HomeMy WebLinkAboutKlawock and Craig Senior Centers High Efficiency Low Emissions Wood Fired Heating System Preliminary Fesability Report Final 09-02-2014-WOODHigh Efficiency Low Emission
Wood Fired Heating System
Pre-Feasibility Report
September 2, 2014
Version: Final
WES Energy & Environment, LLC
902 Market Street • Meadville, PA 16335
(814) 337‐8223
Prepared for:
Tlingit‐Haida Regional Housing Authority
Klawock Senior Center & Craig Senior Center
In Partnership with :
Fairbanks Economic Development CorporaƟon
Alaska Wood Energy Development Task Group
Prepared By:
Biomass Prefeasibility Report Date: September 2, 2014 Tlingit‐Haida Regional Housing Authority
FINAL Prince of Wales Island, Alaska
WES Energy & Environment
Table of Contents
1.0 Executive Summary .............................................................................................................. 1
2.0 Existing Fuel Usage & Heating System ................................................................................. 3
2.1 Klawock Senior Center ..................................................................................................... 3
2.2 Craig Senior Center........................................................................................................... 5
3.0 Forest Resource and Fuel Availability .................................................................................. 7
4.0 Proposed Biomass System Options ..................................................................................... 8
4.1 Klawock Senior Center Biomass System Options ............................................................. 8
4.1.1 Option 1a : 160,000 Btu/hr Wood Pellet System ..................................................... 9
4.1.2 Option 1b : 100,000 Btu/hr Cord Wood System ..................................................... 10
4.2 Craig Senior Center Biomass System Options ................................................................ 12
4.2.1 Option 2a : 110,000 Btu/hr Wood Pellet System ................................................... 13
4.2.2 Option 2b : 100,000 Btu/hr Cord Wood System ..................................................... 14
5.0 Benefit/Cost Analysis ......................................................................................................... 16
6.0 Conclusions & Recommendations ..................................................................................... 19
7.0 General Biomass Technology Information ........................................................................ 21
Appendix A – Conceptual Drawings
Appendix B – Capital Cost Estimates
Appendix C – 20 Year Financing at 4% APR Cash Flow Analysis
Appendix D ‐ Sensitivity Analysis of Annual Savings to Oil and Biomass Prices
Biomass Prefeasibility Report Date: September 2, 2014 Tlingit‐Haida Regional Housing Authority
FINAL Prince of Wales Island, Alaska
WES Energy & Environment
Page 1 of 24
1.0 EXECUTIVE SUMMARY
This preliminary feasibility study evaluates options for the Tlingit‐Haida Regional Housing
Authority to utilize high efficiency low emission wood fired technologies at the Craig Senior
Center and the Klawock Senior Center located on Prince of Wales Island, Alaska. Installation of
a wood fired heating system would present the Tlingit‐Haida Regional Housing Authority with
the opportunity to reduce operating costs, utilize a renewable fuel for heating, and keep fuel
expenditures within the regional economy.
The two centers are located 7 miles away from each other and are each evaluated for
independent wood fired heating systems. Figure 1 shows an aerial picture of the Klawock
Senior Center located in Klawock, Alaska.
Figure 1 – Aerial View of the Klawock Senior Center
Image source: Bing Maps
Biomass Prefeasibility Report Date: September 2, 2014 Tlingit‐Haida Regional Housing Authority
FINAL Prince of Wales Island, Alaska
WES Energy & Environment
Page 2 of 24
Figure 2 shows an aerial picture of the Craig Senior Center located in Craig, Alaska.
Figure 2 – Aerial View of the Craig Senior Center
Image source: Google Earth
Both buildings utilize #1 fuel oil fired boiler plants for space heating and domestic hot water
heating. Two biomass boiler technologies including wood pellet and split cord wood systems
were considered for each facility. A summary of the costs and benefits for each option are
listed in Table ES1.
Biomass Prefeasibility Report Date: September 2, 2014 Tlingit‐Haida Regional Housing Authority
FINAL Prince of Wales Island, Alaska
WES Energy & Environment
Page 3 of 24
Table ES1 – Cost and Benefit Summary
Option
Estimated
Capital
Cost
1st Year Net
Annual Operating
Savings
Simple
Payback,
Years
20 Year Net
Present Value
20 Year B/C
Ratio
1a – Klawock Senior Center Wood
Pellet System $102,275 $4,168 24.5 (10,626) 0.90
1b – Klawock Senior Center Cord
Wood System $97,405 $6,500 15.0 37,842 1.39
2a – Craig Senior Center Wood
Pellet System $131,497 $1,601 82.2 (93,983) 0.29
2b – Craig Senior Center Cord Wood
System $103,667 $3,182 32.6 (36,461) 0.65
Notes:
1 – Net Annual Operating Savings include costs for wood fuel, supplemental fossil fuel, and operation &
maintenance (O&M) costs.
