## Secondary Mill Residues and Urban Wood Waste **Quantities in the United States**

**Final Report**

Prepared for: Northeast Regional Biomass Program

Washington, D.C.

Prepared by Jeffrey E. Fehrs, P.E. Williston, Vermont

December 1999

## Secondary Mill Residues and Urban Wood Waste **Quantities in the United States**

**Final Report**

Prepared for: Northeast Regional Biomass Program CONEG Policy Research Center, Inc. 400 North Capitol Street, Suite 382 Washington, D.C. 20001

Prepared by Jeffrey E. Fehrs, P.E. 20 Hideaway Lane Williston, Vermont 05495

December 1999**Secondary Mill Residues & Urban Wood Waste Quantities in the U.S.** 

i TABLE OF CONTENTS
Page

EXECUTIVE SUMMARY

................................ ................................ ................................ ......... iii

SECTION I: INTRODUCTION ................................ ................................ ................................ . 1 Purpose of this Study

................................ ................................ ................................ .................... 1 Types of Wood Residues and Wastes Included in the Study

................................ .......................... 2 Definitions

................................ ................................ ................................ ................................ .... 2

SECTION II: NATIONAL WOOD WASTE ASSESSMENT SUMMARIES ......................... 5 Characterization of Building-Related Construction and Demolition Debris in the United States

................................ ................................ ......................... 7 Characterization of Municipal Solid Waste in the United States: 1997 Update

.............................. 11 Lignocellulosic Feedstock Resource Assessment

................................ ................................ .......... 15 Urban Tree Residues: Results of the First National Inventory

................................ ........................ 19 Urban Wood Waste Resource Assessment

................................ ................................ .................... 23 Biomass Residue Supply Curves for the United States (Update)

................................ .................... 27 The Changing Solid Waste Wood Resource in the United States, 1990-1998

................................ 31

SECTION III: ESTIMATES OF NATIONAL WOOD WASTE

QUANTITIES AND PRICES ................................ ................................ ............ 37 Methodology Used to Develop Estimates of Quantities and Prices

................................ ................ 37 Results

................................ ................................ ................................ ................................ .......... 45

APPENDIX A: Bibliography

................................ ................................ ................................ ...... A-1 APPENDIX B: Matrix Table

................................ ................................ ................................ ...... B-1 APPENDIX C: Calculated Delivered Residue Cost and Graph of DRC Versus

Cumulative Percent Available

................................ ................................ .......... C-1 APPENDIX D: Calculation of Weighted Average Landfill and Incinerator

Tipping Fee

................................ ................................ ................................ ....... D-1**Secondary Mill Residues & Urban Wood Waste Quantities in the U.S.** 

ii**Secondary Mill Residues & Urban Wood Waste Quantities in the U.S.** 

iii 

### EXECUTIVE SUMMARY The Northeast Regional Biomass Program (NRBP) has undertaken this study is to assist the U.S. Department of Energy and other biomass resources and energy stakeholders by providing a clear understanding on the types and amounts of wood available for fuel (and other uses). This study focuses on secondary mill residues and urban wood wastes, and estimates quantities and prices based on seven national wood waste assessments completed by others. A goal of the study is to build overall confidence in estimates of secondary mill residues and urban wood waste quantities and prices. This is achieved by obtaining a clear understanding existing data on wood residues and wastes, identifying residues or wastes for which data is not available, and analyzing and compiling the data into a defendable estimate of quantities and prices. Overall, the results of the analysis indicate that a tremendous amount of secondary mill residues and urban wood wastes are generated in the U.S., and that a large fraction of that amount is potentially available for fuel. A summary of wood residue and waste quantities is presented below.
National Wood Residue and Waste Quantities

WOOD WASTE TOTOL

GENERATION (Tons/year) AVAILABLE

@ up to $10/ton (Tons/year) AVAILABLE

@ up to $20/ton (Tons/year) AVAILABLE

@ above $20 (c) (Tons/year) Secondary mill 15,644,000 1,342,000 3,783,000 6,101,000 Construction 16,726,000 2,796,000 7,882,000 12,712,000 Demolition 26,400,000 1,742,000 4,910,000 7,920,000 MSW (a) 11,800,000 1,999,000 5,633,000 9,086,000 Yard trimmings 6,300,000 1,199,000 3,379,000 5,450,000 Urban tree residues 51,455,000 9,962,000 28,074,000 45,280,000 Used pallets (b) 6,544,000 230,000 647,000 1,044,000 Railroad ties 1,688,000 n/a n/a n/a Land clearing n/a n/a n/a n/a Used utility poles n/a n/a n/a n/a

TOTAL < 136,557,000 < 19,270,000 < 54,308,000 <87,593,000 (a): Includes used pallets that are disposed in landfills. (b): Includes used pallets that are repaired, refurbished, or recycled. Used pallets are disposed in landfills are included as MSW wood waste. (c): The methodology used to estimate quantities and prices equates wood waste available at $20 and above with that that potentially available for fuel. Wood waste potentially available as fuel is defined as the quantity generated less that used by high value markets and that which is commingled, unseparatable, or contaminated. n/a: Data not available**Secondary Mill Residues & Urban Wood Waste Quantities in the U.S.** 

iv Several conclusions can be drawn from the data:

• More secondary mill residues and urban wood wastes are generated and potentially available that previously estimated.

• Urban tree residues comprise a surprisingly large fraction (about half) of secondary mill residues and wood wastes potentially available.

• Demolition wood waste comprises the largest fraction of C&D wood waste, but due to contamination and commingling issues, less demolition wood is potentially available than construction and renovation wood waste.

• Used railway ties and land clearing wood waste are likely generated in tremendous quantities, but insufficient information is available to estimate the amounts potentially available.

• At a delivered price of $0 - $10/ton, woodfuel is considered to be competitive with fossil fuels, in particular with coal. This analysis indicates that just under 20,000,000 tons/yr are available at a price of $10/ton.**Secondary Mill Residues & Urban Wood Waste Quantities in the U.S.** 

1 

### SECTION I: INTRODUCTION
The U.S. Department of Energy, the Regional Biomass Energy Programs, national laboratories, and others involved in biomass energy require defensible data on biomass resources and costs to aid in their planning and evaluation of biomass technologies, programs, and policies. The U.S. DOE and the national laboratories are spearheading research and development of various energy crops, harvesting and storage technologies, and conversion technologies capable of using biomass resources for energy. Although several crops appear promising for energy conversion, currently they are neither grown commercially (except on a limited basis) nor economically (compared to fossil fuels or biomass residues or wastes used for fuel). The research and development continues to indicate that energy crops can be grown, harvested, and processed economically, and that energy crops will be an important source of fuel and feedstock for biofuels. However, at least in the short term, various low-cost biomass residues and wastes will continue be used for fuel. Today, most power plants and industrial boilers that use biomass as a primary or supplemental fuel rely on wood residues and wastes as fuel. At its peak in early 1990s, thousands of industrial boilers and nearly 50 power plants throughout the U.S. used wood residues and waste as fuel. The facilities produced about 7,000 MW of power and an un-estimated amount of thermal and electrical energy for industrial uses. To date, hundreds, if not thousands of local, state, regional, and national wood residue and waste resource assessments have been completed. The assessments were completed by a wide variety of government agencies, private consultants, research or academic entities, and others. The research methodologies, sources of information, and assumptions used vary depending on the specific goals, research and analytical technique, as well as budget and time constraints. When compared to each other, the assessments often present significant variability in the results, and it is not uncommon for the information or results to appear contradictory. The variability and contradiction can lead to loss of confidence in the results.

PURPOSE OF THIS STUDY The Northeast Regional Biomass Program (NRBP) has undertaken this study is to assist the U.S. Department of Energy and other biomass resources and energy stakeholders by providing a clear understanding on the types and amounts of wood available for fuel (and other uses). This study focuses on secondary mill residues and urban wood wastes, and estimates quantities and prices based on seven national wood waste assessments completed by others. A goal of the study is to build overall confidence in estimates of secondary mill residues and urban wood waste quantities and prices. This is achieved by obtaining a clear understanding existing data on wood residues and wastes, identifying residues or wastes for which data is not**Secondary Mill Residues & Urban Wood Waste Quantities in the U.S.** 

2 available, and analyzing and compiling the data into a defendable estimate of quantities and prices.

TYPES OF WOOD RESIDUES AND WASTES INCLUDED IN THE STUDY The USDA Forest Service performs inventories, collects and analyzes data, and publishes detailed statistics on both logging and timber harvesting, and primary wood products industry activities (primary wood products industry is primarily pulp mills and sawmills). The USDA Forest Service utilizes a rigorous methodology to collect and analyze data, and updates its statistics on a regular basis. A result is the USDA Forest Service statistics are recognized for their completeness and reliability. Due to the USDA Forest Service statistics, reliable information on logging residues and primary wood products industry residues are either directly available or can be readily derived from it. However, similar or as complete data or statistics for most, if not all other types of wood residues or waste are not available from the USDA Forest Service, other government agencies, or other organizations. These other types can be described as “wood residues and wastes produced in the secondary wood products industry or further along in the production process.” This material can be further defined as consisting of two types of wood residues or waste:

• Secondary mill residues , which is produced by secondary wood products industries that manufacture wood products from lumber, engineered wood products, or wood particles. Examples include companies that manufacture furniture, doors, cabinets, flooring, pallets, fences, and building products.

• Urban wood waste , which refers collectively to a wide variety of wood waste present in commercial, industrial, and municipal solid waste. Examples include used wooden pallets and shipping containers, wood contained in construction and demolition debris, used railroad ties, wood commingled with other solid waste, and other types of wood not included in (or defined as) logging residues, primary wood products industry residues, or secondary mill residues. This study focuses on obtaining and reviewing recent national assessments that focus on or include both secondary mill residues and urban wood waste.

DEFINITIONS The following terms are used throughout this study:

• Generationrefers to the wood waste produced by generators prior to reuse, recycling, disposal, or other management. Generation does not include “internal” reuse or recycling, which is reuse or recycling of wood waste before it leaves the generators facility. For instance, the cutting and reuse of boards broken during the production of large pallets on**Secondary Mill Residues & Urban Wood Waste Quantities in the U.S.** 

3 smaller pallets at a pallet manufacturing facility is internal reuse. This definition of generation is different that that used by some. For instance, the U.S. Environmental Protection Agency considers generation not to include waste materials that are reused. For instance, the repair and reuse of used pallets are not included in estimates of MSW generation.

• Potentially Availablerefers to the amount of wood waste generated less that used, reused, or recycled in high value markets, that unavailable due to contamination, and that unavailable due to commingling with other waste materials.

• High Value Markets refers to industries that manufacture products like pulp, lumber, engineered wood products (such as particle and fiberboard) and pay a relatively high price for wood that meets their specification. Overall, it is assumed that wood used by these markets is not available to woodfuel or other “lower” value markets.

• Green tonis the weight in tons of wood waste in its “as is” state, or including any moisture.

• Dry tonreferes to the weight of wood waste in a “bone dry” state, or with no moisture.

• “Assessment” refers to the seven wood waste assessments reviewed and included in this study.

• “Study” refers to this study. Because this study evaluated seven assessments, some of which are referred to as studies, there exists significant potential to confuse the seven assessments with this study. To help reduce confusion, this document is referred to as “this study”.**Secondary Mill Residues & Urban Wood Waste Quantities in the U.S.** 

5 

### SECTION II: NATIONAL WOOD WASTE ASSESSMENT SUMMARIES
Seven national assessments of wood residues and waste were identified through a rigorous literature search as meeting the goals of this study as well as possessing a minimum level of research and analysis. The literature search included interviewing numerous research or technical staff at federal energy, environmental, and forestry agencies, private consulting firms, utilities, trade organizations, and others. The seven assessments were carefully reviewed to obtain a clear understanding of the research and analysis completed, assumptions made, and conclusions. Detailed summaries of the seven studies are presented in this section. The results and assumptions contained in the assessments was “disseminated and reassembled” into estimates of secondary mill residues and urban wood waste quantities and prices, including that potentially available for fuel. The methodology used to and results of the “dissemination and reassembly” are presented in Section III. The assessments reviewed, summarized, and use to estimate national quantities are:
1. Characterization of Building-Related Construction and Demolition Debris in the United States . U.S. EPA. June 1988,
2. Characterization of Municipal Solid Waste in the United States: 1997 Update . U.S. EPA. May 1998.
3. Lignocellulosic Feedstock Resource Assessment . NEOS Corporation. September 1998.
4. Urban Tree Residues: Results of the First National Inventory . . September 1994.
5. Urban Wood Waste Resource Assessment . G. Wiltsee. November 1998.
6. Biomass Residue Supply Curves for the United States (Update) . Antares Group, Inc. June 16, 1999
7. “The Changing Solid Waste Wood Resource in the United States, 1990-1998”. David B. McKeever, USDA Forest Service. For publication in BioCycle Journal of Composting & Recycling

.**Secondary Mill Residues & Urban Wood Waste Quantities in the U.S.** 

7 TITLE: Characterization of Building-Related Construction and Demolition Debris in

the United States.
BY: Franklin Associates (under subcontract to TechLaw, Inc.)

