Improving Woody Biomass Feedstock Logistics by Reducing Ash and Moisture Content

Transcription

1 Improving Woody Biomass Feedstock Logistics by Reducing Ash and Moisture Content A Final Report Submitted to The Southeastern Sun Grant Center Submitted by Dr. W. Dale Greene Warnell School of Forestry & Natural Resources University of Georgia 180 East Green Street Athens, GA Project Period: May 1, 2010 October 31, 2013 Report Submitted: January 18, 2013 This project was funded by a grant from the Southeastern Sun Grant Center with funds provided by the United States Department of Transportation, Research and Innovative Technology Administration.

2 ABSTRACT We examined two practical methods for reducing moisture content and/or ash content in biomass from southern pine harvests. Logging residues are a potential bioenergy feedstock, but contaminants can increase ash content during collection. We found that trommel screens can reduce ash levels in grindings from southern pine roundwood and clean chipped logging residues from 4.0% to 1.4% and 11.9% to 6%, respectively. Green whole-tree chips are a widely used form of forest biomass but are 50% moisture. Felling and transpirationally drying in-field before chipping reduced moisture from 53% to 43% and 39% in 4 and 8 weeks, respectively, without changing ash content (<0.7%). Finally, we used data from the screening and drying studies in a simulation study to estimate costs per million BTU for conventional roundwood, clean chipping, whole-tree chipping, and screened and unscreened grinders processing logging and clean chip residue. Whole tree chipping provided the lowest cost option ($4.39 per mmbtu) at ash content levels less than 1%, and unscreened grinding of clean chip residue produced the least expensive option at 5% ash ($2.87 per mmbtu). Clean chipping and roundwood systems were considerably more expensive than whole-tree chipping operations on all tract sizes.

3 CONTENTS Page Abstract Executive Summary Basic Information Final (Actual) Budget Discussion Information 1. Project Summary 2. How Will Results of this Research be Used? 3. Outcomes/Products (Current and Anticipated) 4. Accomplishments and Successes 5. Project Outcomes and Impacts 6. Citations 7. Licenses/Inventions 8. Students Funded 9. Collaborators/Partners 10. Educational Programs Conducted 11. Related Contracts and Grants 12. Other Information Acknowledgments

4 FIGURES Figure 1. Delivered costs of biomass ($/mmbtu) for five common harvesting systems as moisture content increases. TABLES Table 1. Chip size distribution, bark, foliage, ash, nutrient, and energy content of whole-tree chips fresh and transpirationally dried in the field for four and eight weeks. Table 2. Moisture, ash, nutrient, and energy contents of a screened residue grinding operation processing roundwood and clean chipped debris. Table 3. Truck payloads, chipper productivity, chipper utilization, and chipper fuel consumption of a whole-tree chipping operation processing fresh, four and eight week dried material. Table 4. Average trailer payload, productivity per productive machine hour, and load times for four harvest treatment systems at two residue age classes. Table 5. Delivered cost estimates ($/mmbtu) by levels of ash content. Table 6. Ranking (lowest=1) of delivered cost estimates ($/field ton and $/mmbtu) for biomass harvesting systems under likely conditions.