2 – 20 Year Net Present Value takes the present value of the operating savings for each year using a discount rate
of 3.0% as published in the “Energy Price Indices and Discount Factors for Life‐Cycle Cost Analysis ‐2013” and the
initial capital outlay of the total project cost. A value greater than zero means that savings are greater than
expenses over 20 years in the value of today’s dollars.
3 – 20 Year Benefit/Cost (B/C) Ratio is calculated by dividing the present value of net annual operating savings
over a 20 year period with a discount rate of 3.0% by the Estimated Capital Cost. A value greater than 1 means the
benefits exceed the costs over a 20 year period.
2.0 EXISTING FUEL USAGE & HEATING SYSTEM
The Craig and Klawock Senior Centers both use #1 fuel oil fired heating systems. This section
gives an overview of the fuel use and descriptions of the heating systems for each facility.
2.1 KLAWOCK SENIOR CENTER
The Klawock Senior Center is a 24,980 ft2 facility housing approximately 30 residents and staff.
The facility used approximately 5,000 gallons of #1 fuel oil annually for space heating and
domestic hot water heating. Annual expenditures are approximately $20,650 at the current
fuel price of $4.13 per gallon. An above ground 1,100 gallon fuel oil tank is used for onsite
storage.
The boiler room contains two model WTGO‐7 Weil McLain hot water boilers firing on #1 fuel oil
and rated at 210,000 Btu/hr output and 50 psig. The boilers were installed in 2008 and are in
excellent condition. The hot water heating distribution system is a primary‐secondary piping
system with individual zone pumps distributing water throughout the building. Baseboard fin
tube radiant heaters provide space heating for rooms. A makeup air handling unit with a hot
water coil is used for the kitchen and common area. A digital control system is installed by
Delta Controls, however there is no way to interface with the control system without bringing
in a service technician with a laptop and appropriate software. Domestic hot water is heated
indirectly using the heating boilers and stored in two 120 gallon HTP Superstor tanks. There is
potential room in the existing boiler room to locate hot water thermal storage tanks and one
wood fired boiler.
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Fuel deliveries for calendar year (CY) 2013 are used for the purposes of load modeling and
boiler sizing in this memorandum. The heating degree days for CY 2013 were fairly close to the
30 year average for the region. Thus, CY 2013 weather data from Klawock, Alaska is used with
the 5,000 gallon annual fuel oil use for the purposes of load modeling and boiler sizing in this
study. Figure 2 shows how the daily average heating demand for the Klawock Senior Center
would be expected to vary over the course of a year. During a 24‐hr period, the actual load will
vary above and below this average value. Peak loads are estimated at 130% of the average
load. Peak loads would be experienced for short durations over a 24 hour period.
Figure 3 – Klawock Senior Center Estimated Average Daily Heating Demand for CY 2013
Note: The daily average heating demand model is based on local weather data and annual fuel usage provided
by the Tlingit‐Haida Regional Housing Authority. The model assumes that each person uses 20 gallons of
domestic hot water per day for bathing, cooking, laundry, and hand washing. Actual demand would fluctuate
above and below the average heating demand values shown over a 24‐hr period. The peak demand is estimated
as 130% of the average demand and would only be experienced for short durations over a 24 hour period.
A load duration curve was developed using the daily average heating demand curves. Load
duration curves sort the daily average heating demand over the course of a year from highest
to lowest and plot it over the number of days to show the annual range of facility heating
demand. Figure 4 shows the estimated load duration curve for CY 2013.
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Figure 4 – Klawock Senior Center Estimated Load Duration Curve for CY 2013
Note: The daily average heating demand model is based on local weather data and annual fuel usage provided
by the Tlingit‐Haida Regional Housing Authority. The model assumes that each person uses 20 gallons per day of
domestic hot water. Actual demand would fluctuate above and below the daily average heating demand values
shown over a 24‐hr period. The peak demand is estimated as 130% of the average demand and would only be
experienced for short durations over a 24 hour period.
2.2 CRAIG SENIOR CENTER
The Craig Senior Center is a 5,400 ft2 facility housing 10 residents. The facility used
approximately 3,000 gallons of #1 fuel oil annually for space heating and domestic hot water
heating. Annual expenditures are approximately $12,390 at the current fuel price of $4.13 per
gallon. An above ground 1,000 gallon fuel oil tank is used for onsite storage.