Prairie Village, Kansas FOR: Mu nicipal and Industrial Solid Waste Division

Office of Solid Waste U.S. Environmental Protection Agency DATE: June 1998

SUMMARY Franklin Associates is well known and respected for their work characterizing municipal solid waste generation, reuse and recycling, and disposal in the U.S. Franklin Associates has been completing biannual updates for the U.S. EPA for some 10 –15 years. Similar to the methodology developed for MSW, the construction and demolition (C&D) methodology relies on “readily available national data” which is suitable for periodic updates. The methodology utilizes U.S. Census data on C&D activities along with “point source waste assessment data” (i.e. data on C&D waste generated by specific construction or demolition projects). Overall, it is a sound methodology, but results in a fair amount of uncertainty due to the reliability of both the U.S. Census data and application of point source data to national estimates. As stated in the report, the authors acknowledge this and expect the methodology will be updated and modified over time to more accurately estimate C&D debris generation. Overall, the assessment estimates that 136,000,000 tons of building-related C/D debris was generated throughout the U.S. in 1996. Presented in Table 1 is a summary of the amounts generated.
TABLE 2-1: Summary of 1996 C&D Generation

Residential Non-Residential Total Green tons Percent Green Tons Percent Green Tons Percent Construction 6,500,000 11 4,270,000 6 10,830,000 8 Renovation 31,900,000 55 28,000,000 36 59,900,000 44 Demolition 19,700,000 34 45,100,000 58 64,800,000 48 TOTAL 58,100,000 100 77,370,000 100 135,530,000 100
This assessment reports on six sets of C&D sorting studies, which indicate the wood waste comprises 14% to 67% of C&D debris. Applying the results of the sorting studies to the amount of C&D debris generated, an estimated 9,040,000 and 91,120,000 tons of C&D wood waste were generated nationally in 1996.**Secondary Mill Residues & Urban Wood Waste Quantities in the U.S.** 

8 LIMITATIONS OF THIS ASSESSMENT As the title suggests, this assessment focuses on building-related C&D debris, and does not include other types of C&D debris such as road and bridge construction and demolition, and land clearing debris. It is my experience that road and bridge construction does generate some wood waste, but is relatively small compared to the amount of other types of C&D debris generated, such as concrete, asphalt, steel, dirt or soil, etc. It is likely the amount of wood waste generated by road and bridge construction, repair, and demolition is relatively small compared to the amount generated by building-related C&D activities. The assessment relies on U.S. Census data on C&D related activities, and then applies this data to assumed C&D debris generation rates. This methodology ignores any local, state, or regional factors that affect the amount actually generated. As the authors acknowledge, this lends uncertainty to the results. However, the purpose of the assessment was to estimate C&D debris on a nation basis using a methodology that permits periodic updates as the national data or assumption are updated. The assessment was not an attempt to conduct more detailed state or regional C&D debris assessments. Based on the goals of the assessment, the methodology and assumption are sound and appropriate. The lack of land clearing debris is truly a liability, since not including this material results in significant under-estimation of the amount of wood waste available. Land clearing debris is comprised mostly (if not only) of wood and may be a significant component of C&D debris. Based on studies completed by C.T. Donovan Associates, Inc. on C&D debris generation, reuse/recycling, and disposal in Rhode Island and Vermont, the amount of land clearing debris in C&D debris ranges from about 7% to 20% respectively. Please note the Vermont percentage may be high, since the methodology used to estimate wood waste generation appears to have relied heavily on estimates of wood generated by land clearing activities and under-estimated wood waste generated by other C&D activities.

WHY INCLUDE THIS ASSESSMENT? Many have long argued that C&D wood waste is a significant, appropriate (if properly processed), and available source of wood fuel. At least two wood-fired power plants in the U.S. have been specifically permitted to use C&D wood, and various other use clean, untreated woodfuel separated from C&D debris. This assessment is one of two national assessment I am aware of that estimates C&D debris generation as well as recycling and disposal in the U.S. The other is that completed by David McKeever, the results of which are presented in “The Changing Solid Waste Wood Resource in the United States, 1990-1998” to be published in BioCycle Journal of Composting & Recycling . Both this assessment and that used by McKeever to estimate construction and renovation C&D debris are similar. One could argue that the methodology is not perfect, that local, state, and regional factors have a large effect on the amount of C&D debris actually generated, recycled, and disposed, and that not including land clearing debris means a significant amount of wood waste is not included in the assessment. While this is true, it is also true that**Secondary Mill Residues & Urban Wood Waste Quantities in the U.S.** 

9 this peer-reviewed assessment uses a sound methodology and the best available data to estimate C&D debris and wood waste.**Secondary Mill Residues & Urban Wood Waste Quantities in the U.S.** 

11 TITLE: Characterization of Municipal Solid Waste in the United States: 1997 Update
BY: Franklin Associates

Prairie Village, Kansas FOR: Municipal and Industrial Solid Waste Division

Office of Solid Waste U.S. Environmental Protection Agency DATE: May 1998

SUMMARY For some 10-15 years, Franklin Associates has assisted the U.S. EPA identify the types and amounts of municipal solid waste (MSW) generated, recycled, and disposed in the U.S. and has published a series of annual or biannual updates. These “characterization studies” have gained wide acceptance are regarded as one of, if not the key resource regarding overall MSW generation, recycling, and disposal in the U.S. The approach used in the assessment is a “material flows methodology”, which relies on manufacturing or production data for both durable and non-durable goods to estimate the amount of MSW entering the waste stream. This methodology adjusts production data to account for product life and for the import and export of products. The material flow methodology is not the only methodology that could be used to estimate MSW quantities. The authors discuss using “site-specific” sampling, sorting, and weighing data, but dismiss this methodology due to both the lack of data across the U.S., and the uncertainty that will result when using limited data to project national estimates. Just as important, the materials flow methodology allows estimates to be updated relatively easily as new national manufacturing, production, product life, or import/export data becomes available. Since some materials in MSW cannot be quantified by this approach (such as yard waste, for which there is no production data), quantification of these materials is based on data from waste characterization studies. It is important to note that this assessment quantifies or characterizes the MSW portion of the total solid waste stream. Other types of solid waste, such as industrial process wastes, hazardous wastes, construction and demolition wastes, agricultural wastes, natural resource extraction wastes are not included. The authors characterize MSW as durable goods, nondurable goods, containers and packaging, food wastes, and yard trimmings, which are generated by residential, commercial, institutional, and industrial (packaging and administrative, but not process waste) sources. Wood is clearly a material found in MSW as wood packaging (pallets and shipping containers), furniture, and other miscellaneous products, as well as in yard waste.**Secondary Mill Residues & Urban Wood Waste Quantities in the U.S.** 

12 According to the 1997 Update , the total MSW generation in the U.S. was just under 210,000,000 tons. Of this amount, wood accounted for 5.2%, or just under 11,000,000 tons. Yard waste accounted for 13.4%, or 28,000,000 tons. For wood waste, 4.5% or 490,000 tons was recovered or recycled in some way, while the remaining 95.5% or about 10,500,000 tons was disposed. For yard waste the amount recovered or recycled was 38.6% or just under 11,000,000 tons, and the amount disposed was 61.4%, or about 17,000,000 tons. Used pallets and MSW wood are typically classified together as urban wood waste. Used pallets are generated by many different types of commercial and industrial businesses, and may be managed as either municipal or industrial solid waste. This has lead to some confusion about whether estimates of MSW wood waste include used pallets. The 1997 Updatedoes include used pallets, and incorporates the data on pallet production for the Wooden Pallet and Container Association as well as data on used pallet generation, reuse and recycling, and disposal from research completed by Robert Bush, Philip Araman, and Vijay Reddy. Data published by Bush et al indicate that in 1995, 223,000,000 pallets, or 6,140,000 tons were taken to MSW or C&D landfills. Of this amount, 17%, or about 1,044,000 tons were recovered, mostly for low value uses or products like mulch and fuel. The remaining 83%, or 5,096,000 tons were disposed. According to the 1997 Update , 200,000,000 used pallets, or over 5,000,000 tons were are repaired or refurbished and returned to service in 1996. This quantity is in addition to the quantity of used pallets taken to landfills. Since pallet repair and refurbishing is considered reuse (and not recycling), this quantity is not included in estimates of pallet or MSW generation or recycling presented in the 1997 Update . In addition, the amount of used pallets and other types of wood waste (and other types of MSW) used as fuel is not considered recycling.

LIMITATIONS OF THIS ASSESSMENT There are no significant limitations with this assessment, and the methodology used is appropriate to estimate the amount of wood waste in MSW. An assumption used in the methodology is that “source reduction” is prior to generation. The definition of source reduction used in the 1997 Updateincludes reuse of a material in its current form. An example is refurbishing used pallets so that they can be reused as pallets. Not including source reduction means waste materials that are managed by source reduction activities are not included in estimates of either generation or recycling. This is important because not including source reduction of wood waste may undercount the amount potential available for fuel. Wood waste managed by source reduction activities might be diverted to fuel markets if these markets existed. However, this is judged to be a minor issue since wood waste managed by source reduction activities will likely have much higher value than that processed into fuel. This indicates little, if any wood waste managed by source reduction activities will be available to fuel or other low value markets.**Secondary Mill Residues & Urban Wood Waste Quantities in the U.S.** 

13 WHY INCLUDE THIS ASSESSMENT? Overall, the 1997 Updateis the most comprehensive estimate of national MSW generation, recycling, and disposal available. The methodology used is sound, and permits a defensible estimate of the amount of wood waste in MSW as well as the amount potentially available as fuel.**Secondary Mill Residues & Urban Wood Waste Quantities in the U.S.** 

15 TITLE: Lignocellulosic Feedstock Resource Assessment
BY: Timothy Rooney

NEOS Corporation Lakewood, Colorado FOR: Art Wiselogel, Technical Monitor

National Renewable Energy Laboratory DATE: September 1998

SUMMARY This assessment is a “macro-level screening tool” which evaluates various lignocellulosic materials with potential for conversion to ethanol for use as a motor fuel. It contains state-level resource generation and availability information on 13 different biomass feedstocks. Five of the feedstocks are wood based, and are:

• Primary wood products industry (termed “primary mills”) hardwood residues;
• Primary mill softwood residues;
• Secondary wood products industry (termed “secondary mills”) hardwood residues;
• Secondary mill softwood residues; and
• Urban tree residue (UTR). The NRBP study focuses onsecondary wood products industry residues or wood waste produced further along in the production. The materials included in the Lignocellulosic Feedstock assessment that are of interest to the NRBP study are the hard and softwood secondary mill residues and urban tree residues. The author notes that good data on secondary mill residue generation and availability is not readably available through agencies that track wood products industries trends such as the U.S. Forest Service, state agencies, or others. The USDA Forest Service, other government agencies, or industry associations do not compile the types of data for secondary mills that allows calculation or projection of residue quantities. This is very different than primary mill residues, which the USDA Forest Service does compile data as part of the 1974 Resource Planning Act. Because of the lack of data, the author developed a methodology to estimate state-level secondary mill residue quantities. The methodology utilizes per mill generation factors and 1992 U.S. Bureau of Census data on secondary mills in each state. The per mill generation factors are based on Minnesota Wood Waste Studies: One Man’s Waste is Another Man’s Gold( Minnesota Wood Waste Studies ) published by the Minnesota Department of Natural Resources in 1994. Based on the Minnesota Wood Waste Studies , the author was able to estimate the average amount of residues secondary mills with a specified range of employees generate (for instance, secondary mills with 10 to 19 employees generate on average 280 dry**Secondary Mill Residues & Urban Wood Waste Quantities in the U.S.** 

16 tons/mill/year). State-level quantities were calculated by multiplying the number of secondary mills with a certain range of employees by the appropriate generation factor. Quantities of hardwood versus softwood residues were estimated based on U.S.D.A. Forest Service data on primary wood product industry resides, which is assumed to be representative of secondary mill residues.
Data from Minnesota Wood Waste Studies was also used to estimate the amount of secondary mill residues that are either unused and can be recovered (as a feedstock for ethanol) or used by “non-captive” markets. Non-captive markets are markets that utilize secondary mill residues, but the prices paid indicate the residuals could be diverted to ethanol plants if such plants existed. For instance, pulp markets are assumed to be a “captive” market since it is assumed prices paid for pulp chips will likely exceed the prices paid by ethanol plants. The end uses for secondary mill residues management are presented in Table 2.
TABLE 2-2: End uses of Secondary Mill Residues
End Use Amount (Percent) Fuel, sold or given away 17.3 Fuel, used on site 20.7 Animal bedding 26.2 Mulch 4.1 Pulp and engineered wood products 2.8 Other 1.8 Landfilled or disposed as solid waste 17.2 TOTAL 100.1
Based on secondary mill residue end uses presented in Minnesota Wood Waste Studies , the author assumes that 36% of secondary mill residues currently used are sold in non-captive markets, and that 50% of unused residues are not available due to contamination, quality, or recoverability. The assessment includes information on secondary mill residue prices, which are presented as statewide averages. Little information is presented on the source of the price data, other than it is from the U.S. DOE Energy Information Agency. The results for secondary mill residues generated in the U.S. are presented in Table 2-3. The conversion to green tons assumes UTRs have a moisture content of 20%. Overall, 39% of UTRs are either used in non-captive markets or that are unused and recoverable ((3,627,800 + 1,219,100)/12,515,300 = 39%).**Secondary Mill Residues & Urban Wood Waste Quantities in the U.S.** 

17 TABLE 2-3: Secondary Mill Residues
Generation (Dry tons/yr) Price

(Dry tons/yr) Used by NonCaptive Markets (Dry tons/yr) Unused and

Recoverable (Dry tons/yr) Hardwood 4,827,200 $20.10 1,407,300 459,100 Softwood 7,688,100 $20.03 2,220,500 760,000 TOTAL (dry tons) 12,515,300 3,627,800 1,219,100 TOTAL (green tons) 15,644,125 4,534,750 1,523,875

The data and information on UTR is from Urban Tree Residues: Results of the First National Inventory, Final Report completed by NEOS for the International Society of Arboriculture Research Trust and others in September 1994. The Urban Tree Residueassessment is discussed is a separate summary.