5 EXECUTIVE SUMMARY We examined two practical methods for reducing moisture content and/or ash content in biomass from southern pine harvests. Logging residues are a potential bioenergy feedstock, but contaminants can increase ash content during collection. We studied the use of trommel screens to reduce ash levels in southern pine residue grindings. After screening, average ash levels of grindings from roundwood and clean chipped residues were reduced from 4.0% to 1.4% and 11.9% to 6%, respectively. Whole-tree chips are a widely used form of forest biomass but are 50% moisture if green trees are chipped. Felling trees and allowing transpirational drying in the field before chipping reduced moisture from 53% to 43% and 39% in 4 and 8 weeks, respectively. Drying did not significantly change the ash content (<0.7%). Truck payloads were 16-24% lower for chips from dried trees and this increased thus increased hauling costs by $ per ton (field condition) for each subsequent 4-week drying period. Finally, we used data from the screening and drying studies in a simulation study to estimate costs per million BTU for conventional roundwood, clean chipping, whole-tree chipping, and screened and unscreened grinders processing logging and clean chip residue. Delivered costs for these systems were evaluated for a range of values for moisture content, ash content, tract size, tons of biomass removed per acre and at grinding decks, truck payload, haul distance, and diesel fuel price. Delivered cost per mmbtu decreased by over 50% for all systems as moisture content decreased from 55% to 30%. Whole tree chipping provided the lowest cost option ($4.39 per mmbtu) at ash content levels less than 1%, and unscreened grinding of clean chip residue produced the least expensive option at 5% ash ($2.87 per mmbtu). Tract size had minimal effects on any operation until the acreage declined below 40 acres. Clean chipping and roundwood systems were considerably more expensive than whole-tree chipping operations on all tract sizes. Costs declined significantly as truck payload increased and/or haul distance decreased. Optimizing truck payload to attain legal weight limits by lowering tare weight and/or increasing trailer volume capacity is an opportunity for forest biomass harvesting system managers to achieve lower costs especially when dealing with drier material or low-density screened roundwood grindings. Fuel price increases directly increase cut and haul costs and limit economical haul distances accordingly.

6 BASIC INFORMATION Date of Final Report: January 18, 2013 Project Title: Improving Woody Biomass Feedstock Logistics by Reducing Ash and Moisture Content Principal Investigator: W. Dale Greene, Professor, Warnell School of Forestry & Natural Resources, University of Georgia, Athens, GA All Co-Principal/Other Investigators: Shawn Baker, Research Professional II, Warnell School of Forestry & Natural Resources, University of Georgia, Athens, GA Jason Cutshall, Graduate Research Assistant, Warnell School of Forestry & Natural Resources, University of Georgia, Athens, GA Dana Mitchell, Research Engineer, Southern Research Station, USDA Forest Service, Auburn, AL Collaborators: Plum Creek Timber Company, Athens, GA Collum Lumber, Allendale, SC Graphic Packaging, Macon, GA Shepherd Brothers Timber, Irwinton, GA Project Start Date: May 1, 2010 Project End Date: October 31, 2012

7 FINAL (ACTUAL) BUDGET 1. Actual Dollars Spent: BUDGET ITEM SUN GRANT $ COST SHARE $ a. Total Salaries & Wages $127, $26, b. Fringe Benefits $17, $7, c. Supplies $16, d. Equipment e. Travel $14, f. Publications g. Other (Subcontractors, Consultants) Total DIRECT COSTS (Sum of A-G) $175, $33, Total INDIRECT (i.e. F&A) COSTS $35, $8, (26%) (IDC Usually = Total Direct Costs*.25) h. Graduate Student Tuition i. Permanent Equipment ($5,000 or More) j. Other Costs Not Requiring Indirect $10, (6% waived IDC) Total DOLLARS SPENT (Total Direct + Total Indirect + H + I + J) $210, $52, Describe all Cost Share: a) Sources State of Georgia funds b) Amount from Each Source $52, c) Type from Each Source (ex: in-kind, cash) cash Discussion Information 1. Project Summary We examined two practical methods for reducing moisture content and/or ash content in biomass from southern pine harvests. Logging residues are a potential bioenergy feedstock, but contaminants can increase ash content during collection. We studied the use of trommel screens to reduce ash levels in southern pine residue grindings. After screening, average ash levels of grindings from roundwood and clean chipped residues were reduced from 4.0% to 1.4% and 11.9% to 6%, respectively. Whole-tree chips are a widely used form of forest biomass but are 50% moisture if green trees are chipped. Felling trees and allowing transpirational drying in the field before