The boiler room contains two model P‐WGO‐6 Weil McLain hot water boilers firing on #1 fuel
oil and rated at 184,000 Btu/hr output and 50 psig. The boilers were installed in ~2004 and are
in good condition. The vent piping shows signs of corrosion from condensation in the flue gas.
Return water temperatures should not be below 140°F to the boiler to prevent condensation.
This can be accomplished by controlling water distribution temperatures or through the use of
a boiler protection valve.
The hot water heating distribution system is a primary‐secondary piping system with individual
zone pumps distributing water throughout the building. Baseboard fin tube heaters provide
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space heating for rooms. Thermostats in each room and control valves on the fin tube heaters
are the only control for the system. Domestic hot water is heated indirectly using the heating
boilers and stored in a Crown Mega‐Stor tank. There is no room in the existing boiler room to
locate a wood fired boiler system or thermal storage tanks. Additionally, space constraints
around of the building could provide a challenge for siting a system and onsite fuel storage.
Fuel deliveries for calendar year (CY) 2013 are used for the purposes of load modeling and
boiler sizing in this memorandum. The heating degree days for CY 2013 were fairly close to 30
year average for the region. Thus, CY 2013 weather data from Klawock, Alaska is used with the
3,000 gallon annual fuel oil use for the purposes of load modeling and boiler sizing in this study.
Figure 2 shows how the daily average heating demand for the Craig Senior Center would be
expected to vary over the course of a year. During a 24‐hr period, the actual load will vary
above and below this average value. Peak loads are estimated at 130% of the average load.
Peak loads would be experienced for short durations over a 24 hour period.
Figure 5 – Craig Senior Center Estimated Average Daily Heating Demand for CY 2013
Note: The daily average heating demand model is based on local weather data and annual fuel usage provided
by the Tlingit‐Haida Regional Housing Authority. Actual demand would fluctuate above and below the average
heating demand values shown over a 24‐hr period. The peak demand is estimated as 130% of the average
demand and would only be experienced for short durations over a 24 hour period.
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A load duration curve was developed using the daily average heating demand curves. Load
duration curves sort the daily average heating demand over the course of a year from highest
to lowest and plot it over the number of days to show the annual range of facility heating
demand. Figure 4 shows the estimated load duration curve for CY 2013.
Figure 6 – Craig Senior Center Estimated Load Duration Curve for CY 2013
Note: The daily average heating demand model is based on local weather data and annual fuel usage provided
by the Tlingit‐Haida Regional Housing Authority. Actual demand would fluctuate above and below the daily
average heating demand values shown over a 24‐hr period. The peak demand is estimated as 130% of the
average demand and would only be experienced for short durations over a 24 hour period.
3.0 FOREST RESOURCE AND FUEL AVAILABILITY
Prince of Wales Island is heavily forested with the majority of the land owned by the US Forest
Service and smaller tracts owned by State and private owners. Federal resources on the island
are managed by the Tongass Land Management Plan. The most recent version was adopted in
2008.
Potential fuel suppliers were contacted for pricing and availability of biomass fuel. Table 1 lists
the companies contacted, location, contact information, and fuels available.
Table 1 – Contacted Fuel Supplier’s
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Company Location Phone Fuels
Welcome Inn B&B Thorne Bay 907‐828‐3950 Palletized Split Cordwood
Viking Lumber Klawock 907‐755‐8880 Dry wood chips, Dry Sawdust, Wet Wood
Chips, Compressed Bricks
Tongass Forest Enterprises Ketchikan 907‐617‐4542 Wood Pellets
The biomass fuels considered for evaluation in this report are wood pellets and split cord wood.
Fuel prices used for evaluation are $330 per ton for wood pellets and $250 per 4’ x 4’ x 8’ cord.
Table 2 summarizes the available fuels for heating as well as their cost per mmBtu output
comparison.
Table 2 – Fuel Pricing and Cost per mmBtu
Fuel, Unit Cost per
Unit
Input Heating
Value,
mmBtu per
Unit
Estimated
Boiler
Efficiency
Boiler Output
Heating Value,
mmBtu/Unit
Boiler Output
Heating Cost,
$/mmBtu
Dry Cord Wood, Cord $250.00 18.1 70% 12.67 $19.73
Wood Pellets, Ton $330.00 15.2 80% 12.16 $27.14
#1 Fuel Oil, Gallon $4.13 0.134 80% 0.1072 $38.53
Note:
1 ‐ Assumes 20% moisture content wet basis for cord wood and 18.1 mmBtu per 4’ x 4’ x 8’ cord of Sitka Spruce.1
2 ‐ Input heating value assumes 8% moisture content wet basis for wood pellets with an average High Heating
Value of 8,255 Btu/lb of bone dry wood based on a mixture of Sitka Spruce (8,100 Btu/lb) and Western Hemlock
(8,410 Btu/lb)2.
