HomeMy WebLinkAboutNenana City School District 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
Nenana City School District
City of Nenana
Nenana, Alaska
Presented by
CTA Architects Engineers
Nick Salmon & Nathan Ratz
Lars Construction Management Services
Rex Goolsby
For
Toghotthele Corporation
Nenana School District
City of Nenana
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_FAIRBANKS_NENANA
Pre-Feasibility Assessment for Nenana School and City of Nenana
Integration of Wood-Fired Heating Systems Nenana, Alaska
CTA Architects Engineers i
July 24, 2012
TABLE OF CONTENTS
1.0 Executive Summary ................................................................................................... 1
2.0 Introduction ............................................................................................................... 4
3.0 Existing Building Systems.......................................................................................... 4
4.0 Energy Use ............................................................................................................... 6
5.0 Biomass Boiler Size ................................................................................................... 6
6.0 Wood Fuel Use .......................................................................................................... 8
7.0 Boiler Plant Location and Site Access ....................................................................... 8
8.0 Integration with Existing Heating Systems ............................................................... 10
9.0 Air Quality Permits ................................................................................................... 10
10.0 Wood Heating Options ............................................................................................ 10
11.0 Estimated Costs ...................................................................................................... 11
12.0 Economic Analysis Assumptions ............................................................................. 11
13.0 Results of Evaluation ............................................................................................... 12
14.0 Project Funding ....................................................................................................... 13
15.0 Summary ................................................................................................................. 13
16.0 Recommendation Actions ........................................................................................ 13
Appendixes
Appendix A: Preliminary Estimates of Probable Cost ................................................ 4 pages
Appendix B: Cash Flow Analysis ............................................................................... 9 pages
Appendix C: Site Plan ............................................................................................... 4 pages
Appendix D: Air Quality Report ............................................................................... 10 pages
Appendix E: Wood Fired Heating Technologies ........................................................ 3 pages
Pre-Feasibility Assessment for Nenana School and City of Nenana
Integration of Wood-Fired Heating Systems Nenana, Alaska
CTA Architects Engineers Page 1 of 13
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 Nenana School,
School Administration, School Warehouse, School Living Center, Nenana Native Council
Day Care, Nenana Fire Department, Nenana Water Plant, and the Meda Lord Senior
Center in Nenana, Alaska.
The following tables summarize the current fuel use and the potential wood fuel use:
Table 1.1 - Annual Fuel Use Summary
Fuel Avg. Use Current Annual
Facility Name Type (Gallons) Cost/Gal. Cost
School Fuel Oil 34,000 $3.60 $122,400
School Admin Fuel Oil 1,600 $3.60 $5,760
School Whse. Fuel Oil 4,200 $3.60 $15,120
Student Living
Center Fuel Oil 28,800 $3.60 $103,680
NNC Day
Care Fuel Oil 4550 $3.60 $16,380
Water Plant Fuel Oil 10700 $3.60 $38,520
Fire Dept. Fuel Oil 3950 $3.60 $14,220
Meda Lord
Senior Center Fuel Oil 6566 $4.00 $26,264
Table 1. 2 - Annual Wood Fuel Use Summary
Chipped/
Fuel Cord Wood Ground
Oil Wood Pellets Wood
(Gallons) (Cords) (Tons) (Tons)
School (S) 34,000 297.1 270.9 373.8
School Admin (SA) 1,600 14.0 12.7 17.6
School Warehouse (SW) 4,200 36.7 33.5 46.2
School Living Center (SLC) 28,800 251.7 229.4 316.6
Nenana Native Council Day Care (DC) 4,550 39.8 36.2 50.0
City Water Plant (WP) 10,700 93.5 85.2 117.6
City Fire Dept (FD) 3,950 34.5 31.5 43.4
Meda Lord Senior Center (ML) 6566 57.4 52.3 72.2
S + SA 35,600 311.1 283.6 391.3
S + SA + SW 39,800 347.8 317.1 437.5
S + SA + SW + DC 44,350 387.6 353.3 487.5
S + SA + SW + DC + WP 55,050 481.1 438.6 605.2
S + SA + SW + DC + WP + FD 59,000 515.6 470.0 648.6
S + SA + SW + DC + WP + FD + SLC 87,800 767.3 699.5 1037.3
S + SA + SW + SLC 68,600 599.5 546.5 754.1
Note: Wood fuel use assumes offsetting 85% of the current energy use.
Pre-Feasibility Assessment for Nenana School and City of Nenana
Integration of Wood-Fired Heating Systems Nenana, Alaska
CTA Architects Engineers Page 2 of 13
July 24, 2012
Based on the potential wood fuel use, all options except the Meda Lord Senior Center will
evaluate wood chip and wood pellet boilers. Because of the smaller fuel use, the Meda
Lord Senior Center will evaluate a cord wood boiler system.
Wood Chip Boiler Options:
A.1: Nenana School only.
A.2: Nenana School, Administration Building, and Warehouse.
A.3: Nenana School, Administration Building, Warehouse, and NNC Daycare.
A.4: Nenana School, Administration Building, Warehouse, NNC Daycare, and Water
Plant.
A.5: Nenana School, Administration Building, Warehouse, NNC Daycare, Water
Plant, and Fire Department.
A.6: Nenana School, Administration Building, Warehouse, and Living Center.
Wood Pellet Boiler Options:
B.1: Nenana School only.
Cord Wood Boiler Options:
C.1: Meda Lord Senior Center only.
The following table summarizes the economic evaluation for each option:
Table 1.3 - Economic Evaluation Summary
Nenana 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
A.1 $1,780,000 $59,208 $2,832,089 $1,616,943 0.91 1.59 $2,303,414 $4,911,172 18
A.2 $1,960,000 $72,175 $3,385,501 $1,940,341 0.99 1.73 $2,761,778 $5,862,829 17
A.3 $2,150,000 $81,506 $3,795,177 $2,177,730 1.01 1.77 $3,098,786 $6,569,425 16
A.4 $2,590,000 $99,342 $4,638,894 $2,656,188 1.03 1.79 $3,780,882 $8,035,572 16
A.5 $2,680,000 $106,772 $4,975,009 $2,849,249 1.06 1.86 $4,055,426 $8,617,079 16
A.6 $2,860,000 $112,808 $5,441,730 $3,085,014 1.08 1.90 $4,399,622 $9,458,385 16
B.1 $1,300,000 $7,206 $1,289,692 $590,490 0.45 0.99 $882,087 $2,389,469 24
C.1 $280,000 -$1,773 $220,868 $88,173 0.31 0.79 $137,198 $423,622 26
Connecting the school with several nearby buildings with a wood fired district heating
system appears to be an economically viable project. With the current economic
assumptions, the school alone and the school combined with the administration building
and the school warehouse don’t quite meet the minimum 20 year B/C ratio of 1.0
However, when adding in the daycare, the water plant, and fire department, all these
incremental options have 20 year B/C ratios greater than 1.0. The additional energy
saved by connecting several buildings together offsets the significant additional cost of
underground piping and pumping costs. The best option was A.6 which connected the
Pre-Feasibility Assessment for Nenana School and City of Nenana
Integration of Wood-Fired Heating Systems Nenana, Alaska
CTA Architects Engineers Page 3 of 13
July 24, 2012
school with the administration building, the school warehouse, and the student living
center. Even with the significant piping costs, the extra pumping energy, and the extra
wood fuel needed to offset the heat loss of the long pipe runs, this option remains the
strongest relative to the other options.
Pre-Feasibility Assessment for Nenana School and City of Nenana
Integration of Wood-Fired Heating Systems Nenana, Alaska
CTA Architects Engineers Page 4 of 13
July 24, 2012
2.0 Introduction
The following assessment was commissioned to determine the preliminar y technical and
economic feasibility of integrating a wood fired heating system at the Nenana School,
School Administration, School Warehouse, School Living Center, Nenana Native Council
Day Care, Nenana Fire Department, Nenana Water Plant, and the Meda Lord Senior
Center in Nenana, Alaska.
3.0 Existing Building Systems
The School District is responsible for the School, School Administration, School
Warehouse, and Student Living Center. The City of Nenana is responsible for the Water
Plant and Fire Department. The Nenana Native Council is responsible for the Day Care
and the Alaska Interior Regional Housing Authority is responsible for the Meda Lord
Senior Center. There is a high level of cooperation amongst all the organizations and by
extension with the Toghotthele Native Corporation which currently operates a lumber mill
and is capable of providing chipped or ground wood fuel for use in future wood fired boiler
projects.
The Nenana School is a wood framed and steel stud building constructed in 1955 and
expanded in 1966 and 1986. The gymnasium is a wood framed and steel stud building
constructed in 1972 and was connected to the main school during the 1986 addition. The
entire facility is approximately 70,860 square feet. There are two boiler rooms in the
facility: one in the original school building and one in the gym. In a major mechanical
system retrofit to occurred approximately 15 years ago, new heating water mains were
installed throughout the facility, and the boilers were re-piped to provide heat to this main
loop. That work allows any boiler to provide heat to the entire facility. In the original
building boiler room there are two 2,503,000 Btu/hr output hot water boilers. These boilers
appear to be approximately 15 years old and are in good condition. In the gym boiler
room there are two 950,000 Btu/hr output hot water boilers. These boilers appeared to be
original to the gym construction and are in fair condition. Each boiler room has a large
approximately 500 gallon indirect domestic hot water heater using boiler water as the
heating source.
The Nenana School Administration Building is a wood framed modular building
constructed in 2005. The facility is approximately 2,480 square feet and is heated by a
196,000 Btu/hr output hot water boiler. The boiler is original to the building and in good
condition. The heating system infrastructure is original to the building and in good
condition.
The Nenana School Warehouse is a prefabricated metal building with interior insulation on
metal wall panels on a concrete slab on grade constructed in 1982. The facility is
approximately 6,500 square feet and is heated by one 236,000 Btu/hr output and one
212,000 Btu/hr output hot water boilers. Domestic hot water is provided by a 30 gallon
electric water heater rated at 5.5 KW input. One boiler is original to the building and is in
fair condition, and the other boiler is new, installed within the past year. The heating
system infrastructure is original to the building and in fair condition.
The Nenana Student Living Center is a wood framed dormitory building constructed in
2002 with approximately 88 sleeping rooms and 44 shared restroom/shower facilities. The
facility is approximately 32,700 square feet and is heated by a 1,372,000 Btu/hr output hot
water boiler. Domestic hot water is provided by a 623,000 Btu/hr fuel oil fired hot water
heater with a 85 gallon storage tank. The existing boiler and hot water heater are original
Pre-Feasibility Assessment for Nenana School and City of Nenana
Integration of Wood-Fired Heating Systems Nenana, Alaska
CTA Architects Engineers Page 5 of 13
July 24, 2012
to the building and in good condition. The heating system infrastructure is original to the
building and in good condition.
The Nenana Water Plant is a wood framed building constructed in the mid 1970’s and
houses equipment required to store, heat, and pump the community water system. The
facility is approximately 5,000 square feet and utilizes a 1,110,000 Btu/hr output hot water
boiler. The existing boiler is original to the building and is in fair condition. The heating
system infrastructure is original to the building and in fair condition.