8 chipping reduced moisture from 53% to 43% and 39% in 4 and 8 weeks, respectively. Drying did not significantly change the ash content (<0.7%). Truck payloads were 16-24% lower for chips from dried trees and this increased thus increased hauling costs by $ per ton (field condition) for each subsequent 4-week drying period. Finally, we used data from the screening and drying studies in a simulation study to estimate costs per million BTU for conventional roundwood, clean chipping, whole-tree chipping, and screened and unscreened grinders processing logging and clean chip residue. Whole tree chipping provided the lowest cost option ($4.39 per mmbtu) at ash content levels less than 1%, and unscreened grinding of clean chip residue produced the least expensive option at 5% ash ($2.87 per mmbtu). Clean chipping and roundwood systems were considerably more expensive than whole-tree chipping operations on all tract sizes. 2. How will the Results of this Research be Used? Users of woody biomass feedstocks at bioenergy facilities can use these findings to improve their purchasing decisions and control the ash and moisture content of their raw materials. Tolerance of bioenergy systems to moisture and ash vary depending on the technology used. Where ash content should be kept very low (<2%), use of residues even with trommel screening does not appear to be a valid option. Where higher ash levels can be tolerated, clean chipping residues that are ground then screened or roundwood residues that are ground without screening also appear acceptable. Allowing felled stems to dry through transpiration appears to hold promise to reduce moisture content of whole tree chips, but deployment of such a system requires more logistical planning and coordination. This is due to the separation of felling and the remainder of the logging system and the need to use larger volume trailers to compensate for the lower density of the chips from dried stems. Allowing stems to dry in-field before chipping did not increase ash content. Decision makers should use the correct unit of measure green tons, oven-dry tons, or energy content (mmbtu). For facilities that combust wood directly, energy content (or dry tons) is more logical and systems that deliver at the lowest cost on this basis may appear more expensive when assessed on a green ton basis due to truck payload issues.

9 3. Outcomes/Products (Current and Anticipated) The project developed an effective, easy to implement procedure to incorporate field-drying into a typical tree-length harvesting operation. Prior to this study, most of the trials incorporating transpirational drying were controlled experiments occurring external to operational timber harvests. Our study provided a blueprint for implementing transpirational drying into harvesting activities and clearly demonstrated the potential for reducing moisture contact in as few as four weeks. While other studies have found the potential for greater moisture loss, many of these did not occur during a large-scale harvesting operation. Transpirational drying in late summer for periods of at least four weeks resulted in significant reductions in moisture content with no increase in ash content of the feedstock produced. The first four weeks of drying resulted in the greatest reduction in moisture content (from 53% to 43%) with the additional four weeks producing a smaller, but still significant reduction to 39%. The addition of a trommel screen to a residue collection system can significantly reduce ash content in harvesting residues processed through a grinder. Average ash contents were reduced for both roundwood and clean chipping residues after screening. Roundwood residues consistently demonstrated lower ash levels than clean chipped residue regardless of screening activity. However, the ultimate concern for loggers and landowners is the marketability of the final product. Despite the improvements that were shown, ash levels may remain too high for some purchasers - even after screening, clean chipped residue contained 6% ash on average. Operationally, equipment utilization was low never exceeding 60% for the grinder and only once for the loader. As with many forest operations, trucking delays were often a substantial component. Increasing the number of trucks to match the production of the grinder would have increased the overall utilization and lowered costs, but biomass demand would not support additional deliveries. Improved mill turnaround and expanded market demand could improve productivity. Delivered costs associated with harvesting forest biomass for energy production were shown to increase as moisture and ash content increased. A whole-tree chipping operation was a very suitable harvesting system if wood energy facilities require biomass material to meet an ash content specification of less than 2%. The only grinding system capable of producing material with less than 2% ash was one grinding roundwood logging residue using a screen, but its delivered cost was almost $1.00 per mmbtu higher than that for a whole-tree chipping system due to severely limited truck payloads. The least costly ($2.87 per mmbtu) option where 5% ash content was acceptable was a system grinding clean chipped residue without screening. Costs for roundwood and chipping systems sharply declined as the amount of biomass available on site increased. Truck payload and haul distance had considerable effects on delivered costs. Costs were reduced as truck payload increased and haul distance decreased. Optimizing truck payload to meet legal weight limits by lowering tare weight and increasing trailer volume capacity is an opportunity for forest biomass harvesting system managers to achieve lower costs especially when dealing with drier material or screened roundwood

