HomeMy WebLinkAboutNew Stuyahok Biomass Heating System Final Report Coffman 07-26-2013-BIO
Feasibility Assessment for Biomass Heating Systems
New Stuyahok, Alaska
800 F Street, Anchorage, AK 99501
p (907) 276-6664 f (907) 276-5042
Tony SlatonBarker, PE,
Lee Bolling, CEA, and
David Nicolai, PE
FINAL REPORT – 7/26/2013
Feasibility Assessment for Biomass Heating Systems New Stuyahok, AK
Coffman Engineers, Inc. i
Contents
I. Executive Summary ............................................................................................................ 1
II. Introduction ...................................................................................................................... 2
III. Preliminary Site Investigation – Booster Club .................................................................... 3
BUILDING DESCRIPTION ................................................................................................................................................... 3
EXISTING HEATING SYSTEM .............................................................................................................................................. 3
DOMESTIC HOT WATER................................................................................................................................................... 3
BUILDING ENVELOPE ....................................................................................................................................................... 3
AVAILABLE SPACE ........................................................................................................................................................... 3
STREET ACCESS AND FUEL STORAGE ................................................................................................................................... 3
BUILDING OR SITE CONSTRAINTS ....................................................................................................................................... 4
BIOMASS SYSTEM INTEGRATION ........................................................................................................................................ 4
BIOMASS SYSTEM OPTIONS .............................................................................................................................................. 4
IV. Preliminary Site Investigation – Booster Club Offices ........................................................ 5
BUILDING DESCRIPTION ................................................................................................................................................... 5
EXISTING HEATING SYSTEM .............................................................................................................................................. 5
DOMESTIC HOT WATER................................................................................................................................................... 5
BUILDING ENVELOPE ....................................................................................................................................................... 5
AVAILABLE SPACE ........................................................................................................................................................... 5
STREET ACCESS AND FUEL STORAGE ................................................................................................................................... 5
BUILDING OR SITE CONSTRAINTS ....................................................................................................................................... 5
BIOMASS SYSTEM INTEGRATION ........................................................................................................................................ 6
BIOMASS SYSTEM OPTIONS .............................................................................................................................................. 6
V. Energy Consumption and Costs .......................................................................................... 7
WOOD ENERGY ............................................................................................................................................................. 7
ENERGY COSTS .............................................................................................................................................................. 7
EXISTING FUEL OIL CONSUMPTION .................................................................................................................................... 8
BIOMASS SYSTEM CONSUMPTION ..................................................................................................................................... 8
VI. Preliminary Cost Estimating .............................................................................................. 9
VII. Economic Analysis ......................................................................................................... 11
O&M COSTS .............................................................................................................................................................. 11
DEFINITIONS................................................................................................................................................................ 11
RESULTS ..................................................................................................................................................................... 13
SENSITIVITY ANALYSIS ................................................................................................................................................... 13
VIII. Forest Resource and Fuel Availability Assessments ....................................................... 14
FOREST RESOURCE ASSESSMENTS .................................................................................................................................... 14
AIR QUALITY PERMITTING .............................................................................................................................................. 14
IX. General Biomass Technology Information ....................................................................... 15
HEATING WITH WOOD FUEL ........................................................................................................................................... 15
TYPES OF WOOD FUEL .................................................................................................................................................. 15
HIGH EFFICIENCY CORD WOOD BOILERS ........................................................................................................................... 16
LOW EFFICIENCY CORD WOOD BOILERS ........................................................................................................................... 16
HIGH EFFICIENCY WOOD STOVES .................................................................................................................................... 17
Feasibility Assessment for Biomass Heating Systems New Stuyahok, AK
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BULK FUEL BOILERS ...................................................................................................................................................... 17
GRANTS ..................................................................................................................................................................... 17
Appendices
Appendix A – Site Photos
Appendix B – Economic Analysis Spreadsheet
Appendix C – Site Plan
Appendix D – AWEDTG Field Data Sheet
Feasibility Assessment for Biomass Heating Systems New Stuyahok, AK
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Abbreviations
ACF Accumulated Cash Flow
ASHRAE American Society of Heating, Refrigeration, and Air-Conditioning Engineers
AEA Alaska Energy Authority
AFUE Annual Fuel Utilization Efficiency
AHU Air Handling Unit
ARCH Architectural
B/C Benefit / Cost Ratio
BAS Building Automation System
BTU British Thermal Unit
BTUH BTU per hour
CCF One Hundred Cubic Feet
CEI Coffman Engineers, Inc.
CFM Cubic Feet per Minute
CIRC Circulation
CMU Concrete Masonry Unit
CRAC Computer Room Air Conditioning
CWCO Cold Weather Cut Out
DDC Direct Digital Control
∆T Delta T (Temperature Differential)
ECI Energy Cost Index
ECM Energy Conservation Measure
EF Exhaust Fan
Eff Efficiency
ELEC Electrical
EPDM Ethylene Propylene Diene Monomer
EUI Energy Utilization Index
F Fahrenheit
ft Feet
GPM Gallons Per Minute
HP Horsepower
HPS High Pressure Sodium
HVAC Heating, Ventilating, and Air-Conditioning
IESNA Illuminating Engineering Society of North America
in Inch(es)
IPLC Integrated Power and Load Circuit
IRC Internal Revenue Code
kBTU One Thousand BTUs
kWh Kilowatt-Hour
LED Light-Emitting Diode
MBH Thousand BTUs per Hour
MECH Mechanical
MH Metal Halide
O&M Operations and Maintenance
MMBTU One Million BTUs
P Pump
PC Project Cost
PF Power Factor
Feasibility Assessment for Biomass Heating Systems New Stuyahok, AK
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R R-Value
PH Phase
SC Shading Coefficient
SAT Supply Air Temperature
SF Square Feet, Supply Fan
TEMP Temperature
U U-Value
V Volts
VFD Variable Frequency Drive
W Watts
Feasibility Assessment for Biomass Heating Systems New Stuyahok, AK
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List of Figures
Fig. 1 – New Stuyahok, Alaska – Google Maps ............................................................................................. 2
Fig. 2 – New Stuyahok Buildings Evaluated – Google Maps ......................................................................... 2
List of Tables
Table 1 – Economic Evaluation Summary ..................................................................................................... 1
Table 2 – Energy Comparison ....................................................................................................................... 7
Table 3 – Existing Fuel Oil Consumption ....................................................................................................... 8
Table 4 – Proposed Biomass System Fuel Consumption .............................................................................. 8
Table 5 – Estimate of Probable Costs for Booster Club ................................................................................ 9
Table 6 – Estimate of Probable Costs for Booster Club Office .................................................................... 10
Table 7 – Inflation rates .............................................................................................................................. 11
Table 8 – Economic Definitions ................................................................................................................... 12
Table 9 – Economic Analysis Results ........................................................................................................... 13
Feasibility Assessment for Biomass Heating Systems New Stuyahok, AK
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I. Executive Summary
A preliminary feasibility assessment was completed to determine the technical and economic viability of
biomass heating systems at the Booster Club and Booster Club Office buildings in New Stuyahok, Alaska.