The Nenana Fire Department is a metal building constructed in early 1980’s. The facility is
approximately 4,000 square feet and is heated by two 272,000 Btu/hr output hot water
boilers. Domestic hot water is provided by a 40 gallon electric water heater rated at 4.5
KW input. The existing boilers are approximately 9 years old and in good condition. The
heating system infrastructure is original to the building an in fair condition. The building
was not reviewed during the field visit because CTA had gathered data during a trip to
Nenana in December, 2011. The feasibility assessment of the facility is included in this
report.
The Meda Lord Senior Center is a wood framed building constructed in 1993. The facility
is approximately 13,000 square feet and is heated by three 488,000 Btu/hr output hot
water boilers. Domestic hot water is provided by a 155 gallon indirect water heater using
boiler water as the heating source. The existing boilers are original to the building and in
fair condition. The heating system infrastructure is original to the building and in fair
condition.
Facilities Dropped from Feasibility Study
The Nenana Library was not reviewed during the field visit due to the small size and low
fuel use.
Facilities Added to Feasibility Study
The Nenana Native Council Day Care was added to the potential facilities during the site
visit. The building is a wood framed building constructed in 2006. The facility is
approximately 6,500 square feet and is heated by a 347,000 Btu/hr output hot water boiler.
Domestic hot water is provided by a 120 gallon indirect water heater using boiler water as
the heating source. The existing boiler is original to the building and is in good condition.
The heating system infrastructure is original to the building and in good condition.
Pre-Feasibility Assessment for Nenana School and City of Nenana
Integration of Wood-Fired Heating Systems Nenana, Alaska
CTA Architects Engineers Page 6 of 13
July 24, 2012
4.0 Energy Use
Fuel use summaries for the facilities were provided and the following table summarizes the
data:
Table 4.1 - Annual Fuel Use Summary
Fuel Avg. Use Current Annual
Facility Name Type (Gallons) Cost/Gal. Cost
School Fuel Oil 34,000 $3.60 $122,400
School Admin Fuel Oil 1,600 $3.60 $5,760
School Whse. Fuel Oil 4,200 $3.60 $15,120
Student Living
Center Fuel Oil 28,800 $3.60 $103,680
NNC Day
Care Fuel Oil 4550 $3.60 $16,380
Water Plant Fuel Oil 10700 $3.60 $38,520
Fire Dept. Fuel Oil 3950 $3.60 $14,220
Meda Lord
Senior Center Fuel Oil 6566 $4.00 $26,264
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 augers,
conveyors, draft fans, etc. 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 fuel fired boilers and domestic
water heaters:
Table 5.1 - Connected Boiler Load Summary
Likely
Peak System
Output Load Peak
MBH Factor MBH
School Boiler A Fuel Oil 2503 0.66 1652
Boiler B Fuel Oil 2503 0.66 1652
Boiler C Fuel Oil 950 0.66 627
Boiler D Fuel Oil 950 0.66 627
Total 6906 4558
School Admin Boiler Fuel Oil 196 1.00 196
School Warehouse Boiler Fuel Oil 236 0.67 158
Boiler Fuel Oil 212 0.67 142
Total 300
School Living Center Boiler Fuel Oil 1372 1.00 1372
DWH Fuel Oil 623 1.00 623
Total 1995
Pre-Feasibility Assessment for Nenana School and City of Nenana
Integration of Wood-Fired Heating Systems Nenana, Alaska
CTA Architects Engineers Page 7 of 13
July 24, 2012
Table 5.1 - Connected Boiler Load Summary
Nenana NC Day Care Boiler Fuel Oil 347 1.00 347
City Water Plant Boiler
Fuel Oil 1110 1.00 1110
City Fire Dept Boiler Fuel Oil 272 0.60 163
Boiler Fuel Oil 272 0.60 163
Total 326
Meda Lord Sr. Center Boiler 1 Fuel Oil 488 0.66 322
Boiler 2 Fuel Oil 488 0.66 322
Boiler 3 Fuel Oil 488 0.66 322
Total 1464 966
Total Of All Buildings 13010 9799
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 f ew 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.
Several projects are under consideration in Nenana, therefore the boiler size will vary with
each option as noted below.
Table 5.2 - Proposed Biomass Boiler Size
Likely Biomass
System Biomass Boiler
Peak Boiler Size
MBH Factor MBH
School (S) (Option 1) 4558 0.6 2735
School Admin (SA) 196 0.6 118
School Warehouse (SW) 300 0.6 180
School Living Center (SLC) 1995 0.6 1197
Nenana Native Council Day Care (DC) 347 0.6 208
City Water Plant (WP) 1110 0.6 666
City Fire Dept (FD) 326 0.6 196
Meda Lord Senior Center (ML) 966 0.6 580
S + SA 4754 0.6 2852
S + SA + SW (Option 2) 5054 0.6 3032
S + SA + SW + DC (Option 3) 5401 0.6 3241
S + SA + SW + DC + WP (Option 4) 6511 0.6 3907
S + SA + SW + DC + W P + FD (Option 5) 6838 0.6 4103
S + SA + SW + DC + WP + FD + SLC 9799 0.6 5879
S + SA + SW + SLC (Option 6) 7049 0.6 4229
Pre-Feasibility Assessment for Nenana School and City of Nenana
Integration of Wood-Fired Heating Systems Nenana, Alaska
CTA Architects Engineers Page 8 of 13
July 24, 2012
A district system around the school will be evaluated. Stand-alone systems for the
Student Living Center and the Meda Lord Senior Center will also be evaluated since these
buildings are so far from the school.
6.0 Wood Fuel Use
The types of wood fuel available in the area include cord wood, wood pellets, and
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
Chipped/
Fuel Cord Wood Ground
Oil Wood Pellets Wood
(Gallons) (Cords) (Tons) (Tons)
School (S) 34,000 297.1 270.9 373.8
School Admin (SA) 1,600 14.0 12.7 17.6
School Warehouse (SW) 4,200 36.7 33.5 46.2
School Living Center (SLC) 28,800 251.7 229.4 316.6
Nenana Native Council Day Care (DC) 4,550 39.8 36.2 50.0
City Water Plant (WP) 10,700 93.5 85.2 117.6
City Fire Dept (FD) 3,950 34.5 31.5 43.4
Meda Lord Senior Center (ML) 6566 57.4 52.3 72.2
S + SA 35,600 311.1 283.6 391.3
S + SA + SW 39,800 347.8 317.1 437.5
S + SA + SW + DC 44,350 387.6 353.3 487.5
S + SA + SW + DC + WP 55,050 481.1 438.6 605.2
S + SA + SW + DC + WP + FD 59,000 515.6 470.0 648.6
S + SA + SW + DC + WP + FD + SLC 87,800 767.3 699.5 1037.3
S + SA + SW + SLC 68,600 599.5 546.5 754.1
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%. Chipped/ground fuel was assumed to be 30% MC with a system efficiency of 65%.
The primary project is the school. As can be seen from the potential wood fuel use, the
volume of wood is such that a cord wood system is not really practical and further analysis
will look at pellet and chipped/ground fuel options. A cord wood only system for the Meda
Lord Senior Center will be evaluated since it would be a stand-alone system.
Toghotthele Corporation owns 138,000 acres of land, of which most of it is forested. There
are also State lands around Nenana. With some recent wild fires, there is some desire in
the area to thin some of the forests around the city to create fire breaks. The agricultural
area to the west is also planned to be opened up in the next few years, and there will be
Pre-Feasibility Assessment for Nenana School and City of Nenana
Integration of Wood-Fired Heating Systems Nenana, Alaska
CTA Architects Engineers Page 9 of 13
July 24, 2012
significant amount of wood to be removed as this land is developed. Toghotthele is actively
managing their land and is currently logging some of it. They are looking into purchasing
more logging equipment and even a chipper. If a biomass project was to develop,
Toghotthele would likely be the entity to provide the wood. Wood pellets are also available
from Superior Pellet Fuels out of North Pole and can be trucked down the Parks Highway.
There appears to be a sufficient supply of wood fuel to support a wood fired boiler for this
community.
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 $3.60 $33.46 $26.77
$4.00 $37.17 $29.74
$4.50 $41.82 $33.46
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
Pellets tons 16400000 0.7 11480000 $300.00 $26.13 $18.29
$350.00 $30.49 $21.34
$400.00 $34.84 $24.39
Chips tons 10800000 0.65 7020000 $75.00 $10.68 $6.94
$100.00 $14.25 $9.26
$125.00 $17.81 $11.57
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
stand alone boiler plant would be required. The existing gravel parking lot west of the
Administration building has been identified as the preferred location for a central heating
plant. A stand alone plant for the Meda Lord Senior Center would be located on the west
side of the building.
Any type of biomass boiler system will require access by delivery vehicles, typically 40 foot
long chips vans or some similar type of trailer. Wood fuel is likely to be chipped or ground
by the Toghotthele Native Corporation and delivered to a central boiler plant. The
proposed plant location includes access from three adjacent streets and is in close
proximity to each of the potential facilities with the exception of the Student Living Center
and the Meda Lord Senior Center. Nenana is on the Parks Highway, so highway access
is good.
Pre-Feasibility Assessment for Nenana School and City of Nenana
Integration of Wood-Fired Heating Systems Nenana, Alaska
CTA Architects Engineers Page 10 of 13
July 24, 2012
8.0 Integration with Existing Heating Systems
Integration of a wood fired boiler system would be relatively straight forward in each
location. 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 artic 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
it would be connected to existing supply and return lines in appropriate locations in order
to utilize existing pumping systems within each building.
9.0 Air Quality Permits
Resource System Group has done a preliminary review of potential air quality issues in the
area. Interior Alaska is prone to meteorological conditions that create thermal inversions,
which are unfavorable for the dispersion of emissions. Since this plant will be located at a
school and is also located in the populated area, the air quality will likely be scrutinized
and modeling of emissions, the stack height, and of air pollution control devices is
recommended. Due to the high percentage of “calms” during the winter in interior Alaska,
all options at the school include the cost of an electrostatic precipitator (ESP). 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 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 potential wood fuel use, all options except the Meda Lord Senior Center will
evaluate wood chip and wood pellet boilers. Because of the smaller fuel use, the Meda
Lord Senior Center will evaluate a cord wood boiler system.
Wood Chip Boiler Options:
A.1: Nenana School only.
A.2: Nenana School, Administration Building, and Warehouse.
A.3: Nenana School, Administration Building, Warehouse, and NNC Daycare.
A.4: Nenana School, Administration Building, Warehouse, NNC Daycare, and Water
Plant.
A.5: Nenana School, Administration Building, Warehouse, NNC Daycare, Water
Plant, and Fire Department.
A.6: Nenana School, Administration Building, Warehouse, and Living Center.
Wood Pellet Boiler Options:
B.1: Nenana School only.
Cord Wood Boiler Options:
C.1: Meda Lord Senior Center only.
All wood chip and pellet options assume a central boiler plant is used and located next to
the Administration building. All “A” options assume a new stand-alone boiler plant is
Pre-Feasibility Assessment for Nenana School and City of Nenana
Integration of Wood-Fired Heating Systems Nenana, Alaska
CTA Architects Engineers Page 11 of 13
July 24, 2012
constructed to house the boiler and chip storage. Option B.1 assumes a new stand-alone
boiler plant is constructed to house the boiler with an exterior silo or silos. The cord wood
boiler option 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/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 $3.60/gal, electricity at $0.28/kwh, wood pellets
delivered at $325/ton, and wood chips delivered at $75/ton. The fuel oil, electricity, and
cord wood costs were based on utility bills and reports form the end users. Chipped and
ground wood fuel costs are estimates based on Toghotthele Corporation’s estimates of
delivered costs. Pellet costs were obtained from Superior Pellet Fuels.