10 grindings. Fuel price increases directly increase delivered costs and limit economical haul distances accordingly. In the U.S. South forest biomass in roundwood form, though wetter than dried chips or grindings, is typically more abundant, has an established harvesting and transportation infrastructure, and is perceived to be cheaper than processed biomass to cut and haul to the first delivery point. However, delivered pulpwood prices also include stumpage of approximately $8.00 per ton and forest residue prices generally include up to $2.00 per ton payable to forest landowners. There is also an additional cost to wood energy facilities to convert roundwood into chips. The combination of stumpage prices and additional processing costs for roundwood make in-woods chipping and grinding systems a more attractive option. 4. For Each Objective, Discuss Accomplishments and Successes (Include Modifications) Obj. 1) Quantifying the properties of chips and grindings produced from trees and/or residues that have dried up to 4 weeks in the field Physical characteristics such as moisture and ash content of wood and other cellulosic materials affect combustion performance and maintenance and disposal costs caused by slag deposits formed within some burning mechanisms. The biomass harvesting system employed, the type of woody biomass material, and the manner and duration of how woody biomass is stored and/or piled on-site are all factors that can affect moisture and ash content. This issue is of increased concern with logging residue, as it is frequently piled for extended periods and handled multiple times, increasing contamination. Consequently, direct combustion of some forms of biomass may be limited due to these issues. The wood pelletizing process is less forgiving of contaminants, as is the burning of woody biomass in stoker grate boilers where slag deposits are prone to form. In all phases of the project, samples of the feedstock material were captured and tested to determine properties of interest for use as in bioenergy processes. Moisture, ash, energy and nutrient content of all sampled materials were recorded (Table 1,2). Materials fed through a chipper were also tested to determine the size distribution and bark and foliage contents.

11 Table 1. Chip size distribution, bark, foliage, ash, nutrient, and energy content of whole-tree chips fresh and transpirationally dried in the field for four and eight weeks. Green 4 Weeks 8 Weeks Chip size distribution (%) <3mm 7-3mm 15-7mm 45-15mm >45mm 4.0 a 12.8 a 33.8 a 32.6 a 0.8 a 3.3 a 10.8 a 29.3 a 41.6 a 1.3 a 5.1 a 11.8 a 29.8 a 41.3 a 1.5 a Bark (%) 13.4 a 11.6 a 9.0 b Foliage (%) 2.8 a 2.0 a 1.6 a Ash content (%) 0.67 a 0.54 a 0.69 a Nutrient content C (%) N (ppm) S (ppm) K (ppm) P (ppm) Energy content BTU/o.d. lb. BTU/field lb. 48 a 1700 a 90 a 32 a 5.3 a 48 a 1300 a 80 a 24 a 11 a 48 a 1600 a 70 a 31 a 5.0 a 8203 a 8329 a 8161 a 3737 a 4947 b 4979 b a,b Entries within a row with a different letter are statistically different at the alpha = 0.05 level. Table 2. Moisture, ash, nutrient, and energy contents of a screened residue grinding operation processing roundwood and clean chipped debris. Roundwood Clean Chipped Unscreened Screened Fines Unscreend Screened Fines Moisture Content (%) 30.8a 28.1a 31.6a 40.2B 38.5BC 35C Ash Content (%) 4.0a 1.4a 14.7b 11.9A 6.0B 29.7C Nutrient Content C (%) 47.3a 48.5a 44.2b 45.1A 47.9B 37.3C N (ppm) 2034a 2180a 2968b 2944A 2796AB 3313AC S (ppm) 149a 157a 214b 191A 191A 226A K (ppm) 951a 1012a 1019a 990A 1042A 994A P (ppm) 231a 272a 308a 200A 215A 235A Energy Content BTU/o.d. lb 7710a 7880a 6987b 7338A 7714A 5978B Different letters within each row indicate significantly different values by debris type (p<0.05).