The results of the economic evaluation for both buildings are shown below. It was found that installing
two Tarm Solo 40 wood boilers at the Booster Club and one high efficiency wood stove at the Booster
Club Office are economically justified, due to the fact that the benefit to cost ratio of each option is
greater than 1.0.
Economic Analysis Results
Building Booster Club Booster Club Office
Proposed Biomass System
Two Tarm Solo 40 Wood
Boilers
Blaze King Classic High
Efficiency Wood Stove
Project Capital Cost
($159,566) ($12,887)
Simple Payback
12.2 years 6.9 years
Present Value of Project Benefits (20 year life)
$731,392 $160,906
Present Value of Operating Costs (20 year life)
($360,797) ($109,630)
Benefit / Cost Ratio of Project (20 year life)
2.32 3.98
Net Present Value (20 year life)
$211,030 $38,389
Year Accumulated Cash Flow is Net Positive
First Year First Year
Year Accumulated Cash Flow > Project Capital Cost
9.0 years 5.8 years
Table 1 – Economic Evaluation Summary
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II. Introduction
A preliminary feasibility assessment was completed to determine the technical and economic viability of
biomass heating systems for the Booster Club in New Stuyahok, AK. The locations of the buildings are
shown in Figures 1 and 2.
Fig. 1 – New Stuyahok, Alaska – Google Maps
Fig. 2 – New Stuyahok Buildings Evaluated – Google Maps
Booster
Club Office
Booster Club
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III. Preliminary Site Investigation – Booster Club
Building Description
The Booster Club is a 12,000 SF building built in 1979. It is a former Gymnasium, and it is a standalone
building on the campus of the old, abandoned school. No renovations are currently planned for the
space. It is used two to three times per month as a community gathering place throughout the year. No
energy audit has been conducted at the building. The building heating and lighting is only turned on
when the building is in use, otherwise it is allowed to be at ambient outdoor temperature. The heating
system is only turned on in the building approximately five days per month.
Existing Heating System
The heating system of the building consists of two Toyotomi heating units (Model OM-180, 1.05 gal/hr
fuel consumption, 148,000 btu/hr input), providing hot 50/50 propylene glycol/water for air handling
units and ancillary unit heaters. Two air handlers provide ventilation and heating to the main
gymnasium space. Storage and other ancillary spaces are heated with unit heaters.
The heating system is maintained in operating order. One 550 gallon heating oil tank provides the oil for
the boilers and the (out-of-order) water heater. The tank is located immediately outside the boiler
room, underneath a weather shelter. No spill containment is present around the tank.
Domestic Hot Water
Domestic hot water is not currently in service to the building. Due to regular (planned) freezing of the
building, domestic water is shut off to the building, and the Toyotomi water heater connected as a
domestic water heater is not in service.
Building Envelope
The walls of the building are 2x8 wood stud construction that are estimated to have R-25 fiberglass batt
insulation. The roof is a cold roof with a vented attic space, with an unknown amount and type of
insulation because it could not be accessed. It is estimated that the roof insulation is R-35 fiberglass batt
insulation, which is typical of buildings of this construction type and era. There are few windows in the
building. All are double pane windows, however, some windows have one pane broken. The main
entrance has an unheated arctic entry, and secondary and emergency exits are direct to outdoors.
Available Space
There is no space inside the building large enough or appropriate enough for a Garn or other wood
boiler type system. An addition or a standalone building would be required for a wood boiler.
Street Access and Fuel Storage
The building is situated along a gravel road and a truck can easily access the front and sides of the
building. There is adequate space around the building for a wood storage shed and/or wood boiler
building. Brush may have to be removed and additional gravel may be necessary to situate the new
structures.
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Building or Site constraints
The site is at the bottom of a hill, and there is significant spring snowmelt pooling along the north side of
the building. The ideal location for a standalone building would be across the street to the north, where
no snowmelt pooling was observed. Regrading and additional gravel could be placed to eliminate
drainage issues if it is desired to have new unit closer to the building.
Biomass System Integration
The building has a hydronic system for heating, making integration to a wood boiler a relatively
straightforward task. However, due to the frequent shutdowns of the building, systems like a Garn
would have difficulty restarting, would have increased maintenance costs, reduced efficiency and
increased emissions.
It is known that the two boilers provided, with input ratings of approximately 1.05 GPH each, provide
adequate heating to the facility.
Biomass System Options
There are two options for incorporating biomass systems into the Booster Club: 1) two residential style
wood boilers, such as a Tarm Solo, and 2) a wood boiler system in a detached building, such as a Garn
Light Commercial system. Both systems would require a person to load and fire the wood heating
systems by hand.
A pair of small residential style wood boilers, such as a Tarm Solo, would be the cheapest and lowest
tech option. The Tarm residential-style wood boiler would be easy to operate and would require
minimal maintenance compared to a commercial style wood boiler system. The wood boiler would be
used to provide a base heat load for the building during occupied times. Occupants would fire the boiler
regularly to provide as much heating oil displacement as they wish. The existing Toyotomi boilers would
still be used to make up for additional required heating as required and as system heaters during wood
boiler start-up processes. For this study two Tarm Solo 40 wood boilers were evaluated, each with an
output of 140,000 Btu/hr. Since the building regularly goes cold, the optional water thermal storage
tank is not recommended. This is because it is not realistic to drain the thermal storage tank every time
the building goes cold for freeze projection.
The second option is a large wood fired boiler system, such as a Garn system, which will be more
expensive. A Garn wood fired boiler can be loaded and fired in batches, which heats up a large volume
of water for space heating. This allows a Garn wood fired boiler to be loaded less times throughout the
day than a Tarm wood boiler, which would require a higher loading frequency. The wood fired boiler
system would be located in a detached boiler building and heating pipes would be routed to the
building. Pre-insulated heat pipes are typically installed below grade if the boiler building is a significant
distance from the building to be heated. The downside of the Garn system is that it must be fired
consistently to maintain proper water temperatures, making it a poor candidate for a building that is
shut down and goes cold regularly. Starting a Garn system from a cold state requires that the Garn
water tank be preheated by an auxiliary heat source (such as the building’s boilers) to increase the water
temperature before the Garn can be fired. The Garn option was not evaluated in this study due to this
factor.