It is assumed that the biomass 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 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. In the different central plant
options, there are significant runs of underground pipe to connect to the City Water Plant
and to the Student Living Center. The amount of heat energy lost in these long runs was
estimated and the additional required heating energy was added to the boiler plant load,
that is, the boiler plant was assumed to burn more chips to accommodate the piping heat
losses.
Pre-Feasibility Assessment for Nenana School and City of Nenana
Integration of Wood-Fired Heating Systems Nenana, Alaska
CTA Architects Engineers Page 12 of 13
July 24, 2012
13.0 Results of Evaluation
The following table summarizes the economic evaluation for each option:
Table 13.1 - Economic Evaluation Summary
Nenana 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
A.1 $1,780,000 $59,208 $2,832,089 $1,616,943 0.91 1.59 $2,303,414 $4,911,172 18
A.2 $1,960,000 $72,175 $3,385,501 $1,940,341 0.99 1.73 $2,761,778 $5,862,829 17
A.3 $2,150,000 $81,506 $3,795,177 $2,177,730 1.01 1.77 $3,098,786 $6,569,425 16
A.4 $2,590,000 $99,342 $4,638,894 $2,656,188 1.03 1.79 $3,780,882 $8,035,572 16
A.5 $2,680,000 $106,772 $4,975,009 $2,849,249 1.06 1.86 $4,055,426 $8,617,079 16
A.6 $2,860,000 $112,808 $5,441,730 $3,085,014 1.08 1.90 $4,399,622 $9,458,385 16
B.1 $1,300,000 $7,206 $1,289,692 $590,490 0.45 0.99 $882,087 $2,389,469 24
C.1 $280,000 -$1,773 $220,868 $88,173 0.31 0.79 $137,198 $423,622 26
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.
Because a school is part of this project, a life cycle cost analysis following the
req uirements of the State of Alaska Department of Education & Early Development was
completed and the data is summarized in the following table:
Table 13.2 - Life Cycle Costs of Project Alternatives
Alternate #1 Alternate #2
Existing Boiler Wood Chip Boiler (A.2)
Initial Investment Cost $0 $1,960,000
Operations Cost $3,360,393 $854,631
Maintenance & Repair Cost $0 $56,725
Replacement Cost $0 $0
Residual Value $0 $0
Total Life Cycle Cost $3,360,393 $2,871,356
Pre-Feasibility Assessment for Nenana School and City of Nenana
Integration of Wood-Fired Heating Systems Nenana, Alaska
CTA Architects Engineers Page 13 of 13
July 24, 2012
14.0 Project Funding
The Nenana City School District and the City of Nenana may pursue a biomass project
grant from the Alaska Energy Authority.
The Nenana City School District and the City of Nenana 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
Connecting the school with several nearby buildings with a wood fired district heating
system appears to be an economically viable project. With the current economic
assumptions, the school alone and the school combined with the administration building
and the school warehouse don’t quite meet the minimum 20 year B/C ratio of 1.0
However, when adding in the daycare, the water plant, and fire department, all these
incremental options have 20 year B/C ratios greater than 1.0. The additional energy
saved by connecting several buildings together offsets the significant additional cost of
underground piping and pumping costs. The best option was A.6 which connected the
school with the administration building, the school warehouse, and the student living
center. Even with the significant piping costs, the extra pumping energy, and the extra
wood fuel needed to offset the heat loss of the long pipe runs, this option remains the
strongest relative to the other options.
Additional sensitivity analysis has been performed and is attached. Using option A.6 as
the basis of the analysis, the B/C ratio will exceed 1.0 if wood fuel prices stay below
$85/ton.
The analysis also shows that a central plant with a pellet boiler is not viable, nor is a stand-
alone cord wood boiler system for the Meda Lord Senior Center.
Recommended Actions
Most grant programs will likely require a full feasibility assessment. A full assessment
would provide more detail on the air quality issues, wood fuel resources, review the pipe
routing and potential underground conflicts, and develop a schematic design of the boiler
plant including wood storage size, and schematic design of the heating systems
integration. These schematic designs will also help obtain more accurate costs. Since
several options appear to be viable, more investigation should be engaged to determine
the best project to proceed with.
APPENDIX A
Preliminary Estimates of Probable Cost
Preliminary Estimates of Probable Cost
Biomass Heating Options
Nenana, AK
Chip Option A.1 - School Integration
Chip Storage/ Boiler Building:$270,000
Wood Heating & Wood Handling System: $325,000
Stack/Air Pollution Control Device:$180,000
Mechanical/Electrical within Boiler Building: $150,000
Underground Piping $60,000
School Integration $50,000
Subtotal:$1,035,000
30% Remote Factor $310,500
Subtotal:$1,345,500
Design Fees, Building Permit, Miscellaneous Expenses 15%: $201,825
Subtotal:$1,547,325
15% Contingency:$232,099
Total Project Costs 1,779,424$
Chip Option A.2 - S + SA +SW
Chip Storage/ Boiler Building:$270,000
Wood Heating & Wood Handling System: $325,000
Stack/Air Pollution Control Device:$180,000
Mechanical/Electrical within Boiler Building: $150,000
Underground Piping $115,000
School Integration $50,000
Warehouse and Administration Integration $51,000
Subtotal:$1,141,000
30% Remote Factor $342,300
Subtotal:$1,483,300
Design Fees, Building Permit, Miscellaneous Expenses 15%: $222,495
Subtotal:$1,705,795
15% Contingency:$255,869
Total Project Costs 1,961,664$
Preliminary Estimates of Probable Cost
Biomass Heating Options
Nenana, AK
Chip Option A.3 - S + SA + SW + DC
Chip Storage/ Boiler Building:$270,000
Wood Heating & Wood Handling System: $325,000
Stack/Air Pollution Control Device:$180,000
Mechanical/Electrical within Boiler Building: $150,000
Underground Piping $180,000
School Integration $50,000
Warehouse and Administration Integration $51,000
Day Care Integration $44,000
Subtotal:$1,250,000
30% Remote Factor $375,000
Subtotal:$1,625,000
Design Fees, Building Permit, Miscellaneous Expenses 15%: $243,750
Subtotal:$1,868,750
15% Contingency:$280,313
Total Project Costs 2,149,063$
Chip Option A.4 - S + SA + SW + DC + WP
Chip Storage/ Boiler Building:$270,000
Wood Heating & Wood Handling System: $325,000
Stack/Air Pollution Control Device:$180,000
Mechanical/Electrical within Boiler Building: $150,000
Underground Piping $390,000
School Integration $50,000
Warehouse and Administration Integration $51,000
Day Care Integration $44,000
Water Plant Integration $46,500
Subtotal:$1,506,500
30% Remote Factor $451,950
Subtotal:$1,958,450
Design Fees, Building Permit, Miscellaneous Expenses 15%: $293,768
Subtotal:$2,252,218
15% Contingency:$337,833
Total Project Costs 2,590,050$
Preliminary Estimates of Probable Cost
Biomass Heating Options
Nenana, AK
Chip Option A.5 - S + SA + SW + DC + WP + FH
Chip Storage/ Boiler Building:$270,000
Wood Heating & Wood Handling System: $325,000
Stack/Air Pollution Control Device:$180,000
Mechanical/Electrical within Boiler Building: $150,000
Underground Piping $400,000
School Integration $50,000
Warehouse and Administration Integration $51,000
Day Care Integration $44,000
Water Plant Integration $46,500
Fire Hall Integration $43,000
Subtotal:$1,559,500
30% Remote Factor $467,850
Subtotal:$2,027,350
Design Fees, Building Permit, Miscellaneous Expenses 15%: $304,103
Subtotal:$2,331,453
15% Contingency:$349,718
Total Project Costs 2,681,170$
Chip Option A.6 - S + SA +SW + SLC
Chip Storage/ Boiler Building:$270,000
Wood Heating & Wood Handling System: $325,000
Stack/Air Pollution Control Device:$180,000
Mechanical/Electrical within Boiler Building: $150,000
Underground Piping $590,000
School Integration $50,000
Warehouse and Administration Integration $51,000
SLC Integration $47,500
Subtotal:$1,663,500
30% Remote Factor $499,050
Subtotal:$2,162,550
Design Fees, Building Permit, Miscellaneous Expenses 15%: $324,383
Subtotal:$2,486,933
15% Contingency:$373,040
Total Project Costs 2,859,972$
Preliminary Estimates of Probable Cost
Biomass Heating Options
Nenana, AK
Pellet Option B.1 - School Integration
Boiler Building and Silo:$180,000
Wood Heating & Wood Handling System: $265,000
Stack/Air Pollution Control Device:$50,000
Mechanical/Electrical within Boiler Building: $150,000
Underground Piping $60,000
School Integration $50,000
Subtotal:$755,000
30% Remote Factor $226,500
Subtotal:$981,500
Design Fees, Building Permit, Miscellaneous Expenses 15%: $147,225
Subtotal:$1,128,725
15% Contingency:$169,309
Total Project Costs 1,298,034$
Cord Wood Option C.1 - Meda Lord Senior Center
Biomass Boiler Building:$97,500
Wood Heating and Cord Wood Storage $16,000
Stack:$2,200
Mechanical/Electrical within Boiler Building: $20,200
Underground Piping $12,000
MLSC 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
&
Economic Sensitivity Analysis