LIMITATIONS OF THIS ASSESSMENT The key limitation regarding secondary mill residue is the methodology used to estimate quantities. The methodology used is appropriate and is relatively accurate in estimating wood residue quantities. The same methodology (applying per mill or per employee generation factors to employment data) has been successfully used by others (such as C.T. Donovan Associates, Inc.). However, a key issue regarding accuracy is the assumptions regarding per mill generation factors. The author relies on data from Minnesota, which may or may not represent national trends for secondary mills. Secondary mills include a broad range of industries that utilize various types of wood products as feedstock and technologies to convert the resources into products. This implies residue generation factors, whether per employee, per mill, per boardfeet of wood feedstock, etc. will vary significantly. Included as secondary mills are Standard Industrial Classifications (SIC) codes 2426 to 2499 and 2511 to 2519, and nationally there are about 89,000 establishments within these SIC codes. The large number of secondary mills further suggests there is significant variability in residue generator factors. One issue the author does not address is how conservative are the various assumptions that have been made. Forinstance, have assumptions been made so that the results will under-estimate (versus overestimate) residue generation or availability. However, methodologies that estimate quantities based on SIC codes are likely to underestimate quantities. This is because it is very difficult to identify and/or include all establishments that one is interested in, which leads to underestimates of national quantities. The author assumes that 36% of secondary mill residues currently used are used in non-captive markets. This assumption may slightly overestimate the amount potentially available for fuel. Presented in Table 3 is an analysis of the amount of secondary mill residue used by non-captive markets, based on data presented in Minnesota Wood Waste Studies . The results of this analysis indicate that only 29.4% of secondary mill residues currently used are used by non-**Secondary Mill Residues & Urban Wood Waste Quantities in the U.S.** 

18 captive markets. However, the difference between what the author assumed and that developed in Table 2-4 is relatively small considering the variability in the data and that actually available as fuel. The assumption that 50% of unused residues are not available due to contamination, quality, or recoverability appears reasonable.
TABLE: 2-4: Analysis of Secondary Mill Residue Uses

End Use Amount (Percent) Amount Used by

Non-Captive Markets (Percent) Comments Fuel, sold or given away 17.3 17.3 All since already sold or given away as fuel
Fuel, used on site 20.7 0 Little or none since valuable to generator as fuel Animal bedding 26.2 0 Little or none since high value market
Mulch 4.1 4.1 All since fuel markets can compete with mulch markets Pulp and engineered wood products 2.8 0 Little or none since high value market Other 1.8 0 None since assumed not available TOTAL 72.9 % 21.4 % PERCENT OF TOTAL 21.4/72.9 = 29.4%
Limitations associated with urban tree residues are discussed in the summary of the Urban Tree Residues: Results of the First National Inventory, Final Report

.
WHY INCLUDE THIS ASSESSMENT? To my knowledge, no other national wood waste assessments utilizes a similar methodology or one that produces similar results to estimate quantities of secondary mill residues. Despite concerns over generation factors and other assumptions, I believe the methodology used is both sound and appropriate, and for the purposes of a national assessment of secondary mill residues, it is the best methodology to use.**Secondary Mill Residues & Urban Wood Waste Quantities in the U.S.** 

19 TITLE: Urban Tree Residues: Results of the First National Inventory
BY: NEOS Corporation

Lakewood, Colorado FOR: International Society of Arboriculture Research Trust

Allegheny Power Service Corporation National Arborist Foundation DATE: September 1994
Summary Yard waste is recognized as the second largest component of municipal solid waste (see Characterization of Municipal Solid Waste in the United States: 1997 Update ), but accurate and comprehensive data on the quantities generated is lacking. This assessment is an attempt to quantify “urban tree and landscape residue” (UTR) generated in the contiguous 48 states. UTR is loosely defined as “green” materials generated by urban forestry-related businesses. The components of UTR include:

• Wood, including chips, logs, tops and brush, mixed wood (combination of logs, whole tops, and brush), and whole stumps;
• Leaves collected during seasonal leaf collection; and
• Grass clipping. Although seasonal leaf collection and grass clippings are included in this assessment, these materials are not wood and are of limited value as fuel. Because of this, both materials will not be included in this study. The methodology used to quantify UTR was to conduct telephone and mail surveys of UTR generators throughout the U.S., and to extrapolate the survey data to estimate national UTR quantities. The authors identified a total of nine groups or types of entities that generate UTRs. The groups are:

• Commercial tree care firms;
• Municipal/county park and recreation departments;
• Municipal tree care divisions;
• County tree care divisions;
• Electric utility power line maintenance;
• Nurseries;
• Landscapers and landscape maintenance;
• Excavators and land clearing; and
• Orchards**Secondary Mill Residues & Urban Wood Waste Quantities in the U.S.** 

20 Although orchards are a significant generator of UTR, orchard residues are not included in the assessment. This is because the survey of orchards produced a low response and meaningful data was not obtained. The number of surveys mailed was relatively large (3,878 surveys were mailed), and the response rate was excellent (a total of 44% of the surveys were returned, and 1,330 surveys, or 34% were useable). Since the methodology relies on extrapolating the survey results to national quantities based on the total number of UTR generators, significant research went into identifying the total number of generators within each group. It is important to note the survey was of UTR generators, and as such the results also focus on UTR generation. However, good information was also obtained through the survey on UTR end uses, management, and disposal. No attempt was made to verify or independently estimate the amounts of UTR recycled or disposed through end users or disposal options. The assessment concludes that just over 200,000,000 cubic yards of UTRs were generated in the U.S. in 1994. Of this amount, just over 194,000,000 cubic yards of UTR wood waste (i.e. not including seasonal leaf collection and grass clippings) were generated. A summary of the estimates is presented in Table 2-5. In addition, the assessment states that just over 2,000,000 cubic yards of “natural disaster” (i.e. generated by strong wind and storms, hurricanes, ice, etc.) UTR is generated. It is not explicitly stated whether the natural disaster amount is an annual average or is the amount generated in 1994. It is believed the national estimate of UTR generation includes natural disaster UTR. It is also not explicitly stated what natural disaster UTR consists of (whether wood, leaves, grass clipping, or a mixture), but it is reasonable to assume it consists primarily of wood.

TABLE 2-5: Estimate of 1994 UTR Wood Waste Generation in the U.S. Amount Urban Tree Residue All UTRs (cubic yards) UTR Wood Waste

(cubic yards) Chips 134,352,000 134,352,000 Unchipped logs 30,078,000 30,078,000 Unchipped tops and brush 16,042,000 16,042,000 Unchipped mixed wood 12,031,000 12,031,000 Fall leaves 4,010,000 0 Grass clippings 4,010,000 0 Whole stumps 2,005,000 2,005,000

TOTAL 202,528,000 194,508,000
One issue with this assessment is units, woodfuels are typically reported based on weight (i.e. tons) and not volume (i.e. cubic yards). In order to convert from volume to weight, one needs to know the density of the material in question. In Lignocellulosic Feedstock Resource**Secondary Mill Residues & Urban Wood Waste Quantities in the U.S.** 

21 Assessment , the author provides “conversion factors” (i.e. densities) which were used to convert UTR volumes to weight. The various densities and conversion of UTR wood waste volumes to weight is presented in Table 2-6.
TABLE 2-6: Conversion of 1994 UTR Wood Waste Volumes to Weight
UTR Wood Waste Generation (cubic yards) Density

(green tons/cubic yard) Generation (a) (tons) Chips 134,352,000 0.30 40,306,000 Unchipped logs 30,078,000 0.40 12,031,000 Unchipped tops and brush 16,042,000 0.17 2,727,000 Unchipped mixed wood 12,031,000 0.20 2,406,000 Whole stumps 2,005,000 0.50 1,002,000

TOTAL 194,508,000 58,472,000 (a): The amount of generation calculated has been rounded to the nearest thousand tons.
In terms of UTR management, the assessment states that for types of UTR combined:

• 42% is given away;
• 17% is landfilled;
• 12% is sold (to boiler fuel, compost, mulch, wood products manufacturing, cordwood, and other markets)
• 11% is left on-site;
• 6% is sent to recyclers;
• 3% is burned for energy (assumed to be by the generator); and
• The remaining 9% is open burned, stockpiled, incinerated, or managed in other ways. The information on UTR management indicates that up to 88% of UTRs generation is potentially available for fuel or other uses. Presented in Table 2-7 an analysis of UTR management and calculation of that potentially available.

LIMITATIONS OF THIS ASSESSMENT As the authors acknowledge, the methodology used in the assessment is both sound and well carried out, but there are a few “disappointments” (or liabilities) in the results. The authors note two key liabilities: the inability of industry personnel to accurately estimate UTR quantities and the level of accuracy in national estimates due to large data variations in the survey results. Both of these limitations are significant. There are at least two other important liabilities. The first is units. Volume can easily be converted to weight based on density, if the density is known. But UTR density can vary**Secondary Mill Residues & Urban Wood Waste Quantities in the U.S.** 

22 TABLE 2-7: Analysis of UTRs Potentially Available for Fuel

UTR Management Amount (% of generation) Assumption Regarding Availability Amount Potentially Available (% of generation) Given away 42 All is available 42 Landfilled 17 All is available 17 Sold 12 1⁄2 is available 6 Left on-site 11 All is available 11 Sent to recyclers 6 None is available 0 Burned for energy 3 All is available 3 Open burned, etc. 9 All is available 9

TOTAL 100 % 88 %
significantly depending on UTR type (i.e. chips, logs, tops and brush, mixed wood, and whole stumps), wood species, moisture content, how the UTR was/is collected, processed, and/or stored, and other factors. The second is that the survey date was extrapolated into national quantities based on the number of entities that generate UTR. The number of entities is a valid parameter (to extrapolate this type of data), but the results likely less accurate than if other parameters had been used. For instance, both small and large companies are classified as one entity, but it is likely the larger company with more equipment and employees will generated more UTRs. The results would likely be more accurate if another parameter, such as the number of employees. The number of employees is a better indication of a company’s size and potential for UTR generation, and has been successfully used in various national biomass resource assessments.

WHY INCLUDE THIS ASSESSMENT This assessment is not only the most comprehensive, but also the only national urban tree residue assessment. The methodology used is sound and well carried out, and despite the limitations discussed above, the results will allow reasonable and defensible estimates of various types of residues generated (and potentially available as fuel) by commercial and municipal tree care, utility power line maintenance, and land clearing activities.**Secondary Mill Residues & Urban Wood Waste Quantities in the U.S.** 

23 TITLE: Urban Wood Waste Resource Assessment
BY: George Wilt see

Appel Consultants, Inc. Valencia, California FOR: K. Shane Tyson, Technical Monitor

National Renewable Energy Laboratory DATE: November 1998

SUMMARY This is a very interesting and unique assessment. The assessment estimates the quantity, end uses, and supply curves for three types of urban wood wastes in 30 randomly selected metropolitan areas (as defined by the U.S. Office of Management and Budget) in the contiguous 48 states. The three urban wood wastes are:

• Wood waste in municipal solid waste;
• Industrial wood waste; and
• Construction and demolition wood waste. What is unique about this assessment is the methodology used. The author traveled to each metropolitan area and spent 2 to 5 days doing telephone research/interviews (mostly from hotel rooms!) and conducting site visits. The telephone research included government solid waste/recycling agencies, economic development agencies, chambers of commerce as well as both public- and private sector entities involved in wood waste generation, collection, processing, and disposal. The purpose of the research/interviews and site visits was to obtain representative information on the amounts, management or disposal options, and associated price or cost for the three types of urban wood waste. Traveling to each area combined with the site visits provided the author with an “on-the-ground” perspective of the area. A consistent telephone research/interview and site visit methodology was used for each metropolitan area. The author used the data collected by telephone research/interviews, site visits, and numerous “estimating techniques” developed over the course of the project to estimate the quantity of urban wood waste in each metropolitan area. The 30 areas were completed in sets of five, and after each set was completed it was submitted to the NREL technical monitor (K. Shane Tyson) for feedback and redirection. Once all research, interviews, site visits, and technical reviews were completed, all data was re-reviewed and modified as needed to insure both the data used and analysis was as consistent as possible for all metropolitan areas. For each metropolitan area as well as the combined 30 metropolitan areas, the assessment provides estimates of MSW wood waste, industrial wood, and C/D wood “resources” (believed to be equivalent to generation) as well as estimates of the quantities utilized by end use markets**Secondary Mill Residues & Urban Wood Waste Quantities in the U.S.** 

24 and quantities disposed. The information on quantities combined with price/cost information was used to create supply curves for both each metropolitan area as well as the combined 30 areas. Not surprising, urban wood waste resources in the 30 metropolitan areas varied significantly. However, based on data from 28 areas (two “outlier” areas with data irregularities were disregarded), the author was able to develop a “predictive equation” to estimate urban wood resources in metropolitan areas. The predictive equation can be used to project the urban wood waste quantities for all metropolitan areas in the U.S. The author reports that in 1990, there were 281 areas within the U.S. that met the U.S. Office of Management and Budget (U.S. OMB) definition of a metropolitan area and that the population within the 281 metropolitan areas was 193,007,670. Presented in Table 2-8 is the predictive equation as well as the results of applying the equation to the total population within metropolitan areas. It is important to note the amounts shown in Table 2-8 are not for the entire U.S., but instead for the 281 metropolitan areas within the U.S. The assessment also includes a projected urban wood waste resource supply curve for all metropolitan areas in the U.S. The author projects the total urban wood waste resource (in all 281 areas) is slightly over 64 million tons per year. The curve suggests that 95%, or 60.8 million tons are available at a “price” of $0/ton or less (i.e. negative cost). The remaining 5%, or 3.2 million tons are available at a “price” ranging from $3 to $24/ton.
TABLE: 2-8: Urban Wood Wastes Predictive Equation and Generation in the U.S. (a) Wood Waste Type Predictive Equation (tons/yr/capita) Generation (b)

(tons/yr) MSW Wood 0.203 39,181,000 Industrial Wood 0.039 7,527,000 C/D Wood 0.091 17,564,000

TOTAL 0.333 64,272,000 (a) Based on a 1990 population in the 281 metropolitan areas of 193,007,670. (b) Estimates of urban wood waste generation have been rounded to the nearest thousand tons.

LIMITATIONS OF THIS ASSESSMENT There are few if any significant limitations in the methodology used in this assessment. Overall, the research and analysis used are ideal for completing local resource assessments. Furthermore, I have completed numerous local resource assessments myself, I am very cognizant of the need for and benefit of an “on-the-ground” perspective (I use the term “local flavor”). I am also convinced the author appropriately combined the 30 separate resource assessments into one national urban wood waste resource assessment. However, I do have two concerns. One concern is the supply curves, and how they will or should be used. As the author notes, the supply curves are created by assembling data on both quantities and cost to wood waste generators to manage their wood waste. My concern is that some may interpret the supply curves as urban wood waste availability (for fuel or other uses)**Secondary Mill Residues & Urban Wood Waste Quantities in the U.S.** 

25 curves, which they are not. The reason the supply curves do not reflect availability is the data used to create the curves do not take into account the various factors that affect availability, such as processing costs and transportation. To illustrate, consider wood given or left by tree care companies to the landowner after trimming or removing his/her trees. This wood is considered to have a cost of $0/ton, since there is no cost to the company to manage it. But, this cost is not indicative of the price a power plant would need to pay for the same wood. In order to be delivered to the power plant, the tree care company or another entity would likely need to process (i.e. chip and screen) and transport the wood, both of which are costs and will need to be recovered in the price charged to the power plant. The other concern is the completeness of the individual resource assessments done in each metropolitan area. I have completed numerous local resource assessments, and I am well aware of the time it takes to complete the research. The time is not measured just in hours spent doing research, but also how long it takes to locate the right people (to obtain the information you need), for some people to call back, for leads to be developed, etc. My concern is that the individual resource assessments needed to be completed in a relatively short amount of time, and that this resulted in some sources and quantities of urban wood waste not being identified. The overall result is that the individual and national assessments may underestimate the amount actually generated. Please note this is not a criticism of this assessment, and in fact the issue of undercounting resources is an inherent concern of allbiomass assessments. A minor limitation of the assessment is only areas that meet U.S. Office of Management and Budget definition of a “metropolitan area” are included in the assessment. There are many towns and perhaps cities that generate urban wood waste, but are not accounted for in the assessment (since they do not meet the OMB definition). The means the national urban wood waste estimates and supply curves actually underestimates total quantities. Again, this is not meant to be a criticism, but this limitation should be recognized when using the information in the assessment.