4.0 PROPOSED BIOMASS SYSTEM OPTIONS
Options for using high efficiency low emission biomass systems were evaluated for heating the
Klawock and Craig Senior Centers. The Klawock Senior Center has space to fit one boiler firing
on cord wood or wood pellets and hot water thermal storage in the existing boiler room. The
Craig Senior Center does not have any additional space available and would need to locate the
new boiler and thermal storage outside in a shed style building or container. This section
described the proposed systems in detail.
4.1 KLAWOCK SENIOR CENTER BIOMASS SYSTEM OPTIONS
Two high efficiency low emission biomass fired boiler systems are evaluated for
interconnection with the existing heating system at the Klawock Senior Center. Option 1a
considers a boiler system that would fire on wood pellets. Option 1b considers a boiler system
that would fire on cord wood.
1 http://www.alaskawoodheating.com/energy_content.php
2 Avery, Robert B., Funck, James W., & Wilson, Pamela L. (2010). Fuelwood Characteristics of Northwestern Conifers
and Hardwoods (updated). Portland, Or.: U.S. Department of Agriculture, Forest Service, Pacific Northwest
Research Station.
Biomass Prefeasibility Report Date: September 2, 2014 Tlingit‐Haida Regional Housing Authority
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4.1.1 Option 1a : 160,000 Btu/hr Wood Pellet System
One advanced combustion wood pellet boiler sized at approximately 0.16 mmBtu/hr of heat
output would be combined with approximately 200 gallons of thermal storage to efficiently
meet the range of heating needs. The rated operating range of the system would be from
~0.05 to ~0.16 mmBtu/hr with thermal storage allowing short term peaks to be met. The hot
water thermal storage would be heated to a preset temperature (typically 195°F or higher) that
is higher than distributed for building heat. The thermal storage tank(s) would use a 3‐way
mixing valve to blend hot water in the tank with colder return water from the senior center to
maintain a range of supply water temperatures (160°F – 190°F) determined by an outside air
temperature reset schedule.
The storage would allow the system to meet a 1‐hr peak of ~0.18 mmBtu/hr and a 15 minute
peak of ~0.26 mmBtu/hr. The storage would also allow the boiler to operate efficiently to
provide domestic hot water heating. The storage will hold approximately 88,000 Btu for
domestic hot water usage. This allows the pellet boiler to fire for a period of approximately 30
minutes within its efficient firing range to charge the storage. The heat in the storage is then
used to provide domestic hot water needs, until the temperature drops to ~140oF and the
system has to fire to charge it once more.
The wood pellet boilers, metering bin, expansion tank, valves, fittings, and boiler pump will be
installed in the existing boiler room. A fuel storage bin capable of holding 30 tons of wood
pellets will be located next to the building to accept bulk deliveries of wood pellets
pneumatically or with an auger. Wood pellets will be automatically transferred using a flexible
auger or pneumatic hose from the storage bin to a metering bin that feeds the wood pellet
boiler. The wood pellet boiler will heat the hot water thermal storage system located in the
existing boiler room. The hot water thermal storage will tie in with the existing heating
distribution pipes. The existing fuel oil fired heating boilers would remain to supplement the
biomass system during periods of maintenance and if the heating demand is outside the range
of the biomass system. Appendix A contains a conceptual site plan, floor plan, and schematic
for the biomass system. Figure 7 shows the estimated wood pellet system coverage of the FY
2013 load duration curve.
Biomass Prefeasibility Report Date: September 2, 2014 Tlingit‐Haida Regional Housing Authority
FINAL Prince of Wales Island, Alaska
WES Energy & Environment
Page 10 of 24
Figure 7 – Estimated Wood Pellet System Coverage of Load Duration Curve
Note: The load duration curve model is based on local weather data and annual fuel delivery volumes provided by
Tlingit‐Haida Regional Housing Authority. Potential coverage of 99% is shown. Actual coverage will depend on
management of loads and the use of thermal storage. The system can be used as described in the text to cover
approximately 100% of the annual demand. Management of loads, the use of thermal storage, and operations will
determine actual biomass coverage.