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IV. Preliminary Site Investigation – Booster Club Offices
Building Description
The Booster Club Offices is a 1,200 SF one story building originally built in the mid-1990s. It is used as
office space for the Booster Club staff. It has a kitchen, a gathering space, a mechanical space, and
offices.
It is used 4 to 5 days a week and occasional, incidental use on weekends. It is estimated the building is
occupied between 32 and 40 hours a week. No energy audit has been conducted.
Existing Heating System
The building used to have an oil-fired boiler and baseboard heating; however the boiler room was
destroyed in a recent fire. At the time of inspection, restoration and repairs from the fire damage was
nearing completion. The heating system was in the process of being replaced with Toyo/Monitor space
heaters. Historical fuel data may not accurately forecast future heating costs as a new system is not
installed.
Domestic Hot Water
Domestic hot water was provided by an electric water heater prior to the fire. At the time of inspection,
it was intended to install a new electric water heater.
Building Envelope
The walls of the building are 2x4 wood stud construction that are estimated to have R-12 fiberglass batt
insulation. The roof is a cold roof with a vented attic space, with an unknown amount and type of
insulation because it could not be accessed. It is estimated that the roof insulation is R-20 fiberglass
batt insulation. The windows in the restored section are new double pane windows, and old double
pane windows are present throughout the rest of the structure. There is a no arctic entry for the main
entrance.
Available Space
There is space inside the building for one or several residential style wood stove(s). However, an
addition would be needed to house any wood boiler systems.
Street Access and Fuel Storage
The building is situated along a gravel road and a truck can easily access the building. However, there is
limited space around the sides and back of the structure which could make wood storage an issue.
Wood storage may be able to be done on the east side of the building.
Building or Site constraints
The site is across the street to the north of the Booster Club. It is located near the bottom of the hill, and
due to significant spring snowmelt pooling, access may be difficult until the end of breakup each year. It
will be important to elevate any wood storage to ensure it is above the snowmelt pooling. Alternatively,
additional gravel could be placed and regarding could be completed to alleviate this pooling issue.
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Biomass System Integration
The building currently has no hydronic piping, boiler, or fin-tube baseboard. Thus, to implement a wood
fired boiler system, new hydronic piping and baseboards would need to be installed. A residential style
wood stove could easily be installed in the building.
Biomass System Options
There are two options for incorporating biomass systems into the Booster Club Offices:
1) A high efficiency wood stove, or
2) A high efficiency wood boiler system in a detached building.
Both systems would require a person to load and fire the wood heating systems by hand.
A small residential style wood stove would be the cheapest and lowest tech option. Wood heating with
wood stoves is standard with most homes in New Stuyahok for auxiliary and back-up heating. The wood
stove would be easy to operate and would require minimal maintenance compared to a wood boiler
system. The wood stove would be used to provide a base heat load for the building during occupied
times. Occupants would fire the stove regularly to provide as much heating oil displacement as they
wish. The Toyo/Monitor stove would still be used to make up for additional required heating during
occupied times and as base load heaters when the building is unoccupied. For this study, a Blaze King
Classic high efficiency wood stove with an output of 48,065 BTU/hr for 12 hours was selected as the
proposed biomass system to evaluate.
The second option is a wood fired boiler system, which will be more expensive and require more
maintenance than a wood stove. A wood fired boiler can be loaded and fired in batches, which heats up
a large volume of water for space heating. This allows a wood fired boiler to be loaded less times
throughout the day then a wood stove, which would need a higher loading frequency. The wood fired
boiler system would be located in a detached boiler building and heating pipes would be routed to the
building. Pre-insulated heat pipes are typically installed below grade if the boiler building is a significant
distance from the building to be heated. The Booster Club Offices are close enough to the Booster Club
that one central plant could serve both buildings; however that would require hydronic heat in the
Offices. Due to the significant expense of retrofitting the office building with a hydronic system and the
increased complexity of a wood boiler system, this option was not evaluated in this study.
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V. Energy Consumption and Costs
Wood Energy
The gross energy content of a cord of wood varies depending on tree species and moisture content.
Black spruce, white spruce and birch at 20% moisture content have respective gross energy contents of
15.9 MMBTU/Cord, 18.1 MMBTU/cord and 23.6 MMBTU/cord, according to the UAF Cooperative
Extension. Wet or greenwood has higher moisture contents and require additional heat to evaporate
moisture before the wood can burn. Thus, wood with higher moisture contents will have lower energy
contents. Seasoned or dry wood will typically have 20% moisture content. For this study, cord wood
was estimated to have 16.0 MMBTU/cord. This is a conservativ e estimate based on the fact that the
community has access to both spruce and birch. To determine the delivered $/MMBTU of the biomass
system, a 75% efficiency for the high efficiency wood stoves and Tarm wood boilers was assumed. This
is a conservative estimate based on manufacturer documentation.
Energy Costs
The high price of fuel oil is the main economic driver for the use of lower cost biomass heating. Fuel oil
is shipped into New Stuyahok by barge and currently costs approximately $6.93/gal. For this study, the
energy content of fuel oil is based on 134,000 BTU/gal, according to the UAF Cooperative Extension.
Cord wood is sold in New Stuyahok for approximately $330 per cord.
The table below shows the energy comparison of different fuel types. The system efficiency is used to
calculate the delivered MMBTU’s of energy to the building. The delivered cost of energy to the building,
in $/MMBTU, is the most accurate way to compare costs of different energy types. As shown below,
cord wood is less than half the cost of fuel oil based on the $/MMBTU delivered to the building heat
load.
Fuel Type Units Gross
BTU/unit
System
Efficiency $/unit Delivered
$/MMBTU
Cord Wood cords 16,000,000 75% $330 $27.50
Fuel Oil gal 134,000 80% $6.93 $64.65
Electricity kWh 3,413 99% $0.65 $192.37
Table 2 – Energy Comparison
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Existing Fuel Oil Consumption
Complete heating oil bills were not provided for the two New Stuyahok buildings. The heating oil
consumption for each building was estimated based on interviews during the site visit and engineering
estimates. According to Mr. Wassillie Gust Sr., the Booster Club building consumes approximately 4,500
gallons per year. It was estimated that the Booster Club Office consumes approximately 990 gallons per
year.
Building Name Fuel Type
Avg. Annual
Consumption Net MMBTU/yr Annual Fuel Cost
New Stuyahok
Booster Club Fuel Oil 4,500 gal 482.4 $31,185
New Stuyahok
Booster Club Office Fuel Oil 990 gal 106.1 $6,861
Table 3 – Existing Fuel Oil Consumption
Biomass System Consumption
The Booster Club proposed biomass system is two Tarm Solo 40 wood boilers. For this study it is
estimated that the proposed biomass system will offset 85% of heating oil consumption for the building.