12 Obj. 2) Measuring the production rates of chippers (without screens) and grinders (with screens) processing this material Productivity studies on the chipper examined the impact of transpirational drying on chipping productivity. Drying time of the material had a significant impact on the productivity of the chipper as measured by field tons produced per productive hour (Table 3). Chipper productivity measured in terms of field tons was significantly lower with feedstock dried eight weeks than with either four-week-old or green material (p < 0.05). After converting the material produced to a dry ton basis the productivity from the green treatment was significantly lower (34 dry tons/pmh) than from either of the dried treatments (38 dry tons/pmh). This result should be viewed with caution, because a different loader operator fed the chipper for two of the five days during the green treatment chipping period. The less experienced replacement loader operator averaged 5 dry tons/pmh lower production than the normal operator (p < 0.05). Average loading time was 20 minutes for the eight and four week material but was 22 minutes for the green material. Table 3. Truck payloads, chipper productivity, chipper utilization, and chipper fuel consumption of a whole-tree chipping operation processing fresh, four and eight week dried material. Green 4 Weeks 8 Weeks Trailer load (lbs/cu.ft.) Field Oven dry Chipper productivity (tons/pmh) Field Oven dry a b c 8.56 a 8.85 a 8.80 a 73 a 67 a 63 b 34 a 38 b 38 b Chipper utilization (%) 31% a 33% a 39% b Chipper fuel consumption (gal/ton) Field Oven dry PMH = productive machine hour Utilization data showed that the chipper spent a significantly higher percentage of its time chipping when in the oldest and driest treatment (eight weeks) compared to either the four-week old or green material (p < 0.05). Most of the difference came from mechanical delays in the green and four-weeks-old treatment and handling by a less-experienced replacement operator during some of the green treatment. The mechanical delays were not attributed to the type of material being processed. Given the short timeframe of this study, it is uncertain that this result would be repeated over a longer time period.

13 The field weight of chips in pounds per cubic foot (lbs/cu.ft.) of trailer decreased significantly as drying time was extended from 4 to 8 weeks (p < 0.05). For example, the weight of a 40 foot trailer with a capacity of 2720 cubic feet would weigh 25.0 tons when loaded with green chips and 19.7 tons with material allowed to dry for 8 weeks. When examining the weight of materials in the trailer on a dry-ton basis, there was no significant difference in the dry pounds per cubic foot among treatments (8.56, 8.85, and 8.80 lbs/cu.ft.). Thus the volume of material in the trailer did not differ across the treatments, although the weight was lowered due to the reduced moisture content. Few trommel screens were found in operation at the time of the study, necessitating an adjustment in the study design. Two grinder/screen systems were evaluated in operation to determine the production rates. The modification allowed for direct production comparisons between a screened and unscreened system, a major focus of the study. In the end, we evaluated the system during the processing and loading of over 200 truckloads of material. Grinder production rates were largely a function of the harvest type and age of the residue processed (Table 4). The effect of residue type on overall production can be seen by comparing the screened, large grinder systems for each of the residue types (roundwood vs. clean chipped) at both age classes. Both ages of the clean chipped material averaged significantly greater payloads than the two roundwood treatments. This was likely an effect of the different physical piece sizes that were produced by the grinder for each treatment. The solid, roundwood pieces tended to produce larger, more loosely packed pieces than the smaller clean chipped residue which would load much more densely. Loads of roundwood residue were processed in this system at 47.2 and 46.1 minutes for four and eight week material, while the clean chipped material required only 17.8 and 16.9 minutes. The large grinder system with clean chipped residue produced at rate of 70.1 and 84.7 for the four and eight week material compared to the roundwood systems at 15.3 and Table 4. Average trailer payload, productivity per productive machine hour, and load times for four harvest treatment systems at two residue age classes. Harvest Treatment System Residue Age (Weeks) Truck Payload (Field Tons) Load Time (Minutes) Productivity (T/PMH) Screened, Clean Chipped, Large Grinder Screened, Roundwood, Large Grinder Screened, Clean Chipped, Small Grinder Unscreened, Roundwood, Large Grinder a 17.8a 70.1a b 16.9a 84.7b c 47.2b 15.3c d 46.1b 21.3d a 29.0c 44.6e a 28.4c 44.9e e 30.0c 35.9f a 31.0c 41.6ef