Figure 7 shows 99% biomass coverage of the FY 2013 load duration curve. Actual coverage will
vary depending on weather conditions, peak demands, equipment operation schedules, and
periods when the boilers are shut down for maintenance. This report assumes 95% coverage of
fuel oil usage for estimating the potential fuel use and savings for this memorandum.
4.1.2 Option 1b : 100,000 Btu/hr Cord Wood System
An advanced combustion unit and hot water boiler capable of firing on seasoned cord wood
sized at approximately 100,000 Btu/hr of heat output is evaluated. The boiler would be
combined with approximately 500 gallons of thermal storage to efficiently meet the center’s
range of heating needs.
Welcome Inn B&B in Thorne Bay provides half cords stacked and wrapped on a pallet.
Deliveries could be coordinated with up to 10 cords delivered at once. A local freight company
provides the option to tow a forklift behind the truck for unloading. It is assumed that this
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option is exercised and a forklift is not included in the budget. A 600 ft2 cord wood storage
building will be constructed across the parking lot of the Klawock Senior Center. This will allow
the storage of approximately 15 to 18 cords of wood. The floor will be concrete to allow the
use of a pallet jack to roll a half cord at a time from the storage building, across the parking lot,
and into a more convenient location in the building to load the boiler.
Cord wood systems are manually loaded and operate efficiently while burning hot and fast.
Seasoned wood is loaded into the firebox, is lit, and should be operated at high fire. Cord wood
boilers can “turn‐down” the heating output by reducing air to the firebox. This causes the
wood to smolder and smoke is emitted due to inefficient combustion. If a cord wood system is
rated at an average output of 100,000 Btu/hour over 8 hours, most of the heat is generated
during the first couple hours and then tapers off over the remaining period. Because of this,
hot water thermal storage is crucial for efficient operation. The hot water thermal storage will
provide a buffer for the boiler to charge the tank with more heat than is required for the
building. The heat stored in the tank will then be used over the course of the day to heat the
building. Additionally, the operator should try to gauge how much wood fuel to charge the fire
box with based on expected heat load.The firebox will likely not need to be filled to the top if it
is operating during the summer for only domestic hot water loads.
The hot water thermal storage will hold approximately 240,000 Btu for domestic hot water
usage. Two 120 gallon superstore tanks are currently used for domestic hot water storage that
can store up to 125,000 Btu of heat total. If the operator lit the boiler in the morning to charge
thermal storage system and the existing hot water super store tanks, the boiler would need to
be loaded approximately half full. The tanks could then be charged again at the end of the day
if needed. If the demand for hot water during the day exceeds what is stored in all of the tanks,
the fuel oil system would fire to bridge the gap. The estimated coverage using the cord wood
boiler for the Klawock Senior Center is shown in Figure 8.
Biomass Prefeasibility Report Date: September 2, 2014 Tlingit‐Haida Regional Housing Authority
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Figure 8 – Estimated Cord Wood System Coverage of Load Duration Curve
Note: The load duration curve model is based on local weather data and annual fuel delivery volumes provided by
Tlingit‐Haida Regional Housing Authority. Potential coverage of 80% is shown. Actual coverage will depend on
management of loads and the use of thermal storage.
Figure 8 shows 80% biomass coverage of the FY 2013 load duration curve as the red shaded
portion. The existing fuel oil system will supplement the wood chip boiler during peak loads,
low loads, and during periods of maintenance. Actual coverage will vary depending on
weather conditions, peak demands, equipment operation schedules, and periods when the
boilers are shut down for maintenance. This report assumes 80% coverage of fuel oil usage for
estimating the potential fuel use and savings for this memorandum.
There are currently limited manufacturers who offer an ASME rated cord wood boiler. An open
non pressurized system could be utilized with a non‐ASME rated boiler to heat the system with
piping and control modifications. The non‐ASME rated boiler transfers heat to the existing
pressurized system via a heat exchanger. Cost effective heat exchanger design will reduce the
temperature that can be delivered on the pressure side of the system by about 5 °F.
4.2 CRAIG SENIOR CENTER BIOMASS SYSTEM OPTIONS
Two high efficiency low emission biomass fired boiler systems are evaluated for
interconnection with the existing heating system serving the Craig Senior Center. Option 2a
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considers a boiler system that would fire on wood pellets. Option 2b considers a boiler system
that would fire on cord wood.
