HomeMy WebLinkAboutAleknagik Pre Feasibility Assessment for Integration of Wood Fired Heating Systems Final Report 07-24-2012-BIO
Pre-Feasibility Assessment for
Integration of Wood-Fired Heating Systems
Final Report
July 24, 2012
City of Aleknagik
Aleknagik, Alaska
Presented by
CTA Architects Engineers
Jesse Vigil & Nathan Ratz
Lars Construction Management Services
Rex Goolsby
For
City of Aleknagik
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_ALEKNAGIK
Pre-Feasibility Assessment for City of Aleknagik
Integration of Wood-Fired Heating Systems Aleknagik, 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 ............................................................................................................... 4
5.0 Biomass Boiler Size ................................................................................................... 5
6.0 Wood Fuel Use .......................................................................................................... 6
7.0 Boiler Plant Location and Site Access ....................................................................... 7
8.0 Integration with Existing Heating System ................................................................... 7
9.0 Air Quality Permits ..................................................................................................... 7
10.0 Options ...................................................................................................................... 7
11.0 Estimated Costs ........................................................................................................ 8
12.0 Economic Analysis Assumptions ............................................................................... 8
13.0 Results of Evaluation ................................................................................................. 8
14.0 Project Funding ......................................................................................................... 9
15.0 Summary ................................................................................................................... 9
16.0 Recommended Action ............................................................................................... 9
Appendixes
Appendix A: Preliminary Estimates of Probable Cost ................................................ 1 pages
Appendix B: Cash Flow Analysis ............................................................................... 2 pages
Appendix C: Site Plan ................................................................................................. 1 page
Appendix D: Air Quality Report ................................................................................. 5 pages
Appendix E: Wood Fired Heating Technologies ........................................................ 3 pages
Pre-Feasibility Assessment for City of Aleknagik
Integration of Wood-Fired Heating Systems Aleknagik, Alaska
CTA Architects Engineers Page 1 of 9
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 at the Aleknagik City Hall
Building located in Aleknagik, Alaska. During the field visit the Health Clinic and Fire
Department Garage, Maintenance Garage, and Future Washeteria were also reviewed
and discussed.
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
Building Type (Gallons) Annual Cost Cost/Gal.
City Hall Fuel Oil 1,300 $7,371 $5.67
Health Clinic
/ Fire Depart.
Garage Fuel Oil 2,350 $13,325 $5.67
Maintenance
Garage Fuel Oil 1,127 $6,390 $5.67
Table 1.2 - Annual Wood Fuel Use Summary
Fuel Cord Wood
Oil Wood Pellets
(Gallons) (Cords) (Tons)
City Hall (C) 1,300 11.4 10.4
Heath Clinic (H) 2,650 23.2 21.1
Future Washeteria (W) 1,000 8.7 8.0
C + H 3,950 34.5 31.5
C + H + W 4,950 43.3 39.4
Note: Wood fuel use assumes offsetting 85% of the current energy use.
Based on the potential wood use the cord wood boiler option was investigated and results
are as follows:
Cord Wood Boiler Options:
C.1: City Hall and Health Clinic.
C.2: City Hall, Health Clinic, and Future Washeteria.
The table on the following page summarizes the economic evaluation for each option:
CTA Architects Engineers Page 2 of 9
July 24, 2012
Table 1.3 - Economic Evaluation Summary
Aleknagik Biomass Heating System
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
C.1 $346,000 $797 $264,465 $125,334 0.36 0.76 $186,695 $486,354 27
C.2 $439,000 $4,173 $416,227 $212,664 0.48 0.95 $310,839 $748,746 24
A small district heating system connecting city buildings appears to be a poor candidate
for the use of a wood biomass heating system. 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. Each building individually does not
spend enough on heating fuel to be able to pay for a project through potential savings.
Combining multiple buildings increases the project costs without substantially increasing
the annual fossil fuel use.
Pre-Feasibility Assessment for Aleknagik City Hall
Integration of Wood-Fired Heating Systems Aleknagik, Alaska
CTA Architects Engineers Page 3 of 9
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 at the Alek nagik City Hall
Building located in Aleknagik, Alaska. During the field visit the Health Clinic and Fire
Department Garage, Maintenance Garage, and Future Washeteria were also reviewed
and discussed.