Nenana SchoolOption A.1Nenana, AlaskaWood Chip Boiler Date: July 24, 2012 Analyst: CTA Architects Engineers - Nick Salmon & Nathan Ratz EXISTING CONDITIONSSchool Admin Warehouse Daycare TotalExisting Fuel Type:Fuel Oil Fuel Oil Fuel Oil Fuel OilFuel Units:gal gal gal galCurrent Fuel Unit Cost:$3.60 $3.60 $3.60 $3.60 Estimated Average Annual Fuel Usage:34,00034,000Annual Heating Costs:$122,400 $0 $0 $0 $122,400ENERGY CONVERSION (to 1,000,000 Btu; or 1 dkt)Fuel Heating Value (Btu/unit of fuel):134500 134500 134500 134500Current Annual Fuel Volume (Btu):4,573,000,000 0 0 0Assumed efficiency of existing heating system (%):80% 80% 80% 80% Net Annual Energy Produced (Btu):3,658,400,000 0 0 0 3,658,400,000WOOD FUEL COSTWood Chips$/ton: $75.00Assumed efficiency of wood heating system (%): 65% PROJECTED WOOD FUEL USAGEEstimated Btu content of wood fuel (Btu/lb) - Assumed 30% MC 6400 Tons of wood fuel to supplant net equivalent of 100% annual heating load.440Tons of wood fuel to supplant net equivalent of 85% annual heating load.37425 ton chip van loads to supplant net equivalent of 85% annual heating load.15 Project Capital Cost-$1,780,000 Project Financing InformationPercent Financed0.0%Est. Pwr Use 40000 kWh Type Hr/Wk Wk/Yr Total Hr Wage/Hr TotalAmount Financed$0 Elec Rate $0.280 /kWh Biomass System 4.0 40 160 $20.00 $3,200Amount of Grants$1,780,000 Other 0.0 40 0 $20.00 $01st 2 Year Learning 3.0 40 120 $20.00 $2,400Interest Rate5.00%Term10Annual Finance Cost (years)$0 30.1 years Net Benefit B/C Ratio$2,832,089 $1,052,089 1.59$1,616,943 -$163,0570.91Year Accumulated Cash Flow > 0#N/AYear Accumulated Cash Flow > Project Capital Cost18Inflation FactorsO&M Inflation Rate2.0%Fossil Fuel Inflation Rate5.0%Wood Fuel Inflation Rate3.0%Electricity Inflation Rate3.0%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 $3.60 34000 gal $122,400 $128,520 $134,946 $141,693 $148,778 $156,217 $164,028 $172,229 $180,841 $189,883 $199,377 $209,346 $219,813 $230,803 $242,344 $309,299 $394,752 $503,815Displaced heating costs $3.600 gal $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0Displaced heating costs $3.600 gal $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0Displaced heating costs $3.600 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)$75.00 85% 374 tons $28,032 $28,873 $29,739 $30,631 $31,550$32,496 $33,471 $34,475 $35,510 $36,575 $37,672 $38,802 $39,966 $41,165 $42,400 $49,154 $56,982 $66,058Small load existing fuel$3.60 15% 5100 gal $18,360 $19,278 $20,242 $21,254 $22,317 $23,433 $24,604 $25,834 $27,126 $28,482 $29,907 $31,402 $32,972 $34,621 $36,352 $46,395 $59,213 $75,572Small load existing fuel$3.60 15% 0 gal $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0Small load existing fuel$3.60 15% 0 gal $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0Small load existing fuel$3.60 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$3,200 $3,264 $3,329 $3,396 $3,464 $3,533 $3,604 $3,676 $3,749 $3,824 $3,901 $3,979 $4,058 $4,140 $4,222 $4,662 $5,147$5,683Additional Operation and Maintenance Costs First 2 years$2,400 $2,448Additional Electrical Cost $0.280$11,200 $11,536 $11,882 $12,239 $12,606 $12,984 $13,373 $13,775 $14,188 $14,613 $15,052 $15,503 $15,969 $16,448 $16,941 $19,639 $22,767 $26,394Annual Operating Cost Savings$59,208$63,121$69,754$74,174$78,842$83,771$88,975$94,469$100,268$106,388$112,845$119,659$126,848$134,430$142,428$189,449$250,643$330,108Financed Project Costs - Principal and Interest0000000000 Displaced System Replacement Costs (year one only)0Net Annual Cash Flow59,208 63,121 69,754 74,174 78,842 83,771 88,975 94,469 100,268 106,388 112,845 119,659 126,848 134,430 142,428 189,449 250,643 330,108Accumulated Cash Flow59,208 122,330 192,084 266,258 345,100 428,871 517,846 612,315 712,583 818,970 931,816 1,051,475 1,178,323 1,312,753 1,455,181 2,303,414 3,427,827 4,911,172Additional Power UseAdditional MaintenanceSimple Payback: Total Project Cost/Year One Operating Cost Savings:Net Present Value (30 year analysis):Net Present Value (20 year analysis):
Nenana School + Admin + Warehouse Option A.2Nenana, AlaskaWood Chip Boiler Date: July 24, 2012 Analyst: CTA Architects Engineers - Nick Salmon & Nathan Ratz EXISTING CONDITIONSSchool Admin Warehouse Daycare TotalExisting Fuel Type:Fuel Oil Fuel Oil Fuel Oil Fuel OilFuel Units:gal gal gal galCurrent Fuel Unit Cost:$3.60 $3.60 $3.60 $3.60 Estimated Average Annual Fuel Usage:34,000 1,600 4,20039,800Annual Heating Costs:$122,400 $5,760 $15,120 $0 $143,280ENERGY CONVERSION (to 1,000,000 Btu; or 1 dkt)Fuel Heating Value (Btu/unit of fuel):134500 134500 134500 134500Current Annual Fuel Volume (Btu):4,573,000,000 215,200,000 564,900,000 0Assumed efficiency of existing heating system (%):80% 80% 80% 80% Net Annual Energy Produced (Btu):3,658,400,000 172,160,000 451,920,000 0 4,282,480,000WOOD FUEL COSTWood Chips$/ton: $75.00Assumed efficiency of wood heating system (%): 65% PROJECTED WOOD FUEL USAGEEstimated Btu content of wood fuel (Btu/lb) - Assumed 30% MC 6400 Tons of wood fuel to supplant net equivalent of 100% annual heating load.515Tons of wood fuel to supplant net equivalent of 85% annual heating load.43825 ton chip van loads to supplant net equivalent of 85% annual heating load.18 Project Capital Cost-$1,960,000 Project Financing InformationPercent Financed0.0%Est. Pwr Use 40000 kWh Type Hr/Wk Wk/Yr Total Hr Wage/Hr TotalAmount Financed$0 Elec Rate $0.280 /kWh Biomass System 4.0 40 160 $20.00 $3,200Amount of Grants$1,960,000 Other 0.0 40 0 $20.00 $01st 2 Year Learning 3.0 40 120 $20.00 $2,400Interest Rate5.00%Term10Annual Finance Cost (years)$0 27.2 years Net Benefit B/C Ratio$3,385,501 $1,425,501 1.73$1,940,341 -$19,6590.99Year Accumulated Cash Flow > 0#N/AYear Accumulated Cash Flow > Project Capital Cost17Inflation FactorsO&M Inflation Rate2.0%Fossil Fuel Inflation Rate5.0%Wood Fuel Inflation Rate3.0%Electricity Inflation Rate3.0%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 $3.60 34000 gal $122,400 $128,520 $134,946 $141,693 $148,778 $156,217 $164,028 $172,229 $180,841 $189,883 $199,377 $209,346 $219,813 $230,803 $242,344 $309,299 $394,752 $503,815Displaced heating costs $3.60 1600 gal $5,760 $6,048 $6,350 $6,668 $7,001 $7,351 $7,719 $8,105 $8,510 $8,936 $9,382 $9,852 $10,344 $10,861 $11,404 $14,555 $18,577 $23,709Displaced heating costs $3.60 4200 gal $15,120 $15,876 $16,670 $17,503 $18,378 $19,297 $20,262 $21,275 $22,339 $23,456 $24,629 $25,860 $27,153 $28,511 $29,937 $38,207 $48,764 $62,236Displaced heating costs $3.600 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)$75.00 85% 438 tons $32,813 $33,798 $34,812 $35,856 $36,932$38,040 $39,181 $40,356 $41,567 $42,814 $44,099 $45,422 $46,784 $48,188 $49,633 $57,539 $66,703 $77,327Small load existing fuel$3.60 15% 5100 gal $18,360 $19,278 $20,242 $21,254 $22,317 $23,433 $24,604 $25,834 $27,126 $28,482 $29,907 $31,402 $32,972 $34,621 $36,352 $46,395 $59,213 $75,572Small load existing fuel$3.60 15% 240 gal $864 $907 $953 $1,000 $1,050 $1,103 $1,158 $1,216 $1,277 $1,340 $1,407 $1,478 $1,552 $1,629 $1,711 $2,183 $2,786 $3,556Small load existing fuel$3.60 15% 630 gal $2,268 $2,381 $2,500 $2,625 $2,757 $2,895 $3,039 $3,191 $3,351 $3,518 $3,694 $3,879 $4,073 $4,277 $4,490 $5,731 $7,315 $9,335Small load existing fuel$3.60 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$3,200 $3,264 $3,329 $3,396 $3,464 $3,533 $3,604 $3,676 $3,749 $3,824 $3,901 $3,979 $4,058 $4,140 $4,222 $4,662 $5,147$5,683Additional Operation and Maintenance Costs First 2 years$2,400 $2,448Additional Electrical Cost $0.280$11,200 $11,536 $11,882 $12,239 $12,606 $12,984 $13,373 $13,775 $14,188 $14,613 $15,052 $15,503 $15,969 $16,448 $16,941 $19,639 $22,767 $26,394Annual Operating Cost Savings$72,175$76,832$84,248$89,494$95,033$100,879$107,049$113,561$120,432$127,681$135,329$143,395$151,903$160,875$170,335$225,913$298,161$391,893Financed Project Costs - Principal and Interest0000000000 Displaced System Replacement Costs (year one only)0Net Annual Cash Flow72,175 76,832 84,248 89,494 95,033 100,879 107,049 113,561120,432 127,681 135,329 143,395 151,903 160,875 170,335 225,913 298,161 391,893Accumulated Cash Flow72,175 149,006 233,254 322,748 417,781 518,660 625,710 739,271 859,703 987,384 1,122,713 1,266,108 1,418,010 1,578,885 1,749,220 2,761,778 4,100,544 5,862,829Additional Power UseAdditional MaintenanceSimple Payback: Total Project Cost/Year One Operating Cost Savings:Net Present Value (30 year analysis):Net Present Value (20 year analysis):