The remaining 15% of the heat for the building will come from the existing heating oil-fired boilers. The
proposed biomass system for the Booster Club would have a total annual energy cost of $17,093. This
annual energy cost includes wood and fuel oil costs, as well as the cost of the additional electricity
required to operate the Tarm boiler heating system. It is estimated that 1,752 kWh annually will be
required to operate the system pumps required by the Tarm system.
The Booster Club Office proposed biomass is a high efficiency wood stove. While wood stoves are
capable of providing the majority of the space heat for the building, a conservative estimate of 50%
heating oil offset was used for the study. Due to the fact that the building is not occupied constantly
and that the wood stoves are hand fired, a 50% heating oil offset is a realistic estimate for this study. If
the building tenants wish to offset more heating oil, the wood stove can be fired on a more frequent
schedule.
Building Name
Fuel Type % Heating
Source
Net
MMBTU/yr
Annual
Consumption
Energy
Cost
Total
Energy
Cost
New Stuyahok
Booster Club
Cord Wood 85% 410.0 34.2 cords $11,276
$17,093 Fuel Oil 15% 72.4 675 gal $4,678
Electricity N/A N/A 1,752 kWh $1,139
New Stuyahok
Booster Club
Office
Cord Wood 50% 53.1 4.4 cords $1,459
$4,890
Fuel Oil 50% 53.1 495 gal $3,430
Table 4 – Proposed Biomass System Fuel Consumption
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VI. Preliminary Cost Estimating
An estimate of probable costs was completed for the two proposed biomass systems: 1) installation of
two Tarm Solo 40 wood boilers at the Booster Club and 2) installation of one Blaze King Classic high
efficiency wood stove for the Booster Club Office.
The estimate includes general conditions and overhead and profit for the general contractor. A 10%
remote factor was used to account for increased shipping and installation costs in New Stuyahok.
Engineering design and permitting was estimated at 15% and a 10% contingency was used.
Estimate of Probable Costs for Booster Club
Two Tarm Solo 40 Wood Boilers
Category Description Unit Unit Cost Quantity Cost
Wood Boilers Tarm Solo 40 Unit Job $ 12,885.00 2 $ 25,770
Shipping Job $ 5,000.00 1 $ 5,000
Installation Job $ 17,000.00 2 $ 34,000
$ 64,770
Interior Mechanical & Electrical HX, Piping & Materials Bldg $ 30,000.00 1 $ 30,000
Subtotal $ 30,000
Subtotal Material and Installation Cost
$ 94,770
General Conditions 10% $ 9,477
Subtotal $ 104,247
Overhead and Profit 10% $ 10,425
Subtotal $ 114,672
Remote Factor 10% $ 11,467
Subtotal $ 126,139
Design Fees and Permitting 15% $ 18,921
Subtotal $ 145,060
Contingency 10% $ 14,506
Total Project Cost $ 159,566
Table 5 – Estimate of Probable Costs for Booster Club
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Estimate of Probable Costs for Booster Club Office
High Efficiency Wood Stove
Category Description Unit Unit Cost Quantity Cost
High Efficiency Wood Stove Wood Stove Each $2,500.00 1 $2,500
Blower Fan Each $500.00 1 $500
Stack Each $500.00 1 $500
Subtotal $3,500
Installation Area Prep hrs $150.00 8 $1,200
Stove and Chimney Install hrs $150.00 8 $1,200
Additional Parts Allowance Each $1,000.00 1 $1,000
Subtotal $3,400
Shipping 600 lbs Shipping Job $1,500.00 1 $1,500
Subtotal $1,500
Subtotal Material and Installation Cost
$8,400
General Conditions 5% $420
Subtotal $8,820
Overhead and Profit 5% $441
Subtotal $9,261
Remote Factor 10% $926
Subtotal $10,187
Design Fees and Permitting 15% $1,528
Subtotal $11,715
Contingency 10% $1,172
Total Project Cost $12,887
Table 6 – Estimate of Probable Costs for Booster Club Office
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VII. Economic Analysis
The following assumptions were used to complete the economic analysis for the proposed biomass
systems in New Stuyahok.
Inflation Rates
Discount Rate for Net Present Value Analysis 3%
Wood Fuel Escalation Rate 3%
Fossil Fuel Escalation Rate 5%
Electricity Escalation Rate 3%
O&M Escalation Rate 2%
Table 7 – Inflation rates
The real discount rate, or minimum attractive rate of return, is 3.0% and is the current rate used for all
Life Cycle Cost Analysis by the Alaska Department of Education and Early Development. This is a typical
rate used for completing economic analysis for public entities in Alaska. The escalation rates used for
the wood, heating oil, electricity and O&M rates are based on rates used in the Alaska Energy Authority
funded 2012 biomass pre-feasibility studies. These are typical rates used for this level of evaluation and
were used so that results are consistent and comparable to the 2012 studies.
O&M Costs
Non-fuel related operations and maintenance costs (O&M) were estimated at $500 and $50 per year,
for the Tarm Boilers and Blaze King Classic Wood Stove, respectively. For the first two years of service,
an additional $500 and $50 per year were added to the Tarm Boilers and Blaze King Classic Wood Stove,
respectively, to account for maintenance staff getting used to operating the new system.
Definitions
There are many different economic terms used in this study. A listing of all of the terms with their
definition is provided below for reference.
Economic Term Description
Project Capital Cost This is the opinion of probable cost for designing and constructing the
project.
Simple Payback The Simple Payback is the Project Capital Cost divided by the first year
annual energy savings. The Simple Payback does not take into account
escalated energy prices.
Present Value of Project
Benefits (20 year life)
The present value of all of the heating oil that would have been consumed by
the existing heating oil-fired heating system, over a 20 year period.
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Economic Term Description
Present Value of
Operating Costs (20 year
life)
The present value of all of the proposed biomass systems operating costs
over a 20 year period. This includes wood fuel, additional electricity, and
O&M costs for the proposed biomass system to provide 85% of the building’s
heat. It also includes the heating oil required for the existing oil-fired boilers
to provide the remaining 15% of heat to the building.
Benefit / Cost Ratio of
Project (20 year life)
This is the benefit to cost ratio over the 20 year period. A project that has a
benefit to cost ratio greater 1.0 is economically justified. It is defined as
follows:
Where:
PV = The present value over the 20 year period
Reference Sullivan, Wicks and Koelling, “Engineering Economy”, 14th ed.,
2009, pg. 440, Modified B-C Ratio.
Net Present Value (20
year life)
This is the net present value of the project over a 20 year period. If the
project has a net present value greater than zero, the project is economically
justified. This quantity accounts for the project capital cost, project benefits
and operating costs.
