HomeMy WebLinkAboutBethel Pre Feasibility Assessment for Integration of Wood Fired Heating Systems Final Report AVCP Tugkar Lomack Blds 7-24-2012-BIO
Pre-Feasibility Assessment for
Integration of Wood-Fired Heating Systems
Final Report
July 24, 2012
AVCP: Tugkar & Lomack Buildings
Bethel, Alaska
Presented by
CTA Architects Engineers
Jesse Vigil, Nick Salmon & Nathan Ratz
Lars Construction Management Services
Rex Goolsby
For
AVCP
In partnership with
Fairbanks Economic Development Corporation
Alaska Wood Energy Development Task Group
Funded by
Alaska Energy Authority and U.S. Forest Service
306 W. Railroad, Suite 104
Missoula, MT 59802
406.728.9522
www.ctagroup.com
CTA Project: FEDC_BETHEL
Pre-Feasibility Assessment for AVCP: Tugkar & Lomack Buildings
Integration of Wood-Fired Heating Systems Bethel, Alaska
CTA Architects Engineers i
July 24, 2012
TABLE OF CONTENTS
1.0 Executive Summary ................................................................................................... 1
2.0 Introduction ............................................................................................................... 3
3.0 Existing Building Systems.......................................................................................... 3
4.0 Energy Use ............................................................................................................... 3
5.0 Biomass Boiler Size ................................................................................................... 4
6.0 Wood Fuel Use .......................................................................................................... 5
7.0 Boiler Plant Location and Site Access ....................................................................... 6
8.0 Integration with Existing Heating Systems ................................................................. 6
9.0 Air Quality Permits ..................................................................................................... 6
10.0 Wood Heating Options .............................................................................................. 6
11.0 Estimated Costs ........................................................................................................ 7
12.0 Economic Analysis Assumptions ............................................................................... 7
13.0 Results of Evaluation ................................................................................................. 7
14.0 Project Funding ......................................................................................................... 8
15.0 Summary ................................................................................................................... 8
16.0 Recommended Action ............................................................................................... 8
Appendixes
Appendix A: Preliminary Estimates of Probable Cost ................................................ 2 pages
Appendix B: Cash Flow Analysis ............................................................................... 4 pages
Appendix C: Site Plan ............................................................................................... 3 pages
Appendix D: Air Quality Report ................................................................................. 9 pages
Appendix E: Wood Fired Heating Technologies ........................................................ 3 pages
Pre-Feasibility Assessment for AVCP: Tugkar & Lomack Buildings
Integration of Wood-Fired Heating Systems Bethel, Alaska
CTA Architects Engineers Page 1 of 8
July 24, 2012
1.0 Executive Summary
The following assessment was commissioned to determine the preliminary technical and
economic feasibility of integrating a wood fired heating system in the AVCP: Tugkar &
Lomack Buildings. The Tugkar & Lomack buildings are on separate sites approximately
0.3 of a mile from each other. Each building was reviewed as a standalone system due to
the cost of infrastructure to connect the buildings, as well as the additional energy needed
to drive the increased pump size.
The following tables summarize the current fuel use and the potential wood fuel use:
Table 1.1 - Fuel Use Summary
Fuel Avg. Use Average Average
Facility
Name Type (Gallons) Annual Cost Cost/Gal.
Tugkar Fuel Oil 5,017 $31,607 $6.29
Lomack Fuel Oil 6,698 $42,197 $6.29
Table 1.2 - Annual Wood Fuel Use Summary
Chipped/
Fuel Cord Wood Ground
Oil Wood Pellets Wood
(Gallons) (Cords) (Tons) (Tons)
Tugkar 5,017 45.2 41.2 67.3
Lomack 6,698 60.3 54.9 89.9
Note: Wood fuel use assumes offsetting 85% of the current energy use.
Based on the available wood fuel, a pellet option and cord wood option will be evaluated.
The options reviewed were:
Pellet Wood Boiler Options:
B.1T: Tugkar Building.
B.1L: Lomack Building.
Cord Wood Boiler Options:
C.1T: Tugkar Building.
C.1L: Lomack building.
The table on the following page summarizes the economic evaluation for each option:
Pre-Feasibility Assessment for AVCP: Tugkar & Lomack Buildings
Integration of Wood-Fired Heating Systems Bethel, Alaska
CTA Architects Engineers Page 2 of 8
July 24, 2012
Table 1.3 - Economic Evaluation Summary
Bethel Tugkar and Lomack Biomass Heating Systems
Year 1 NPV NPV 20 Yr 30 Yr
Project Operating 30 yr 20 yr B/C B/C ACF ACF YR
Cost Savings at 3% at 3% Ratio Ratio YR 20 YR 30 ACF=PC
B.1T $656,000 -$2,588 162,281 $57,108 0.09 0.25 $92,049 $319,361 >30
C.1T $279,000 -$9,540 $55,611 -$37,797 -0.14 0.20 -$33,362 $170,253 >30
B.1L $656,000 $239 $333,623 $148,273 0.23 0.51 $223,694 $623,391 >30
C.1L $279,000 -$9,327 $150,815 $2610 0.01 0.54 -$48,443 $349,899 >29
The Tugkar and Lomack buildings appear to be poor candidates for the use of wood
biomass heating systems. With the current economic assumptions, the economic viability
of all the options is poor and none of the options meet the minimum requirement of the 20
year B/C ratio exceeding 1.0. Even with the high cost of fuel oil, each building individually
does not spend enough on heating fuel to be able to pay for a project through potential
savings.
Pre-Feasibility Assessment for AVCP: Tugkar & Lomack Buildings
Integration of Wood-Fired Heating Systems Bethel, Alaska
CTA Architects Engineers Page 3 of 8
July 24, 2012
2.0 Introduction
The following assessment was commissioned to determine the preliminary technical and
economic feasibility of integrating a wood fired heating system in the AVCP: Tugkar &
Lomack Buildings. The Tugkar & Lomack buildings are on separate sites approximately .3
of a mile from each other. Each building was reviewed as a standalone system due to the
cost of infrastructure to connect the buildings, as well as the additional energy needed to
drive the increased pump size.
3.0 Existing Building Systems
AVCP: Tugkar (3rd and Main) Building
The Tugkar Building is a two story wood framed building constructed in 1990 and
expanded in 1992. The facility is approximately 11,731 square feet and is heated by three
160,000 Btu/hr output hot water boilers. Domestic hot water is provided by an electric
water heater rated at 4.5 KW input with a 28 gallon storage tank. One of the Burnham
Boilers is original to the building and is in good condition. The remaining two Burnham
Boilers have been installed as a replacement to the original boilers at an unspecified time.
AVCP: Lomack Building
The Lomack Building is a two story wood framed building constructed in 1987 and
remodeled in 2004. The facility is approximately 14,714 square feet and is heated by two
hot water boilers rated at 284,000 and 302,000 Btu/hr output. Domestic hot water is
provided by one electric water heater rated at 4.5 KW input with a 50 gallon storage
capacity. Both of the existing boilers are original to the building and are in fair condition.