Nenana School Buildings + Daycare Option A.3Nenana, AlaskaWood Chip Boiler Date: July 24, 2012 Analyst: CTA Architects Engineers - Nick Salmon & Nathan Ratz EXISTING CONDITIONSSchool Admin Warehouse Daycare TotalExisting Fuel Type:Fuel Oil Fuel Oil Fuel Oil Fuel OilFuel Units:gal gal gal galCurrent Fuel Unit Cost:$3.60 $3.60 $3.60 $3.60 Estimated Average Annual Fuel Usage:34,000 1,600 4,200 4,550 44,350Annual Heating Costs:$122,400 $5,760 $15,120 $16,380 $159,660ENERGY CONVERSION (to 1,000,000 Btu; or 1 dkt)Fuel Heating Value (Btu/unit of fuel):134500 134500 134500 134500Current Annual Fuel Volume (Btu):4,573,000,000 215,200,000 564,900,000 611,975,000Assumed efficiency of existing heating system (%):80% 80% 80% 80% Net Annual Energy Produced (Btu):3,658,400,000 172,160,000 451,920,000 489,580,000 4,772,060,000WOOD FUEL COSTWood Chips$/ton: $75.00Assumed efficiency of wood heating system (%): 65% PROJECTED WOOD FUEL USAGEEstimated Btu content of wood fuel (Btu/lb) - Assumed 30% MC 6400 Tons of wood fuel to supplant net equivalent of 100% annual heating load.574Tons of wood fuel to supplant net equivalent of 85% annual heating load.48825 ton chip van loads to supplant net equivalent of 85% annual heating load.20 Project Capital Cost-$2,150,000 Project Financing InformationPercent Financed0.0%Est. Pwr Use 43000 kWh Type Hr/Wk Wk/Yr Total Hr Wage/Hr TotalAmount Financed$0 Elec Rate $0.280 /kWh Biomass System 4.0 40 160 $20.00 $3,200Amount of Grants$2,150,000 Other 0.0 40 0 $20.00 $01st 2 Year Learning 3.0 40 120 $20.00 $2,400Interest Rate5.00%Term10Annual Finance Cost (years)$0 26.4 years Net Benefit B/C Ratio$3,795,177 $1,645,177 1.77$2,177,730 $27,7301.01Year Accumulated Cash Flow > 0#N/AYear Accumulated Cash Flow > Project Capital Cost16Inflation FactorsO&M Inflation Rate2.0%Fossil Fuel Inflation Rate5.0%Wood Fuel Inflation Rate3.0%Electricity Inflation Rate3.0%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 $3.60 34000 gal $122,400 $128,520 $134,946 $141,693 $148,778 $156,217 $164,028 $172,229 $180,841 $189,883 $199,377 $209,346 $219,813 $230,803 $242,344 $309,299 $394,752 $503,815Displaced heating costs $3.60 1600 gal $5,760 $6,048 $6,350 $6,668 $7,001 $7,351 $7,719 $8,105 $8,510 $8,936 $9,382 $9,852 $10,344 $10,861 $11,404 $14,555 $18,577 $23,709Displaced heating costs $3.60 4200 gal $15,120 $15,876 $16,670 $17,503 $18,378 $19,297 $20,262 $21,275 $22,339 $23,456 $24,629 $25,860 $27,153 $28,511 $29,937 $38,207 $48,764 $62,236Displaced heating costs $3.60 4550 gal $16,380 $17,199 $18,059 $18,962 $19,910 $20,905 $21,951 $23,048 $24,201 $25,411 $26,681 $28,015 $29,416 $30,887 $32,431 $41,391 $52,827 $67,422Biomass System Operating CostsWood Fuel ($/ton, delivered to boiler site)$75.00 85% 488 tons $36,565 $37,662 $38,792 $39,955 $41,154$42,389 $43,660 $44,970 $46,319 $47,709 $49,140 $50,614 $52,133 $53,697 $55,307 $64,117 $74,329 $86,167Small load existing fuel$3.60 15% 5100 gal $18,360 $19,278 $20,242 $21,254 $22,317 $23,433 $24,604 $25,834 $27,126 $28,482 $29,907 $31,402 $32,972 $34,621 $36,352 $46,395 $59,213 $75,572Small load existing fuel$3.60 15% 240 gal $864 $907 $953 $1,000 $1,050 $1,103 $1,158 $1,216 $1,277 $1,340 $1,407 $1,478 $1,552 $1,629 $1,711 $2,183 $2,786 $3,556Small load existing fuel$3.60 15% 630 gal $2,268 $2,381 $2,500 $2,625 $2,757 $2,895 $3,039 $3,191 $3,351 $3,518 $3,694 $3,879 $4,073 $4,277 $4,490 $5,731 $7,315 $9,335Small load existing fuel$3.60 15% 683 gal $2,457 $2,580 $2,709 $2,844 $2,986 $3,136 $3,293 $3,457 $3,630 $3,812 $4,002 $4,202 $4,412 $4,633 $4,865 $6,209 $7,924 $10,113Additional Operation and Maintenance Costs$3,200 $3,264 $3,329 $3,396 $3,464 $3,533 $3,604 $3,676 $3,749 $3,824 $3,901 $3,979 $4,058 $4,140 $4,222 $4,662 $5,147$5,683Additional Operation and Maintenance Costs First 2 years$2,400 $2,448Additional Electrical Cost $0.280$12,040 $12,401 $12,773 $13,156 $13,551 $13,958 $14,376 $14,808 $15,252 $15,709 $16,181 $16,666 $17,166 $17,681 $18,212 $21,112 $24,475 $28,373Annual Operating Cost Savings$81,506$86,722$94,727$100,595$106,789$113,326$120,225$127,505$135,187$143,290$151,837$160,853$170,360$180,386$190,957$253,044$333,731$438,382Financed Project Costs - Principal and Interest0000000000 Displaced System Replacement Costs (year one only)0Net Annual Cash Flow81,506 86,722 94,727 100,595 106,789 113,326 120,225 127,505 135,187 143,290 151,837 160,853 170,360 180,386 190,957253,044 333,731 438,382Accumulated Cash Flow81,506 168,228 262,955 363,550 470,339 583,665 703,890 831,396 966,582 1,109,872 1,261,710 1,422,562 1,592,923 1,773,309 1,964,266 3,098,786 4,597,653 6,569,425Additional Power UseAdditional MaintenanceSimple Payback: Total Project Cost/Year One Operating Cost Savings:Net Present Value (30 year analysis):Net Present Value (20 year analysis):
Nenana School Buildings + Daycare + Water Plant Option A.4Nenana, AlaskaWood Chip Boiler Date: July 24, 2012 Analyst: CTA Architects Engineers - Nick Salmon & Nathan Ratz EXISTING CONDITIONSSchool Bldgs Daycare Water Plant Fire Dept TotalExisting Fuel Type:Fuel Oil Fuel Oil Fuel Oil Fuel OilFuel Units:gal gal gal galCurrent Fuel Unit Cost:$3.60 $3.60 $3.60 $3.60 Estimated Average Annual Fuel Usage:39,800 4,550 10,70055,050Annual Heating Costs:$143,280 $16,380 $38,520 $0 $198,180ENERGY CONVERSION (to 1,000,000 Btu; or 1 dkt)Fuel Heating Value (Btu/unit of fuel):134500 134500 134500 134500Current Annual Fuel Volume (Btu):5,353,100,000 611,975,000 1,439,150,000 0Assumed efficiency of existing heating system (%):80% 80% 80% 80% Net Annual Energy Produced (Btu):4,282,480,000 489,580,000 1,151,320,000 0 5,923,380,000WOOD FUEL COSTWood Chips$/ton: $75.00Assumed efficiency of wood heating system (%): 65% PROJECTED WOOD FUEL USAGEEstimated Btu content of wood fuel (Btu/lb) - Assumed 30% MC 6400 Tons of wood fuel to supplant net equivalent of 100% annual heating load.712Tons of wood fuel to supplant net equivalent of 85% annual heating load.60525 ton chip van loads to supplant net equivalent of 85% annual heating load.24 Project Capital Cost-$2,590,000 Project Financing InformationPercent Financed0.0%Est. Pwr Use 50000 kWh Type Hr/Wk Wk/Yr Total Hr Wage/Hr TotalAmount Financed$0 Elec Rate $0.280 /kWh Biomass System 4.0 40 160 $20.00 $3,200Amount of Grants$2,590,000 Other 0.0 40 0 $20.00 $01st 2 Year Learning 3.0 40 120 $20.00 $2,400Interest Rate5.00%Term10Annual Finance Cost (years)$0 26.1 years Net Benefit B/C Ratio$4,638,894 $2,048,894 1.79$2,656,188 $66,1881.03Year Accumulated Cash Flow > 0#N/AYear Accumulated Cash Flow > Project Capital Cost16Inflation FactorsO&M Inflation Rate2.0%Fossil Fuel Inflation Rate5.0%Wood Fuel Inflation Rate3.0%Electricity Inflation Rate3.0%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 $3.60 39800 gal $143,280 $150,444 $157,966 $165,865 $174,158 $182,866 $192,009 $201,609 $211,690 $222,274 $233,388 $245,057 $257,310 $270,176 $283,685 $362,061 $462,092 $589,760Displaced heating costs $3.60 4550 gal $16,380 $17,199 $18,059 $18,962 $19,910 $20,905 $21,951 $23,048 $24,201 $25,411 $26,681 $28,015 $29,416 $30,887 $32,431 $41,391 $52,827 $67,422Displaced heating costs $3.60 10700 gal $38,520 $40,446 $42,468 $44,592 $46,821 $49,162 $51,620 $54,202 $56,912 $59,757 $62,745 $65,882 $69,176 $72,635 $76,267 $97,338 $124,231 $158,554Displaced heating costs $3.600 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)$75.00 85% 660 tons $49,511 $50,997 $52,527 $54,103 $55,726$57,397 $59,119 $60,893 $62,720 $64,601 $66,539 $68,535 $70,592 $72,709 $74,891 $86,819 $100,647 $116,677Small load existing fuel$3.60 15% 5970 gal $21,492 $22,567 $23,695 $24,880 $26,124 $27,430 $28,801 $30,241 $31,753 $33,341 $35,008 $36,759 $38,597 $40,526 $42,553 $54,309 $69,314 $88,464Small load existing fuel$3.60 15% 683 gal $2,457 $2,580 $2,709 $2,844 $2,986 $3,136 $3,293 $3,457 $3,630 $3,812 $4,002 $4,202 $4,412 $4,633 $4,865 $6,209 $7,924 $10,113Small load existing fuel$3.60 15% 1605 gal $5,778 $6,067 $6,370 $6,689 $7,023 $7,374$7,743 $8,130 $8,537 $8,964 $9,412 $9,882 $10,376 $10,895 $11,440 $14,601 $18,635 $23,783Small load existing fuel$3.60 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$3,200 $3,264 $3,329 $3,396 $3,464 $3,533 $3,604 $3,676 $3,749 $3,824 $3,901 $3,979 $4,058 $4,140 $4,222 $4,662 $5,147$5,683Additional Operation and Maintenance Costs First 2 years$2,400 $2,448Additional Electrical Cost $0.280$14,000 $14,420 $14,853 $15,298 $15,757 $16,230 $16,717 $17,218 $17,735 $18,267 $18,815 $19,379 $19,961 $20,559 $21,176 $24,549 $28,459 $32,992Annual Operating Cost Savings$99,342$105,747$115,011$122,209$129,809$137,833$146,303$155,243$164,678$174,634$185,137$196,218$207,907$220,235$233,236$309,643$409,025$538,024Financed Project Costs - Principal and Interest0000000000 Displaced System Replacement Costs (year one only)0Net Annual Cash Flow99,342 105,747 115,011 122,209 129,809 137,833 146,303 155,243 164,678 174,634 185,137 196,218 207,907 220,235 233,236 309,643 409,025 538,024Accumulated Cash Flow99,342 205,088 320,099 442,308 572,117 709,950 856,254 1,011,497 1,176,175 1,350,809 1,535,946 1,732,164 1,940,0712,160,306 2,393,542 3,780,882 5,616,846 8,035,572Additional Power UseAdditional MaintenanceSimple Payback: Total Project Cost/Year One Operating Cost Savings:Net Present Value (30 year analysis):Net Present Value (20 year analysis):