14 Both grinder sizes processing clean chipping residues produced comparable truck payloads, however the truck loading time of the different machine sizes varied significantly 17.8 and 16.9 minutes for the large grinder compared with 29.0 and 28.4 minutes with the small grinder. Again, this translated to improved hourly productivity for the large grinder system 70.1 and 84.7 field T/PMH, respectively, as opposed to 44.6 and 44.9 field T/PMH with the small grinder. Payloads for the unscreened roundwood processed by the larger grinder system were significantly larger than those for the screened roundwood system. This can be attributed to the additional weight of fine materials that remained in the material streams without screening. The addition of the screen also significantly increased the average load times. For these reasons, adding a screen to the system effectively halved the hourly productivity for both age classes - a result of smaller payloads combined with longer processing times. Obj. 3) Assessing the value added to biomass feedstocks when ash and moisture content are reduced in the field Data on production and the properties of chip and wood residue products were used to estimate costs per million BTU for forest biomass harvesting systems. Delivered cost per mmbtu decreased by over 50% for all systems as moisture content decreased from 55% to 30% (Figure 1). The system grinding clean chipping residues without using a screen (GCC) had the lowest estimated delivered costs ranging from $2.68 per mmbtu at 30% MC to $4.17 at 55% MC. The grinding system processing and screening clean chipping residues (GCC/S) and the system grinding roundwood logging residues without using a screen (GRW) had marginally higher estimated cut and haul costs per mmbtu, respectively, than the GCC system. The whole-tree chipping system (WTC) had the highest costs of the economically feasible systems. Estimated cut and haul costs for the system grinding and screening roundwood logging residues (GRW/S) were by far the highest. This system was not considered to be an economically feasible biomass harvesting option. This system averaged 11.7 net tons of truck payload, a 47 minute loading time, and 15.3 tons per productive hour. By comparison, a 780 hp grinder processing and screening clean chip residues averaged 23.5 net tons of truck payload, a 16.9 minute loading time, and 84.7 tons per productive hour.

15 Delivered Cost ($/mmbtu) $7 $6 $5 $4 $3 GRW/ S WTC GR GCC/ W GCC S $2 30% 35% 40% 45% 50% 55% Moisture Content Figure 1. Delivered costs of biomass ($/mmbtu) for five common harvesting systems as moisture content increases. Ash content is another key characteristic affecting net energy content. The whole-tree chipping system produced the lowest estimated delivered cost per mmbtu at the lowest percent ash, $4.39 per mmbtu at 0.5% ash and $4.41 at 1% ash (Table 5). Ash content were less than 0.7% in whole-tree chips. The GCC system produced the lowest estimated delivered cost per mmbtu of $2.87 at 5% ash, but this system also produced loads with high ash content (up to 30%). If target ash content is less than 2%, the WTC system was the lowest delivered cost option followed by the GRW/S system. No other system was observed to reduce ash below 2%. If 2% ash is acceptable, then the GCC/S system is the lowest delivered cost option at $3.33 per mmbtu. If ash content of up to 10% is acceptable, then the GRW, GCC, or GCC/S systems are options with the lowest costs observed for the GCC system. Delivered costs for the CC and GRW/S systems were not significantly different. We compared delivered cost per field ton and per mmbtu for each system to determine the impact of moisture and ash content on delivered price in the current payment system (field tons) compared to ayment based on energy content (Table 6). The GCC system had the lowest delivered cost per field ton and per mmbtu ($22.48 and $2.71, respectively) and the GRW/S system had highest costs at $46.49 and $4.20, respectively. When factoring in moisture and ash content costs per mmbtu for the GRW and WTC-40% (40% moisture content) systems were lowered relative to their cost per field ton equivalent measure. Harvesting roundwood (RW) and producing pulp quality clean chips (CC) were among the costliest harvesting systems based on field tons and mmbtu after factoring in stumpage prices and additional processing costs for roundwood.