Table 3.1 - Existing Heating System Summary
Heat BTU/hr Condition
Building System Output
Tugkar
Burnham
Boiler 160,000 Good
Burnham
Boiler 160,000 Good
Burnham
Boiler 160,000 Good
Lomack
Burnham
Boiler 284,000 Fair
Burnham
Boiler 302,000 Fair
4.0 Energy Use
Fuel oil bills for the facilities were provided. The following table summarizes the data:
Table 4.1 - Fuel Use Summary
Fuel Avg. Use Average Average
Facility
Name Type (Gallons) Annual Cost Cost/Gal.
Tugkar Fuel Oil 5,017 $31,607 $6.29
Lomack Fuel Oil 6,698 $42,197 $6.29
Pre-Feasibility Assessment for AVCP: Tugkar & Lomack Buildings
Integration of Wood-Fired Heating Systems Bethel, Alaska
CTA Architects Engineers Page 4 of 8
July 24, 2012
Electrical energy consumption will increase with the installation of the wood fired boiler
system because of the power needed for the biomass boiler components such as draft
fans and the additional pumps needed to integrate into the existing heating systems. The
cash flow analysis accounts for the additional electrical energy consumption and reduces
the annual savings accordingly.
5.0 Biomass Boiler Size
The following table summarized the connected load of the heating equipment:
Table 5.1 - Connected Boiler Load Summary
Likely
Peak System
Output Load Peak
MBH Factor MBH
Tugkar
Burnham
Boiler Fuel Oil 160 0.66 106
Burnham
Boiler Fuel Oil 160 0.66 106
Burnham
Boiler Fuel Oil 160 0.66 106
Total 317
Lomack
Burnham
Boiler Fuel Oil 284 0.66 187
Burnham
Boiler Fuel Oil 302 0.66 199
Total 387
Total Of All Buildings 1066 704
Typically a wood heating system is sized to meet approximately 85% of the typical annual
heating energy use of the building. The existing heating systems would be used for the
other 15% of the time during peak heating conditions, during times when the biomass
heating system is down for servicing, and during swing months when only a few hours of
heating each day are required. Recent energy models have found that a boiler sized at
50% to 60% of the building peak load will typically accommodate 85% of the boiler run
hours.
Table 5.2 - Proposed Biomass Boiler Size
Likely Biomass
System Biomass Boiler
Peak Boiler Size
MBH Factor MBH
Tugkar 317 0.6 190
Lomack 387 0.6 232
Pre-Feasibility Assessment for AVCP: Tugkar & Lomack Buildings
Integration of Wood-Fired Heating Systems Bethel, Alaska
CTA Architects Engineers Page 5 of 8
July 24, 2012
The buildings are too far apart to consider a district heating system to connect them
together. Each building would require its own wood fired boiler and the table above shows
the estimated biomass boiler size.
6.0 Wood Fuel Use
The types of wood fuel available in the area include cord wood, wood pallets, and wood
pellets. The estimated amount of wood fuel needed of each wood fuel type for each
building was calculated and is listed below:
Table 1.2 - Annual Wood Fuel Use Summary
Chipped/
Fuel Cord Wood Ground
Oil Wood Pellets Wood
(Gallons) (Cords) (Tons) (Tons)
Tugkar 5,017 45.2 41.2 67.3
Lomack 6,698 60.3 54.9 89.9
Note: Wood fuel use assumes offsetting 85% of the current energy use.
The amount of wood fuel shown in the table is for offsetting 85% of the total fuel oil use.
The moisture content of the wood fuels and the overall wood burning system efficiencies
were accounted for in these calculations. The existing fuel oil boilers were assumed to be
80% efficient. Cord wood was assumed to be 20% moisture content (MC) with a system
efficiency of 65%. Wood pellets were assumed to be 7% MC with a system efficiency of
70%.
The unit fuel costs for fuel oil and the different fuel types were calculated and equalized to
dollars per million Btu ($/MMBtu) to allow for direct comparison. The Delivered $/MMBtu
is the cost of the fuel based on what is actually delivered to the heating system, which
includes all the inefficiencies of the different systems. The Gross $/MMBtu is the cost of
the fuel based on raw fuel, or the higher heating value and does not account for any
system inefficiencies. The following table summarizes the equalized fuel costs at different
fuel unit costs:
Table 6.2 - Unit Fuel Costs Equalized to $/MMBtu
Net
Gross System System
Delivered Gross
Fuel Type Units Btu/unit Efficiency Btu/unit $/unit $/MMBtu $/MMBtu
Fuel Oil gal 134500 0.8 107600 $5.50 $51.12 $40.89
$6.29 $58.46 $46.77
$7.00 $65.06 $52.04
Cord
Wood cords 16173800 0.65 10512970 $550.00 $52.32 $34.01
$600.00 $57.07 $37.10
$650.00 $61.83 $40.19
Pellets tons 16400000 0.7 11480000 $400.00 $34.84 $24.39
$460.00 $40.07 $28.05
Pre-Feasibility Assessment for AVCP: Tugkar & Lomack Buildings
Integration of Wood-Fired Heating Systems Bethel, Alaska
CTA Architects Engineers Page 6 of 8
July 24, 2012
Table 6.2 - Unit Fuel Costs Equalized to $/MMBtu
$520.00 $45.30 $31.71
7.0 Boiler Plant Location and Site Access
The existing boiler rooms in both buildings are not large enough to fit a new biomass boiler
so a new stand alone boiler plant would be required. The best location for a plant would
be adjacent to each building as indicated on the site plans located in Appendix C.
Any type of biomass boiler system will require access by delivery vehicles. For cord wood
systems this would likely be pick-up trucks and trucks with trailers. For pellet boilers, this
would require area for a trailer to turn around. A wood pellet boiler with an adjacent silo
appears to be the most appropriate solution. Wood pellet fuel would need to be conveyed
into the silo utilizing a pneumatic blower or grain auger. A pneumatic blower allows greater
flexibility in the relationship between the delivery vehicle and silo.
8.0 Integration with Existing Heating Systems
Integration of a wood fired heating system varies from facility to facility. The integration of
the building to the biomass boiler would require the installation of new heating hot water
supply and return pipes to connect to the existing boiler supply and return pipes.
The field visit confirmed the location of each boiler room and heating unit location in order
to identify an approximate point of connection from a district heating loop to each existing
building. Connections would typically be achieved with arctic pipe extended to the face of
each building, and extended up the exterior surface of the building in order to penetrate
exterior wall into the boiler room or building. Once the heating water supply and return
piping enters the existing
9.0 Air Quality Permits
Resource System Group (RSG) has completed and air quality feasibility study for three
new wood boilers in Bethel, Alaska. Bethel has favorable meteorology for dispersion of
emissions. Prevailing winds would likely blow emissions towards the southeast. In
addition, the proposed wood boilers will be small emission sources, whose sizes preclude
them from state permitting requirements. Therefore, we do not suggest advanced
emission control such as an ESP or baghouse. However, other design criteria have been
suggested to minimize emissions and maximize dispersion. These projects may be subject
to federal requirements.
10.0 Wood Heating Options
The technologies available to produce heating energy from wood based biomass are
varied in their approach, but largely can be separated into three types of heating plants:
cord wood, wood pellet and wood chip/ground wood fueled. See Appendix E for these
summaries.
