The energy associated
with research and development, sales, and administrative personnel or related activities have
not been included in this analysis.
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For each system evaluated, small amounts of miscellaneous materials are associated with the
processes that are not included in the LCA results. Generally these materials make up less than
1 percent of the mass of raw materials for the system. For example, the use of biocides and
other conditioning chemicals for cooling water are not documented and included in the
inventory results, except to the extent that these materials contributed to waterborne
emissions from the facilities.
A.3.3 Parameters Tracked and Reported
The main categories of LCA inputs and outputs that were tracked and reported as part of this
study include annual estimates for the following:
• Energy consumption and production.
• Criteria air emissions
• Greenhouse gas emissions.
• Waterborne pollutants.
• Residual solid wastes.
Descriptions of what comprises each of these main categories are provided in the following
sections.
Energy Consumption
Annual energy consumed is aggregated across process and transportation steps in the life cycle
of each conversion technology module. All fuel and electrical energy units are converted to
British thermal unit (BTU) values. Electricity production assumes the average U.S. conversion
efficiency of fuel to electricity and accounts for transmission and distribution losses in the
power lines. Therefore, the KWh value is the aggregated amount of electricity used by the
system, as delivered to the various facilities in the life cycle. The BTU value accounts for the
average mix of fuels (for example, coal, natural gas, hydroelectricity, nuclear) used by utilities to
produce electricity in the United States.
Where energy is produced by a process and displaces the production of electricity or a fuel by a
utility or the petroleum sector, respectively, such as the combustion of MSW with energy
recovery, a credit is given to the extent that it displaces power generation by the utility sector
or production of the fuel. For this study, we used the U.S. average electrical energy grid mix to
calculate the life cycle inventory burdens associated with electrical energy consumption, as well
as the credits associated with electrical energy offsets. Figure A-2 presents the fuel mix in the
U.S. average electrical energy grid (U.S. EIA, 2009).
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I Coal
I Natural gas
ION
I Nuclear
Hydro
Other (including biomass)
Figure A-2. U.S. Average Electrical Energy Grid Mix of Fuels (U.S. EIA, 2009).
Air Emissions
Air emissions can result from two primary sources in the life cycle: process-related activities or
fuel-related activities. Process emissions are those that are emitted during a processing step,
but not as a result of fuel combustion. For example, calcination of limestone to produce lime
emits C02. The quantity of C02 emitted from this process would be listed under process air
emissions. Fuel-related emissions are those emissions that result from the combustion of fuels.
For example, the combustion of wood byproducts in a paper mill produces a fuel-related solid
waste, ash. The emissions reported on the data tables in the product summaries are the
quantities that reach the environment (air, water, and land) after pollution control measures
have been taken.
Atmospheric emissions include substances released to the air that are regulated or classified as
pollutants. Emissions are reported as pounds of pollutant per annual tonnage of waste
managed. Atmospheric emissions also include C02 releases, which are calculated from fuel
combustion data or process chemistry. C02 emissions are not regulated; however, we are
reporting them in this study because of the growing concern about global warming. C02
emissions are labeled as being from either fossil or nonfossil fuels.
C02 released from the combustion of fossil carbon sources (for example, coal, natural gas, or
petroleum) or released during the reaction of chemicals derived from these materials is
classified as fossil C02. C02 released from mineral sources (for example, the calcining of
limestone to lime), is also classified as fossil C02. C02 from sources other than fossil carbon
sources (that is, from biomass) is classified as nonfossil carbon dioxide. Nonfossil C02 includes
C02 released from the combustion of plant or animal material or released during the reaction
of chemicals derived from these materials. The labeling of the C02 releases as either fossil or
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nonfossil is done to aid in the interpretation of the results. The source of C02 releases is an
important issue in the context of the natural carbon cycle and global warming.
Waterborne Pollutants
Waterborne wastes are produced from both process activities and fuel-production activities.
These are reported as pounds of pollutant per tonnage of waste managed. Similar to air
emissions, the waterborne pollutants include substances released to surface water and
groundwater that are regulated or classified as pollutants. The values reported are the average
quantity of pollutants still present in the wastewater stream after wastewater treatment and
represent discharges into receiving waters.
Air or waterborne emissions that are not regulated or reported to regulatory agencies are not
reported in the inventory results presented in the material summaries. Reliable data for any
such emissions would be difficult to obtain, except for a site-specific study where additional
testing was authorized. Conversely, some air and waterborne emissions data that are regulated
and reported may not have been included in the inventory results. The data used represent the
best available from existing sources.
Solid Waste
Similar to air and water emissions, solid wastes are produced from process and fuel production
activities and are reported as pounds of pollutant per tonnage of waste managed. Process solid
wastes include mineral processing wastes (such as red mud from alumina manufacturing);
wastewater treatment sludge; solids collected in air pollution control devices; trim or waste
materials from manufacturing operations that are not recycled; and packaging materials from
material suppliers.
Fuel-related solid wastes are fuel production and combustion residues, such as the ash
generated by burning coal or wood.
A.4 Key Data and Assumptions Used in the Technology LCAs
Table A-l presents key LCA assumptions for the different conversion technologies, as well as
for supporting waste management activities (collection) and landfill disposal.
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Table A-l. Key Assumptions Used in the LCIs.
Parameter
General
Waste Input
Waste Composition
Transportation Distances
Conversion facility to ash landfill
Gasification facility to landfill
AD facility to landfill
Gasification
Basic Design
Waste Input Heating Value
Assumed Offset for Energy Recovery
Pyrolysis
Basic Design
Waste Input Heating Value
Assumed Offset for Energy Recovery
AD
Basic Design
Waste Input Gas Yield
Assumed Offset for Energy Recovery
WTE
Basic Design
Plant Heat Rate
Assumed Offset for Energy Recovery
Landfill
Basic Design
Time Period for Calculating Emissions
Landfill Gas Collection Efficiency
Landfill Gas Management
Assumed Offset
Assumption
Gasification: 1 ton of mixed non-recycled waste
Pyrolysis: Iton of plastics
Anaerobic digestion (AD): Iton of organics
Gasification: average U.S. post-recovery composition from U.S. EP,
(2008)
Pyrolysis: 100% plastics
AD: food waste, yard waste, paper
30 miles one way
30 miles one way
30 miles one way
Accepts mixed waste; includes recyclables recovery; syngas as
the main product
12 MMBtu/ton (based on waste composition)
Solid waste to electricity: U.S. average electricity grid mix of
fuels
Only accepts plastics; does not include recyclables recovery;
oil/wax as the main product
28 MMBtu/ton (plastics only)
Fuel oil
Only accepts food, yard, and paper wastes; assumed biogas as
the main product
3,281 ft3/ton
Solid waste to electricity: U.S. average electricity grid mix of
fuels
Mass burn with electricity production and metals recovery from
ash (for MSW combustion only)
14,000 (low end) and 18,000 (high end)
U.S. average electricity grid mix of fuels
Conventional, Subtitle DType
100 years
75%
Flare (low end) and Energy Recovery (high end)
U.S. average electricity grid mix of fuels
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