3.0 Existing Building Systems
Aleknagik City Hall
The Aleknagik City Hall is a single story wood framed building constructed in 1980 that is
approximately 3,315 square feet. The space is divided 5 separate uses: the City Hall,
Post Office, Rental Office Space, Village Public Safety Officer Program (VSPO) Office,
and a Garage / Storage Space. Each space is heated by a single Toyo Stove. In the City
Hall Offices plug-in personal electric heaters are used to provide supplemental heat. The
table below indicates the current system outputs:
Table 3.1 - Existing Heating System Summary
Heat BTU/hr Condition
Building System Output
City Hall
Toyo
Stove 40,000 Good
Rental Office
Toyo
Stove 40,000 Good
Post Office
Toyo
Stove 40,000 Good
VSPO
Toyo
Stove 14,800 Good
Garage /
Storage
Toyo
Stove 22,000 Poor / Inoperable
There is also an existing fuel oil furnace located in the central mechanical room. The
system has been decommissioned; however the ductwork and furnace are still in place.
Domestic hot water is provided by one electric water heater rated at 4.5 KW input and 30
gallons of storage.
Facilities Added to Feasibility Study
Health Clinic and Fire Department Garage
The Aleknagik Health Clinic and Fire Department Garage were designed in 2006 and were
added to the feasibility study during the field visit. The Health Clinic is approximately
2,563 square feet and the Fire Department Garage is approximately 952 square feet. The
facilities share a common 159,000 Btu/hr output hot water boiler.
Domestic hot water is provided by a 148,000 Btu/hr fuel oil fired hot water heater with 5.1
gallon storage tank. The existing boiler and heating system infrastructure is original to the
building and is in good condition but in need of commissioning to improve performance.
During the visit one of the zone valves appeared to be stuck open, causing the boiler to
run continuously, causing the temperature in the Health Clinic to be higher than desired.
Pre-Feasibility Assessment for Aleknagik City Hall
Integration of Wood-Fired Heating Systems Aleknagik, Alaska
CTA Architects Engineers Page 4 of 9
July 24, 2012
Future Washeteria
Although a Washeteria is not currently located at the north village, a desire to construct a
new facility adjacent to the Health Clinic and City Hall was discussed. If it could be located
in the vicinity of the Health Clinic and City Building it would be a potential candidate for
integration into a small district heating system. Since there currently is no plan or
schedule for this work an estimated case was included in the assessment. The fuel
volumes were calculated based on the typical washeterias constructed in villages of
similar size.
Additional Facilities Reviewed but not added to Feasibility Study
Maintenance Garage
The Maintenance Garage that is adjacent to the City Hall building was reviewed as part of
the field visit. This facility was constructed during the 1980’s and is a manufactured metal
building. The existing Garage is heated by 2 fuel oil unit heaters, however only one is
currently in operation. A 142,000 btu/hr waste oil heater has also been recently added to
the space. Domestic hot water is provided by one electric water heater rated at 4.5 KW
input and has 32 gallons of storage. With the relatively small heat demand of the building
and the recent addition of the waste oil heater it was determined that the building would
not be incorporated into a district system.
4.0 Energy Use
Fuel is delivered to a 10,000 gallon tank located on site. Each individual building has a
smaller 500-1000 gallon tank that is refilled from the 10,000 gallon tank. Fuel use
summaries for the facilities were provided and the following table summarizes the data:
Table 4.1 - Fuel Use Summary
Fuel Avg. Use Average Average
Building Type (Gallons) Annual Cost Cost/Gal.
City Hall Fuel Oil 1,300 $7,371 $5.67
Health Clinic
/ Fire Depart.
Garage Fuel Oil 2,350 $13,325 $5.67
Maintenance
Garage Fuel Oil 1,127 $6,390 $5.67
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.