WHY INCLUDE THIS ASSESSMENT I believe this assessment is one of the most comprehensive and useful assessments of urban wood waste completed to date, both from the national perspective, but also from the perspective of local influences on wood waste generation and management. I firmly believe the methodology used, and in particularly the site visits, provide a heightened understanding and awareness of both the resource and how it is managed. The end result is increased confidence and reliability of both the data and the analysis.**Secondary Mill Residues & Urban Wood Waste Quantities in the U.S.** 

26 TITLE: Biomass Residue Supply Curves for the United States (Update)
BY: Antares Group, Inc.

Landover, Maryland FOR: U.S. Department of Ene rgy’s Biomass Power Program

National Renewable Energy Laboratory DATE: June 16, 1999

SUMMARY This assessment was completed at the request of both the U.S. Department of Energy and the National Renewable Energy Laboratory. The goal of the assessment was to provide the Energy Information Agency (EIA) with credible and defensible information on wood residue and waste supply and costs for use in national energy modeling efforts. In order for EIA modelers to be comfortable with the data, when assumptions were required, conservative assumptions were made. The goal was accomplished, and for the first time ever biomass was included in EIA’s energy models for the Annual Energy Outlook 1999 report. Previously, biomass was treated outside EIS’s models and consequently the full role of biomass as an energy source in the U.S. was not presented. This assessment is also presently being used by a several corporate interests for their biopower market investigations, and by the Electric Power Research Institute EPRI for climate change modeling efforts. This assessment develops supply curves for the portion of seven types of wood waste that are considered to be “available”. Available is defined as “not currently destined for other productive uses.” The seven types of wood waste are:

• Forest wood residues, which includes both silvicultural and site conversion wood waste;
• Bark residues from primary wood product industries (“primary mills”);
• Wood residues from primary mills;
• Construction wood waste;
• Demolition wood waste;
• Woody yard trimmings; and
• Other wood waste, which includes pallets, shipping containers, secondary wood products industry wood residues, industrial wood waste, and wood in municipal solid waste (MSW wood). Of interest to this study are construction wood waste, demolition wood waste, woody yard trimmings, and other wood waste. Supply curves are developed for each state, as well as the five biomass energy program regions, 15 electric supply regions, and the U.S. as a whole.**Secondary Mill Residues & Urban Wood Waste Quantities in the U.S.** 

27 The supply curves of available wood waste were developed using a unique methodology. The methodology uses state-level information on available wood waste quantities and projects the “delivered residue cost” (DRC) based on disposal (in landfills), collection and processing, and transportation costs. The DRC is estimated as follows: DRC = RPC + RTC - 1⁄2(LFT)
Where: RPC = Average collection and processing cost, which vary for the 7 types of wood wastes. RTC = Transportation cost, which vary depending on one of four assumed tr ansportation distances and state specific transportation cost index. LFT = Average cost to disposed solid waste in landfills (i.e. “tipping fee”), which vary depending on the state. When available, state-specific data was used to quantify the amount of available wood waste in each state. For instance, information on available wood waste in each of the 11 states in the Northeast Regional Biomass Program (NRBP) is from The Potential for Producing Ethanol from Biomass in the Northeast by C.T. Donovan Associates, Inc. and published by the NRBP in September 1994. If state-specific data was not available, then national data was used and the state quantity calculated based on a factor that closely tracks the activity that produces the material. For instance, state construction wood waste estimates are based on number of housing starts in the state compared to the national housing starts. The various factors used for each wood waste type are presented in Table 2-9. In general, national estimates of available wood waste are based on work done by David McKeever of the U.S.D.A. Forest Service, Forest Products Laboratory.

TABLE 2-9: Factors Used to Estimate State Quantities and Wood Waste Collection and

Processing Costs Wood Waste Type Factor Collection and Processing Cost Forest residues Timber Harvest $17/green ton Bark Timber Harvest $4/green ton Primary mill residues Timber Harvest $4/green ton
Construction Housing Starts $12/green ton Demolition Population $12/green ton Yard waste MSW $12/green ton Other MSW $12/green ton

Collection and processing costs for the seven types of wood wastes were obtained from several published sources, and the average value was used to calculate the DRC. A summary of the collection and processing costs are presented in Table 2-9. All available wood waste is assumed to be within 100 miles of potential power plant sites, and transportation costs are based on four assumed transportation distances: 25, 50, 75, and 100**Secondary Mill Residues & Urban Wood Waste Quantities in the U.S.** 

28 miles. In some states, a maximum transportation distance of 100 miles does not make sense due to the size of the state. In smaller states (less than 31,416 square miles, the area of a 100 mile radius circle), the maximum transportation distance was adjusted downward. The authors researched freight costs, and a national freight cost of 24.11¢/mile is used, and was derived from national statistics on local (non-intercity) freight costs. The freight cost in each state was adjusted based on U.S. Department of Commerce transportation cost index. For wood waste that tends to be generated in rural settings (forest residues, bark, and primary mill residues) the state’s lowest transportation index was used. For wood waste tending to be generated in urban settings (construction wood waste, demolition wood waste, yard waste, and other wood waste), the index for the major city (in the state) was used. For the wood waste types that are commonly disposed in landfills (i.e. construction wood waste, demolition wood waste, yard waste, and other wood waste), it is assumed that wood waste processors/recyclers will charge a tipping fee that is one-half of the fee charged to dispose municipal solid waste in landfills. The reduced fee reflects a financial incentiveprocessors/recyclers will charge to divert wood waste from landfills to their facilities. The statespecific tipping fee used is the state average, and is based on data published in the magazine Solid Waste Digest

in 1998. For wood waste that is not typically landfilled (i.e. forestry residues, bark, and primary mill residues), no tipping fee is assumed (i.e. $0/ton). For each state, a total of 28 data points (seven wood waste types and four transportation distances) were calculated and used to plot the state supply curve. Each data point consists or is the product of both a wood waste quantity and the corresponding DRC. The state-level quantity of each wood waste type was “allocated” to the four transportation distances based on area (of a circle with a radius equal to the transportation distance). In some cases, the assumed fee charged by processors/recyclers (i.e. one-half of the state average landfill tipping fee) exceeds the collection, processing, and transportation cost, resulting in a negative DRC. A negative DRC implies power plants are paid to accept processed wood waste as fuel, which is unrealistic. It is assumed that the minimum price power plants will pay for woodfuel is 50¢/million Btu (MMBtu), and a “market floor price” of 50¢/MMBtus is assumed in all supply curves. The data used to create the state supply curves is aggregated together to create a national supply curve and supply curves for the five regional biomass programs. Supply curves are also created for the 15 electric supply regions, but since some of these regions include portions of states, “mapping factors” were used to adjust the state-specific data for use in the regional supply curves. Mapping factors are the area a specific supply region occupies in a state divided by the total area of the state. As shown in Table 2-10, this assessment concludes that just over 111,000,000 green tons/year of all types of wood residues and wastes are available in the U.S. (i.e. “not currently destined for other productive uses”). The study further concludes that of this amount: Allocation of Wood Waste Quantities Transportation Distance Quantity

(% Of Total) 25 miles 6 50 miles 19 75 miles 31 100 miles 44 100%**Secondary Mill Residues & Urban Wood Waste Quantities in the U.S.** 

29 • 34%, or about 38 million tons/year are low cost residues (< $1.00/MMBtu) consisting of construction wood waste, demolition wood waste, yard waste, and other waste wood;

• 6%, or about 7 million tons/year are medium cost residues ($1.00 to $3.00/MMBtu) consisting of primary mill residues and bark;

• 60%, or about 67 million tons/year are high cost residues ($2.50 to $5.00/MMBtu) consisting of forestry residuals.
TABLE 2-10: Wood Residues and Wastes Potentially Available for Fuel
Wood Waste Amount Potentially Available (tons) Silviculture/site conversion 72,192,000 Primary mill bark residues 1,956,000 Primary mill residues 6,015,000 Woody yard trimmings 10,123,000 Construction residues 6,238,000 Demolition residues 7,864,000 Other wood wastes (a) 6,759,000

TOTAL 111,147,000 (a) Includes some, but not all secondary mill residues.

LIMITATIONS OF THIS ASSESSMENT This assessment offers a very innovative approach and methodology to developing national and regional biomass supply curves I am aware of. However, embedded in the methodology are two assumptions that lead to underestimation of the available wood waste resource. The first is little, if any available secondary wood products industry (“secondary mill”) wood waste is accounted for by the methodology. The authors acknowledge that secondary mill residues are underestimated in the assessment. Secondary mill residues are not addressed as a separate wood waste type, but instead are assumed to be a part of “other wood waste” which is essentially MSW wood waste (i.e. wood waste managed as municipal solid waste). Estimates of MSW will likely include only a fraction of the amount of secondary mill residues actually produced, since secondary mill residues are managed as industrial waste and not as MSW (although in some cases it may be). The amount of available secondary mill residue could be significant. The assessment Lignocellulosic Feedstock Resource Assessment completed by NEOS Corporation for the National Renewable Energy Laboratory in September 1998 (see attached summary) conservatively estimates the amount of “unused and recoverable” (similar to the definition of “available” used in this assessment) secondary mill residues at about 1.2 million tons/year. The second is the implicit assumption in the assessment that “energy production uses will not compete for materials already used productively.” While this is a valid and likely necessary assumption to make, but it also means that a great reservoir of potentially low cost woodfuel is**Secondary Mill Residues & Urban Wood Waste Quantities in the U.S.** 

30 not addressed. If and when woodfuel markets expand, it is reasonable to expect wood waste will be diverted from low value markets (such as landfill cover, compost amendment, and mulch) to fuel markets due to economic and other factors or benefits. It is not possible to estimate how much wood would be diverted, but it does not seem unreasonable to assume it is roughly equivalent to the low cost residues estimated in this assessment. A concern I have about the methodology used is the “delivered residual cost” (DRC), which is determined using the identical formula for all residuals in all states. This means a rigid procedure is used to estimate a very dynamic and in some cases volatile parameter. Factors such as the centralized biomass resources (which occurs in many areas and may greatly impact transportation costs), landfill bans (on yard waste and other types of clean, untreated wood), logging restrictions, and other market dynamics (a good example is the demise of biomass power plants in the Northeast and California) are not incorporated into the methodology and thus can not affect the results. The end result of the methodology’s “inflexibility” is of more concern in the state and regional supply curves and less of a concern in the national supply curve. It would be very interesting to run some “sensitivity analysis”, that is vary the collection, processing, transportation, and disposal costs to reflect state or regional trends or factors, and observe what the impact is on the state, regional, and national supply curves.

WHY INCLUDE THIS ASSESSMENT? Without a doubt, this assessment is one of the most important analyses of wood waste supply and cost completed to date. The assessment includes an estimate of the overall quantity of wood waste available for use as fuel and a sound methodology to project woodfuel prices. It provides a not only a valuable tool to estimate wood waste amounts and costs, but also to understand the impact of economic factors on delivered price. The assessment will be of great value in my task of estimating the overall amounts and price of wood waste in the U.S.**Secondary Mill Residues & Urban Wood Waste Quantities in the U.S.** 

31 TITLE: The Changing Solid Waste Wood Resource in the United States, 1990-1998 (a)
BY: David McKeever (a)

Forest Products Laboratory USDA Forest Service Madison, Wisconsin FOR: BioCycle Journal of Composting & Recycling (a)
DATE: Prepared for publication November 1998 1
(a): Dav id McKeever with others at the Forest Products Laboratory have completed several reports, papers, articles, and presentation on wood waste generation, recycling, and disposal in the U.S. The article published in BioCycle Journal of Composting & Recyclingin January 1998 is the latest public presentation of their research. Collectively, the documents authored (solely or with other co-authors) by David McKeever are referred to by the title used in the BioCyclearticle.

SUMMARY The assessment provides estimates of wood waste generation, recovery or combustion, and available for recovery (for fuel or other uses) in the U.S. The assessment focus on three sources of wood waste:

• Municipal solid waste (MSW), including the wood waste components of MSW as well as woody yard trimmings;
• Construction and demolition (C&D) activities; and
• Primary wood products industry, including bark and wood residues. The NRBP study focuses onsecondary wood products industry residues or wood waste produced further along in the production. The sources of wood wastes included in this assessment that are of interest to the NRBP study are MSW and C&D activities. The author utilizes the most recent MSW data published by Franklin Associates, and thus represents the most current U.S. EPA information on MSW wood waste. Presented in Table 2- 11 is a summary of the estimated amounts of MSW wood waste generation, recycling, disposal, and that available for recovery. The estimates of MSW wood waste do not include pallets that were repaired, refurbished, or recycled. The author sites the research by Robert Bush, Philip Araman, and Vijay Reddy which indicate that 5,300,000 million tons of used pallets were repaired or recycled. The quantity of pallets repaired or recycled are not included in the quantities presented in Table 2-11. It appears that land clearing debris is not included since this material it is typically not managed as MSW (and thus is not included in estimates of MSW wood), is not included as a type of construction wood waste, and is clearly not a demolition wood waste or primary mill residue. It**Secondary Mill Residues & Urban Wood Waste Quantities in the U.S.** 

32 TABLE 2-11: MSW Wood Waste Generation, Recycling, Disposal, and Available for

Recovery in 1998. Amount Percent of Generation MSW Wood Waste Generation (a) 11,800,000 tons Recycling and Composting (a) 600,000 tons 5.1% Combustion (b) 3,100,000 tons 26.3% Unacceptable for Recovery (c) 2,700,000 tons 22.9% Remainder = Available 5,400,000 tons 45.8% (a): Does not included an estimated 5,300,000 tons of used pallets that were repaired or recycled. (b): Assumed to be in waste-to-energy facilities, facilities that burn refuse-derived fuel, and incinerators. (c): Due to commingling, contamination, or other reasons.
also appears secondary wood products industry (“secondary mills”) residues are also not included. Secondary mill residues would be classified as “industrial process waste” in the U.S. Environmental Protection Agency’s MSW characterization studies (see the summary of Characterization of Municipal Solid Waste in The United States: 1997 Update ), which are used by the author to estimate the amount of wood waste in MSW. Industrial process wastes are not included in the U.S. EPA estimates of MSW. The estimates of MSW wood waste and yard trimmings generation and recycling are also based on estimates in the U.S. EPA MSW characterization studies. Yard waste is noted to be the largest component of MSW, and comprises about 12% of total MSW generation. Presented in Table 2-12 are the estimated amounts of woody yard trimmings MSW wood waste generation, recycling, disposal, and that available for recovery. The author assumes that 95% of yard trimmings is woody, which is based on information presented in Urban Tree Residues: Results of the First National Inventory . This assumption is consistent with the results presented in Table 2-5. However, there may be large differences between yard trimmings in MSW and UTRs. As noted in Characterization of Municipal Solid Waste in The United States: 1997 Update , there is little data on the composition of yard trimming, and yard trimming are assumed to consist of 50% grass, 25% brush, and 25% leaves. The assumed composition in the 1997 Updatesuggests yard trimmings contain at most 25% wood as brush.