4.2.1 Option 2a : 110,000 Btu/hr Wood Pellet System
One advanced combustion wood pellet boiler sized at approximately 0.11 mmBtu/hr of heat
output would be combined with approximately 200 gallons of thermal storage to efficiently
meet the range of heating needs. The rated operating range of the system would be from
~0.03 to ~0.11 mmBtu/hr with thermal storage allowing short term peaks to be met. The hot
water thermal storage would be heated to a preset temperature (typically 195°F or higher) that
is higher than distributed for building heat. The thermal storage tank would use a 3‐way mixing
valve to blend hot water in the tank with colder return water from the senior center to
maintain a range of supply water temperatures (160°F – 190°F) determined by an outside air
temperature reset schedule.
The storage would allow the system to meet a 1‐hr peak of ~0.13 mmBtu/hr and a 15 minute
peak of ~0.20 mmBtu/hr. The storage would also allow one boiler to operate efficiently to
provide domestic hot water heating. The storage will hold approximately 88,000 Btu for
domestic hot water usage. This allows one pellet boiler to fire for a period of approximately 50
minutes within its efficient firing range to charge the storage. The heat in the storage is then
used to provide domestic hot water needs, until the temperature drops to ~140oF and the
system has to fire to charge it once more.
The wood pellet boiler, thermal storage tank, metering bin, expansion tank, valves, fittings, and
distribution pumps will be factory installed in a roll off shipping container. The container can
vary depending on the manufacturer selected, but can be a roll off shipping container or wood
paneled storage box. A fuel storage bin capable of holding 30 tons of wood pellets will be
installed for fuel storage. Smaller storage bins could be used, but typical bulk deliveries are
made in ~20 ton loads. This can be located adjacent to the building if a portion of the deck is
removed or in the front parking lot. Wood pellets will be automatically transferred using a
flexible auger or pneumatic hose from the storage bin to a metering bin that feeds the wood
pellet boiler. Heating distribution pipes will be installed from the wood pellet heating plant to
the existing fuel oil fired boiler plant. The thermal storage system will be located in the existing
fuel oil boiler plant and tie‐in with the existing hot water heating system. The existing fuel oil
fired heating boilers would remain to supplement the biomass system during periods of
maintenance and if the heating demand is outside the range of the biomass system. Appendix
A contains a conceptual site plan, floor plan, and schematic for the biomass system. Figure 9
shows the estimated wood pellet system coverage of the FY 2013 load duration curve.
Biomass Prefeasibility Report Date: September 2, 2014 Tlingit‐Haida Regional Housing Authority
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Figure 9 – Estimated Wood Pellet System Coverage of Load Duration Curve
Note: The load duration curve model is based on local weather data and annual fuel delivery volumes provided by
Tlingit‐Haida Regional Housing Authority. Potential coverage of 100% is shown. Actual coverage will depend on
management of loads and the use of thermal storage.
Figure 9 shows 100% biomass coverage of the FY 2013 load duration curve. Actual coverage
will vary depending on weather conditions, peak demands, equipment operation schedules,
and periods when the boilers are shut down for maintenance. This report assumes 95%
coverage of fuel oil usage for estimating the potential fuel use and savings for this
memorandum.
4.2.2 Option 2b : 100,000 Btu/hr Cord Wood System
An advanced combustion unit and hot water boiler capable of firing on seasoned cord wood
sized at approximately 100,000 Btu/hr of heat output is evaluated. The boiler would be
combined with approximately 500 gallons of thermal storage to efficiently meet the center’s
range of heating needs. This boiler size was chosen because typically it is the smallest boiler
offered by manufacturers. The boiler operator would have to take care to charge the firebox
based on expected load to ensure that the boiler does not idle and produce excess smoke.
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The hot water thermal storage will hold approximately 240,000 Btu for domestic hot water
usage. One 100 gallon tank is currently used for domestic hot water storage that can store up
to 52,000 Btu of heat total. If the operator lit the boiler in the morning to charge the thermal
storage system and the existing hot water super store tanks, the boiler would need to be
loaded approximately half full. The tanks could then be charged again at the end of the day if
needed. If the demand for hot water during the day exceeds what is stored in all of the tanks,
the fuel oil system would fire to bridge the gap. The estimated coverage using the cord wood
boiler for the Craig Senior Center is shown in Figure 10.
Figure 10 – Estimated Cord Wood System Coverage of Load Duration Curve
Note: The load duration curve model is based on local weather data and annual fuel delivery volumes provided by
Tlingit‐Haida Regional Housing Authority. Potential coverage of 86% is shown. Actual coverage will depend on
management of loads and the use of thermal storage.
Figure 10 shows 86% coverage of the FY 2013 load duration curve using the cord wood system.
The existing fuel oil system in the boiler room will supplement the cord wood system as
needed. Actual coverage will vary depending on weather conditions, peak demands,
equipment operation schedules, and periods when the boilers are shut down for maintenance.