Pre-Feasibility Assessment for Aleknagik City Hall
Integration of Wood-Fired Heating Systems Aleknagik, Alaska
CTA Architects Engineers Page 5 of 9
July 24, 2012
5.0 Biomass Boiler Size
The following table summarized the connected load of fuel fired boilers and domestic water
heaters:
Table 5.1 - Connected Boiler Load Summary
Likely
Peak System
Output Load Peak
MBH Factor MBH
City Hall (C) Toyo A Fuel Oil 40 0.66 26
Toyo B Fuel Oil 40 0.66 26
Toyo C Fuel Oil 40 0.66 26
Toyo D Fuel Oil 15 0.66 10
Toyo E Fuel Oil 22 0.66 15
Total 103
Heath Clinic
(H) Boiler Fuel Oil 159 1.00 159
Future Washeteria (W) Fuel Oil 80 1.00 80
Total Of All Buildings 396 262
Typically a wood heating system is sized to meet approximately 85% of the typical annual
heating energy use of the building. The existing heating boilers would be used for the
other 15% of the time during peak heating conditions, during times when the biomass
boiler 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.
Because of the small scale of the heating system, the output will be based on the smallest
cordwood boiler size available, or approximately 170,000 Btu/hr.
Table 5.2 - Proposed Biomass Boiler Size
Likely Biomass
System Biomass Boiler
Peak Boiler Size
MBH Factor MBH
City Hall (C) 103 0.6 62
Heath Clinic (H) 159 0.6 95
Future Washeteria (W) 80 0.6 48
C + H 262 0.6 157
C + H + W 342 0.6 205
Pre-Feasibility Assessment for Aleknagik City Hall
Integration of Wood-Fired Heating Systems Aleknagik, Alaska
CTA Architects Engineers Page 6 of 9
July 24, 2012
6.0 Wood Fuel Use
The fuel source that is available in the area consists entirely of seasoned cord wood cut
and gathered locally. At the time of this report there is not an infrastructure in place to
transport wood pellets or chipped/ground wood fuel. The estimated amount of wood fuel
needed of each wood fuel type for each building was calculated and is listed below:
Table 6.1 - Annual Wood Fuel Use Summary
Fuel Cord Wood
Oil Wood Pellets
(Gallons) (Cords) (Tons)
City Hall (C) 1,300 11.4 10.4
Heath Clinic (H) 2,650 23.2 21.1
Future Washeteria (W) 1,000 8.7 8.0
C + H 3,950 34.5 31.5
C + H + W 4,950 43.3 39.4
Note: Wood fuel use assumes offsetting 85% of the current energy 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%. Chipped/ground fuel was assumed to be 40% MC with a system efficiency of 65%.
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 $5.00 $46.47 $37.17
$5.67 $52.70 $42.16
$6.00 $55.76 $44.61
Cord
Wood cords 16173800 0.65 10512970 $200.00 $19.02 $12.37
$250.00 $23.78 $15.46
$300.00 $28.54 $18.55
Pre-Feasibility Assessment for Aleknagik City Hall
Integration of Wood-Fired Heating Systems Aleknagik, Alaska
CTA Architects Engineers Page 7 of 9
July 24, 2012
7.0 Boiler Plant Location and Site Access
None of the existing boiler rooms are large enough to fit a new biomass boiler so a new
standalone boiler plant would be required. The existing gravel parking lot south of the Fire
Department Garage has been identified as the preferred location for a central heating
plant.
Any type of biomass boiler system will require access by delivery vehicles, typically a truck
or truck and trailer. There is ample room on the site for both a standalone boiler plant and
additional wood storage. The location is also under ¼ mile to the Aleknagik north village
landing. This would allow cord wood to be delivered by barge or boat in the summer
reducing the cost of overland hauling.
8.0 Integration with Existing Heating System
Integration of a wood fired boiler system would be relatively straight forward at the Health
Clinic and Fire Department Garage. The field visit confirmed the location of each boiler
room 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. Once hot supply and return piping enters the
existing boiler room, they would be connected to existing supply and return pipes in
appropriate locations in order to utilize existing pumping systems within each building.
The integration of a wood fired boiler system to the City Building would be more
challenging. Currently the facility is heated by individual Toyo Stoves. A new heating
system would have to be installed to distribute the hot supply water. The existing fuel oil
furnace in the mechanical room could be removed and the room could be used for the
distribution system including a heat exchanger and pumping system. New radiators would
be needed throughout the facility. The existing furnace could also possibly be replaced
with a fan coil unit with at heating coil served by the new biomass boiler system, and this
connected to the existing ductwork, if the ductwork is in good condition.