Year Accumulated Cash
Flow > Project Capital
Cost
This is the number of years it takes for the accumulated cash flow of the
project to be greater than or equal to the project capital cost. This is similar
to the project’s simple payback, except that it incorporates the inflation
rates. This quantity is the payback of the project including escalating energy
prices and O&M rates. This quantity is calculated as follows:
Where:
J = Year that the accumulated cash flow is greater than or equal to the
Project Capital Cost.
= Project Cash flow for the kth year.
Table 8 – Economic Definitions
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Results
The economic analysis was completed in order to determine the simple payback, benefit to cost ratio,
and net present value of the proposed biomass system at each building. The results are shown in the
table below.
Based on the economic analysis it was determined that all of the proposed biomass systems at the two
buildings in New Stuyahok have benefit to cost ratios above 1.0, and would be typically considered
economically justified. The driving factors that make these projects cost effective are their relatively low
project capital cost, combined with the high price of heating oil.
It should be noted that the labor for loading and firing both biomass systems was not taken into account
in the economic evaluation. Due to the small size of these systems, it is estimated this effort is relatively
small and would have minimal impacts on overall costs of the systems. In order to obtain the heating oil
offsets targeted in this study, building occupants must be responsible for loading and firing the biomass
systems at the proper frequency.
Economic Analysis Results
Building Booster Club Booster Club Office
Proposed Biomass System
Two Tarm Solo 40 Wood
Boilers
Blaze King Classic High
Efficiency Wood Stove
Project Capital Cost
($159,566) ($12,887)
Simple Payback
12.2 years 6.9 years
Present Value of Project Benefits (20 year life)
$731,392 $160,906
Present Value of Operating Costs (20 year life)
($360,797) ($109,630)
Benefit / Cost Ratio of Project (20 year life)
2.32 3.98
Net Present Value (20 year life)
$211,030 $38,389
Year Accumulated Cash Flow is Net Positive
First Year First Year
Year Accumulated Cash Flow > Project Capital Cost
9.0 years 5.8 years
Table 9 – Economic Analysis Results
Sensitivity Analysis
A sensitivity analysis for the two New Stuyahok buildings was not completed because all projects are
economically justified, with high benefit to cost ratios. Even if the price of heating oil drops to $4.58 per
gallon, the Booster Club Tarm system will still have a benefit to cost ratio of 1.0. The Booster Club Office
will still have a benefit to cost ratio of 1.0 if heating oil drops to $3.62 per gallon.
Feasibility Assessment for Biomass Heating Systems New Stuyahok, AK
Coffman Engineers, Inc. 14
VIII. Forest Resource and Fuel Availability Assessments
Forest Resource Assessments
Fuel availability assessments were not available for the New Stuyahok area. During the site visit it was
found that the land around the New Stuyahok village is densely forested, with a high density of spruce
and some birch trees. Due to the limited length of roads, wood harvesting is typically accomplished
outside of the village area with snow machines pulling sleds in the winter and by river boat in the
summer. Wood harvesting is not completed in the village itself to preserve the trees in the village.
Per Coffman’s discussions with Mr. Will Putman with the State Forestry Service, most of the permits for
wood harvesting are owned and controlled by village corporations within the state. If harvesting is to
take place in these areas, permission will need to be obtained from the village corporation prior to
harvesting. If more than 40 acres per year or 50 cords of wood are collected per year, the harvesting is
classified as a commercial operation. For a commercial harvest, the practices outlined in the Forest
Resources and Practices Act will need to be followed. The Forest Resource and Practices Act protects the
water and habitat within the harvesting site and applies to state, federal, and native corporation land. If
less than 40 cords of wood are used per year, the use is considered as a personal use and a commercial
permit is not required.
Air Quality Permitting
Currently, air quality permitting is regulated according to the Alaska Department of Environmental
Conservation Section 18 AAC 50 Air Quality Control regulations. Per these regulations, a minor air
quality permit is required if a new wood boiler or wood stove produces one of the following conditions
per Section 18 AAC 50.502 (C)(1): 40 tons per year (TPY) of carbon dioxide (CO2), 15 TPY of particulate
matter greater than 10 microns (PM-10), 40 TPY of sulfur dioxide, 0.6 TPY of lead, 100 TPY of carbon
monoxide within 10 kilometers of a carbon monoxide nonattainment area, or 10 TPY of direct PM -2.5
emissions. These regulations assume that the device will operate 24 hours per day, 365 days per year
and that no fuel burning equipment is used. If a new wood boiler or wood stove is installed in addition
to a fuel burning heating device, the increase in air pollutants cannot exceed the following per AAC
50.502 (C)(3): 10 TPY of PM-10, 10 TPY of sulfur dioxide, 10 TPY of nitrogen oxides, 100 TPY of carbon
monoxide within 10 kilometers of a carbon monoxide nonattainment area, or 10 TPY of direct PM -2.5
emissions. Per the Wood-fired Heating Device Visible Emission Standards (Section 18 AAC 50.075), a
person may not operate a wood-fired heating device in a manner that causes black smoke or visible
emissions that exceed 50 percent opacity for more than 15 minutes in any hour in an area where an air
quality advisory is in effect.
From Coffman’s discussions with Patrick Dunn at the Alaska Department of Environmental Conservation,
these regulations are focused on permitting industrial applications of wood burning equipment. In his
opinion, it would be unlikely that an individual wood boiler would require an air quality permit unless
several boilers were to be installed and operated at the same site. If several boilers were installed and
operated together, the emissions produced could be greater than 40 tons of CO2 per year. This would
require permitting per AAC 50.502 (C)(1) or (C)(3). Permitting would not be required on the residential
wood fired stoves unless they violated the Wood-fired Heating Device Visible Emission Standards
(Section 18 AAC 50.075). For recent similar systems installed in Alaska, no air quality permits were
required or obtained.
Feasibility Assessment for Biomass Heating Systems New Stuyahok, AK
Coffman Engineers, Inc. 15
IX. General Biomass Technology Information
Heating with Wood Fuel
Wood fuels are among the most cost-effective and reliable sources of heating fuel for communities
adjacent to forestland when the wood fuels are processed, handled, and combusted appropriately.
Compared to other heating energy fuels, such as oil and propane, wood fuels typically have lower
energy density and higher associated transportation and handling costs. Due to this low bulk density,
wood fuels have a shorter viable haul distance when compared to fossil fuels. This short haul distance
also creates an advantage for local communities to utilize locally-sourced wood fuels, while
simultaneously retaining local energy dollars.
Most villages in rural Alaska are particularly vulnerable to high energy prices due to the large number of
heating degree days and expensive shipping costs. For many communities, wood-fueled heating can
lower fuel costs. For example, cordwood sourced at $250 per cord is just 25% of the cost per MMBTU as
#1 fuel oil sourced at $7 per gallon. In addition to the financial savings, the local communities also
benefit from the multiplier effect of circulating energy dollars within the community longer, more stable
energy prices, job creation, and more active forest management.