16 Table 5. Delivered cost estimates ($/mmbtu) by levels of ash content. Delivered Cost ($/mmbtu) by Harvesting System % Ash WTC GRW GRW/S GCC GCC/S 0.5% $4.39 $ % $4.41 $ % $ % $3.44 $5.35 $ % $ % $ % $3.51 $ % $ % $3.59 $ % $3.66 $ % $3.75 $3.03 $ % $ % $ % $ % $3.89 Table 6. Ranking (lowest=1) of delivered cost estimates ($/field ton and $/mmbtu) for biomass harvesting systems under likely conditions. System Delivered Cost ($/F-ton) Rank Delivered Cost ($/mmbtu) Rank GCC $ $ GCC/S $ $ GRW $ $ WTC-50% $ $ WTC-40% $ $ RW $ $ CC $ $ GRW/S $ $4.20 8

17 5. Discuss Project Outcomes and Impacts Users of woody biomass feedstocks at bioenergy facilities can use these findings to improve their purchasing decisions and control the ash and moisture content of their raw materials. Tolerance of bioenergy systems to moisture and ash vary depending on the technology used. Where ash content should be kept very low (<2%), use of residues even with trommel screening does not appear to be a valid option. Where higher ash levels can be tolerated, clean chipping residues that are ground then screened or roundwood residues that are ground without screening also appear acceptable. Allowing felled stems to dry through transpiration appears to hold promise to reduce moisture content of whole tree chips, but deployment of such a system requires more logistical planning and coordination. This is due to the separation of felling and the remainder of the logging system and the need to use larger volume trailers to compensate for the lower density of the chips from dried stems. Allowing stems to dry in-field before chipping did not increase ash content. Decision makers should use the correct unit of measure green tons, oven-dry tons, or energy content (mmbtu). For facilities that combust wood directly, energy content (or dry tons) is more logical and systems that deliver at the lowest cost on this basis may appear more expensive when assessed on a green ton basis due to truck payload issues.

18 6. Provide a List and Complete Citation Since Project Inception of: a) Peer-Reviewed Articles i. Submitted: Cutshall, J. and W.D. Greene. (in review) Factors affecting costs of forest biomass harvesting systems and their implications for stakeholders. Biomass and Bioenergy ii. In Press: Cutshall, J., S.A. Baker, and W.D. Greene. (in press) Transpirational drying effects on energy and ash content from whole-tree southern pine plantation chipping operations. Southern Journal of Applied Forestry (accepted April 2012). Dukes, C.C., W.D. Greene, and S.A. Baker. (in press) In-woods screening of wood grindings for biomass feedstock applications. Biomass and Bioenergy (accepted December 2012). iii. Published: b) Books and Book Chapters i. Submitted: ii. iii. In Press: Published: c) Outreach Publications & Materials i. Submitted: ii. In Press: Dukes, C.C., S.A. Baker, and W.D. Greene. (in press) In-Woods Screening of Wood Grindings for Biomass Feedstock Applications. Technical Release, Forest Resources Association. iii. Published: Cutshall, J., S.A. Baker, and W.D. Greene Increasing energy content in loblolly pine by transpirational drying. Technical Release 12-R-17, Forest Resources Association

19 d) Website URLs or Other Electronic Outreach i. Submitted: ii. Published: e) Oral & Poster Presentations i. In Preparation: ii. Presented: Presentations: S.A. Baker, and W.D. Greene Improving biomass feedstock quality. Elmia World Bioenergy, Jönköping, Sweden. Cutshall, J.B., C.C. Dukes, W.D. Greene, S.A. Baker, and D. Mitchell Improving Woody Biomass Feedstock Logistics by Reducing Ash & Moisture Content. Forest Products Society Annual Meeting, Washington, DC. Greene, W.D Harvesting in a Tough Economy: USA South Perspective. New Zealand Institute of Forestry Annual Meeting, Christchurch, New Zealand. Cutshall, J.B., S.A. Baker, and W.D. Greene Improving Woody Biomass Feedstock Logistics by Reducing Ash & Moisture Content. Council on Forest Engineering Annual Meeting, New Bern, NC. Cutshall, J.B., W.D. Greene, and S.A. Baker Improving Woody Biomass Feedstock Logistics by Reducing Ash & Moisture Content. Sun Grant Program National Convention, New Orleans, LA. Greene, W.D Wood bioenergy and timberland investing. National Council of Real Estate Investment Fiduciaries Timberland Committee, Orlando, FL. Cutshall, J., D. Greene, S. Baker, and D. Mitchell. Transpirational drying effects on energy and ash content from whole-tree chipping operations in a southern pine plantation. Southeastern Natural Resources Graduate Student Symposium, Mississippi State University. Baker, S., D. Greene, and A. Aman. Evaluation of biomass harvesting systems in the southern US. 4 th International Forest Engineering Conference, White River, South Africa.