9.0 Air Quality Permits
Resource System Group has done a preliminary review of potential air quality issues in the
area. The meteorological conditions of Aleknagik do not create thermal inversions very
often, which it good because inversions are unfavorable for the dispersion of emissions.
The proposed boiler size at this location is small enough, that the boiler is not likely to
require any State or Federal permits. See the air quality memo in Appendix D.
10.0 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.
Pre-Feasibility Assessment for Aleknagik City Hall
Integration of Wood-Fired Heating Systems Aleknagik, Alaska
CTA Architects Engineers Page 8 of 9
July 24, 2012
Based on the potential wood use the cord wood boiler option was investigated and results
are as follows:
Cord Wood Boiler Options:
C.1: City Hall and Health Clinic.
C.2: City Hall, Health Clinic, and Future Washeteria.
Option C.1 and C.2 would be installed in a freestanding 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/o7r further
design occurs, the costs may be able to be reduced.
12.0 Economic Analysis Assumptions
The cash flow analysis assumes fuel oil at $5.65/gal, electricity at $0.65/kwh, and cord
wood delivered at $200/cord. The fuel oil, electricity, and cord wood costs are based on
the costs reported by the facility.
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 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
Aleknagik Biomass Heating System
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
C.1 $346,000 $797 $264,465 $125,334 0.36 0.76 $186,695 $486,354 27
C.2 $439,000 $4,173 $416,227 $212,664 0.48 0.95 $310,839 $748,746 24
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.
Pre-Feasibility Assessment for Aleknagik City Hall
Integration of Wood-Fired Heating Systems Aleknagik, Alaska
CTA Architects Engineers Page 9 of 9
July 24, 2012
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
The City of Aleknagik may pursue a biomass project grant from the Alaska Energy
Authority.
The City of Aleknagik 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
A small district heating system connecting city buildings appears to be a poor candidate
for the use of a wood biomass heating system. 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. Each building individually does not
spend enough on heating fuel to be able to pay for a project through potential savings.
Combining multiple buildings increases the project costs without substantially increasing
the annual fossil fuel use.
16.0 Recommended Action
Revisit the viability of a wood heating project if after the W asheteria and/or other buildings
are constructed and the campus of City buildings end up using over 10,000 gallons of fuel
oil for heating.
APPENDIX A
Preliminary Estimates of Probable Cost
Preliminary Estimates of Probable Cost
Biomass Heating Options
Alegnagik, AK
Option C.1 - City Hall + Health Center
Biomass Boiler Building Including Wood Storage Area: $55,000
Wood Boiler System:$32,000
Stack:$4,200
Mechanical/Electrical within Boiler Building: $20,200
Underground Piping $45,000
City Hall Integration $32,000
Health Clinic Integration $13,000
Subtotal:$201,400
30% Remote Factor $60,420
Subtotal:$261,820
Design Fees, Building Permit, Miscellaneous Expenses 15%: $39,273
Subtotal:$301,093
15% Contingency:$45,164
Subtotal:346,257$
Total Project Costs $346,257
Option C.2 - City Hall + Health Center + Future Washeteria
Biomass Boiler Building Including Wood Storage Area: $55,000
Wood Boiler System:$32,000
Stack:$4,200
Mechanical/Electrical within Boiler Building: $20,200
Underground Piping $75,000
City Hall Integration $32,000
Health Clinic Integration $13,000
Future Washeteria Integration $24,000