This report assumes 80% coverage for the cord wood system for estimating the potential fuel
use and savings for the Craig Senior Center.
0.00
0.02
0.04
0.06
0.08
0.10
0.12
0.14
0.16
11325374961738597109121133145157169181193205217229241253265277289301313325337349361Heat Demand of Boiler Output (mmBtu/hr)Days
Biomass Coverage Daily Average Heating Demand Daily Peak Heating Demand
Biomass Prefeasibility Report Date: September 2, 2014 Tlingit‐Haida Regional Housing Authority
FINAL Prince of Wales Island, Alaska
WES Energy & Environment
Page 16 of 24
5.0 BENEFIT/COST ANALYSIS
Capital costs are estimated for each option based on recent quotations and bids provided by
boiler manufacturers and recent bids for similar projects. These costs include the fuel storage
and handling system, biomass combustion unit, boiler, accessory equipment, installation,
integration with the existing heating and domestic hot water systems, professional fees, and
contingency. The estimated capital costs for each Option are listed in Table 3. Tables showing
the detailed cost breakdowns are found in Appendix B.
Table 3 – Estimated Project Capital Costs
Option Estimated
Capital Cost
1a – Klawock Senior Center Wood Pellet System $102,275
1b – Klawock Senior Center Cord Wood System $97,405
2a – Craig Senior Center Wood Pellet System $131,497
2b – Craig Senior Center Cord Wood System $103,667
It is assumed that existing staff would coordinate deliveries, empty ash bins, and check on the
system. Ash removal costs have been estimated at $70 per ton of ash and $220 per container
delivery. Option 1b would generate the largest quantity of ash and would result in
approximately 3 cubic yards annually. Wood ash can be used as a direct replacement for lime
and costs for removal could be reduced if it is used as a soil amendment on school grounds or
other locations.
An increase in electricity use would occur from the circulation pumps and fuel handling system.
Electricity costs using a price of $0.1272/ kWh have been estimated considering motors for
pumps, augers, and fans for the wood pellet system and motors for pumps and fans for the
cord wood system. Annual operation and maintenance (O&M) costs are estimated for each
option and are listed in Table 4.
Table 4 – Estimated Annual O&M Costs
Task Option 1a Option 1b Option 2a Option 2b
Electricity $350 $180 $360 $180
Ash Removal $240 $340 $230 $300
Annual Service $1,000 $1,000 $1,000 $1,000
Totals $1,590 $1,520 $1,590 $1,480
Note:
1 – Electricity costs are estimated at $0.1272/kWh as provided by Tlingit‐Haida Regional housing Authority.
2 – Ash removal costs are estimated at $70/ton and $220 per container delivery. Ash generation is estimated at
0.5% by weight for wood pellets and 4% by weight for cord wood. Ash is a valuable product that can be used a soil
amendment and costs for removal could be mitigated if used as such.
Biomass Prefeasibility Report Date: September 2, 2014 Tlingit‐Haida Regional Housing Authority
FINAL Prince of Wales Island, Alaska
WES Energy & Environment
Page 17 of 24
Annual operating savings are estimated considering fuel costs and O&M costs. Table 5 shows
the estimated annual operating savings for each option.
Table 5 – Estimated Annual Operating Savings
Option
Current
Annual
Fuel Oil
Cost
Estimated
Annual
Biomass
Cost
Estimated
Annual Fuel Oil
Cost with
Biomass System
Estimated
Additional
Annual O&M
Costs
Estimated
Annual
Savings
1a – Klawock Senior Center Wood
Pellet System $20,650 $13,860 $1,033 $1,590 $4,168
1b – Klawock Senior Center Cord
Wood System $20,650 $8,500 $4,130 $1,520 $6,500
2a – Craig Senior Center Wood
Pellet System $12,390 $8,580 $620 $1,590 $1,601
2b – Craig Senior Center Cord
Wood System $12,390 $5,250 $2,478 $1,480 $3,182
A benefits summary is listed in Table 6 showing the estimated capital cost, 1st year net
operating savings, simple payback, 20 year Net Present Value, and 20 Year Benefits to Cost
(B/C) ratio.