Based on the available wood fuel, a pellet option and cord wood option will be evaluated.
The options reviewed were:
Pellet Wood Boiler Options:
B.1T: Tugkar Building.
Pre-Feasibility Assessment for AVCP: Tugkar & Lomack Buildings
Integration of Wood-Fired Heating Systems Bethel, Alaska
CTA Architects Engineers Page 7 of 8
July 24, 2012
B.1L: Lomack Building.
Cord Wood Boiler Options:
C.1T: Tugkar Building.
C.1L: Lomack building.
Wood pellet boiler options assume a freestanding boiler building with adjacent free
standing pellet silo. The cord wood boiler option assumes a free standing building with
interior cordwood fuel storage.
11.0 Estimated Costs
The total project costs are at a preliminary design level and are based on RS Means and
recent biomass project bid data. The estimates are shown in the appendix. These costs
are conservative and if a deeper level feasibility analysis is undertaken and/or further
design occurs, the costs may be able to be reduced.
12.0 Economic Analysis Assumptions
The cash flow analysis assumes fuel oil at $6.29/gal, electricity at $0.50/kwh, cord wood
delivered at $600/cord, and wood pellets delivered at $460/ton. The fuel oil, electricity,
and cord wood costs are based on the costs reported by the facility. Pellet costs were
obtained from an engineering study investigating using pellet boilers at the AVCP Housing
Authority Complex.
It is assumed that the wood boiler would supplant 85% of the estimated heating use, and
the existing heating systems would heat the remaining 15%. Each option assumes the
total project can be funded with grants and non obligated capital money. The following
inflation rates were used: O&M - 2%, Fossil Fuel – 5%, Wood Fuel – 3%, Discount Rate
for NPV calculation – 3%. The fossil fuel inflation rate is based on the DOE EIA website.
DOE is projecting a slight plateau with a long term inflation of approximately 5%. As a
point of comparison, oil prices have increased at an annual rate of over 8% since 2001.
The analysis also accounts for additional electrical energy required for the wood fired
boiler system as well as the system pumps to distribute heating hot water to the buildings.
Wood fired boiler systems also will require more maintenance, and these additional
maintenance costs are also factored into the analysis.
13.0 Results of Evaluation
The following table summarizes the economic evaluation for each option:
Table 13.1 - Economic Evaluation Summary
Bethel Tugkar and Lomack Biomass Heating Systems
Year 1 NPV NPV 20 Yr 30 Yr
Project Operating 30 yr 20 yr B/C B/C ACF ACF YR
Cost Savings at 3% at 3% Ratio Ratio YR 20 YR 30 ACF=PC
B.1T $656,000 -$2,588 162,281 $57,108 0.09 0.25 $92,049 $319,361 >30
C.1T $279,000 -$9,540 $55,611 -$37,797 -0.14 0.20 -$33,362 $170,253 >30
B.1L $656,000 $239 $333,623 $148,273 0.23 0.51 $223,694 $623,391 >30
C.1L $279,000 -$9,327 $150,815 $2610 0.01 0.54 -$48,443 $349,899 >29
Pre-Feasibility Assessment for AVCP: Tugkar & Lomack Buildings
Integration of Wood-Fired Heating Systems Bethel, Alaska
CTA Architects Engineers Page 8 of 8
July 24, 2012
The benefit to cost ratio (B/C) takes the net present value (NPV) of the net energy savings
and divides it by the construction cost of the project. A B/C ratio greater than or equal to
1.0 indicates an economically advantageous project.
Accumulated cash flow (ACF) is another evaluation measure that is calculated in this
report and is similar to simple payback with the exception that accumulated cash flow
takes the cost of financing and fuel escalation into account. For many building owners,
having the accumulated cash flow equal the project cost within 15 years is considered
necessary for implementation. If the accumulated cash flow equals project cost in 20
years or more, that indicates a challenged project. Positive accumulated cash flow should
also be considered an avoided cost as opposed to a pure savings.
14.0 Project Funding
AVCP may pursue a biomass project grant from the Alaska Energy Authority.
AVCP could also enter into a performance contract for the project. Companies such as
Siemens, McKinstry, Johnson Controls and Chevron have expressed an interest in
participating in funding projects of all sizes throughout Alaska. This allows the facility
owner to pay for the project entirely from the guaranteed energy savings, and to minimize
the project funds required to initiate the project. The scope of the project may be
expanded to include additional energy conservation measures such as roof and wall
insulation and upgrading mechanical systems.
15.0 Summary
The Tugkar and Lomack buildings appear to be poor candidates for the use of wood
biomass heating systems. With the current economic assumptions, the economic viability
of all the options is poor and none of the options meet the minimum requirement of the 20
year B/C ratio exceeding 1.0. Even with the high cost of fuel oil, each building individually
does not spend enough on heating fuel to be able to pay for a project through potential
savings.
16.0 Recommended Actions
Because of the availability of wood pallets at low or no cost, further investigation into
specialized wood stoves or boilers that can burn pallets would be recommended.
Additional analysis would be required to determine the quantity and quality of wood pallets
in Bethel, as well as the cost.
Additional investigation should also be completed on increasing the cord wood production
volume and infrastructure. If the cost per cord could be reduced the project would become
more viable.