Subtotal:$255,400
30% Remote Factor $76,620
Subtotal:$332,020
Design Fees, Building Permit, Miscellaneous Expenses 15%: $49,803
Subtotal:$381,823
15% Contingency:$57,273
Subtotal:439,096$
Total Project Costs $439,096
APPENDIX B
Cash Flow Analysis
Aleknagik Municipal Buildings, City Hall and Health Clinic Option C.1Aleknagik, AlaskaCord Wood Boiler Date: July 24, 2012 Analyst: CTA Architects Engineers - Nick Salmon & Nathan Ratz EXISTING CONDITIONSCity Hall Health ClinicTotalExisting Fuel Type:Fuel Oil Fuel Oil Fuel Oil Fuel OilFuel Units:gal gal gal galCurrent Fuel Unit Cost:$5.70 $5.70 $5.70 $5.70 Estimated Average Annual Fuel Usage:1,300 2,350 03,650Annual Heating Costs:$7,410 $13,395 $0 $0 $20,805ENERGY CONVERSION (to 1,000,000 Btu; or 1 dkt)Fuel Heating Value (Btu/unit of fuel):138500 138500 138500 138500Current Annual Fuel Volume (Btu):180,050,000 325,475,000 0 0Assumed efficiency of existing heating system (%):80% 80% 80% 80% Net Annual Energy Produced (Btu):144,040,000 260,380,000 0 0 404,420,000WOOD FUEL COSTCord Wood$/cord: $200.00Assumed 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.38Cords of wood fuel to supplant net equivalent of 85% annual heating load.3325 ton chip van loads to supplant net equivalent of 85% annual heating load.N/A Project Capital Cost-$346,000 Project Financing InformationPercent Financed0.0%Est. Pwr Use 1150 kWh Type Hr/Wk Wk/Yr Total Hr Wage/Hr TotalAmount Financed$0 Elec Rate $0.650 /kWh Biomass System 10.0 40 400 $20.00 $8,000Amount of Grants$346,000 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)$0 434.1 years Net Benefit B/C Ratio$264,465 -$81,535 0.76$125,334 -$220,6660.36Year Accumulated Cash Flow > 0#N/AYear Accumulated Cash Flow > Project Capital Cost27Inflation 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 $5.70 1300 gal $7,410 $7,781 $8,170 $8,578 $9,007 $9,457 $9,930 $10,427 $10,948 $11,495 $12,070 $12,674 $13,307 $13,973 $14,671 $18,725 $23,898 $30,501Displaced heating costs $5.70 2350 gal $13,395 $14,065 $14,768 $15,506 $16,282 $17,096 $17,951 $18,848 $19,791 $20,780 $21,819 $22,910 $24,055 $25,258 $26,521 $33,848 $43,200 $55,136Displaced heating costs $5.700 gal $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0Displaced heating costs $5.700 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)$200.00 85% 33 cords $6,540 $6,736 $6,938 $7,146 $7,360 $7,581 $7,809 $8,043 $8,284 $8,533 $8,789 $9,052 $9,324 $9,604 $9,892 $11,467 $13,294 $15,411Small load existing fuel$5.70 15% 195 gal $1,112 $1,167 $1,225 $1,287 $1,351 $1,419 $1,490 $1,564 $1,642 $1,724 $1,811 $1,901 $1,996 $2,096 $2,201 $2,809 $3,585 $4,575Small load existing fuel$5.70 15% 353 gal $2,009 $2,110 $2,215 $2,326 $2,442 $2,564 $2,693 $2,827 $2,969 $3,117 $3,273 $3,436 $3,608 $3,789 $3,978 $5,077 $6,480 $8,270Small load existing fuel$5.70 15% 0 gal $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0Small load existing fuel$5.70 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 $0.650$748 $785 $824 $865 $909 $954 $1,002 $1,052 $1,104 $1,160 $1,218 $1,278 $1,342 $1,410 $1,480 $1,889 $2,411 $3,077Annual Operating Cost Savings$797$1,256$3,412$3,971$4,567$5,202$5,879$6,599$7,366$8,181$9,047$9,968$10,946$11,984$13,086$19,676$28,461$40,096Financed Project Costs - Principal and Interest0000000000 Displaced System Replacement Costs (year one only)0Net Annual Cash Flow797 1,256 3,412 3,971 4,567 5,202 5,879 6,599 7,366 8,181 9,047 9,968 10,946 11,984 13,086 19,676 28,461 40,096Accumulated Cash Flow797 2,053 5,464 9,435 14,002 19,204 25,083 31,682 39,048 47,229 56,276 66,244 77,190 89,175 102,261 186,695 310,436 486,354Additional Power UseAdditional MaintenanceSimple Payback: Total Project Cost/Year One Operating Cost Savings:Net Present Value (30 year analysis):Net Present Value (20 year analysis):