TABLE 2-12: Woody Yard Trimmings Generation, Recycling, Disposal, and Available for

Recovery in 1998. Amount Percent of Generation Woody Yard Trimmings Generation (a) 25,200,000 tons Recycling and Composting (a) 11,100,000 tons 44.0% Combustion (b) 3,900,000 tons 15.5% Unusable (c) 3,400,000 tons 13.5%

Remainder =Available 6,800,000 tons 27.0% The author notes that construction debris and demolition debris are typically referred to or combined into a single form of waste, but in reality they are generated by different activities and**Secondary Mill Residues & Urban Wood Waste Quantities in the U.S.** 

33 have different characteristics. Because of this, the generation, recycling, disposal, and availability of construction (and the related repair and remodeling) debris should be evaluated separately from demolition debris.Estimates of wood waste generated by construction and repair/remodeling of residential and nonresidential buildings is based on construction activities as well as the wood products used in their construction. The author notes there is much information available regarding these parameters from the U.S. Department of Commerce, Bureau of Census, Wood Products Council, and others. David McKeever and others at the USDA Forest Service have also published extensively on these parameters. The amount of wood waste generation by building-related construction activities is based on actual case studies. The methodology the author has developed over the years and uses in this assessment appears similar to that used by Franklin Associates in Characterization of Building-Related Construction and Demolition Debris in the United States . A summary of the results for construction wood waste is presented in Table 2-13.

TABLE 2-13: Building-Related Construction Wood Waste Generation and Available for

Recovery in 1998.

GENERATION AVAILABLE FOR RECOVERY
Amount (tons) Amount

(tons) Percent of

Generation (%) Residential Buildings Construction 3,400,000 3,000,000 88.2 Repair/remodeling 4,300,00 2,800,000 65.1

Subtotal 7,700,000 5,800,000 75.3 Non-Residential Buildings Construction and repair/remodeling 1,000,000 900,000 90.0

TOTAL 8,700,000 6,700,000 77.0
Estimates of building-related demolition debris and wood waste are based on a per capita generation rate of about 1.3 pounds/capita/day derived from quantities estimate in Characterization of Building-Related Construction and Demolition Debris in the United States . The amount of demolition debris generated in 1998 was calculated to be 66,000,000 tons based on the 1998 U.S. population, or about a 1.8% increase from that estimated by Franklin Associates for 1996. The author assumes wood waste comprises 40% of demolition debris, or about 26,400,000 tons in 1998. The amount of demolition wood waste considered to be available for recovery is based on information provided by a C&D recycling facility located in Massachusetts and projections of advances in C&D recovery, separation, and recycling technologies. Overall, 30% or about 9,000,000 tons of demolition wood waste generated in 1998 is considered available.**Secondary Mill Residues & Urban Wood Waste Quantities in the U.S.** 

34 LIMITATIONS OF THIS ASSESSMENT There are few limitations associated with this assessment and the quantities of MSW wood waste, woody yard trimming, construction and repair/remodeling, and demolition wood waste. For construction and repair/remodeling wood waste, the author uses a rigorous methodology that is similar to that used by Franklin Associates in Characterization of Building-Related Construction and Demolition Debris in the United States . The estimate by Franklin Associates is for building-related construction and repair/renovation debris, and not for the wood waste component within. Thus, it is difficult to compare Franklin Associates’ estimates to David McKeever’s. However, assuming wood waste comprises 35% of building-related construction and repair/renovation debris estimated by Franklin Associates, the two estimates appear relatively close. One limitation of the estimate of construction and repair/renovation wood waste is the amounts judged to be available for recovery. There is little if any information presented on how the quantities were derived, and thus it is not possible to verify or evaluate whether the assumption are reasonable. This assessment relies of previous research by Franklin Associates and others to estimate the amount of MSW wood waste, woody yard trimmings, and demolition wood waste, which are adjusted to reflect 1998 quantities. The methodologies used to adjust data to reflect 1998 quantities appear to be appropriate. However, several of the assumptions regarding wood waste quantities or availability should be mentioned:

• No explanation is provided regarding the how amount of MSW wood and woody yard trimmings judged to be unacceptable for recovery was derived, thus it is not possible to verify or evaluate whether the assumptions used are reasonable.

• The estimate of woody yard trimming assumes that 95% of yard trimmings is wood waste, which is based on estimates wood waste in UTRs. However, UTRs and yard trimmings are different materials, and the quantities of wood waste within each will likely differ. It appears more reasonable and conservative to assume wood waste comprises no more than 25% of yard trimmings.

• Demolition wood waste is assumed to contain 40% wood waste. The literature often cites C&D debris (combined together) as containing 25% to 40% wood waste. The six C&D sorting studies identified in Characterization of Building-Related Construction and Demolition Debris in the United States indicate C&D debris contains between 14% and 67% wood waste. There is significant variability in the data on wood waste in C&D debris, and there appears to be little or no information regarding demolition debris only, and thus it in not possible to evaluate whether 40% accurately reflects actual amounts.**Secondary Mill Residues & Urban Wood Waste Quantities in the U.S.** 

35 WHY INCLUDE THIS ASSESSMENT? This assessment provides an important estimate of construction and repair/remodeling wood waste. This estimate can be compared to or verify other estimates of construction wood waste estimates, such as that in Characterization of Building-Related Construction and Demolition Debris in the United States . The assessment also provides adjustments of MSW wood waste, woody yard waste, and demolition wood waste to reflect 1998 quantities.**Secondary Mill Residues & Urban Wood Waste Quantities in the U.S.** 

37 

### SECTION III: ESTIMATE OF NATIONAL WOOD WASTE QUANTITIES AND PRICES

The seven wood waste assessments identified and discussed in Section 2 were included in this study because they are judged to be the most complete and utilize the most appropriate or accurate methodologies to estimate national wood waste quantities and/or prices. However, without further analysis the assessments cannot be used to estimate the quantity and price of secondary mill residues and urban wood waste available nationally. The reasons for this include:

• None of the assessments include all types of secondary mill residues and urban wood waste;

• All of the assessments include wood waste that is included in other wood waste assessments, leading to potential for double counting wood waste when results are combined; and

• With the exception of Biomass Residue Supply Curves for the U.S. (Update) , and perhaps Lignocellulosic Feedstock Resource Assessment , none of the assessments include an analysis of the prices residues and wood waste will be available at. The information and data presented in each assessment as well as the assumptions used were reviewed and analyzed, and estimates of national quantities of secondary mill residues and urban wood wastes were developed. The methodology used included developing a matrix table which tracked the various steps used in the review and analysis, as well as obtaining additional information on wood waste that were not included in the seven assessments.
METHODOLOGY USED TO DEVELOP ESTIMATES OF QUANTITIES AND PRICES The methodology used involved various steps as well as developing a matrix table to track and document the results of each step. The matrix table is presented in Appendix B. The steps are described below:
Identify The Types Of Wood Waste Included In Each Assessment The seven assessments included a wide range of wood residues or wastes as well as other types of biomass feedstocks. In this preliminary step, the types of secondary mill residues or urban wood waste included in each assessment were identified.**Secondary Mill Residues & Urban Wood Waste Quantities in the U.S.** 

38 Further Interpret The Types Of Wood Waste Many of the types of wood residue or waste included in an assessment are actually a combination of many different wood wastes. For instance, “MSW wood waste” may be comprised of household wood waste, commercial wood waste, institutional wood waste, pallets, and yard waste. Based on the review of each assessment and the assumptions used, the types of wood residue or waste were further delineated to identify the specific types of wood that are or are not included.
Identify The Types Of Wood Waste That Are Included In Other Assessments A key aspect of developing a defendable estimate of biomass quantities is demonstration that most, if not all types of appropriated biomass are included, and that “double counting” does not occur. Double counting is counting more than once a specific type of biomass. Within each assessment, all wood wastes were reviewed to determine which assessments also included the wood waste.
Choose Which Assessment To Use For Each Type Of Wood Wastes This is a difficult step, and involves determining which assessment(s) provides the most complete or comprehensive assessment for a particular type of wood residue or waste. In some cases it is obvious which assessment’s methodology is best or which assessment is the most complete, in other cases it is less so. For each type of wood residue or waste, the quantity estimated by the assessment judged to be the most complete, comprehensive, and/or current was used in the estimate of the national quantity.

Estimate National Generation Generation, as defined in this study, is the amount of wood waste produced by all generators prior to any reuse, recycling, disposal, or other diversion. Mathematically, generation should equal the sum of reuse, recycling, and discards. The estimate of national wood waste generation is the sum of that estimated for all individual types of secondary mill residues and urban wood waste. It is important to note that generation is not the amount potentially available for fuel or other uses. Generation includes that which is available for fuel as well as that not available due to reuse, higher value markets, contamination, commingling, and other factors.
Estimate Amounts Potentially Available For Fuel This is a tricky step because it involves assumptions, and different assumptions will lead to different results. For the purpose of this study, two assumptions were made. The first is to**Secondary Mill Residues & Urban Wood Waste Quantities in the U.S.** 

39 assume commingled and/or contaminated wood waste is not available for use as fuel. Commingling and/or contamination are issues with wood waste in construction and demolition (C&D) debris as well as wood waste in municipal solid waste (MSW). Contamination refers to the presence (or potential presence) of variable amounts of non-wood materials that negativelyimpact fuel quality, air emissions, and/or ash emissions. Contamination does not include sourceseparated treated wood waste, which is wood containing non-wood materials such as adhesives. For instance, residues from the manufacture of plywood (or other wood products containing adhesives) are considered available for fuel since they can be used as fuel in certain applications. The second is to assume wood residues or wastes currently used by "high-value" markets such as pulp, sawtimber, or engineered wood products manufacturing are not available for use as fuel. It is beyond the scope of this study to complete a analysis of the amount of commingled and/or contaminated wood is present in secondary mill residues or urban wood waste as well as how much of these residues or wastes are utilized by high-value markets. Instead, the research completed by others was relied on. Specifically:

• For secondary mill residues , the material is assumed to be source separated (and not commingled or contaminated) since it is generated in an industrial/manufacturing setting with relatively high potential for source separation. This assumption likely results in some overestimating the amount of residues potentially available since some secondary mills will generate residues that cannot be used as fuel, even if source-separated. However, this amount is judged to be relatively small. And when combined with the concern that the methodology used to estimate secondary mill residues tends to underestimate residue generation, this assumption should not lead to significant overestimation of available secondary mill residues. The amount of secondary mill residues used in high value markets is estimated based on estimates of “captive markets” presented in Lignocellulosic Feedstock Resource Assessment . Although not specifically defined, the term “captive markets” implies it is those markets that pay a high enough price for wood residues that there is little potential the residues they receive will be diverted to lower value markets such as fuel.

• For urban tree residues (UTRs) , the material is assumed not to be commingled or contaminated since it is comprised solely of tree and other woody biomass residues. As shown in Table 2-7, the results of the survey used in the study Urban Tree Residues: Results of the First National Inventoryindicated that 88% of the material is given away, sold or used as fuel, used in low-value markets (such as compost or mulch), or is disposed,. This indicates 88% the material is potentially available as fuel. This estimate is likely conservative (i.e. the actual percentage is higher), since at least some of the 12% assumed to not be available (due to being used in high value markets) is likely actually used by low value markets, and thus actually would be available.