APPENDIX A
Preliminary Estimates of Probable Cost
Preliminary Estimates of Probable Cost
AVCP Tugkar and Lomack Biomass Heating Options
Bethel, AK
Option B.1 - Tugkar
Biomass Boiler Building:$90,000
Wood Heating, Wood Handling System, & Pellet Silo: $140,000
Stack/Air Pollution Control Device:$50,000
Mechanical/Electrical within Boiler Building: $75,000
Underground Piping $12,000
Tugkar Integration $14,500
Subtotal:$381,500
30% Remote Factor $114,450
Subtotal:$495,950
Design Fees, Building Permit, Miscellaneous Expenses 15%: $74,393
Subtotal:$570,343
15% Contingency:$85,551
Total Project Costs 655,894$
Option C.1 - Tugkar
Biomass Boiler Building Including Wood Storage Area: $97,500
Wood Boiler System:$16,000
Stack:$2,200
Mechanical/Electrical within Boiler Building: $20,200
Underground Piping $12,000
Tugkar Integration $14,500
Subtotal:$162,400
30% Remote Factor $48,720
Subtotal:$211,120
Design Fees, Building Permit, Miscellaneous Expenses 15%: $31,668
Subtotal:$242,788
15% Contingency:$36,418
Total Project Costs 279,206$
Preliminary Estimates of Probable Cost
AVCP Tugkar and Lomack Biomass Heating Options
Bethel, AK
Option B.1 - Lomack
Biomass Boiler Building:$90,000
Wood Heating, Wood Handling System, & Pellet Silo: $140,000
Stack/Air Pollution Control Device:$50,000
Mechanical/Electrical within Boiler Building: $75,000
Underground Piping $12,000
Lomack Integration $14,500
Subtotal:$381,500
30% Remote Factor $114,450
Subtotal:$495,950
Design Fees, Building Permit, Miscellaneous Expenses 15%: $74,393
Subtotal:$570,343
15% Contingency:$85,551
Total Project Costs 655,894$
Option C.1 - Lomack
Biomass Boiler Building Including Wood Storage Area: $97,500
Wood Boiler System:$16,000
Stack:$2,200
Mechanical/Electrical within Boiler Building: $20,200
Underground Piping $12,000
Lomack Integration $14,500
Subtotal:$162,400
30% Remote Factor $48,720
Subtotal:$211,120
Design Fees, Building Permit, Miscellaneous Expenses 15%: $31,668
Subtotal:$242,788
15% Contingency:$36,418
Total Project Costs 279,206$
APPENDIX B
Cash Flow Analysis
AVCP: TugkarOption B.1Bethel, AlaskaWood Pellet Boiler Date: July 24, 2012 Analyst: CTA Architects Engineers - Jesse Vigil & Nathan Ratz EXISTING CONDITIONSTugkarTotalExisting Fuel Type:Fuel Oil Fuel Oil Fuel Oil Fuel OilFuel Units:gal gal gal galCurrent Fuel Unit Cost:$6.29 Estimated Average Annual Fuel Usage:5,0175,017Annual Heating Costs:$31,557 $0 $0 $0 $31,557ENERGY CONVERSION (to 1,000,000 Btu; or 1 dkt)Fuel Heating Value (Btu/unit of fuel):134500 134500 134500 134500Current Annual Fuel Volume (Btu):674,786,500 0 0 0Assumed efficiency of existing heating system (%):80% 80% 80% 80% Net Annual Energy Produced (Btu):539,829,200 0 0 0 539,829,200WOOD FUEL COSTWood Pellets$/ton: $460.00Assumed efficiency of wood heating system (%): 70% PROJECTED WOOD FUEL USAGEEstimated Btu content of wood fuel (Btu/lb) - Assumed 7% MC 8200 Tons of wood fuel to supplant net equivalent of 100% annual heating load.47Tons of wood fuel to supplant net equivalent of 85% annual heating load.4025 ton chip van loads to supplant net equivalent of 85% annual heating load.2 Project Capital Cost-$656,000 Project Financing InformationPercent Financed0.0%Est. Pwr Use 15650 kWh Type Hr/Wk Wk/Yr Total Hr Wage/Hr TotalAmount Financed$0 Elec Rate $0.500 /kWh Biomass System 2.0 40 80 $20.00 $1,600Amount of Grants$656,000 Other 0.0 40 0 $20.00 $01st 2 Year Learning 2.0 40 80 $20.00 $1,600Interest Rate5.00%Term10Annual Finance Cost (years)$0 -253.5 years Net Benefit B/C Ratio$162,281 -$493,719 0.25$57,108 -$598,8920.09Year Accumulated Cash Flow > 08Year Accumulated Cash Flow > Project Capital Cost31Inflation FactorsO&M Inflation Rate2.0%Fossil Fuel Inflation Rate5.0%Wood Fuel Inflation Rate3.0%Electricity Inflation Rate5.0%Discount Rate for Net Present Value Calculation 3.0%Year Year Year Year Year Year Year Year Year Year Year Year Year Year Year Year Year YearCash flow Descriptions Unit Costs HeatingSource ProportionAnnual Heating Source VolumesHeating Units 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 20 25 30Existing Heating System Operating CostsDisplaced heating costs $6.29 5017 gal $31,557 $33,135 $34,792 $36,531 $38,358 $40,276 $42,289 $44,404 $46,624 $48,955 $51,403 $53,973 $56,672 $59,505 $62,481 $79,743 $101,774 $129,893Displaced heating costs $0.000 gal $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0Displaced heating costs $0.000 gal $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0Displaced heating costs $0.000 gal $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0Biomass System Operating CostsWood Fuel ($/ton, delivered to boiler site)$460.00 85% 40 tons $18,386 $18,938 $19,506 $20,091 $20,694$21,315 $21,954 $22,613 $23,291 $23,990 $24,709 $25,451 $26,214 $27,001 $27,811 $32,240 $37,375 $43,328Small load existing fuel$6.29 15% 753 gal $4,734 $4,970 $5,219 $5,480 $5,754 $6,041 $6,343 $6,661 $6,994 $7,343 $7,710 $8,096 $8,501 $8,926 $9,372 $11,961 $15,266 $19,484Small load existing fuel$0.00 15% 0 gal $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0Small load existing fuel$0.00 15% 0 gal $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0Small load existing fuel$0.00 15% 0 gal $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0Additional Operation and Maintenance Costs$1,600 $1,632 $1,665 $1,698 $1,732 $1,767 $1,802 $1,838 $1,875 $1,912 $1,950 $1,989 $2,029 $2,070 $2,111 $2,331 $2,573$2,841Additional Operation and Maintenance Costs First 2 years$1,600 $1,632Additional Electrical Cost $0.500$7,825 $8,216 $8,627 $9,058 $9,511 $9,987 $10,486 $11,011 $11,561 $12,139 $12,746 $13,383 $14,053 $14,755 $15,493 $19,773 $25,236 $32,209Annual Operating Cost Savings-$2,588-$2,253-$225$204$667$1,166$1,704$2,282$2,904$3,571$4,287$5,054$5,875$6,754$7,694$13,437$21,323$32,030Financed Project Costs - Principal and Interest0000000000 Displaced System Replacement Costs (year one only)0Net Annual Cash Flow(2,588) (2,253) (225)204 667 1,166 1,704 2,282 2,904 3,571 4,287 5,054 5,875 6,7547,694 13,437 21,323 32,030Accumulated Cash Flow(2,588) (4,841) (5,066) (4,862) (4,195) (3,029) (1,325)957 3,861 7,431 11,718 16,771 22,646 29,400 37,094 92,049 181,911 319,361Additional Power UseAdditional MaintenanceSimple Payback: Total Project Cost/Year One Operating Cost Savings:Net Present Value (30 year analysis):Net Present Value (20 year analysis):