In all of the Lake and Peninsula Communities studied, the community’s wood supply and demand are
isolated from outside markets. The local cordwood market is influenced by land ownership, existing
forest management and ecological conditions, local demand and supply, and the State of Alaska Energy
Assistance program.
Types of Wood Fuel
Wood fuels are specified by energy density, moisture content, ash content, and granulometry. Each of
these characteristics affects the wood fuel’s handling characteristics, storage requirements, and
combustion process. Higher quality fuels have lower moisture, ash, dirt, and rock contents , consistent
granulometry, and higher energy density. Different types of fuel quality can be used in wood heating
projects as long as the infrastructure specifications match the fuel content characteristics. Typically,
lower quality fuel will be the lowest cost fuel, but it will require more expensive storage, handling, and
combustion infrastructure, as well as additional maintenance.
Projects in rural Alaska must be designed around the availability of wood fuels. Some fuels can be
harvested and manufactured on site, such as cordwood, woodchips, and briquettes. The economic
feasibility of manufacturing on site is determined by a financial assessment of the project. Typically,
larger projects offer more flexibility in terms of owning and operating the wood harvesting and
manufacturing equipment, such as a wood chipper, splitter, or equipment to haul wood out of forest,
than smaller projects.
Due to the limited wood fuel demand, large financial obligations and operating complexities, it is
unlikely that the Lake and Peninsula communities in this study will be able to manufacture pellets.
However, some communities may be able to manufacture bricks or fire logs made from pressed wood
material. These products can substitute for cordwood in woodstoves and boilers, while reducing supply
pressure on larger diameter trees that are generally preferred for cordwood.
Feasibility Assessment for Biomass Heating Systems New Stuyahok, AK
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High Efficiency Cord Wood Boilers
High Efficiency Low Emission (HELE) cordwood boilers are designed to burn cordwood fuel cleanly and
efficiently. The boilers use cordwood that is typically seasoned to 25% moisture content (MC) or less and
meet the dimensions required for loading and firing. The amount of cordwood burned by the boiler will
depend on the heat load profile of the building and the utilization of the fuel oil system as back up.
Three HELE cordwood boiler suppliers include Garn (www.garn.com), Greenwood
(www.greenwoodusa.com) and TarmUSA (www.woodboilers.com). All three of these suppliers have
units operating in Alaska. Greenwood and TarmUSA have a number of residential units operating in
Alaska and have models that range between 100,000 to 300,000 BTU/hr. Garn boilers, manufactured by
Dectra Corporation, are used in Tanana, Kasilof, Dot Lake, Thorne Bay, Coffman Cove and other
locations to heat homes, washaterias, schools, and community buildings.
The Garn boiler has a unique construction, which is basically a wood boiler housed in a large water tank.
Garn boilers come in several sizes and are appropriate for facilities using 100,000 to 1,000,000 BTUs per
hour. The jacket of water surrounding the fire box absorbs heat and is piped into buildings via a heat
exchanger, and then transferred to an existing building heating system, infloor radiant tubing, unit
heaters, or baseboard heaters. In installations where the Garn boiler is in a detached building, there are
additional heat exchangers, pumps and a glycol circulation loop that are necessary to transfer heat to
the building while allowing for freeze protection. Radiant floor heating is the most efficient heating
method when using wood boilers such as Garns, because they can operate using lower supply water
temperatures compared to baseboards.
Garn boilers are approximately 87% efficient and store a large quantity of water. For example, the Garn
WHS-2000 holds approximately 1,825 gallons of heated water. Garns also produce virtually no smoke
when at full burn, because of a primary and secondary gasification (2,000 ºF) burning process. Garns are
manually stocked with cordwood and can be loaded multiple times a day during periods of high heating
demand. Garns are simple to operate with only three moving parts: a handle, door and blower. Garns
produce very little ash and require minimal maintenance. Removing ash and inspecting fans are typical
maintenance requirements. Fans are used to produce a draft that increases combustion temperatures
and boiler efficiency. In cold climates, Garns can be equipped with exterior insulated storage tanks for
extra hot water circulating capacity. Most facilities using cordwood boilers keep existing oil-fired
systems operational to provide heating backup during biomass boiler downtimes and to provide
additional heat for peak heating demand periods.
Low Efficiency Cord Wood Boilers
Outdoor boilers are categorized as low-efficiency, high emission (LEHE) systems. These boiler systems
are not recommended as they produce significant emission issues and do not combust wood fuels
efficiently or completely, resulting in significant energy waste and pollution. These systems require
significantly more wood to be purchased, handled and combusted to heat a facility as compared to a
HELE system. The Alaska Department of Environmental Conservation has issued nuisance abatement
orders for air pollution for outdoor wood boilers in Fairbanks. Fairbanks is ranked number four on Time
Magazine's list of most air polluted cities in America. Additionally, several states have placed a
moratorium on installing LEHE boilers because of air quality issues (Washington). These LEHE systems
can have combustion efficiencies as low as twenty five (25%) percent and produce more than nine times
the emission rate of standard industrial boilers. In comparison, Garns can operate around 87%
efficiency.
Feasibility Assessment for Biomass Heating Systems New Stuyahok, AK
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High Efficiency Wood Stoves
Newer high efficiency wood stoves are available on the market that produce minimal smoke, minimal
ash and require less firewood. New EPA-certified wood stoves produce significantly less smoke than
older uncertified wood stoves. High efficiency wood stoves are easy to operate with minimal
maintenance compared to other biomass systems. The Blaze King Classic high efficiency wood stove
(www.blazeking.com) is a recommended model, due to its built-in thermostats that monitor the heat
output of the stove. This stove automatically adjusts the air required for combustion. This unique
technology, combined with the efficiencies of a catalytic combustor with a built-in thermostat, provides
the longest burn times of any wood stove. The Blaze King stove allows for optimal combustion and less
frequent loading and firing times.
Bulk Fuel Boilers
Bulk fuel boilers usually burn wood chips, sawdust, bark or pellets and are designed around the wood
resources that are available from the local forests or local industry. Several large facilities in Tok, Craig,
and Delta Junction (Delta Greely High School) are using bulk fuel biomass systems. Tok uses a
commercial grinder to process woodchips. The chips are then dumped into a bin and are carried by a
conveyor belt to the boiler. The wood fuel comes from timber scraps, local sawmills and forest thinning
projects. The Delta Greely High School has a woodchip bulk fuel boiler that heats the 77,000 square foot
facility. The Delta Greely system, designed by Coffman engineers, includes a completely separate boiler
building which includes chip storage bunker and space for storage of tractor trailers full of chips (so
handling of frozen chips could be avoided). Woodchips are stored in the concrete bunker and augers
move the material on a conveyor belt to the boilers. The automated fuel handling requirements for bulk
fuel systems are not cost-effective for small and medium sized structures due to higher maintenance
costs and complexities. Due to these reasons, a bulk fuel boiler system is not recommended for small
rural communities in Alaska with limited financial and human resources.