• For C&D and MSW wood waste , the amount commingled, contaminated, and reused/recycled is based on research completed by David McKeever and presented in BioCycle Journal of Composting & Recyclingarticles as well as personal communications. For wood waste generated by construction and renovation of buildings, of the 8,700,000 tons/year generated, an estimated 2,100,000 tons/year, or 24% are either being recovered or**Secondary Mill Residues & Urban Wood Waste Quantities in the U.S.** 

40 are not usable. Of this amount, it is not possible to determine how much is not available due to commingling or contamination, or how much is recovered. Thus, a conservative (i.e. underestimates the amount potentially available for fuel) assumption was made that 76% (100%-24%=76%) is available for fuel. For demolition wood waste, David McKeever assumes an initial recovery rate of 30%, which is in part based on the performance of a recycling facility located in Massachusetts that accepts and processes demolition wood waste. For MSW wood, David McKeever estimates MSW wood waste generation at 11,800,000 tons/year. Of this amount, 2,700,000 tons/year, or about 23% are unacceptable for recovery because of contamination, commingling, or other reasons. This implies that about 77% (100%-23%=77%) are potentially available for recovery and use as fuel. The amount of a wood residue or waste generated less the amount commingled, contaminated, or used in high value markets is the amount potentially available for fuel. High value markets for wood residues or wastes, such as pulp, sawtimber, engineered wood products manufacturing often pay $23/green ton and upwards for wood delivered to the to the plant. The price paid by these markets can be highly variable depending on the economy, location, season, competing resources, transportation distances, and other factors. However, the results of many wood residue or waste assessments completed across the U.S. indicate $23/ton is representative of the overall price paid by high value markets.
Estimate The Amount Available At Greater Than $20/ton Delivered A simplifying assumption is made that the amount of wood residues and waste available at a price of $20/ton or greater is assumed to be the amount potentially available. This assumption is made based on the overall price high value markets pay for wood feedstocks as well as the methodology used to estimate the amount potentially available. Since the amount potentially available assumes quantities used by high value markets is not available, it is reasonable to assume that all other available quantities are available up to (and above) the price high value markets pay.
Estimate The Amount Available At $10 and $20/ton Delivered To estimate the quantity of wood residues and waste potentially available at or up to specified prices, the methodology developed by Antares Group, Inc. and presented in Urban Wood Waste Resource Assessmentwas adopted and modified slightly. As described in the previous section, this methodology involves determining the “delivered residue cost” (DRC), which is based on wood residue or waste collection and processing costs, transportation costs, and disposal (in landfills). The DRC is estimated as follows:**Secondary Mill Residues & Urban Wood Waste Quantities in the U.S.** 

41 DRC = RPC + RTC - 1⁄2(LFT) Where:
RPC = Average collection and processing cost, which vary for the 7 types of wood wastes. RTC = Transportation cost, which vary dependin g on one of four assumed transportation distances and state specific transportation cost index. LFT = Average cost to disposed solid waste in landfills (i.e. “tipping fee”), which vary depending on the state.
The methodology used in Urban Wood Waste Resource Assessment includes determining DRC based on assumed processing costs and state-specific data on the transportation cost index, state size, and average tipping fee. Within each state, the quantity of a wood residue or waste type generated (or available) is “allocated” to one of four transportation distances based on area. The transportation distances are 25 miles, 50 miles, 75 miles, and 100 miles, and the corresponding allocation is 6%, 19%, 31%, and 44% respectively. For this study, it is desirable to know what amounts or percent of wood residue or waste that is available at or up to a specified delivered price. To do this, the equation used to calculate DRC was used to estimate the national average DRC for each type of wood residue or waste for transportation distances of 25, 50, 75, and 100 miles. The calculated national average DRC was then graphed against the corresponding allocation expressed as a cumulative. This graph allows estimation of the percent of a mill residue or urban wood waste available at specified national average DRC. The allocation is expressed as a cumulative percent so the graph plots DRC (on the “y” axis) against 0% to100% of available wood residue or waste. A summary of the calculated DRC and graph of DRC versus cumulative percent available is presented in Appendix C. The residue collection and processing costs (RPC) estimated by Antares Group were used (the costs are presented in Table 2-8), as was a national freight cost of 24.11¢/mile. The RPC for secondary mill residues and used pallets were not specifically estimated in Urban Wood Waste Resource Assessment , but it is reasonable to assume these cost are also $12/ton, or the same as for construction wood waste, demolition wood waste, yard waste, and other wood waste. This is because these residues are similar in nature, and thus the collection and processing costs should also be similar. In addition, the “other wood waste” category identified and used in Urban Wood Waste Resource Assessment likely includes some secondary mill residues and used pallets, indicating it is reasonable to assume the collection and processing cost for the three types of wood wastes is the same. The average national landfill tipping fee was estimated based on information presented in the article “The State of Garbage in America: 11 thAnnual BioCycle Nationwide Survey” published in BioCycle Journal of Composting & Recyclingin April 1999. The BioCyclearticle contains information on solid waste generation, landfill tipping fee, and incineration tipping fee for each state. Based on the BioCycledata, the average weighted landfill and incinerator tipping fee for the U.S. was calculated to be $24.50/ton. The data used in and the results of the spreadsheet software used to calculate the average weighted tipping fee is presented in Appendix D.**Secondary Mill Residues & Urban Wood Waste Quantities in the U.S.** 

42 Analysis of the graph of calculated DRC versus percent of wood residue or waste was plotted indicates that about 22% of secondary mill residues and urban wood waste are available (including delivery) at a price of up to $10/green ton, and 62% or available at a price of up to $20/green ton. In addition, 100% or all secondary mill residues and urban wood waste would be available at a price of about 23.86/green ton. This amount is extremely close to the anticipated price paid by high value markets for wood residues and wastes.
Identify Types Of Wood Wastes Not Included Also important in developing a defendable estimate of national quantities is identifying what key or important types of wood residues or waste are not included. Since the focus of this study is on wood residues and waste that are potentially available for fuel (as well as other uses), the focus of this step is to identify key types of waste wood fuel that are not included. Based on the review of the seven assessments, four types of wood waste are not included or incomplete amounts are included in the seven assessments. These are:

• Used pallets
• Landclearing wood waste;
• Used wood railroad ties; and
• Used wood utility poles. Presented below is a brief description of the four types of wood waste as well as readily available information on quantities.

Used Pallets Used pallets typically contain only clean, untreated wood and metallic fasteners. A small portion of used pallets may be contaminated with paint or other surface coatings, non-wood materials (such as adhesives or preservatives), or materials that spilled on to the pallets. The majority, if not all metallic fasteners can be removed using magnetic or other separation technologies. In general, ground or chipped pallets consist of only clean, untreated wood and an excellent source of woodfuel. The types and amounts of used pallets contained in the various wood waste assessments is neither consistent or clear. For instance, the quantity of used pallet generation reported in Characterization of Municipal Solid Waste in the United States, 1997 Updatedoes not include pallets that are repaired or refurbished, since this is considered to be “reuse”, and waste materials that are reused are not included in estimates of MSW generation. Similarly, used pallets that are repaired, refurbished, or recycled are not included is estimates of MSW wood waste reported in The Changing Solid Waste Wood Resource in the United States, 1990- 1998 . Presented in Table 3-1 is a summary of used pallet generation, reuse/recycling, and**Secondary Mill Residues & Urban Wood Waste Quantities in the U.S.** 

43 disposal which is intended to provide a more clear picture of used pallet quantities as well as that potentially available for fuel. According to Characterization of Municipal Solid Waste in the United States, 1997 Update , nearly 200,000,000 pallets were repaired or refurbished in 1996 (but, as noted above, this quantity is not included in MSW quantities). Assuming pallets have an average weight of 55 pounds, this indicates that over 5,500,000 pallets were repaired or refurbished in 1996. The average pallet weight is adopted from pallet generation data from Robert Bush, Philip Araman, and Vijay Reddy. According to data compiled by Robert Bush et al, over 223,000,000 used pallets, or about 6,140,000 tons were taken to MSW or C&D landfills in 1996. Of this amount, 17%, or 1,044,000 tons were recovered, mostly for use in low value end uses or products. The remaining 5,096,000 million tons were disposed in either MSW or C&D landfills. The repair or refurbishing of used pallets is a high value use, and these pallets will not be available for fuel or other lower value uses. However, the 6,140,000 tons of used pallets taken to landfills can be assumed to be available. This is because this amount is either used by low value markets (that fuel markets could compete with), or is disposed. Contamination and commingling of used pallets with other wastes will likely limit the actual amount that is available. However, since used pallets tend to be clean, contamination is likely a minor issue. Commingling may have a bigger impact on availability than contamination. However, pallets to be taken to landfills are often already separated, or are easily separated at the generator, by haulers, at landfills, or at transfer stations. Thus it can be assumed that commingling is also a relatively minor issue. It is important to note that assuming contamination and commingling are minor issues (and all used pallets taken to landfills are available) will result in minor overestimation of the amount actually available.
TABLE 3-1: Estimates of Used Pallet Generation, Reuse/Recycling, and Disposal Reuse/Recycling
Pallet Management Generation (a) (tons/yr) High Value

Markets (b) (tons/yr) Low Value

Markets (c) (tons/yr) Disposal (b)

(tons/yr) Taken to Landfills 6,140,000 0 1,044,000 5,096,000 Repaired/Refurbished 5,500,000 5,500,000 0 0

TOTAL 11,640,000 5,500,000 1,044,000 5,096,000 (a): Generation includes usedpallets that have served their initial function and have been recovered for reuse, repair, or refurbishing. (b): Pallet repair and refurbishing is considered to be a high value market, and the amount of used pallets repaired or refurbished is assumed not to be available for fuel. (c): Used pallets recycled via low value markets and disposed are considered available for fuel.
Land clearing Wood Waste Wood waste generated by clearing land of trees and stumps prior to construction of buildings, other structures, or roads. Land clearing wood consists primarily, if not solely of clean,**Secondary Mill Residues & Urban Wood Waste Quantities in the U.S.** 

44 untreated wood. Since land clearing wood is similar to pulpwood and sawtimber harvested from the forest, it is sold to these markets when possible. Land clearing wood is also chipped for fuel, mulch, or other markets, or may be sold as cordwood. Because land clearing wood is generated as part of construction activities, it is often identified as a type of C&D debris or wood waste. In Urban Wood Waste Resource Assessment , land clearing wood is specifically identified as a component of C&D wood waste. However, incomplete information on the amount of land clearing wood generated was obtained, as the author notes, “It was not possible to obtain even rough estimates of the amounts of wood generated by construction contractors, demolition contractors, and land clearing companies.” Information was obtained on the amounts of C&D reused or recycled as well as disposed, but it is not possible to estimate how much is C&D wood and how much is land clearing wood. In Characterization of Building-Related Construction and Demolition Debris in the U.S. , land clearing debris is identified as a component of C&D debris, but is specifically not included in the types of C&D debris included in the assessment.

Used Railroad Ties Used railroad ties (ties) are generated by the repair, refurbishing, or removal of railroad tracks.Ties can be made of various materials such as concrete or plastic, but the majority is creosotetreated wood. Used creosote-treated wood ties have successfully been used as fuel in various applications, including wood-fired power plants and co-firing at coal-fired utility power plants. According to the Railway Tie Association (RTA), approximately 12,500,000 ties are used in Class 1 railroads, with an unknown amount used in Class II and other railroads. The majority of ties used in Class 1 railroads are due to track maintenance and upgrades, as opposed to new track construction. This indicates that a corresponding amount of ties are replaced annually. The average weight of a tie is about 250 pounds, and the overall weight of used creosote-treated ties generated annually is calculated to be 1,688,000 tons. Anecdotic information on tie generation for non-Class I railways suggest the quantities will likely greatly surpass that of Class I railways, but this information cannot be verified. Information on used tie collection, processing, and transportation is not available, and thus it is not possible to estimate the amounts available.
Used utility poles Used utility poles are generated by the repair or replacement of utility poles. Utility poles can be made of various materials such as steel or concrete, but the majority is treated wood. Wood utility poles are commonly treated with creosote, pentachlorophenol (penta), or chromated copper arsenate (CCA), or other preservatives. Similar to creosote-treated railway ties, creosote-treated utility poles have been successfully used as fuel in various applications. At least one large wood-fired power plant was permitted to burn up to 50% penta-treated wood. However, there are air emission issues surrounding penta , and it appears penta use as a preservative for utility poles may be declining. CCA-treated wood appears to have limited, if any use as woodfuel due to the presence of chromium, copper, and arsenic. One issue surrounding utility poles is “ground treatments” which are preservatives, insecticides, or other chemicals applied to the utility pole at or near the ground level. Ground treatments are used to increase the in-ground life of the pole. The issue is that ground treatments can contaminate poles**Secondary Mill Residues & Urban Wood Waste Quantities in the U.S.** 

45 that would otherwise be viable woodfuels. An example is the use of the preservative CCA as a ground treatment for creosote-treated poles. Information on used utility pole generation, collection, processing, transportation cost, recycling, and disposal is limited, if available at all, and it is not possible to estimate quantities.

RESULTS Presented in Table 3-2 are the results of the national estimate of secondary mill residues and urban wood waste quantities and prices. The amount generated is estimated to be over 136,000,000 tons/year. Generation refers to production of wood residues or wastes prior to any reuse, recycling, disposal, or other management except internal reuse or cycling. Of this amount, over 87,000,000 tons/yr, or 64% of that generated, is potentially available for fuel or other lower value uses. At a price of up to $10/ton, it is estimated that just under 20,000,000 tons/yr are available, and at a price of up to $20, an estimated 54,000,000 tons are available. It is important to note the overall generation and available quantities are minimums, the actual amount likely exceed that report. This is because reliable data on several types of wood waste (with potential to be used as woodfuel) is not currently available, and could not be included in the estimates The results include some interesting results, including

• At a delivered price of $0 - $10/ton, woodfuel is considered to be competitive with fossil fuels, in particular with coal. This analysis indicates that just under 20,000,000 tons/yr are available at a price of $10/ton.

• At about 45,000,000 tons/year, UTRs represents the largest single source of available wood waste. The amount of UTRs available exceeds the other types of wood waste by at least a factor of 4.

• Although demolition wood waste is generation in large quantities, issues surrounding commingling, contamination, and separation greatly affect its potential availability. The opposite is true of construction wood waste.