AVCP: LomackOption B.1Bethel, AlaskaWood Pellet Boiler Date: July 24, 2012 Analyst: CTA Architects Engineers - Jesse Vigil & Nathan Ratz EXISTING CONDITIONSLomackTotalExisting Fuel Type:Fuel Oil Fuel Oil Fuel Oil Fuel OilFuel Units:gal gal gal galCurrent Fuel Unit Cost:$6.29$4.10 Estimated Average Annual Fuel Usage:6,6986,698Annual Heating Costs:$42,130 $0 $0 $0 $42,130ENERGY CONVERSION (to 1,000,000 Btu; or 1 dkt)Fuel Heating Value (Btu/unit of fuel):134500 134500 134500 134500Current Annual Fuel Volume (Btu):900,881,000 0 0 0Assumed efficiency of existing heating system (%):80% 80% 80% 80% Net Annual Energy Produced (Btu):720,704,800 0 0 0 720,704,800WOOD FUEL COSTWood Pellets$/ton: $460.00Assumed efficiency of wood heating system (%): 70% PROJECTED WOOD FUEL USAGEEstimated Btu content of wood fuel (Btu/lb) - Assumed 7% MC 8200 Tons of wood fuel to supplant net equivalent of 100% annual heating load.63Tons of wood fuel to supplant net equivalent of 85% annual heating load.5325 ton chip van loads to supplant net equivalent of 85% annual heating load.2 Project Capital Cost-$656,000 Project Financing InformationPercent Financed0.0%Est. Pwr Use 15650 kWh Type Hr/Wk Wk/Yr Total Hr Wage/Hr TotalAmount Financed$0 Elec Rate $0.500 /kWh Biomass System 2.0 40 80 $20.00 $1,600Amount of Grants$656,000 Other 0.0 40 0 $20.00 $01st 2 Year Learning 2.0 40 80 $20.00 $1,600Interest Rate5.00%Term10Annual Finance Cost (years)$0 2,742.4 years Net Benefit B/C Ratio$333,623 -$322,377 0.51$148,273 -$507,7270.23Year Accumulated Cash Flow > 0#N/AYear Accumulated Cash Flow > Project Capital Cost31Inflation FactorsO&M Inflation Rate2.0%Fossil Fuel Inflation Rate5.0%Wood Fuel Inflation Rate3.0%Electricity Inflation Rate5.0%Discount Rate for Net Present Value Calculation 3.0%Year Year Year Year Year Year Year Year Year Year Year Year Year Year Year Year Year YearCash flow Descriptions Unit Costs HeatingSource ProportionAnnual Heating Source VolumesHeating Units 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 20 25 30Existing Heating System Operating CostsDisplaced heating costs $6.29 6698 gal $42,130 $44,237 $46,449 $48,771 $51,210 $53,770 $56,459 $59,282 $62,246 $65,358 $68,626 $72,057 $75,660 $79,443 $83,415 $106,461 $135,875 $173,415Displaced heating costs $0.000 gal $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0Displaced heating costs $0.000 gal $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0Displaced heating costs $4.100 gal $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0Biomass System Operating CostsWood Fuel ($/ton, delivered to boiler site)$460.00 85% 53 tons $24,547 $25,283 $26,042 $26,823 $27,627$28,456 $29,310 $30,189 $31,095 $32,028 $32,989 $33,978 $34,998 $36,048 $37,129 $43,043 $49,898 $57,846Small load existing fuel$6.29 15% 1005 gal $6,320 $6,636 $6,967 $7,316 $7,681 $8,066$8,469 $8,892 $9,337 $9,804 $10,294 $10,809 $11,349 $11,916 $12,512 $15,969 $20,381 $26,012Small load existing fuel$0.00 15% 0 gal $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0Small load existing fuel$0.00 15% 0 gal $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0Small load existing fuel$4.10 15% 0 gal $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0Additional Operation and Maintenance Costs$1,600 $1,632 $1,665 $1,698 $1,732 $1,767 $1,802 $1,838 $1,875 $1,912 $1,950 $1,989 $2,029 $2,070 $2,111 $2,331 $2,573$2,841Additional Operation and Maintenance Costs First 2 years$1,600 $1,632Additional Electrical Cost $0.500$7,825 $8,216 $8,627 $9,058 $9,511 $9,987 $10,486 $11,011 $11,561 $12,139 $12,746 $13,383 $14,053 $14,755 $15,493 $19,773 $25,236 $32,209Annual Operating Cost Savings$239$838$3,148$3,876$4,658$5,495$6,392$7,352$8,378$9,475$10,647$11,898$13,232$14,654$16,170$25,345$37,785$54,506Financed Project Costs - Principal and Interest0000000000 Displaced System Replacement Costs (year one only)0Net Annual Cash Flow239 838 3,148 3,876 4,658 5,495 6,392 7,352 8,378 9,475 10,647 11,898 13,232 14,654 16,170 25,345 37,785 54,506Accumulated Cash Flow239 1,077 4,226 8,102 12,760 18,255 24,646 31,998 40,376 49,852 60,499 72,396 85,628 100,282 116,452 223,694 386,250 623,390Additional Power UseAdditional MaintenanceSimple Payback: Total Project Cost/Year One Operating Cost Savings:Net Present Value (30 year analysis):Net Present Value (20 year analysis):
AVCP: TugkarOption C.1Bethel, AlaskaCord Wood Boiler Date: July 24, 2012 Analyst: CTA Architects Engineers - Jesse Vigil & Nathan Ratz EXISTING CONDITIONSTugkarTotalExisting Fuel Type:Fuel Oil Fuel Oil Fuel Oil Fuel OilFuel Units:gal gal gal galCurrent Fuel Unit Cost:$6.29 Estimated Average Annual Fuel Usage:5,0175,017Annual Heating Costs:$31,557 $0 $0 $0 $31,557ENERGY CONVERSION (to 1,000,000 Btu; or 1 dkt)Fuel Heating Value (Btu/unit of fuel):134500 134500 134500 134500Current Annual Fuel Volume (Btu):674,786,500 0 0 0Assumed efficiency of existing heating system (%):80% 80% 80% 80% Net Annual Energy Produced (Btu):539,829,200 0 0 0 539,829,200WOOD FUEL COSTCord Wood$/cord: $600.00Assumed efficiency of wood heating system (%): 65% PROJECTED WOOD FUEL USAGEEstimated Btu content of wood fuel (Btu/cord) - Assumed 20% MC, 6,700 Btu/lb x 28.4 lb/cf x 85 cf16,173,800 Cords of wood fuel to supplant net equivalent of 100% annual heating load.51Cords of wood fuel to supplant net equivalent of 85% annual heating load.4425 ton chip van loads to supplant net equivalent of 85% annual heating load.N/A Project Capital Cost-$279,000 Project Financing InformationPercent Financed0.0%Est. Pwr Use 1150 kWh Type Hr/Wk Wk/Yr Total Hr Wage/Hr TotalAmount Financed$0 Elec Rate $0.500 /kWh Biomass System 10.0 40 400 $20.00 $8,000Amount of Grants$279,000 Other 0.0 40 0 $20.00 $01st 2 Year Learning 2.0 40 80 $20.00 $1,600Interest Rate5.00%Term10Annual Finance Cost (years)$0 -29.2 years Net Benefit B/C Ratio$55,611 -$223,389 0.20-$37,797 -$316,797-0.14Year Accumulated Cash Flow > 023Year Accumulated Cash Flow > Project Capital Cost31Inflation FactorsO&M Inflation Rate2.0%Fossil Fuel Inflation Rate5.0%Wood Fuel Inflation Rate3.0%Electricity Inflation Rate5.0%Discount Rate for Net Present Value Calculation 3.0%Year Year Year Year Year Year Year Year Year Year Year Year Year Year Year Year Year YearCash flow Descriptions Unit Costs HeatingSource ProportionAnnual Heating Source VolumesHeating Units 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 20 25 30Existing Heating System Operating CostsDisplaced heating costs $6.29 5017 gal $31,557 $33,135 $34,792 $36,531 $38,358 $40,276 $42,289 $44,404 $46,624 $48,955 $51,403 $53,973 $56,672 $59,505 $62,481 $79,743 $101,774 $129,893Displaced heating costs $0.000 gal $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0Displaced heating costs $0.000 gal $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0Displaced heating costs $0.000 gal $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0Biomass System Operating CostsWood Fuel ($/ton, delivered to boiler site)$600.00 85% 44 tons $26,188 $26,974 $27,783 $28,616 $29,475$30,359 $31,270 $32,208 $33,174 $34,169 $35,194 $36,250 $37,338 $38,458 $39,612 $45,921 $53,235 $61,714Small load existing fuel$6.29 15% 753 gal $4,734 $4,970 $5,219 $5,480 $5,754 $6,041 $6,343 $6,661 $6,994 $7,343 $7,710 $8,096 $8,501 $8,926 $9,372 $11,961 $15,266 $19,484Small load existing fuel$0.00 15% 0 gal $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0Small load existing fuel$0.00 15% 0 gal $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0Small load existing fuel$0.00 15% 0 gal $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0Additional Operation and Maintenance Costs$8,000 $8,160 $8,323 $8,490 $8,659 $8,833 $9,009 $9,189 $9,373 $9,561 $9,752 $9,947 $10,146 $10,349 $10,556 $11,654 $12,867 $14,207Additional Operation and Maintenance Costs First 2 years$1,600 $1,632Additional Electrical Cost $0.500$575 $604 $634 $666 $699 $734 $771 $809 $850 $892 $937 $983 $1,033 $1,084 $1,138 $1,453 $1,854 $2,367Annual Operating Cost Savings-$9,540-$9,205-$7,167-$6,720-$6,229-$5,691-$5,104-$4,463-$3,767-$3,010-$2,190-$1,304-$345$689$1,803$8,753$18,552$32,122Financed Project Costs - Principal and Interest0000000000 Displaced System Replacement Costs (year one only)0Net Annual Cash Flow(9,540) (9,205) (7,167) (6,720) (6,229) (5,691) (5,104) (4,463) (3,767) (3,010) (2,190) (1,304) (345)689 1,803 8,753 18,552 32,122Accumulated Cash Flow(9,540) (18,744) (25,911) (32,632) (38,861) (44,552) (49,656) (54,119) (57,885) (60,896) (63,086) (64,390) (64,735) (64,046) (62,244) (33,362)38,493 170,235Additional Power UseAdditional MaintenanceSimple Payback: Total Project Cost/Year One Operating Cost Savings:Net Present Value (30 year analysis):Net Present Value (20 year analysis):
AVCP: LomackOption C.1Bethel, AlaskaCord Wood Boiler Date: July 24, 2012 Analyst: CTA Architects Engineers - Jesse Vigil & Nathan Ratz EXISTING CONDITIONSLomackTotalExisting Fuel Type:Fuel Oil Fuel Oil Fuel Oil Fuel OilFuel Units:gal gal gal galCurrent Fuel Unit Cost:$6.29 Estimated Average Annual Fuel Usage:6,6986,698Annual Heating Costs:$42,130 $0 $0 $0 $42,130ENERGY CONVERSION (to 1,000,000 Btu; or 1 dkt)Fuel Heating Value (Btu/unit of fuel):134500 134500 134500 134500Current Annual Fuel Volume (Btu):900,881,000 0 0 0Assumed efficiency of existing heating system (%):80% 80% 80% 80% Net Annual Energy Produced (Btu):720,704,800 0 0 0 720,704,800WOOD FUEL COSTCord Wood$/cord: $600.00Assumed efficiency of wood heating system (%): 65% PROJECTED WOOD FUEL USAGEEstimated Btu content of wood fuel (Btu/cord) - Assumed 20% MC, 6,700 Btu/lb x 28.4 lb/cf x 85 cf16,173,800 Cords of wood fuel to supplant net equivalent of 100% annual heating load.69Cords of wood fuel to supplant net equivalent of 85% annual heating load.5825 ton chip van loads to supplant net equivalent of 85% annual heating load.N/A Project Capital Cost-$279,000 Project Financing InformationPercent Financed0.0%Est. Pwr Use 1150 kWh Type Hr/Wk Wk/Yr Total Hr Wage/Hr TotalAmount Financed$0 Elec Rate $0.500 /kWh Biomass System 10.0 40 400 $20.00 $8,000Amount of Grants$279,000 Other 0.0 40 0 $20.00 $01st 2 Year Learning 2.0 40 80 $20.00 $1,600Interest Rate5.00%Term10Annual Finance Cost (years)$0 -29.9 years Net Benefit B/C Ratio$150,815 -$128,185 0.54$2,610 -$276,3900.01Year Accumulated Cash Flow > 019Year Accumulated Cash Flow > Project Capital Cost29Inflation FactorsO&M Inflation Rate2.0%Fossil Fuel Inflation Rate5.0%Wood Fuel Inflation Rate3.0%Electricity Inflation Rate5.0%Discount Rate for Net Present Value Calculation 3.0%Year Year Year Year Year Year Year Year Year Year Year Year Year Year Year Year Year YearCash flow Descriptions Unit Costs HeatingSource ProportionAnnual Heating Source VolumesHeating Units 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 20 25 30Existing Heating System Operating CostsDisplaced heating costs $6.29 6698 gal $42,130 $44,237 $46,449 $48,771 $51,210 $53,770 $56,459 $59,282 $62,246 $65,358 $68,626 $72,057 $75,660 $79,443 $83,415 $106,461 $135,875 $173,415Displaced heating costs $0.000 gal $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0Displaced heating costs $0.000 gal $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0Displaced heating costs $0.000 gal $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0Biomass System Operating CostsWood Fuel ($/ton, delivered to boiler site)$600.00 85% 58 tons $34,962 $36,011 $37,092 $38,204 $39,351$40,531 $41,747 $42,999 $44,289 $45,618 $46,987 $48,396 $49,848 $51,344 $52,884 $61,307 $71,072 $82,391Small load existing fuel$6.29 15% 1005 gal $6,320 $6,636 $6,967 $7,316 $7,681 $8,066$8,469 $8,892 $9,337 $9,804 $10,294 $10,809 $11,349 $11,916 $12,512 $15,969 $20,381 $26,012Small load existing fuel$0.00 15% 0 gal $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0Small load existing fuel$0.00 15% 0 gal $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0Small load existing fuel$0.00 15% 0 gal $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0Additional Operation and Maintenance Costs$8,000 $8,160 $8,323 $8,490 $8,659 $8,833 $9,009 $9,189 $9,373 $9,561 $9,752 $9,947 $10,146 $10,349 $10,556 $11,654 $12,867 $14,207Additional Operation and Maintenance Costs First 2 years$1,600 $1,632Additional Electrical Cost $0.500$575 $604 $634 $666 $699 $734 $771 $809 $850 $892 $937 $983 $1,033 $1,084 $1,138 $1,453 $1,854 $2,367Annual Operating Cost Savings-$9,327-$8,806-$6,567-$5,904-$5,181-$4,393-$3,537-$2,609-$1,603-$516$657$1,922$3,284$4,750$6,325$16,078$29,700$48,437Financed Project Costs - Principal and Interest0000000000 Displaced System Replacement Costs (year one only)0Net Annual Cash Flow(9,327) (8,806) (6,567) (5,904) (5,181) (4,393) (3,537) (2,609) (1,603) (516)657 1,922 3,284 4,750 6,325 16,078 29,700 48,437Accumulated Cash Flow(9,327) (18,132) (24,700) (30,604) (35,784) (40,177) (43,714) (46,323) (47,926) (48,443) (47,786) (45,864) (42,579) (37,829) (31,504)28,041 147,525 349,899Additional Power UseAdditional MaintenanceSimple Payback: Total Project Cost/Year One Operating Cost Savings:Net Present Value (30 year analysis):Net Present Value (20 year analysis):