Grants
There are many grant opportunities for biomass work state, federal, and local for feasibility studies,
design and construction. If a project if determined to be pursued, a thorough search of websites and
discussions with the AEA Biomass group would be recommended to make sure no possible funding
opportunities are missed. Below are some funding opportunities and existing past grants that have
been awarded.
Currently, there is a funding opportunity for tribal communities that develop clean and renewable
energy resources through the U.S. Department of Energy. On April 30, 2013, the Department of Energy
announced up to $7 million was available to deploy clean energy projects in tribal communities to
reduce reliance on fossil fuel and promote economic development on tribal lands. The Energy
Department’s Tribal Energy Program, in cooperation with the Office of Indian Energy, will help Native
American communities, tribal energy resource development organizations, and tribal consortia to install
community or facility scale clean energy projects.
http://apps1.eere.energy.gov/tribalenergy/
The Department of Energy (DOE), Alaska Native programs, focus on energy efficiency and add ocean
energy into the mix. In addition the communities are eligible for up to $250,000 in energy -efficiency aid.
The Native village of Kongiganak will get help strengthening its wind-energy infrastructure, increasing
energy efficiency and developing “smart grid technology”. Koyukuk will get help upgrading its energy
Feasibility Assessment for Biomass Heating Systems New Stuyahok, AK
Coffman Engineers, Inc. 18
infrastructure, improving energy efficiency and exploring biomass options. The village of Minto will
explore all the above options as well as look for solar-energy ideas. Shishmaref, an Alaska Native village
faced climate-change-induced relocation, will receive help with increasing energy sustainability and
building capacity as it relocates. And the Yakutat T’lingit Tribe will also study efficiency, biomass and
ocean energy. This DOE program would be a viable avenue for biomass funding.
http://energy.gov/articles/alaska-native-communities-receive-technical-assistance-local-clean-energy-
development
The city of Nulato was awarded a $40,420 grant for engineering services for a wood energy project by
the United States Department of Agriculture (USDA) and the United States Forest Service. Links
regarding the award of the Woody Biomass Utilization Project recipients are shown below:
http://www.fs.fed.us/news/2012/releases/07/renewablewoods.shtml
http://www.usda.gov/wps/portal/usda/usdahome?contentid=2009/08/0403.xml
Delta Junction was awarded a grant for engineering from the Alaska Energy Authority from the
Renewable Energy Fund for $831,203. This fund provides assistance to utilities, independent power
producers, local governments, and tribal governments for feasibility studies, reconnaissance studies,
energy resource monitoring, and work related to the design and construction of eligible facilities.
http://www.akenergyauthority.org/re-fund-6/4_Program_Update/FinalREFStatusAppendix2013.pdf
http://www.akenergyauthority.org/PDF%20files/PFS-BiomassProgramFactSheet.pdf
http://www.akenergyauthority.org/RenewableEnergyFund/RFA_Project_Locations_20Oct08.pdf
The Alaska Wood Energy Development Task Group (AWEDTG) consists of a coalition of federal and state
agencies and not-for-profit organizations that have signed a Memorandum of Understanding (MOU) to
explore opportunities to increase the utilization of wood for energy and biofuels production in Alaska. A
pre-feasibility study for Aleknagik was conducted in 2012 for the AWEDTG. The preliminary costs for the
biomass system(s) are $346,257 for the city hall and health center system and $439,096 for the city hall,
health center, and future washeteria system.
http://www.akenergyauthority.org/biomasswoodenergygrants.html
http://www.akenergyauthority.org/BiomassWoodEnergy/Aleknagik%20Final%20Report.pdf
The Emerging Energy Technology Fund grand program provides funds to eligible applicants for
demonstrations projects of technologies that have a reasonable expectation to be commercially viable
within five years and that are designed to: test emerging energy technologies or methods of conserving
energy, improve an existing energy technology, or deploy an existing technology that has not previously
been demonstrated in Alaska.
http://www.akenergyauthority.org/EETFundGrantProgram.html
Feasibility Assessment for Biomass Heating Systems New Stuyahok, AK
Coffman Engineers, Inc.
Appendix A
Site Photos
Feasibility Assessment for Biomass Heating Systems New Stuyahok, AK
Coffman Engineers, Inc.
1. Booster Club - South elevation 2. Booster Club - West elevation
3. Booster Club - North elevation 4. Booster Club - North elevation
5. Booster Club – East Elevation 6. Booster Club –Fuel tank
Feasibility Assessment for Biomass Heating Systems New Stuyahok, AK
Coffman Engineers, Inc.
7. Booster Club – Gym 8. Booster Club – Boiler B1
9. Booster Club – Boiler B1 and B2 10. Booster Club – DHW Boiler
11. Booster Club – CP-1 12. Booster Club – Standby CP-2
Feasibility Assessment for Biomass Heating Systems New Stuyahok, AK
Coffman Engineers, Inc.
13. Booster Club – CP-3 14. Booster Club – Circ Pumps (CP1,2,3)
15. Booster Club - AHUs 16. Booster Club - AHUs
17. Booster Club – Johnson Controls BAS 18. Booster Club – EF-1
Feasibility Assessment for Biomass Heating Systems New Stuyahok, AK
Coffman Engineers, Inc.
19. Booster Club Office – Elevation 20. Booster Club Office – Elevation
21. Booster Club Office – Renovations due to fire
damage 22. Booster Club Office – Current Repairs
23. Booster Club Office – Current Repairs 24. Booster Club Office – Current Repairs
Feasibility Assessment for Biomass Heating Systems New Stuyahok, AK
Coffman Engineers, Inc.