Nenana School Buildings + Daycare + Water Plant + Fire Dept. Option A.5Nenana, AlaskaWood Chip Boiler Date: July 24, 2012 Analyst: CTA Architects Engineers - Nick Salmon & Nathan Ratz EXISTING CONDITIONSSchool Bldgs Daycare Water Plant Fire Dept TotalExisting Fuel Type:Fuel Oil Fuel Oil Fuel Oil Fuel OilFuel Units:gal gal gal galCurrent Fuel Unit Cost:$3.60 $3.60 $3.60 $3.60 Estimated Average Annual Fuel Usage:39,800 4,550 10,700 3,950 59,000Annual Heating Costs:$143,280 $16,380 $38,520 $14,220 $212,400ENERGY CONVERSION (to 1,000,000 Btu; or 1 dkt)Fuel Heating Value (Btu/unit of fuel):134500 134500 134500 134500Current Annual Fuel Volume (Btu):5,353,100,000 611,975,000 1,439,150,000 531,275,000Assumed efficiency of existing heating system (%):80% 80% 80% 80% Net Annual Energy Produced (Btu):4,282,480,000 489,580,000 1,151,320,000 425,020,000 6,348,400,000WOOD FUEL COSTWood Chips$/ton: $75.00Assumed efficiency of wood heating system (%): 65% PROJECTED WOOD FUEL USAGEEstimated Btu content of wood fuel (Btu/lb) - Assumed 30% MC 6400 Tons of wood fuel to supplant net equivalent of 100% annual heating load.763Tons of wood fuel to supplant net equivalent of 85% annual heating load.64925 ton chip van loads to supplant net equivalent of 85% annual heating load.26 Project Capital Cost-$2,680,000 Project Financing InformationPercent Financed0.0%Est. Pwr Use 55000 kWh Type Hr/Wk Wk/Yr Total Hr Wage/Hr TotalAmount Financed$0 Elec Rate $0.280 /kWh Biomass System 4.0 40 160 $20.00 $3,200Amount of Grants$2,680,000 Other 0.0 40 0 $20.00 $01st 2 Year Learning 3.0 40 120 $20.00 $2,400Interest Rate5.00%Term10Annual Finance Cost (years)$0 25.1 years Net Benefit B/C Ratio$4,975,009 $2,295,009 1.86$2,849,249 $169,2491.06Year Accumulated Cash Flow > 0#N/AYear Accumulated Cash Flow > Project Capital Cost16Inflation FactorsO&M Inflation Rate2.0%Fossil Fuel Inflation Rate5.0%Wood Fuel Inflation Rate3.0%Electricity Inflation Rate3.0%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 $3.60 39800 gal $143,280 $150,444 $157,966 $165,865 $174,158 $182,866 $192,009 $201,609 $211,690 $222,274 $233,388 $245,057 $257,310 $270,176 $283,685 $362,061 $462,092 $589,760Displaced heating costs $3.60 4550 gal $16,380 $17,199 $18,059 $18,962 $19,910 $20,905 $21,951 $23,048 $24,201 $25,411 $26,681 $28,015 $29,416 $30,887 $32,431 $41,391 $52,827 $67,422Displaced heating costs $3.60 10700 gal $38,520 $40,446 $42,468 $44,592 $46,821 $49,162 $51,620 $54,202 $56,912 $59,757 $62,745 $65,882 $69,176 $72,635 $76,267 $97,338 $124,231 $158,554Displaced heating costs $3.60 3950 gal $14,220 $14,931 $15,678 $16,461 $17,284 $18,149 $19,056 $20,009 $21,009 $22,060 $23,163 $24,321 $25,537 $26,814 $28,155 $35,933 $45,861 $58,531Biomass System Operating CostsWood Fuel ($/ton, delivered to boiler site)$75.00 85% 704 tons $52,768 $54,351 $55,982 $57,661 $59,391$61,173 $63,008 $64,898 $66,845 $68,850 $70,916 $73,043 $75,235 $77,492 $79,816 $92,529 $107,267 $124,351Small load existing fuel$3.60 15% 5970 gal $21,492 $22,567 $23,695 $24,880 $26,124 $27,430 $28,801 $30,241 $31,753 $33,341 $35,008 $36,759 $38,597 $40,526 $42,553 $54,309 $69,314 $88,464Small load existing fuel$3.60 15% 683 gal $2,457 $2,580 $2,709 $2,844 $2,986 $3,136 $3,293 $3,457 $3,630 $3,812 $4,002 $4,202 $4,412 $4,633 $4,865 $6,209 $7,924 $10,113Small load existing fuel$3.60 15% 1605 gal $5,778 $6,067 $6,370 $6,689 $7,023 $7,374$7,743 $8,130 $8,537 $8,964 $9,412 $9,882 $10,376 $10,895 $11,440 $14,601 $18,635 $23,783Small load existing fuel$3.60 15% 593 gal $2,133 $2,240 $2,352 $2,469 $2,593 $2,722 $2,858 $3,001 $3,151 $3,309 $3,474 $3,648 $3,831 $4,022 $4,223 $5,390 $6,879 $8,780Additional Operation and Maintenance Costs$3,200 $3,264 $3,329 $3,396 $3,464 $3,533 $3,604 $3,676 $3,749 $3,824 $3,901 $3,979 $4,058 $4,140 $4,222 $4,662 $5,147$5,683Additional Operation and Maintenance Costs First 2 years$2,400 $2,448Additional Electrical Cost $0.280$15,400 $15,862 $16,338 $16,828 $17,333 $17,853 $18,388 $18,940 $19,508 $20,094 $20,696 $21,317 $21,957 $22,615 $23,294 $27,004 $31,305 $36,291Annual Operating Cost Savings$106,772$113,642$123,397$131,113$139,260$147,861$156,941$166,524$176,637$187,309$198,568$210,445$222,974$236,188$250,124$332,021$438,541$576,802Financed Project Costs - Principal and Interest0000000000 Displaced System Replacement Costs (year one only)0Net Annual Cash Flow106,772 113,642 123,397 131,113 139,260 147,861 156,941 166,524 176,637 187,309 198,568 210,445 222,974 236,188 250,124 332,021 438,541 576,802Accumulated Cash Flow106,772 220,414 343,810 474,923 614,183 762,044 918,985 1,085,509 1,262,146 1,449,455 1,648,023 1,858,468 2,081,442 2,317,630 2,567,755 4,055,426 6,023,947 8,617,079Additional Power UseAdditional MaintenanceSimple Payback: Total Project Cost/Year One Operating Cost Savings:Net Present Value (30 year analysis):Net Present Value (20 year analysis):
Nenana School + Admin+ Warehouse + Student Living Center Option A.6Nenana, AlaskaWood Chip Boiler Date: July 24, 2012 Analyst: CTA Architects Engineers - Nick Salmon & Nathan Ratz EXISTING CONDITIONSSchool Admin Warehouse SLC TotalExisting Fuel Type:Fuel Oil Fuel Oil Fuel Oil Fuel OilFuel Units:gal gal gal galCurrent Fuel Unit Cost:$3.60 $3.60 $3.60 $3.60 Estimated Average Annual Fuel Usage:34,000 1,600 4,200 28,800 68,600Annual Heating Costs:$122,400 $5,760 $15,120 $103,680 $246,960ENERGY CONVERSION (to 1,000,000 Btu; or 1 dkt)Fuel Heating Value (Btu/unit of fuel):134500 134500 134500 134500Current Annual Fuel Volume (Btu):4,573,000,000 215,200,000 564,900,000 3,873,600,000Assumed efficiency of existing heating system (%):80% 80% 80% 80% Net Annual Energy Produced (Btu):3,658,400,000 172,160,000 451,920,000 3,098,880,000 7,381,360,000WOOD FUEL COSTWood Chips$/ton: $75.00Assumed efficiency of wood heating system (%): 65% PROJECTED WOOD FUEL USAGEEstimated Btu content of wood fuel (Btu/lb) - Assumed 30% MC 6400 Tons of wood fuel to supplant net equivalent of 100% annual heating load.887Tons of wood fuel to supplant net equivalent of 85% annual heating load.75425 ton chip van loads to supplant net equivalent of 85% annual heating load.30 Project Capital Cost-$2,860,000 Project Financing InformationPercent Financed0.0%Est. Pwr Use 90000 kWh Type Hr/Wk Wk/Yr Total Hr Wage/Hr TotalAmount Financed$0 Elec Rate $0.280 /kWh Biomass System 4.0 40 160 $20.00 $3,200Amount of Grants$2,860,000 Other 0.0 40 0 $20.00 $01st 2 Year Learning 3.0 40 120 $20.00 $2,400Interest Rate5.00%Term10Annual Finance Cost (years)$0 25.4 years Net Benefit B/C Ratio$5,441,730 $2,581,730 1.90$3,085,014 $225,0141.08Year Accumulated Cash Flow > 0#N/AYear Accumulated Cash Flow > Project Capital Cost16Inflation FactorsO&M Inflation Rate2.0%Fossil Fuel Inflation Rate5.0%Wood Fuel Inflation Rate3.0%Electricity Inflation Rate3.0%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 $3.60 34000 gal $122,400 $128,520 $134,946 $141,693 $148,778 $156,217 $164,028 $172,229 $180,841 $189,883 $199,377 $209,346 $219,813 $230,803 $242,344 $309,299 $394,752 $503,815Displaced heating costs $3.60 1600 gal $5,760 $6,048 $6,350 $6,668 $7,001 $7,351 $7,719 $8,105 $8,510 $8,936 $9,382 $9,852 $10,344 $10,861 $11,404 $14,555 $18,577 $23,709Displaced heating costs $3.60 4200 gal $15,120 $15,876 $16,670 $17,503 $18,378 $19,297 $20,262 $21,275 $22,339 $23,456 $24,629 $25,860 $27,153 $28,511 $29,937 $38,207 $48,764 $62,236Displaced heating costs $3.60 28800 gal $103,680 $108,864 $114,307 $120,023 $126,024 $132,325 $138,941 $145,888 $153,183 $160,842 $168,884 $177,328 $186,194 $195,504 $205,279 $261,994 $334,378 $426,761Biomass System Operating CostsWood Fuel ($/ton, delivered to boiler site)$75.00 85% 884 tons $66,308 $68,297 $70,346 $72,456 $74,630$76,869 $79,175 $81,550 $83,997 $86,517 $89,112 $91,786 $94,539 $97,375 $100,297 $116,271 $134,790 $156,259Small load existing fuel$3.60 15% 5100 gal $18,360 $19,278 $20,242 $21,254 $22,317 $23,433 $24,604 $25,834 $27,126 $28,482 $29,907 $31,402 $32,972 $34,621 $36,352 $46,395 $59,213 $75,572Small load existing fuel$3.60 15% 240 gal $864 $907 $953 $1,000 $1,050 $1,103 $1,158 $1,216 $1,277 $1,340 $1,407 $1,478 $1,552 $1,629 $1,711 $2,183 $2,786 $3,556Small load existing fuel$3.60 15% 630 gal $2,268 $2,381 $2,500 $2,625 $2,757 $2,895 $3,039 $3,191 $3,351 $3,518 $3,694 $3,879 $4,073 $4,277 $4,490 $5,731 $7,315 $9,335Small load existing fuel$3.60 15% 4320 gal $15,552 $16,330 $17,146 $18,003 $18,904 $19,849 $20,841 $21,883 $22,977 $24,126 $25,333 $26,599 $27,929 $29,326 $30,792 $39,299 $50,157 $64,014Additional Operation and Maintenance Costs$3,200 $3,264 $3,329 $3,396 $3,464 $3,533 $3,604 $3,676 $3,749 $3,824 $3,901 $3,979 $4,058 $4,140 $4,222 $4,662 $5,147$5,683Additional Operation and Maintenance Costs First 2 years$2,400 $2,448Additional Electrical Cost $0.280$25,200 $25,956 $26,735 $27,537 $28,363 $29,214 $30,090 $30,993 $31,923 $32,880 $33,867 $34,883 $35,929 $37,007 $38,117 $44,188 $51,226 $59,385Annual Operating Cost Savings$112,808$120,447$131,022$139,615$148,697$158,296$168,439$179,154$190,473$202,427$215,051$228,380$242,452$257,306$272,983$365,326$485,836$642,716Financed Project Costs - Principal and Interest0000000000 Displaced System Replacement Costs (year one only)0Net Annual Cash Flow112,808 120,447 131,022 139,615 148,697 158,296 168,439 179,154 190,473 202,427 215,051 228,380 242,452 257,306 272,983 365,326 485,836 642,716Accumulated Cash Flow112,808 233,255 364,277 503,892 652,590 810,886 979,324 1,158,478 1,348,951 1,551,378 1,766,430 1,994,810 2,237,262 2,494,568 2,767,551 4,399,622 6,575,026 9,458,385Additional Power UseAdditional MaintenanceSimple Payback: Total Project Cost/Year One Operating Cost Savings:Net Present Value (30 year analysis):Net Present Value (20 year analysis):