APPENDIX C
Site Plan
AVCP HOUSINGLOMACK BUILDINGTUGKAR BUILDING1600'800'400'0SCALE: 1:800MISSOULA, MT(406)728-9522Fax (406)728-8287Date®BIOMASS PRE-FEASIBILITY ASSESSMENTBETHEL, ALASKABETHEL OVERVIEWSSFNHR07/24/2012FEDCJ:BethelNORTHREF.SITE PLAN
PREFERRED PLANTLOCATIONALTERNATE BIOMASSLOCATION10'-0"100'50'25'0SCALE: 1:50MISSOULA, MT(406)728-9522Fax (406)728-8287Date®BIOMASS PRE-FEASIBILITY ASSESSMENTBETHEL, ALASKATUGKAR BUILDINGSSFNHR07/24/2012FEDCJ:BethelSITE PLANNORTHREF.LEGENDPIPE ROUTINGBOILER ROOM
LOMACK BUILDINGPREFERRED BIOMASSLOCATION25'-0"84'-0"10'-0"100'50'25'0SCALE: 1:50MISSOULA, MT(406)728-9522Fax (406)728-8287Date®BIOMASS PRE-FEASIBILITY ASSESSMENTBETHEL, ALASKALOMACK BUILDINGSSFNHR07/24/2012FEDCJ:BethelSITE PLANNORTHREF.LEGENDPIPE ROUTINGBOILER ROOM
APPENDIX D
Air Quality Report
55 Railroad Row White River Junction, Vermont 05001
TEL 802.295.4999 FAX 802.295.1006 www.rsginc.com
INTRODUCTION
At your request, RSG has conducted an air quality feasibility study for three biomass energy
installations in Bethel. Bethel is located in southwest Alaska at the head of the Wood River and
has a population of 6,000 people. The following equipment is proposed:
A 250,000 Btu/hr (heat output) cord wood boiler at the Tukgar Building.
A 3,100,000 Btu/hr (heat output) pellet boiler at the AVCP Housing Complex.
A 250,000 Btu/hr (heat output) cord wood boiler at the Lomack Building.
STUDY AREA
A USGS map of the study area is provided in Figure 1 below. As shown, the area is flat with
much low‐lying areas along the Kuskokwin River. Relative to other sites in Alaska, the area is
densely populated. Our review of the area did not reveal any significant emission sources or
ambient air quality issues.
To: Nick Salmon
From: John Hinckley
Subject: Bethel Cluster Feasibility Study
Date: 24 July 2012
Bethel Air Quality Feasibility Study Resource Systems Group, Inc.
24 July 2012 page 2
Figure 1: USGS Map Illustrating the Study Area
Bethel Air Quality Feasibility Study Resource Systems Group, Inc.
24 July 2012 page 3
Figure 1 shows CTA Architects’ plan of the location of the proposed biomass facility at the
Tukgar Building and the surrounding buildings. As shown, two locations are being considered
for the proposed biomass equipment. The site is relatively flat and relatively densely populated
with one to two story tall buildings. The precise stack location and dimensions, and the biomass
equipment specifications have not been determined.
Figure 1: Overview of Tukgar Site
Bethel Air Quality Feasibility Study Resource Systems Group, Inc.
24 July 2012 page 4
Figure 2 shows CTA Architects’ plan of the proposed biomass facility at the AVCP Building and
the surrounding buildings. Most of the buildings are approximately one to two stories tall. A
stand‐alone biomass facility is planned on the southeast corner of the site. The remote location
of the facility will provide a dispersion buffer between the stack and the office buildings.
Figure 2: Overview of AVCP Housing Site
Bethel Air Quality Feasibility Study Resource Systems Group, Inc.
24 July 2012 page 5
Figure 3 shows CTA Architects’ plan of the proposed biomass facility at the Lomack Building
and the surrounding buildings. Most of the buildings are approximately one to two stories tall.
An addition is planned for the northern side of the building.
Figure 3: Overview of Lomack Building Building Site
Bethel Air Quality Feasibility Study Resource Systems Group, Inc.
24 July 2012 page 6
METEOROLOGY
Meteorological data from Bethel, AK, was reviewed to develop an understanding of the weather
conditions. As shown, there is a relatively low percentage of “calms” or times when the wind is
not blowing.1 This data indicates only 1% of the year when calm winds occur, which suggests
there will be minimal time periods when thermal inversions and therefore poor emission
dispersion conditions can occur.
Figure 4: Wind Speed Data from Bethel, AK
1 See: http://climate.gi.alaska.edu/Climate/Wind/Direction/Bethel/BET.html
Bethel Air Quality Feasibility Study Resource Systems Group, Inc.
24 July 2012 page 7
Figure 5 is a wind rose developed from wind speed and direction data collected in Bethel.1 This
shows prevailing winds are from the northeast (NNE and NE), meaning, they frequently blow
towards the southeast. Average wind speeds are up to 12 miles per hour in those directions.
This suggests emissions would typically be blown towards the southeast.
Figure 5: Wind Rose Showing Wind Speed and Direction
1 See: http://climate.gi.alaska.edu/Climate/Wind/Direction/Bethel/BET.html
Bethel Air Quality Feasibility Study Resource Systems Group, Inc.
24 July 2012 page 8
DESIGN & OPERATION RECOMMENDATIONS
The following are suggested for designing this project:
Burn natural wood, whose characteristics (moisture content, bark content, species,
geometry) ‐ result in optimal combustion in the equipment selected for the project.
Do not install a rain cap above the stack. Rain caps obstruct vertical airflow and reduce
dispersion of emissions.
Construct the stack to at least 1.5 times the height of the tallest roofline of the adjacent
building. Hence, a 20 foot roofline would result in a minimum 30 foot stack.
Operate and maintain the boiler according to manufacturer’s recommendations.
Perform a tune‐up at least every other year as per manufacturer’s recommendations
and EPA guidance (see below for more discussion of EPA requirements)
Conduct regular observations of stack emissions. If emissions are not characteristic of
good boiler operation, make corrective actions.
These design and operation recommendations are based on the assumption that state‐of‐the‐
art combustion equipment is installed.
STATE AND FEDERAL PERMIT REQUIREMENTS
This project will not require an air pollution control permit from the Alaska Department of
Environmental Quality given the boilers’ relatively small size and corresponding quantity of
emissions. However, this project will be subject to new proposed requirements in the federal
“Area Source Rule” (40 CFR 63 JJJJJJ). A federal permit is not needed. However, there are various
record keeping, reporting and operation and maintenance requirements which must be
performed to demonstrate compliance with the requirements in the Area Source Rule. The
proposed changes have not been finalized. Until that time, the following requirements are
applicable:
Submit initial notification form to EPA within 120 days of startup.