20 Baker, S. and D. Greene. Chip properties from operational harvests of pine stands in the southern US. Southern Region Council on Forest Engineering, Hot Springs, AR. Cutshall, J., D. Greene, S. Baker, and D. Mitchell. Transpirational drying effects on energy and ash content from whole-tree chipping operations in a southern pine plantation. Southern Region Council on Forest Engineering, Hot Springs, AR. Dukes, C., J. Cutshall, S. Baker, and D. Greene. In-woods screening of wood grindings for biomass feedstock applications. Council on Forest Engineering Annual Meeting, Quebec City. Baker, S. and D. Greene. Chip properties from operational harvests of pine stands in the southern US. Council on Forest Engineering Annual Meeting, Quebec City. Cutshall, J., D. Greene, S. Baker, and D. Mitchell. Transpirational drying effects on energy and ash content from whole-tree chipping operations in a southern pine plantation. Council on Forest Engineering Annual Meeting, Quebec City. Posters: Dukes, C.C., W.D. Greene, J.B. Cutshall, and S.A. Baker In-Woods Screening of Wood Grindings for Biomass Feedstock Applications. Council on Forest Engineering Annual Meeting, New Bern, NC. Dukes, C.C., W.D. Greene, J.B. Cutshall, and S.A. Baker In-Woods Screening of Wood Grindings for Biomass Feedstock Applications. Sun Grant Program National Convention, New Orleans, LA. iii. Other 7. Licenses/Inventions (provide complete citation as appropriate) a) In Preparation: b) Disclosed: c) Applied: d) Obtained:

21 8. Name of Students Funded on Project, including Department, Institution, Thesis/Dissertation Title (if applicable), Degree Obtained (if applicable), and Program Area: Student Name Jason Cutshall Cory Dukes Department Institution Thesis/Dissertation Title Forestry & UGA Options for Natural reducing moisture Resources and ash content in forest biomass Forestry & Natural Resources UGA harvesting systems In-woods screening of wood grindings for biomass feedstock applications Degree Obtained/Date PhD MS Program Area Forestry Forestry 9. Name and Institution/Agency/Company of Collaborators and/or Partners (Original and New) Plum Creek Timber Company, Athens, GA Collum Lumber, Allendale, SC Graphic Packaging, Macon, GA Shepherd Brothers Timber, Irwinton, GA 10. Educational Programs Conducted (including courses developed, indicate title, subject matter and audience) Georgia Bioenergy Conference, February 2011, Forsyth, GA 150 attending. Co-hosted by the Georgia Forestry Association. Presentation and information booth at Forest Resources Association EXPO in Hot Springs, AR, May Internal and External Grants and Contracts Related to this Project since Project Inception (provide complete citation) a) Proposals Submitted (not funded): USDA, AFRI. $1,020,454. Developing a sustainable advanced woody bioenergy system in the Southeast. Dale Greene and others. Submitted September US Department of Energy, Southeastern Sun Grant Program. $47,156. Expanding the harvesting contractor forces in the Southeast to support a large-scale woody biomass industry. Dale Greene, Shawn Baker, John Schelhas. Submitted March 2011.

22 USDA Biomass Research and Development Initiative. $317,790. Southeast integrated biorefinery. Dale Greene and others at UGA, American Process Inc., ArborGen. Submitted November USDA Biomass Research and Development Initiative. $447,110. Southeast integrated biorefinery. Dale Greene and others at UGA, American Process Inc., ArborGen. Submitted April b) Proposals Funded: Rayonier Inc. $21,100. Chip properties associated with biomass harvests in Georgia coastal plain pine plantations. Shawn Baker and Dale Greene. August 2010 March Attach any Photographs, Data and Supporting Information You Deem Appropriate

23 Acknowledgments Support for this research was provided in part [include in part as appropriate] by a grant from the Southeastern Sun Grant Center with funds provided by the U.S. Department of Transportation Research and Innovative Technology Administration (DTOS59-07-G-00050).