Nenana SchoolOption B.1Nenana, AlaskaWood Pellet Boiler Date: July 24, 2012 Analyst: CTA Architects Engineers - Nick Salmon & Nathan Ratz EXISTING CONDITIONSSchoolTotalExisting Fuel Type:Fuel Oil Fuel Oil Fuel Oil Fuel OilFuel Units:gal gal gal galCurrent Fuel Unit Cost:$3.60 $3.60 $3.60 $3.60 Estimated Average Annual Fuel Usage:34,00034,000Annual Heating Costs:$122,400 $0 $0 $0 $122,400ENERGY CONVERSION (to 1,000,000 Btu; or 1 dkt)Fuel Heating Value (Btu/unit of fuel):134500 134500 134500 134500Current Annual Fuel Volume (Btu):4,573,000,000 0 0 0Assumed efficiency of existing heating system (%):80% 80% 80% 80% Net Annual Energy Produced (Btu):3,658,400,000 0 0 0 3,658,400,000WOOD FUEL COSTWood Pellets$/ton: $325.00Assumed 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.319Tons of wood fuel to supplant net equivalent of 85% annual heating load.27125 ton chip van loads to supplant net equivalent of 85% annual heating load.11 Project Capital Cost-$1,300,000 Project Financing InformationPercent Financed0.0%Est. Pwr Use 20000 kWh Type Hr/Wk Wk/Yr Total Hr Wage/Hr TotalAmount Financed$0 Elec Rate $0.280 /kWh Biomass System 2.0 40 80 $20.00 $1,600Amount of Grants$1,300,000 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)$0 180.4 years Net Benefit B/C Ratio$1,289,692 -$10,308 0.99$590,490 -$709,5100.45Year 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 Rate3.0%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 $3.60 34000 gal $122,400 $128,520 $134,946 $141,693 $148,778 $156,217 $164,028 $172,229 $180,841 $189,883 $199,377 $209,346 $219,813 $230,803 $242,344 $309,299 $394,752 $503,815Displaced heating costs $3.600 gal $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0Displaced heating costs $3.600 gal $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0Displaced heating costs $3.600 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)$325.00 85% 271 tons $88,034 $90,675 $93,396 $96,197 $99,083 $102,056 $105,117 $108,271 $111,519 $114,865 $118,311 $121,860 $125,516 $129,281 $133,160 $154,369 $178,955 $207,458Small load existing fuel$3.60 15% 5100 gal $18,360 $19,278 $20,242 $21,254 $22,317 $23,433 $24,604 $25,834 $27,126 $28,482 $29,907 $31,402 $32,972 $34,621 $36,352 $46,395 $59,213 $75,572Small load existing fuel$3.60 15% 0 gal $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0Small load existing fuel$3.60 15% 0 gal $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0Small load existing fuel$3.60 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 $0.280$5,600 $5,768 $5,941 $6,119 $6,303 $6,492 $6,687 $6,887 $7,094 $7,307 $7,526 $7,752 $7,984 $8,224 $8,471 $9,820 $11,384 $13,197Annual Operating Cost Savings$7,206$9,535$13,703$16,425$19,343$22,470$25,818$29,399$33,227$37,317$41,683$46,343$51,312$56,608$62,251$96,385$142,627$204,746Financed Project Costs - Principal and Interest0000000000 Displaced System Replacement Costs (year one only)0Net Annual Cash Flow7,206 9,535 13,703 16,425 19,343 22,470 25,818 29,399 33,227 37,317 41,683 46,343 51,312 56,608 62,251 96,385 142,627 204,746Accumulated Cash Flow7,206 16,741 30,443 46,868 66,211 88,681 114,499 143,897 177,124 214,441 256,124 302,467 353,778 410,387 472,637 882,087 1,497,212 2,389,469Additional Power UseAdditional MaintenanceSimple Payback: Total Project Cost/Year One Operating Cost Savings:Net Present Value (30 year analysis):Net Present Value (20 year analysis):
Meda Lord Senior CenterOption C.1Nenana, AlaskaCord Wood Boiler Date: July 24, 2012 Analyst: CTA Architects Engineers - Nick Salmon & Nathan Ratz EXISTING CONDITIONSMLSCTotalExisting Fuel Type:Fuel Oil Fuel Oil Fuel Oil Fuel OilFuel Units:gal gal gal galCurrent Fuel Unit Cost:$3.60 $3.60 $3.60 $3.60 Estimated Average Annual Fuel Usage:6,5666,566Annual Heating Costs:$23,638 $0 $0 $0 $23,638ENERGY CONVERSION (to 1,000,000 Btu; or 1 dkt)Fuel Heating Value (Btu/unit of fuel):134500 134500 134500 134500Current Annual Fuel Volume (Btu):883,127,000 0 0 0Assumed efficiency of existing heating system (%):80% 80% 80% 80% Net Annual Energy Produced (Btu):706,501,600 0 0 0 706,501,600WOOD FUEL COSTCord Wood$/ton: $200.00Assumed efficiency of wood heating system (%): 65% PROJECTED WOOD FUEL USAGEEstimated Btu content of wood fuel (Btu/lb) - 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.67Cords of wood fuel to supplant net equivalent of 85% annual heating load.5725 ton chip van loads to supplant net equivalent of 85% annual heating load.N/A Project Capital Cost-$280,000 Project Financing InformationPercent Financed0.0%Est. Pwr Use 3000 kWh Type Hr/Wk Wk/Yr Total Hr Wage/Hr TotalAmount Financed$0 Elec Rate $0.280 /kWh Biomass System 10.0 40 400 $20.00 $8,000Amount of Grants$280,000 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 -158.0 years Net Benefit B/C Ratio$220,868 -$59,132 0.79$88,173 -$191,8270.31Year Accumulated Cash Flow > 05Year Accumulated Cash Flow > Project Capital Cost26Inflation FactorsO&M Inflation Rate2.0%Fossil Fuel Inflation Rate5.0%Wood Fuel Inflation Rate3.0%Electricity Inflation Rate3.0%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 $3.60 6566 gal $23,638 $24,819 $26,060 $27,363 $28,732 $30,168 $31,677 $33,260 $34,924 $36,670 $38,503 $40,428 $42,450 $44,572 $46,801 $59,731 $76,234 $97,296Displaced heating costs $3.600 gal $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0Displaced heating costs $3.600 gal $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0Displaced heating costs $3.600 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% 57 cords $11,424 $11,767 $12,120 $12,484 $12,858 $13,244 $13,641 $14,051 $14,472 $14,906 $15,354 $15,814 $16,289 $16,777 $17,281 $20,033 $23,224 $26,923Small load existing fuel$3.60 15% 985 gal $3,546 $3,723 $3,909 $4,105 $4,310 $4,525 $4,751 $4,989 $5,239 $5,500 $5,775 $6,064 $6,367 $6,686 $7,020 $8,960 $11,435 $14,594Small load existing fuel$3.60 15% 0 gal $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0Small load existing fuel$3.60 15% 0 gal $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0Small load existing fuel$3.60 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 $0.280$840 $865 $891 $918 $945 $974 $1,003 $1,033 $1,064 $1,096 $1,129 $1,163 $1,198 $1,234 $1,271 $1,473 $1,708 $1,980Annual Operating Cost Savings-$1,773-$1,328$817$1,368$1,959$2,592$3,271$3,998$4,775$5,606$6,493$7,440$8,450$9,527$10,674$17,611$27,000$39,592Financed Project Costs - Principal and Interest0000000000 Displaced System Replacement Costs (year one only)0Net Annual Cash Flow(1,773) (1,328)817 1,368 1,959 2,592 3,271 3,998 4,775 5,606 6,493 7,440 8,450 9,527 10,674 17,611 27,000 39,592Accumulated Cash Flow(1,773) (3,100) (2,284) (916)1,043 3,635 6,906 10,905 15,680 21,286 27,779 35,220 43,67053,196 63,870 137,198 252,302 423,622Additional Power UseAdditional MaintenanceSimple Payback: Total Project Cost/Year One Operating Cost Savings:Net Present Value (30 year analysis):Net Present Value (20 year analysis):
Fuel Oil Fuel Oil Estimated Wood Simple Fuel Oil Wood Biomass Year 1 NPV NPV 20 Yr 30 YrLine Project Usage Unit Cost Power Use Fuel Cost Payback O&M & Elec Fuel Weekly Additional Operating 30 yr 20 yr B/C B/C ACF ACF YRNo. Cost Gal $/Gal. kwh $/cord ton yrs Inflation Inflation Inflation O&M Hrs O&M Savings at 3% at 3% Ratio Ratio YR 20 YR 30 ACF=PCAll Options - Base CasesA.1 $1,780,000 34,000 $3.60 40,000 $75 30.1 2.0% 5.0% 3.0% 4.0 $3,200 $59,208 $2,832,089 $1,616,943 0.91 1.59 $2,303,414 $4,911,172 18A.2 $1,960,000 39,800 $3.60 40,000 $75 27.2 2.0% 5.0% 3.0% 4.0 $3,200 $72,175 $3,385,501 $1,940,341 0.99 1.73 $2,761,778 $5,862,829 17A.3 $2,150,000 44,350 $3.60 43,000 $75 26.4 2.0% 5.0% 3.0% 4.0 $3,200 $81,506 $3,795,177 $2,177,730 1.01 1.77 $3,098,786 $6,569,425 16A.4 $2,590,000 55,050 $3.60 50,000 $75 26.1 2.0% 5.0% 3.0% 4.0 $3,200 $99,342 $4,638,894 $2,656,188 1.03 1.79 $3,780,882 $8,035,572 16A.5 $2,680,000 59,000 $3.60 55,000 $75 25.1 2.0% 5.0% 3.0% 4.0 $3,200 $106,772 $4,975,009 $2,849,249 1.06 1.86 $4,055,426 $8,617,079 16A.6 $2,860,000 68,600 $3.60 90,000 $75 25.4 2.0% 5.0% 3.0% 4.0 $3,200 $112,808 $5,441,730 $3,085,014 1.08 1.90 $4,399,622 $9,458,385 16B.1 $1,300,000 34,000 $3.60 20,000 $325 180.4 2.0% 5.0% 3.0%2.0 $1,600 $7,206 $1,289,692 $590,490 0.45 0.99 $882,087 $2,389,469 24C.1 $280,000 6,566 $3.60 3,000 $200 -158.0 2.0% 5.0% 3.0% 10.0 $8,000 -$1,773 $220,868 $88,173 0.31 0.79 $137,198 $423,622 261Option A.6 is the strongest economic case and will be used for further sensitivity analysis.23A.6 - Adjusting Fuel Oil Inflation Rate4 $2,680,000 59,000 $3.60 55,000 $75 25.1 2.0% 5.0% 3.0% 4.0 $3,200 $106,772 $4,975,009 $2,849,249 1.06 1.86 $4,055,426$8,617,079 165 $2,860,000 68,600 $3.60 90,000 $75 25.4 2.0% 6.0% 3.0% 4.0 $3,200 $112,808 $6,808,757 $3,589,605 1.26 2.38 $5,180,433$12,107,386 156 $2,860,000 68,600 $3.60 90,000 $75 25.4 2.0% 7.0% 3.0% 4.0 $3,200 $112,808 $8,459,179 $4,157,775 1.45 2.96 $6,064,159$15,340,638 147 $2,860,000 68,600 $3.60 90,000 $75 25.4 2.0% 8.0% 3.0% 4.0 $3,200 $112,808 $10,455,463 $4,797,897 1.68 3.66 $7,064,717 $19,291,766 138 $2,860,000 68,600 $3.60 90,000 $75 25.4 2.0% 9.0% 3.0% 4.0 $3,200 $112,808 $12,874,011 $5,519,433 1.93 4.50 $8,197,877 $24,124,941 129 $2,860,000 68,600 $3.60 90,000 $75 25.4 2.0% 10.0% 3.0% 4.0$3,200 $112,808 $15,808,228 $6,333,076 2.21 5.53 $9,481,488 $30,041,735 121011A.6 - Adjusting Fuel Oil Cost12 $2,860,000 68,600 $3.50 90,000 $75 26.7 2.0% 5.0% 3.0% 4.0$3,200 $106,977 $5,214,151 $2,948,258 1.03 1.82 $4,206,814 $9,070,980 1613 $2,860,000 68,600 $3.75 90,000 $75 23.5 2.0% 5.0% 3.0% 4.0$3,200 $121,555 $5,783,098 $3,290,148 1.15 2.02 $4,688,833 $10,039,492 1514 $2,860,000 68,600 $4.00 90,000 $75 21.0 2.0% 5.0% 3.0% 4.0$3,200 $136,132 $6,352,045 $3,632,039 1.27 2.22 $5,170,852 $11,008,005 1415 $2,860,000 68,600 $4.50 90,000 $75 17.3 2.0% 5.0% 3.0% 4.0$3,200 $165,287 $7,489,940 $4,315,821 1.51 2.62 $6,134,890 $12,945,029 1316 $2,860,000 68,600 $5.00 90,000 $75 14.7 2.0% 5.0% 3.0% 4.0$3,200 $194,442 $8,627,835 $4,999,603 1.75 3.02 $7,098,928 $14,882,054 111718A.6 - Adjusting Wood Fuel Cost19 $2,860,000 68,600 $3.60 90,000 $75 25.4 2.0% 5.0% 3.0% 4.0$3,200 $112,808 $5,441,730 $3,085,014 1.08 1.90 $4,399,622 $9,458,385 1620 $2,860,000 68,600 $3.60 90,000 $85 27.5 2.0% 5.0% 3.0% 4.0$3,200 $103,967 $5,184,223 $2,913,343 1.02 1.81 $4,162,059 $9,037,768 1621 $2,860,000 68,600 $3.60 90,000 $100 31.5 2.0% 5.0% 3.0% 4.0 $3,200 $90,705 $4,797,964 $2,655,837 0.93 1.68 $3,805,716 $8,406,843 1722 $2,860,000 68,600 $3.60 90,000 $110 34.9 2.0% 5.0% 3.0% 4.0 $3,200 $81,864 $4,540,457 $2,484,166 0.87 1.59 $3,568,153 $7,986,226 182324 NPV: Net Present ValueACF: Accumulated Cash FlowYR ACF=PC : Year Accumulated Cash Flow equals Project CostJuly 24, 2012Economic Sensitiviy AnalysisNenana Biomass Heating System