Aleknagik Municipal Buildings, City Hall, Clinic, Future Washateria Option C.2Aleknagik, AlaskaCord Wood Boiler Date: July 24, 2012 Analyst: CTA Architects Engineers - Nick Salmon & Nathan Ratz EXISTING CONDITIONSCity Hall Health Clinic Washateria TotalExisting Fuel Type:Fuel Oil Fuel Oil Fuel Oil Fuel OilFuel Units:gal gal gal galCurrent Fuel Unit Cost:$5.70 $5.70 $5.70 $5.70 Estimated Average Annual Fuel Usage:1,300 2,350 1,1274,777Annual Heating Costs:$7,410 $13,395 $6,424 $0 $27,229ENERGY CONVERSION (to 1,000,000 Btu; or 1 dkt)Fuel Heating Value (Btu/unit of fuel):138500 138500 138500 138500Current Annual Fuel Volume (Btu):180,050,000 325,475,000 156,089,500 0Assumed efficiency of existing heating system (%):80% 80% 80% 80% Net Annual Energy Produced (Btu):144,040,000 260,380,000 124,871,600 0 529,291,600WOOD FUEL COSTCord Wood$/cord: $200.00Assumed 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.50Cords of wood fuel to supplant net equivalent of 85% annual heating load.4325 ton chip van loads to supplant net equivalent of 85% annual heating load.N/A Project Capital Cost-$439,000 Project Financing InformationPercent Financed0.0%Est. Pwr Use 1250 kWh Type Hr/Wk Wk/Yr Total Hr Wage/Hr TotalAmount Financed$0 Elec Rate $0.650 /kWh Biomass System 10.0 40 400 $20.00 $8,000Amount of Grants$439,000 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)$0 105.2 years Net Benefit B/C Ratio$416,227 -$22,773 0.95$212,664 -$226,3360.48Year Accumulated Cash Flow > 0#N/AYear Accumulated Cash Flow > Project Capital Cost24Inflation 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 $5.70 1300 gal $7,410 $7,781 $8,170 $8,578 $9,007 $9,457 $9,930 $10,427 $10,948 $11,495 $12,070 $12,674 $13,307 $13,973 $14,671 $18,725 $23,898 $30,501Displaced heating costs $5.70 2350 gal $13,395 $14,065 $14,768 $15,506 $16,282 $17,096 $17,951 $18,848 $19,791 $20,780 $21,819 $22,910 $24,055 $25,258 $26,521 $33,848 $43,200 $55,136Displaced heating costs $5.70 1127 gal $6,424 $6,745 $7,082 $7,436 $7,808 $8,199 $8,609 $9,039 $9,491 $9,966 $10,464 $10,987 $11,536 $12,113 $12,719 $16,233 $20,718 $26,442Displaced heating costs $5.700 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)$200.00 85% 43 cords $8,559 $8,816 $9,080 $9,353 $9,633 $9,922 $10,220 $10,526 $10,842 $11,167 $11,502 $11,848 $12,203$12,569 $12,946 $15,008 $17,399 $20,170Small load existing fuel$5.70 15% 195 gal $1,112 $1,167 $1,225 $1,287 $1,351 $1,419 $1,490 $1,564 $1,642 $1,724 $1,811 $1,901 $1,996 $2,096 $2,201 $2,809 $3,585 $4,575Small load existing fuel$5.70 15% 353 gal $2,009 $2,110 $2,215 $2,326 $2,442 $2,564 $2,693 $2,827 $2,969 $3,117 $3,273 $3,436 $3,608 $3,789 $3,978 $5,077 $6,480 $8,270Small load existing fuel$5.70 15% 169 gal $964 $1,012 $1,062 $1,115 $1,171 $1,230 $1,291 $1,356 $1,424 $1,495 $1,570 $1,648 $1,730 $1,817 $1,908$2,435 $3,108 $3,966Small load existing fuel$5.70 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 $0.650$813 $853 $896 $941 $988 $1,037 $1,089 $1,143 $1,200 $1,260 $1,323 $1,390 $1,459 $1,532 $1,609 $2,053 $2,620 $3,344Annual Operating Cost Savings$4,173$4,841$7,218$8,010$8,852$9,747$10,698$11,708$12,779$13,916$15,122$16,401$17,756$19,193$20,714$29,769$41,757$57,545Financed Project Costs - Principal and Interest0000000000 Displaced System Replacement Costs (year one only)0Net Annual Cash Flow4,173 4,841 7,218 8,010 8,852 9,747 10,698 11,708 12,779 13,916 15,122 16,401 17,756 19,193 20,714 29,769 41,757 57,545Accumulated Cash Flow4,173 9,014 16,232 24,242 33,094 42,841 53,539 65,247 78,026 91,942 107,064 123,465 141,222 160,414 181,128 310,839 494,319 748,746Additional 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