Complete biennial tune ups per EPA method.
Submit tune‐up forms to EPA.
Please note the following:
Oil and coal fired boilers are also subject to this rule.
Gas fired boilers are not subject to this rule.
More requirements are applicable to boilers equal to or greater than 10 MMBtu/hr heat
input. These requirements typically warrant advanced emission controls, such as a
baghouse or an electrostatic precipitator (ESP).
The compliance guidance documents and compliance forms can be obtained on the following
EPA web page: http://www.epa.gov/boilercompliance/
Bethel Air Quality Feasibility Study Resource Systems Group, Inc.
24 July 2012 page 9
SUMMARY
RSG has completed an air quality feasibility study for three new wood boilers in Bethel, Alaska.
The boilers are not subject to state permitting requirements, but are subject to federal
requirements. Design criteria have been suggested to minimize emissions and maximize
dispersion. We do not suggest advanced emission controls (ESP, baghouse) for the following
reasons:
1. Bethel has favorable meteorology for dispersion of emissions.
2. The wood boilers will be relatively small emission sources.
3. There are no applicable federal or state emission limits.
4. The Bethel area is relatively rural with no significant emission sources.
Given the prevailing winds, we recommend wherever possible to construct boiler stacks on the
south to southwest sides of buildings.
While not mandatory, we recommend exploring the possibility of a cyclone or multi‐cyclone
technology for control of fly ash and larger particulate emissions. We also recommend
developing a compliance plan for the aforementioned federal requirements.
Please contact me if you have any comments or questions.
APPENDIX E
Wood Fired Heating Technologies
WOOD FIRED HEATING TECHNOLOGIES
CTA has developed wood-fired heating system projects using cord wood, wood pellet
and wood chips as the primary feedstock. A summary of each system type with the
benefits and disadvantages is noted below.
Cord Wood
Cord wood systems are hand-stoked wood boilers with a limited heat output of 150,000-
200,000 British Thermal Units per hour (Btu/hour). Cord wood systems are typically
linked to a thermal storage tank in order to optimize the efficiency of the system and
reduce the frequency of stoking. Cord wood boiler systems are also typically linked to
existing heat distribution systems via a heat exchanger. Product data from Garn, HS
Tarm and KOB identify outputs of 150,000-196,000 Btu/hr based upon burning eastern
hardwoods and stoking the boiler on an hourly basis. The cost and practicality of stoking
a wood boiler on an hourly basis has led most operators of cord wood systems to
integrate an adjacent thermal storage tank, acting similar to a battery, storing heat for
later use. The thermal storage tank allows the wood boiler to be stoked to a high fire
mode 3 times per day while storing heat for distribution between stoking. Cord wood
boilers require each piece of wood to be hand fed into the firebox, hand raking of the
grates and hand removal of ash. Ash is typically cooled in a barrel before being stock
piled and later broadcast as fertilizer.
Cordwood boilers are manufactured by a number of European manufacturers and an
American manufacturer with low emissions. These manufacturers currently do not
fabricate equipment with ASME (American Society of Mechanical Engineers)
certifications. When these non ASME boilers are installed in the United States,
atmospheric boilers rather than pressurized boilers are utilized. Atmospheric boilers
require more frequent maintenance of the boiler chemicals.
Emissions from cord wood systems are typically as follows:
PM2.5 >0.08 lb/MMbtu
NOx 0.23 lb/MMbtu
SO2 0.025 lb/MMbtu
CO2 195 lb/MMbtu
Benefits:
Small size
Lower cost
Local wood resource
Simple to operate
Disadvantages:
Hand fed - a large labor commitment
Typically atmospheric boilers (not ASME rated)
Thermal Storage is required
Page 1
Wood Pellet
Wood pellet systems can be hand fed from 40 pound bags, hand shoveled from 2,500
pound sacks of wood pellets, or automatically fed from an adjacent agricultural silo with
a capacity of 30-40 tons. Pellet boilers systems are typically linked to existing heat
distribution systems via a heat exchanger. Product data from KOB, Forest Energy and
Solagen identify outputs of 200,000-5,000,000 Btu/hr based upon burning pellets made
from waste products from the western timber industry. A number of pellet fuel
manufacturers produce all tree pellets utilizing bark and needles. All tree pellets have
significantly higher ash content, resulting in more frequent ash removal. Wood pellet
boilers typically require hand raking of the grates and hand removal of ash 2-3 times a
week. Automatic ash removal can be integrated into pellet boiler systems. Ash is
typically cooled in a barrel before being stock piled and later broadcast as fertilizer.
Pellet storage is very economical. Agricultural bin storage exterior to the building is
inexpensive and quick to install. Material conveyance is also borrowed from agricultural
technology. Flexible conveyors allow the storage to be located 20 feet or more from the
boiler with a single auger.
Emissions from wood pellet systems are typically as follows:
PM2.5 >0.09 lb/MMbtu
NOx 0.22 lb/MMbtu
SO2 0.025 lb/MMbtu
CO2 220 lb/MMbtu
Benefits:
Smaller size (relative to a chip system)
Consistent fuel and easy economical storage of fuel
Automated
Disadvantages:
Higher system cost
Higher cost wood fuel ($/MMBtu)
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Page 3
Wood Chip
Chip systems utilize wood fuel that is either chipped or ground into a consistent size of
2-4 inches long and 1-2 inches wide. Chipped and ground material includes fine
sawdust and other debris. The quality of the fuel varies based upon how the wood is
processed between the forest and the facility. Trees which are harvested in a manner
that minimizes contact with the ground and run through a chipper or grinder directly into
a clean chip van are less likely to be contaminated with rocks, dirt and other debris. The
quality of the wood fuel will also be impacted by the types of screens placed on the
chipper or grinder. Fuel can be screened to reduce the quantity of fines which typically
become airborne during combustion and represent lost heat and increased particulate
emissions.
Chipped fuel is fed from the chip van into a metering bin, or loaded into a bunker with a
capacity of 60 tons or more. Wood chip boilers systems are typically linked to existing
heat distribution systems via a heat exchanger. Product data from Hurst, Messersmith
and Biomass Combustion Systems identify outputs of 1,000,000 - 50,000,000 Btu/hr
based upon burning western wood fuels. Wood chip boilers typically require hand raking
of the grates and hand removal of ash daily. Automatic ash removal can be integrated
into wood chip boiler systems. Ash is typically cooled in a barrel before being stock piled
and later broadcast as fertilizer.
Emissions from wood chip systems are typically as follows:
PM2.5 0.21 lb/MMbtu
NOx 0.22 lb/MMbtu
SO2 0.025 lb/MMbtu
CO2 195 lb/MMbtu
Benefits:
Lowest fuel cost of three options ($/MMBtu)
Automated
Can use local wood resources
Disadvantages:
Highest initial cost of three types
Larger fuel storage required
Less consistent fuel can cause operational and performance issues