APPENDIX C
Site Plan
NENANA SCHOOL CLUSTERMEDA LORD SENIOR CENTERLIVING CENTERMISSOULA, MT(406)728-9522Fax (406)728-8287Date®BIOMASS PRE-FEASIBILITY ASSESSMENTNENANA, ALASKANENANA OVERVIEWSSFNRH07/24/2012FEDCJ:NENANA800'400'200'0SCALE: 1:400NORTHREF.SITE PLAN
SCHOOL1,250285'-0"200'-0"BOILER PLANTSCHOOL ADMIN.SCHOOL WAREHOUSENENANA NATIVECOUNCIL DAY CAREWATER PLANTFIREHALL2,500' TO S.L.C.400'200'100'0SCALE: 1:200MISSOULA, MT(406)728-9522Fax (406)728-8287Date®BIOMASS PRE FEASIBILITY ASSESSMENTNENANA, ALASKANENANA SCHOOL CLUSTERSSFNHR07/24/2012FEDCJ:NENANANORTHREF.LEGENDPIPE ROUTINGBOILER ROOMSITE PLAN
STUDENT LIVINGCENTER2,500' TO BOILER PLANT100'500'25'0SCALE: 1:50MISSOULA, MT(406)728-9522Fax (406)728-8287Date®BIOMASS PRE-FEASIBILITY ASSESSMENTNENANA, ALASKASTUDENT LIVING CENTERSSFNHR07/24/2012FEDCJ:NENANANORTHREF.LEGENDPIPE ROUTINGBOILER ROOMSITE PLAN
MEDA LORD SENIOR CENTERBOILER PLANT75'-0"35'-0"MISSOULA, MT(406)728-9522Fax (406)728-8287Date®BIOMASS PRE-FEASIBILITY ASSESSMENTNENANA, ALASKANENANA MEDA LORD SENIOR CENTERSSFNHR07/24/2012FEDCJ:NENANA100'50'25'0SCALE: 1:50NORTHREF.LEGENDPIPE ROUTINGBOILER ROOMSITE PLAN
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 Manley, Minto and Nenana. These sites are located in the interior of Alaska near
Fairbanks. The following equipment is proposed:
Minto ‐ one 300,000 Btu/hr (heat output) cord wood boiler at the Minto Health Clinic.
Manley ‐ one 150,000 Btu/hr (heat output) cord wood boiler at the Village Express
Maintenance Shop.
Nenana – one 4,200,000 Btu/hr (heat output) wood chip boiler at the Nenana School.
MINTO STUDY AREA
A USGS map of the Minto study area is provided in Figure 1 below. As shown, the area is flat
with much low‐lying areas to the east and hilly to the west. The site is adjacent to a hillside. The
area is relatively sparsely 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: Fairbanks Cluster Feasibility Study
Date: 24 July 2012
Fairbanks Air Quality Feasibility Study Resource Systems Group, Inc.
24 July 2012 page 2
Figure 1: USGS Map Illustrating the Minto Study Area
Fairbanks Air Quality Feasibility Study Resource Systems Group, Inc.
24 July 2012 page 3
Figure 2 shows CTA Architects’ plan of the location of the proposed biomass facility and the
surrounding buildings in Minto. The site is relatively flat and sparsely populated with buildings.
The facility will be located in a remote building on the southeast side of two buildings. The
precise dimensions of that building, the stack location and dimensions, and the biomass
equipment specifications have not been determined. The degree of separation of the biomass
building from the other buildings will create a buffer for emissions dispersion.
Figure 2: Location of Proposed Facility in Minto
Fairbanks Air Quality Feasibility Study Resource Systems Group, Inc.
24 July 2012 page 4
A USGS map of the Manley study area is provided Figure 3. As shown, the area is hilly to
mountainous to the north and flat to the south. The site is near the higher terrain to the north.
The area is relatively sparsely populated. Our review of the area did not reveal any significant
emission sources or ambient air quality issues.
Figure 3: USGS Map Illustrating the Manley Hot Springs Study Area
Fairbanks Air Quality Feasibility Study Resource Systems Group, Inc.
24 July 2012 page 5
Figure 4 shows CTA Architects’ plan of the location of the proposed biomass facility and the
surrounding buildings. The site is surrounded by forest, relatively flat and has only a few
buildings. The facility will be located in a new building on the west side of the site. A generator
building is also indicated on the plan. The precise dimensions of that building, the stack location
and dimensions, and the biomass equipment specifications have not been determined.
Figure 4: Location of Proposed Facility in Manley
Fairbanks Air Quality Feasibility Study Resource Systems Group, Inc.
24 July 2012 page 6
A USGS map of the Nenana study area is provided Figure 3. As shown, the area is hilly to
mountainous to the north and flat to the south and northeast. The site is across the river from
higher terrain to the north. The area is moderately populated relative to the other sites
discussed. Our review of the area did not reveal any significant emission sources or ambient air
quality issues.
Figure 5: USGS Map Illustrating the Nenana Study Area
Fairbanks Air Quality Feasibility Study Resource Systems Group, Inc.
24 July 2012 page 7
Figure 6 shows CTA Architects’ plan of the location of the proposed biomass facility at the
Nenana School and the surrounding buildings. The site is relatively flat and relatively densely
populated with one to two story tall buildings. The proposed biomass equipment will be
installed in a remote building located to the east of the school. This will provide a buffer for
dispersion of air emissions between the stack and surrounding buildings. The precise stack
location and dimensions, and the biomass equipment specifications have not been determined.
Figure 6: Overview of Nenana School Cluster Site
Fairbanks Air Quality Feasibility Study Resource Systems Group, Inc.
24 July 2012 page 8
METEOROLOGY
Meteorological data from Fairbanks, AK was reviewed to develop an understanding of weather
conditions. While Fairbanks is approximately 90 miles, 50 miles, and 45 miles away from
Manley, Minto, and Nenana respectively, it is located in a similar climactic zone (Alaska
Interior) and is therefore a good proxy of weather in those locations. As shown, there is a
relatively high percentage of “calms” or times when the wind is not blowing during the colder
months.1 These conditions create thermal inversions which are unfavorable for the dispersion
of emissions.
Figure 7: Wind Speed Data from Fairbanks, AK
DESIGN & OPERATION RECOMMENDATIONS
The following are suggested for designing the stack:
1 See: http://climate.gi.alaska.edu/Climate/Wind/Speed/Fairbanks/FAI.html
Fairbanks Air Quality Feasibility Study Resource Systems Group, Inc.
24 July 2012 page 9
Burn natural wood, whose characteristics (moisture content, bark content, species,
geometry) results 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.
For the Nenana School: while there are no state or federal requirements mandating
advanced emission control from and ESP or baghouse, we feel advanced emission
control should be strongly considered. Alternatively, the school should consider using
pellets in lieu of wood chips.
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/
Fairbanks Air Quality Feasibility Study Resource Systems Group, Inc.
24 July 2012 page 10
SUMMARY
RSG has completed an air quality feasibility study for Minto, Manley, and Nenana, 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.
The following conditions suggest advanced emission control devices (ESP, baghouse) are not
mandatory:
1. The wood boilers, with the exception of the boiler at Nenana, will be relatively small
emission sources.
2. The wood boilers will be located in a separate building which will create a dispersion
buffer between the boiler stack and the building.
3. There are no applicable federal or state emission limits.
Sustained poor meteorology suggests emissions should be minimized as much as possible.
Given these findings, we would recommend at minimum the following be done to minimize
emissions:
1. Nenana: consider burning pellets in lieu of wood chips or consider advanced emission
control. If wood chips are preferable, consider conducting air dispersion modeling to
determine the stack height and degree of emission control.
2. While not mandatory, we recommend exploring the possibility of a cyclone or multi‐
cyclone technology for control of fly ash and larger particulate emissions for all the
aforementioned boilers.
3. Obtain a not‐to‐exceed emission guarantees from boiler equipment vendors.
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
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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