• Anecdotic information indicates that railroad ties and site clearing wood waste may represent additional large sources of potentially available wood. Research into the quantities and availability of these wood wastes should be conducted so a more complete picture of the wood waste availability is obtained.**Secondary Mill Residues & Urban Wood Waste Quantities in the U.S.** 

46 TABLE 3-2: National Wood Waste Quantities and Prices

WOOD WASTE TOTOL

GENERATION (Tons/year) AVAILABLE

@ up to $10/ton (Tons/year) AVAILABLE

@ up to $20/ton (Tons/year) AVAILABLE

@ above $20 (c) (Tons/year) Secondary mill 15,644,000 1,342,000 3,783,000 6,101,000 Construction 16,726,000 2,796,000 7,882,000 12,712,000 Demolition 26,400,000 1,742,000 4,910,000 7,920,000 MSW (a) 11,800,000 1,999,000 5,633,000 9,086,000 Yard trimmings 6,300,000 1,199,000 3,379,000 5,450,000 Urban tree residues 51,455,000 9,962,000 28,074,000 45,280,000 Used pallets (b) 6,544,000 230,000 647,000 1,044,000 Railroad ties 1,688,000 n/a n/a n/a Land clearing n/a n/a n/a n/a Used utility poles n/a n/a n/a n/a

TOTAL < 136,557,000 < 19,270,000 < 54,308,000 <87,593,000 (a): Includes used pallets that are disposed in landfills. (b): Includes used pallets that are repaired, refurbished, or recycled. Used pallets are disposed in landfills are included as MSW wood waste. (c): The methodology used to estimate quantities and prices equates wood waste available at $20 and above with that that potentially available for fuel. Wood waste potentially available as fuel is defined as the quantity generated less that used by high value markets and that which is commingled, unseparatable, or contaminated. n/a: Data not available.**Secondary Mill Residues & Urban Wood Waste Quantities in the U.S.** 

A- 1 

## Appendix A - BIBLIOGRAPHY Antares Group Inc. Biomass Residue Supply Curves for the United States (Update)

. Prepared for the U.S. Dept. of Energy’s Biomass Power Program and the National Renewable Energy Laboratory. Washington, D.C. and Golden, CO. June 16, 1999. Appel Consultants, Inc. Urban Wood Waste Resource Assessment . Prepared for the National Renewable Energy Laboratory. Golden, CO. NREL/SR-580-25918. November 1998. Araman, Philip, Project Leader. USDA Forest Service, Southern Research Station. Blacksburg, VA. Personal Communication. August 10, 1999. Araman, Philip A., Robert J. Bush, E. Bradley Hager, and A.L. Hammett. “Landfill Potential Source of Cores”. Published in Pallet Enterprise . Richmond, VA. February 1999. Bush, Robert J., Philip A. Araman, and Vijay S. Reddy. “Construction and Demolition Landfills and Wood Pallets - What’s Happening in the United States”. Published in Pallet Enterprise

. Richmond, VA. March 1997. Chapman, Mary, Forster - Economic Action. USDA Forest Service, State and Private Forestry, Northeastern Area. Durham, NH. Personal Communication. August 13, 1999. Comer, Kevin. Antares Group Inc. Landover, MD. Personal Communications. July, August, and September 1999. C.T. Donovan Associates, Inc. Recycling Construction and Demolition Waste in Rhode Island . Prepared for the Rhode Island Governor’s Office of Housing, Energy, and Intergovernmental Relations. Providence, RI. December 1992. C.T. Donovan Associates, Inc. Recycling Construction and Demolition Waste in Vermont

. Prepared for the Vermont Agency of Natural Resources, Recycling and Resource Conservation Section. Waterbury, Vermont. December 1990. Gauntt, James, Executive Director. Railway Tie Association. Fayetteville, GA. Personal Communications. December 10 and 20, 1999. Glen, Jim, Senior Editor. BioCycle Journal of Composting & Recycling . Emmaus, PA. Personal Communication. October 10, 1999. Glenn, Jim. “The State of Garbage in America: 11 thAnnual BioCycle Nationwide Survey”. Published in BioCycle Journal of Composting & Recycling . Emmaus, PA. April 1998. Lee, Eugene. U.S. Environmental Protection Agency, Office of Solid Waste. Washington, D.C. Personal Communication. August 6, 1999.**Secondary Mill Residues & Urban Wood Waste Quantities in the U.S.** 

A- 2 McKeever, David, Research Forester. USDA Forest Service, Forest Products Laboratory. Madison, WI. Personal Communications. July, October, November, and December 1999. McKeever, David. “The Changing Solid Waste Wood Resource in the United States, 1990- 1998”. Prepared for publication in BioCycle Journal of Composting & Recycling

. Emmaus, PA. November 1999. McKeever, David. “Wood Residual Quantities in the United States”. Published in BioCycle Journal of Composting & Recycling . Emmaus, PA. January 1998. NEOS Corporation. Lignocellulosic Feedstock Resource Assessment . Prepared for the National Renewable Energy Laboratory. Golden, CO. NREL/TP-580-24189. September 1998 NEOS Corporation. Urban Tree Residues: Results of the First National Inventory

. Prepared for the International Society of Arboriculture Research Trust, Allegheny Power Service Corporation, and National Arborist Foundation. September 1994. Perhac, Ralph. University of Tennessee. Personal Communication. July 8, 1999. Rooney, Tim. McNeil Technologies, Inc. Golden, CO. Personal Communications. October and November 1999. U.S. Environmental Protection Agency. Characterization of Building-Related Construction and Demolition Debris in the United States . EPA530-R-98-010. Washington, D.C. June 1998. Prepared by Franklin Associates, Prairie Village, KS. U.S. Environmental Protection Agency. Characterization of Municipal Solid Waste in the United States . EPA530-R-98-007. Washington, D.C. May 1998. Prepared by Franklin Associates, Prairie Village, KS. Walsh, Marie, Ph.D., Agricultural Economist. Oak Ridge National Laboratory. Oak Ridge, TN. Personal Communication. September 10, 1999. Wiltsee, George. Appel Consultants, Inc. Valencia, CA. Personal Communication. September 13, 1999. Wiselogel, Art, Senior Scientist. National Renewable Energy Laboratory. Golden, CO. Personal Communication. September 10, 1999. Wright, Lynn, Deputy Program Manager, Bioenergy Feedstock Development Program. Oak Ridge National Laboratory. Oak Ridge, TN. Personal Communication. September 10, 1999. Wood, John. Franklin Associates. Prairie Village, KS. Personal Communication. December 14, 1999.**Secondary Mill Residues & Urban Wood Waste Quantities in the U.S.** 

B- 1 

## Appendix B - Matrix TableASSESSMENT NUMBER WOOD WASTE ASSESSMENT

Author, Date of Report WASTE INCLUDED (as identified by the assessment's author) WASTE INCLUDED (as further intrepreted by J.E. Fehrs, P.E.) ANNUAL WOOD WASTE GENERATION IDENTIFIED IN ASSESSMENT UNITS

Building-related construction and repair/renovation debris Debris from construction, remodeling, and repair of residential and non-residential buildings. Does not include debris from road & bridge construction or repair. Does not include landclearing debris.  Construction and renovation debris comprise 8% and 44% of C&D debris respectively.  Assessment 1 includes the results of 6 building-related C&D waste composition studies, which indicate wood waste comprises 14 to 65% of C&D debris.  C/D debris typically contains between 15 and 40% wood waste. 9,901,000 to 47,382,000 Green tons/yr

1 Characterization of BuildingRelated Construction and Demolition Debris in the U.S. Franklin Associates, Ltd , 1998 Building-related demolition debris Debris from demolition of residential and non-residential buildings. Does not include debris from road & bridge demolition.  Demolition debris comprise 48% of C&D debris respectively.  Assessment 1 includes the results of 6 building-related C&D waste composition studies, which indicate wood waste comprises 14 to 65% of C&D debris. 9,792,000 to 26,112,000 Green tons/yr

Wood in MSW Household wood waste. Commercial wood waste. Institutional wood waste. Recycled or landfilled p allets and shipping containers. Industrial wood waste.  Does not include reused pallets 10, 840,000 Green tons/yr

2 Characterization of Municipal Solid Waste in the U.S., 1997 Update Franklin Associates, Ltd, 1988 Yard trimmings Leaves, grass, and tree and brush trimmings  Residential, institutional, and commercial sources  Estimated to contain no more that 25% wood (as tree trimmings) <7,000,000 Green tons/yr

Secondary mills residues 12,515,000 Dry tons/yr

3 Lignocellulosic Feedstock Resource Assessment NEOS 1998 Urban tree residues (UTRs) Information on UTR is from Assessment 4. 37,953,000 Dry tons/yr

4 Urban Tree Residues: Results of the First National Inventory NEOS 1994 Urban tree residues (UTRs) or "Green" materials generated by urban forestry related businesses Solid wood residues generated by tree maintenance and landscaping activities on municipal and (residential, commercial, industrial, and institutional) private property. Believed to include storm-related UTR. Does not include non-wood UTRs such as grass and leaves. Does not include residues from landclearing activities. Does not include residues from orchards. 194,508,000 Cubic yards/yr

Wood waste in MSW Household wood waste. Commercial wood waste. Institutional wood waste. Yard waste. Municipal tree waste. Utility tree waste. 39,000,000 Green tons/yr

Industrial wood waste Pallets Industrial wood waste Primary mill residues Secondary mill residues 8,000,000 Green tons/yr

5 Urban Wood Waste Resoruce Assessment Appel Consultants, Inc., 1998 C/D wood waste Building-related C&D wood waste Bridge &road-related C&D wood waste Landclearing wood waste 17,000,000 Green tons/yr Construction wood waste  Same as Assessment 7 6,238,000 Green tons/yr Demolition wood waste  Wood waste from demolition of buildings. 7,864,000 Green tons/yr

Woody yard trimmings  Same as that for Assessment 2  Assumes 95% of yard trimmings is wood 10,123,000 Green tons/yr

6 Biomass Residue Sipply Curves for the U.S. (Update) Antares Group Inc., 1999 Other wood waste Similar to MSW wood waste. Pallets and shipping containers. Industrial wood waste.  Some, but likely not all secondary mill residues. 6,759,000 Green tons/yr

Wood in MSW  Same as that for Assessment 2.  Includes used pallets discarded in landfills.  Does not in include used pallets that are repaired, refurbished, or recycled. 11,800,000 Green tons/yr

Woody Yard Trimmings  Same as that for Assessment 2  Assumes 95% of yard trimmings is wood 25,200,000 Green tons/yr

Construction wood waste  New residential and non-residential building construction wood waste  Residential and non-residential building repair and remodeling wood waste  Does not included road & bridge construction wood waste  Does not include landclearing wood 8,700,000 Green tons/yr

7 The Changing Solid Waste Wood Resource in the U.S., 1990-1998 David McKeever, 1999 Demolition wood waste  Same as that for Assessment 1 26,400,000 Green tons/yr 8 Railroad ties  Used railroad ties 12,500,000 Ties

9 Other wood waste Used pallets  Repaired, refurbished, or recycled used pallets not inlcuded in MSW wood waste. 6,544,000 Green tons/yr

Page 1 of 5ASSESSMENT NUMBER WOOD WASTE ASSESSMENT

Author, Date of Report

1 Characterization of BuildingRelated Construction and Demolition Debris in the U.S. Franklin Associates, Ltd , 1998

2 Characterization of Municipal Solid Waste in the U.S., 1997 Update Franklin Associates, Ltd, 1988

3 Lignocellulosic Feedstock Resource Assessment NEOS 1998

4 Urban Tree Residues: Results of the First National Inventory NEOS 1994

5 Urban Wood Waste Resoruce Assessment Appel Consultants, Inc., 1998

6 Biomass Residue Sipply Curves for the U.S. (Update) Antares Group Inc., 1999

7 The Changing Solid Waste Wood Resource in the U.S., 1990-1998 David McKeever, 1999 8

9 Other wood waste Year IS OF WOOD WASTE INCLUDED IN OTHER ASSESSMENTS? AMOUNT TO INCLUDE IN ESTIMATE OF NATIONAL WOOD WASTE GENERATION (Green tons/yr)

1996 5,6,7 12,376,000

1996 5,6,7 0

1996 5,6,7 0

1996 3,4,5,6,7 0

1996 5 15,644,000

1996 2,4,5,6,7 0

1994 2,3,5,67 51,455,000

1997/1998 2,3,4,6,7 0

1997/1998 3,7 0

1997/1998 1,6,7 0 None 1,5,7 0 None 1,5,7 0

None 2,3,4,5,7 0

None 2,5,7 0

1998 2,3,4,5,6 11,800,000

1998 2,3,4,5,6 6,300,000

1998 1,5,6 4,350,000

1998 1,5,6 26,400,000 1999 1,688,000

1995 6,544,000 TOTAL = 136,557,000

Page 2 of 5ASSESSMENT NUMBER WOOD WASTE ASSESSMENT

Author, Date of Report

1 Characterization of BuildingRelated Construction and Demolition Debris in the U.S. Franklin Associates, Ltd , 1998

2 Characterization of Municipal Solid Waste in the U.S., 1997 Update Franklin Associates, Ltd, 1988

3 Lignocellulosic Feedstock Resource Assessment NEOS 1998

4 Urban Tree Residues: Results of the First National Inventory NEOS 1994

5 Urban Wood Waste Resoruce Assessment Appel Consultants, Inc., 1998

6 Biomass Residue Sipply Curves for the U.S. (Update) Antares Group Inc., 1999

7 The Changing Solid Waste Wood Resource in the U.S., 1990-1998 David McKeever, 1999 8

9 Other wood waste COMMENTS REGARDING GENERATION AMOUNT POTENTIALLY AVAILABLE OF$20 OR GREATER Used similar methodology as that used in Assessment 7 to estimate building-related construction and renovation debris, but differences in data intrepretation and use resulted in differences in wood waste estimates. Assessment 1 includes the results of 6 building-related C&D waste composition studies, which indicate wood waste comprises 14 to 65% of C&D debris. An overall wood waste composition of 35% is assumed. Assume building-related construction and renovation wood waste generation is the average of that estimated in Assessment 1 and 7 (include 1/2 of generation estimated in Assessment 1). 9,406,000

Use demolition wood waste estimates from Assessment 7 due to being adjusted to reflect 1998 quantities.

Believed to be the most comprehensive data on wood waste in MSW. Use estimates of MSW wood waste in Assessment 7 due to being adjusted to 1998. According to Assessment 2, contains at most 25% wood waste. It is likely that some UTRs generated by "urban forestry related" businesses estimated in Assessment 4 are also included in yard trimming possible leading to double counting.

Believed to be the most comprehensive, if not the only national data on secondary mill residues Likely underestimates secondary mill residue quantities Assumes secondary mill residues have a moisture content of 20% 6,101,000 This estimate is based on UTR data from Assessment 4. Uses slightly different assumptions for calculating green tons available compared to that done for Assessment 4.
Use estimates of UTR from 4.
Converted to green tons/yr based on densities presented in Assessment 3 Very complete estimate of UTRs Uses a similar methodology to estimate national availability of UTRs as Assessment 3, but different assumptions have lead to differences in estimates of the quantity potentially available 45,280,000

Estimate is for urban areas of U.S., and does not include wood waste from rural areas Residential, commercial, and institutional wood waste are included in Assessment 2 Yard waste is included in Assessment 2, but is assumed to not include wood Municipal and utility tree waste are included in Assessment 4. Pallets and shipping containers are included in Assessment 2. Primary mill residues are not part of this study. Secondary mill residues are included in Assessment 3. It is likely minimal quantities of other industrial wood wastes are included as industrial wood waste. Estimate is for urban areas of U.S., and does not include C/D wood waste from rural areas The quantity of C&D wood waste generated is incomplete. Construction and renovation wood waste is included in Assessments 1 & 7.
Demolition wood waste is included in Assessment 7. Construction and renovation wood waste is included in Assessment 1 & 7. Demolition wood waste is included in Assessment 7 The amount of yard trimmings assumed to be woody (95%) is judged to be too high. Likely contains some yard waste generated by "urban forestry related" businesses, which is estimated in Assessment 4. Woody yard trimmings are included in yard waste in Assessment 7.