CITY HALL / OFFICESMAINTENANCE SHOPCLINICCLINICFIRE DEPT.GARAGEPROPOSEDBOILER PLANTFUTUREWASHETERIA55'-0"85'-0"95'-0"80'-0"116'-0"45'-0"MISSOULA, MT(406)728-9522Fax (406)728-8287Date®BIOMASS PRE-FEASIBILITY ASSESSMENTALEKNAGIK, ALASKAALEKNAGIK MAIN CITY HALLSSFNHR07/24/2012FEDCJ:aleknagikSITESITE PLAN100'50'25'0SCALE: 1:50NORTHREF.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 a biomass energy
installation in Aleknagik. Aleknagik is located in ‐ southwest Alaska at the head of the Wood
River and has a population of 219 people. A cord wood boiler is planned for the Aleknagik Main
City Hall. The boiler will have an estimated heat output of 205,000 Btu’s per hour and a heat
input of 256,250 Btu’s per hour, assuming 80% thermal efficiency.
STUDY AREA
A USGS map of the study area is provided below in Figure 1. As shown, the study area is located
on Lake Aleknagik in the midst of hilly to mountainous topography and very little development.
Our review of the area did not reveal any significant emission sources or ambient air quality
issues.
Figure 1: USGS Map Illustrating the Study Area
To: Nick Salmon
From: John Hinckley
Subject: Aleknagik Cluster Feasibility Study
Date: 24 July 2012
Aleknagik Air Quality Feasibility Study Resource Systems Group, Inc.
24 July 2012 page 2
Figure 2 shows CTA Architects’ plan of the location of the proposed biomass facility and
surrounding buildings. The site is relatively flat and sparsely populated with buildings. The
facility will be located in a separate building south of the fire department garage. The precise
dimensions of that building, the stack location and dimensions, and the biomass equipment
specifications have not been determined.
Figure 2: Location of Proposed Biomass Facility
Aleknagik Air Quality Feasibility Study Resource Systems Group, Inc.
24 July 2012 page 3
METEOROLOGY
Aleknagik is located relatively close (approximately 40 miles) to the ocean and therefore has a
mostly maritime climate. Meteorological data from Bethel, AK, was reviewed to develop an
understanding of the weather conditions. Bethel is approximately 150 miles away, but also
located in the same climactic region of Alaska and therefore experiences similar weather
patterns. As shown in the bottom of Figure 3, there is a relatively low percentage of “calms”
(times when the wind is not blowing) during most of the year.1 This data indicates only 1% of
the year when “calms” occur, which suggests there will be minimal time periods when thermal
inversions and, as a result, poor emission dispersion conditions occur.
Figure 3: Wind Speed Data from Bethel, AK
1 See: http://climate.gi.alaska.edu/Climate/Wind/Direction/Bethel/BET.html
Aleknagik Air Quality Feasibility Study Resource Systems Group, Inc.
24 July 2012 page 4
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/
Aleknagik Air Quality Feasibility Study Resource Systems Group, Inc.
24 July 2012 page 5
SUMMARY & CONCLUSIONS
RSG has completed an air quality feasibility study for a new cord wood boiler for the Aleknagik
Main City Hall. The boiler is not subject to state permitting requirements, but is subject to
federal requirements. Design criteria have been suggested to minimize emissions and maximize
dispersion.
The following conditions suggest advanced emission control devices (ESP, baghouse) are not
warranted:
1. Aleknagik is a very rural area with no significant emission sources.
2. Aleknagik has favorable meteorology for emissions dispersion.
3. The wood boiler will be a relatively small emission source.
4. There are no applicable federal or state emission limits.
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)
Page 2
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