Appendix B
Economic Analysis Spreadsheet
New Stuyahok Booster ClubNew Stuyahok, AlaskaProject Capital Cost($159,566)Simple Payback = Total Project Cost / First Year Cost Savings12.2 yearsPresent Value of Project Benefits (20 year life)$731,392Present Value of Operating Costs (20 year life)($360,797)Benefit / Cost Ratio of Project (20 year life)2.32Net Present Value (20 year life)$211,030Year Accumulated Cash Flow is Net PositiveFirst YearYear Accumulated Cash Flow > Project Capital Cost9.0 yearsDiscount Rate for Net Present Value Analysis3%Wood Fuel Escalation Rate3%Fossil Fuel Escalation Rate5%Electricity Escalation Rate3%O&M Escalation Rate2%YearYearYearYearYearYearYearYearYearYearYearYearYearYearYearYearYearYearYearYear1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20Existing Heating System Operating CostsExisting Heating Oil Consumption$6.934,500gal$31,185$32,744$34,381$36,101$37,906$39,801$41,791$43,880$46,074$48,378$50,797$53,337$56,004$58,804$61,744$64,831$68,073$71,477$75,050$78,803Biomass System Operating CostsWood Fuel (Delivered to site)$330.0085%34.2cord($11,286)($11,625)($11,973)($12,333)($12,702)($13,084)($13,476)($13,880)($14,297)($14,726)($15,167)($15,622)($16,091)($16,574)($17,071)($17,583)($18,111)($18,654)($19,214)($19,790)Fossil Fuel$6.9315%675gal($4,678)($4,912)($5,157)($5,415)($5,686)($5,970)($6,269)($6,582)($6,911)($7,257)($7,620)($8,001)($8,401)($8,821)($9,262)($9,725)($10,211)($10,721)($11,258)($11,820)Electricity$0.651,752kWh($1,139)($1,173)($1,208)($1,244)($1,282)($1,320)($1,360)($1,401)($1,443)($1,486)($1,530)($1,576)($1,624)($1,672)($1,723)($1,774)($1,827)($1,882)($1,939)($1,997)Operation and Maintenance Costs($500)($510)($520)($531)($541)($552)($563)($574)($586)($598)($609)($622)($634)($647)($660)($673)($686)($700)($714)($728)Additional Operation and Maintenance Costs for first 2 years($500)($510)$0$0$0$0$0$0$0$0$0$0$0$0$0$0$0$0$0$0Total Operating Costs($18,103)($18,729)($18,859)($19,523)($20,211)($20,926)($21,668)($22,437)($23,236)($24,066)($24,927)($25,821)($26,749)($27,714)($28,715)($29,755)($30,835)($31,958)($33,124)($34,336)Annual Operating Cost Savings$13,082 $14,015 $15,523 $16,578 $17,694 $18,875 $20,123 $21,443 $22,838 $24,312 $25,870 $27,516 $29,254 $31,090 $33,029 $35,076 $37,237 $39,519 $41,926 $44,467Accumulated Cash Flow$13,082 $27,098 $42,620 $59,198 $76,892 $95,767 $115,891 $137,334 $160,172 $184,484 $210,354 $237,870 $267,124 $298,215 $331,244 $366,320 $403,558 $443,076 $485,003 $529,470Net Present Value($146,865) ($133,654) ($119,449) ($104,719) ($89,456) ($73,649) ($57,287) ($40,359) ($22,856) ($4,765)$13,924 $33,223 $53,144 $73,698 $94,898 $116,757 $139,286 $162,499 $186,409 $211,030Energy UnitsHeating Source ProportionEconomic Analysis ResultsInflation RatesDescription Unit CostAnnual Energy Units
New Stuyahok Booster Club OfficeNew Stuyahok, AlaskaProject Capital Cost($12,887)Simple Payback = Total Project Cost / First Year Cost Savings6.9 yearsPresent Value of Project Benefits (20 year life)$160,906Present Value of Operating Costs (20 year life)($109,630)Benefit / Cost Ratio of Project (20 year life)3.98Net Present Value (20 year life)$38,389Year Accumulated Cash Flow is Net PositiveFirst YearYear Accumulated Cash Flow > Project Capital Cost5.8 yearsDiscount Rate for Net Present Value Analysis3%Wood Fuel Escalation Rate3%Fossil Fuel Escalation Rate5%Electricity Escalation Rate3%O&M Escalation Rate2%YearYearYearYearYearYearYearYearYearYearYearYearYearYearYearYearYearYearYearYear1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20Existing Heating System Operating CostsExisting Heating Oil Consumption$6.93990gal$6,861$7,204$7,564$7,942$8,339$8,756$9,194$9,654$10,136$10,643$11,175$11,734$12,321$12,937$13,584$14,263$14,976$15,725$16,511$17,337Biomass System Operating CostsWood Fuel (Delivered to site)$330.0050%4.4cord($1,452)($1,496)($1,540)($1,587)($1,634)($1,683)($1,734)($1,786)($1,839)($1,895)($1,951)($2,010)($2,070)($2,132)($2,196)($2,262)($2,330)($2,400)($2,472)($2,546)Fossil Fuel$6.9350%495gal($3,430)($3,602)($3,782)($3,971)($4,170)($4,378)($4,597)($4,827)($5,068)($5,322)($5,588)($5,867)($6,160)($6,468)($6,792)($7,131)($7,488)($7,862)($8,256)($8,668)Electricity$0.650kWh$0$0$0$0$0$0$0$0$0$0$0$0$0$0$0$0$0$0$0$0Operation and Maintenance Costs($50)($51)($52)($53)($54)($55)($56)($57)($59)($60)($61)($62)($63)($65)($66)($67)($69)($70)($71)($73)Additional Operation and Maintenance Costs for first 2 years($50)($51)$0$0$0$0$0$0$0$0$0$0$0$0$0$0$0$0$0$0Total Operating Costs($4,982)($5,199)($5,374)($5,611)($5,858)($6,117)($6,387)($6,670)($6,966)($7,276)($7,600)($7,939)($8,294)($8,665)($9,054)($9,461)($9,887)($10,332)($10,799)($11,287)Annual Operating Cost Savings$1,878 $2,004 $2,190 $2,331 $2,481 $2,640 $2,807 $2,984 $3,170 $3,367 $3,575 $3,795 $4,027 $4,271 $4,530 $4,802 $5,089 $5,392 $5,712 $6,049Accumulated Cash Flow$1,878 $3,883 $6,072 $8,404 $10,885 $13,524 $16,331 $19,315 $22,485 $25,853 $29,428 $33,223 $37,250 $41,521 $46,051 $50,853 $55,942 $61,335 $67,047 $73,096Net Present Value($11,063) ($9,174) ($7,170) ($5,099) ($2,959) ($748)$1,534 $3,890 $6,319 $8,825 $11,408 $14,070 $16,812 $19,636 $22,543 $25,535 $28,615 $31,782 $35,040 $38,389Energy UnitsHeating Source ProportionEconomic Analysis ResultsInflation RatesDescription Unit CostAnnual Energy Units
Feasibility Assessment for Biomass Heating Systems New Stuyahok, AK
Coffman Engineers, Inc.
Appendix C
Site Plan
Feasibility Assessment for Biomass Heating Systems New Stuyahok, AK
Coffman Engineers, Inc.
Site Plan of New Stuyahok Buildings
Booster
Club Office
Booster
Club
Feasibility Assessment for Biomass Heating Systems New Stuyahok, AK
Coffman Engineers, Inc.
Appendix D
AWEDTG Field Data Sheet