 MSW wood waste is included in Assessment 7.  Industrial wood waste is included in Assessment 5.  May be small amount of double counting secondary wood waste with Assessment 3.

Adjusts Franklin Associates MSW wood waste data to 1998 9,086,000 Adjusts Franklin Associates yard trimmings data to 1998 The amount of yard waste that is wood assumed in Assessment 7 (95%) is judged to be too high. Likely contains some yard waste generated by "urban forestry related" businesses estimated in Assessment 4. Assume yard waste consists of 25% non-UTR wood waste. 5,450,000 Used similar methodology as that used in Assessment 1, but differences in data intrepretation and use resulted in differences in wood waste estimates. Assume building-related construction and renovation wood waste generation is the average of that estimated in Assessment 1 and 7 (include 1/2 of generation estimated in Assessment 7). 3,306,000

Used estimates of demolition debris from Assessment 2 and adjustes data to 1998 7,920,000 Ties weight approximately 250 pounds/ea. Includes only used pallets that are repaired, refurbished, or recycled. Pallets that are disposed are included in MSW wood waste. 1044000 TOTAL = 87,593,000

Page 3 of 5ASSESSMENT NUMBER WOOD WASTE ASSESSMENT

Author, Date of Report

1 Characterization of BuildingRelated Construction and Demolition Debris in the U.S. Franklin Associates, Ltd , 1998

2 Characterization of Municipal Solid Waste in the U.S., 1997 Update Franklin Associates, Ltd, 1988

3 Lignocellulosic Feedstock Resource Assessment NEOS 1998

4 Urban Tree Residues: Results of the First National Inventory NEOS 1994

5 Urban Wood Waste Resoruce Assessment Appel Consultants, Inc., 1998

6 Biomass Residue Sipply Curves for the U.S. (Update) Antares Group Inc., 1999

7 The Changing Solid Waste Wood Resource in the U.S., 1990-1998 David McKeever, 1999 8

9 Other wood waste COMMENTS REGARDING WOOD WASTE POTENTIAL AVAILABLILITY AT $20/Green Ton or Greater AMOUNT POTENTIALLY AVAILABLE AT $0 - $10/Green Ton COMMENTS REGARDING WOOD WASTE POTENTIALLY AVAILABLE AT $0-10/ Green Ton

Based on data provided in Assessment 7, about 24% of construction and renovation wood waste is either currently reused/recycled or is not usable (due to contamination, commingling, etc.) The amount reused /recycled only is not known. Assume 76% (100% - 24% = 76%) is available. 2,069,000 Using a similar methodology to that developed in Assessment 6, an estimated 22% of construction wood waste potentially available is projected to be available at a delivered price of up to $10.

Based on data presented in Assessment 3, 39% of secondary mill residues are used by "noncaptive" (ie. low-value) markets or are unused and recoverable. The remaining 61% are used by high value markets and are assumed not to be available due to their market value. 1,342,000 Using a similar methodology to that developed in Assessment 6, an estimated 22% of secondary mill residues potentially available are projected to be available at a delivered price of up to $10.

Based on survey results presented in Assessment 4, 88% of URTs generated are used in low value markets, disposed, or stockpiles. The amount potentially available is assumed to be 88%. 9,962,000 Using a similar methodology to that developed in Assessment 6, an estimated 22% of UTRs are potentially available are projected to be available at a delivered price of up to $10.

About 23% of MSW wood is unacceptable for recovery (Assessment 7, 1998 data). Based on data presented in Assessment 2, 4.5% of MSW wood waste was recycled in 1996. It is likely most, if not all markets for MSW wood waste are low-value markets such as mulch, compost amendment, or fuel. The amount assumed to be available is that acceptable for recovery (100%-23%=77%). The amount recycled is also assumed to be available. 1,999,000 Using a similar methodology to that developed in Assessment 6, an estimated 22% of MSW wood waste potentially available is projected to be available at a delivered price of up to $10.

According to Assessment 7, about 3.4 million tons, or 13.5% of yard waste generated in 1998 was "disposed as unusable". The remainder was recycled, composted, or burned. It is likely no or minimal amounts were used in high value markets such as pulp and sawtimber. The amount assumed to be available is 86.5% (100% - 13.5% = 86.5%). 1,199,000 Using a similar methodology to that developed in Assessment 6, an estimated 22% of woody yard waste potentially available is projected to be available at a delivered price of up to $10.

Based on data provided in Assessment 7, about 24% of construction and renovation wood waste is either currently reused/recycled or is not usable (due to contamination, commingling, etc.) The amount reused /recycled only is not known. Assume 76% (100% - 24% = 76%) is available. 727,000 Using a similar methodology to that developed in Assessment 6, an estimated 22% of construction wood waste potentially available is projected to be available at a delivered price of up to $10.

Based on data provided in Assessment 7, about 30% of demolition wood is considered recoverable. 1,742,000 Using a similar methodology to that developed in Assessment 6, an estimated 22% of demolition wood waste potentially available is projected to be available at a delivered price of up to $10.

An estimated 1,044,000 tons of used pallets are recycled as feedstock in low value markets, and are considered available. 230,000 Using a similar methodology to that developed in Assessment 6, an estimated 22% of used pallets potentially available is projected to be available at a delivered price of up to $10. TOTAL = 19,270,000

Page 4 of 5ASSESSMENT NUMBER WOOD WASTE ASSESSMENT

Author, Date of Report

1 Characterization of BuildingRelated Construction and Demolition Debris in the U.S. Franklin Associates, Ltd , 1998

2 Characterization of Municipal Solid Waste in the U.S., 1997 Update Franklin Associates, Ltd, 1988

3 Lignocellulosic Feedstock Resource Assessment NEOS 1998

4 Urban Tree Residues: Results of the First National Inventory NEOS 1994

5 Urban Wood Waste Resoruce Assessment Appel Consultants, Inc., 1998

6 Biomass Residue Sipply Curves for the U.S. (Update) Antares Group Inc., 1999

7 The Changing Solid Waste Wood Resource in the U.S., 1990-1998 David McKeever, 1999 8

9 Other wood waste AMOUNT POTENTIALLY AVAILABLE AT $10 = $20/Green Ton COMMENTS REGARDING WOOD WASTE POTENTIALLY AVAILABLE AT $10 - $20/Green Ton

5,832,000 Using a similar methodology to that developed in

Assessment 6, an estimated 62% of construction wood waste potentially available is projected to be available at a delivered price of up to $20.

3,783,000 Using a similar methodology to that developed in

Assessment 6, an estimated 62% of secondary mill residues potentially available are projected to be available at a delivered price of up to $10.

28,074,000 Using a similar methodology to that developed in

Assessment 6, an estimated 62% of UTRs are potentially available are projected to be available at a delivered price of up to $10.

5,633,000 Using a similar methodology to that developed in

Assessment 6, an estimated 62% of MSW wood waste potentially available is projected to be available at a delivered price of up to $20.

3,379,000 Using a similar methodology to that developed in

Assessment 6, an estimated 62% of woody yard waste potentially available is projected to be available at a delivered price of up to $20.

2,050,000 Using a similar methodology to that developed in

Assessment 6, an estimated 62% of construction wood waste potentially available is projected to be available at a delivered price of up to $20.

4,910,000 Using a similar methodology to that developed in

Assessment 6, an estimated 62% of demolition wood waste potentially available is projected to be available at a delivered price of up to $20.

647,000 Using a similar methodology to that developed in Assessment 6, an estimated 62% of used pallets potentially available is projected to be available at a delivered price of up to $20. TOTAL = 54,308,000

Page 5 of 5**Secondary Mill Residues & Urban Wood Waste Quantities in the U.S.** 

C- 1 

## Appendix C - Calculated Delivered Residue Cost **And Graph of DRC Versus Cumulative Percent Available**Page 1 of 1



## Graph of DRC Versus Cumulative Percent of Wood Waste Available

y = -0.002x 2+ 0.4237x + 1.5786

R 2= 0.9768

$0 $10 $20 $30

0 20 40 60 80 100 Cumulative Percent (of available wood waste)DRC ($/green ton)**Secondary Mill Residues & Urban Wood Waste Quantities in the U.S.** 

C- 2**Secondary Mill Residues & Urban Wood Waste Quantities in the U.S.** 

C- 3 Calculated Delivered Residue Cost and Cumulative Percent of Wood Waste Available (a)

Percent Available Transportation Distance (miles) Processing

Cost (b) ($/ton) Transportation

Cost (c) ($/ton) Incentive (d)

($/ton) Delivered Residual

Cost (e) ($/ton) (Percent) (Cumulative Percent) 25 12 6.03 (12.25) 5.78 6 6 50 12 12.06 (12.25) 11.81 19 25 75 12 18.08 (12.25) 17.83 31 56 100 12 24.11 (12.25) 23.86 44 100 (a): Based on the equation developed by Antares Group Inc. (b): Wood waste processing costs developed by Antares Group Inc. are assumed to apply to secondary mill residues and urban wood wastes. (c): Based on a transportation cost of 24.11¢/mile. (d): Assumed to be 1⁄2 of the national weighted averagelandfill and incinerator tipping fee. (e): The DRC is the sum of the processing, transportation, and incentive.**Secondary Mill Residues & Urban Wood Waste Quantities in the U.S.** 

D- 1 

## Appendix D - Calculation of Weighted Average Landfill and **Incinerator Tipping Fee**Calculation of Weighted Average Landfill and Incinerator Tipping Fee for the U.S.

State SW Generation Percent Landfilled Amount

Landfilled Percent

Incinerated Amount

Incinerated Avg. Landfill

Tipping Fee Average

Incinerator Tipping Fee (Amt Landfilled) x

(Avg Landfill Tipping Fee) (Amt. Incinerated) x

(Avg. Incinerator Tipping Fee) (Tons/Yr) (%) (Tons/Yr) (%) (Tons/Yr) ($) ($) (Tons/Yr)*($) (Tons/Yr)*($)
Alabama 5630000 72 4053600 5 281500 33 40 133768800 11260000 Arizona 5142000 83 4267860 0 0 22 93892920 0 Arkansas 3316000 67 2221720 0 0 27 59986440 0 California 56000000 67 37520000 0 0 39 34 1463280000 0 Colorado 5085000 82 4169700 0 0 33 137600100 0 Connecticut 3047000 12 365640 64 1950080 64 64 23400960 124805120 Delaware 825000 48 396000 30 247500 58.5 58.5 23166000 14478750 DC 0 0 0 92 0 0 0 Florida 23770000 45 10696500 16 3803200 43 55 459949500 209176000 Georgia 10745000 66 7091700 0 0 28 198567600 0 Idaho 0 0 21 0 0 Illinois 13300000 71 9443000 0 0 28 264404000 0 Indiana 5876000 67 3936920 10 587600 30 27.5 118107600 16159000 Iowa 2518000 66 1661880 0 0 30.5 50687340 0 Kansas 2380000 87 2070600 0 0 23 47623800 0 Kentucky 6320000 68 4297600 0 0 25 107440000 0 Louisiana 4100000 81 3321000 0 0 23 76383000 0 Maine 1635000 18 294300 20 327000 47 47 13832100 15369000 Maryland 5700000 47 2679000 25 1425000 48 51 128592000 72675000 Massachusetts 0 21 0 45 0 0 0 Michigan 0 70 0 5 0 0 0 Minnesota 5010000 27 1352700 28 1402800 50 50 67635000 70140000 Mississippi 3070000 81 2486700 5 153500 18 18 44760600 2763000 Missouri 7950000 70 5565000 0 0 27 150255000 0 Montana 1001000 93 930930 2 20020 32 65 29789760 1301300 Nebraska 2000000 71 1420000 0 0 25 35500000 0 Nevada 2,800,000 86 2408000 0 0 23 55384000 0 New Hampshire 880000 54 475200 20 176000 55 55 26136000 9680000 New Jersey 7,800,000 37 2886000 20 1560000 60 51 173160000 79560000 New Mexico 2640000 90 2376000 0 0 23 54648000 0 New York 0 46 0 11 0 0 0 North Carolina 12575000 67 8425250 0 0 31 261182750 0 North Dakota 501,000 74 370740 0 0 25 9268500 0 Ohio 12335000 83 10238050 0 0 30 307141500 0 Oklahoma 2,545,000 78 1985100 10 254500 18 18 35731800 4581000 Oregon 4100000 59 2419000 11 451000 25 67 60475000 30217000 Pennsylvania 9,200,000 52 4784000 22 2024000 49 69 234416000 139656000 Rhode Island 420000 73 306600 0 0 35 10731000 0 South Carolina 10,010,000 56 5605600 2 200200 29 29 162562400 5805800 South Dakota 510000 58 295800 0 0 32 9465600 0 Tennessee 9,513,000 55 5232150 10 951300 35 43 183125250 40905900 Texas 0 65 0 1 0 0 0 Utah 0 75 0 3 0 0 0 Vermont 550000 63 346500 7 38500 65 65 22522500 2502500 Virginia 10,000,000 42 4200000 18 1800000 35 35 147000000 63000000 Washington 0 59 0 8 0 0 0 West Virginia 2,000,000 80 1600000 0 0 48 76800000 0 Wisconsin 5600000 61 3416000 3 168000 30 45.5 102480000 7644000 Wyoming 530,000 95 503500 0 0 10 5035000 0 TOTALS 268929000 5665887820 921679370

Weighted Average = [(Amt. Landfilled)x(Avg. Lanfill Tipping Fee) + (Amt. Incinterated)x(Avg. Incinerator Tippping Fee)]/(SW Generation) Weighted Average = $ 24.4955627
Notes: Bold numbers were adjusted from that presented in the BioCycle article to allow calculation of weighted average tipping fee Blank spaces indicate that the corresponding data was not presented in the BioCycle article

Page 1 of 1**Secondary Mill Residues & Urban Wood Waste Quantities in the U.S.** 

D- 2