Table 6 – Cost and Benefit Summary
Option Estimated
Capital Cost
1st Year
Net
Annual
Operating
Savings
Simple
Payback,
Years
20 Year Net
Present Value
20 Year B/C
Ratio
1a – Klawock Senior Center Wood
Pellet System $102,275 $4,168 24.5 (10,626) 0.90
1b – Klawock Senior Center Cord
Wood System $97,405 $6,500 15.0 37,842 1.39
2a – Craig Senior Center Wood
Pellet System $131,497 $1,601 82.2 (93,983) 0.29
2b – Craig Senior Center Cord
Wood System $103,667 $3,182 32.6 (36,461) 0.65
Notes:
1 – Net Annual Operating Savings include costs for wood fuel, supplemental fossil fuel, and operation &
maintenance (O&M) costs.
2 – 20 Year Net Present Value takes the present value of the operating savings for each year using a discount rate
of 3.0% as published in the “Energy Price Indices and Discount Factors for Life‐Cycle Cost Analysis ‐2013” and the
initial capital outlay of the total project cost. A value greater than zero means that savings are greater than
expenses over 20 years in the value of today’s dollars.
3 – 20 Year Benefit/Cost (B/C) Ratio is calculated by dividing the present value of net annual operating savings over
a 20 year period with a discount rate of 3.0% by the Estimated Capital Cost. A value greater than 1 means the
benefits exceed the costs over a 20 year period.
Biomass Prefeasibility Report Date: September 2, 2014 Tlingit‐Haida Regional Housing Authority
FINAL Prince of Wales Island, Alaska
WES Energy & Environment
Page 18 of 24
A cash flow analysis was completed for financing the projects assuming a 20 year financing term
at a 4.0% interest rate. None of the Options had a positive first year cash flow after annual
payments. However, Option 1b was very close to breaking even and grant funding or better
financing rates could easily make this a positive cash flow project. The detailed analyses are
shown in Appendix C.
A sensitivity analysis was completed comparing 20 year net present value for each option over
a range of annual oil inflation rates and 3.0% for remaining O&M costs. Table 7 shows the
results of the 20 year net present value sensitivity analysis.
Table 7 – 20 Year Net Present Value Sensitivity to Oil Inflation Rate
Option
20 Year NPV
with Oil
Inflation at
3.0% Annually
20 Year NPV
with Oil
Inflation at
3.3% Annually
20 Year NPV
with Oil
Inflation at
4.0% Annually
20 Year NPV
with Oil
Inflation at
6.8% Annually
1a – Klawock Senior Center Wood
Pellet System ($21,353) ($10,626) $15,914 $146,943
1b – Klawock Senior Center Cord
Wood System $28,614 $37,647 $59,997 $170,338
2a – Craig Senior Center Wood
Pellet System ($100,419) ($93,983) ($78,059) $559
2b – Craig Senior Center Cord
Wood System ($41,880) ($36,461) ($23,051) $43,154
Note: Net Present Values are calculated using annual inflation rates of 3% for wood fuel and O&M costs, the
inflation rate for oil stated in the table, the initial capital cost, and a discount rate of 3%
Table 8 lists the assumptions and values used to develop costs and savings in this study.
Biomass Prefeasibility Report Date: September 2, 2014 Tlingit‐Haida Regional Housing Authority
FINAL Prince of Wales Island, Alaska
WES Energy & Environment
Page 19 of 24
Table 8 – Assumptions and Values Used in the Report
Item Value and Unit Source
Klawock Senior Center annual #1 fuel oil use 5,000 gallons Tlingit‐Haida Regional Housing Authority
Craig Senior Center annual #1 fuel oil use 3,000 gallons Tlingit‐Haida Regional Housing Authority
Option 1a portion of fuel oil replaced 95%WES E&E estimate
Option 1b portion of fuel oil replaced 80%WES E&E estimate
Option 2a portion of fuel oil replaced 95%WES E&E estimate
Option 2b portion of fuel oil replaced 80%WES E&E estimate
#1 Fuel oil heat content 134,000 Btu/gal WES E&E assumption
Cord wood moisture content wet basis 20%WES E&E assumption
Wood pellet moisture content wet basis 8%WES E&E assumption
Cord wood high heating value (Sitka Spruce) 18.1 mmBtu/Cord University of Alaska Fairbanks
Cooperative Extension Service
Wood pellet high heating value 15.2 mmBtu/ton WES E&E assumption
#1 Fuel oil boiler efficiency (HHV) 80%WES E&E assumption
Cord wood boiler efficiency (HHV) 70%WES E&E assumption
Wood pellet boiler efficiency (HHV) 80%WES E&E assumption
#1 Fuel oil price $4.13/gallon Tlingit‐Haida Regional Housing Authority
Electricity price $0.1274 Tlingit‐Haida Regional Housing Authority
Cord wood price $250.00/Cord Budget quote
Wood pellet price $330.00/ton Budget quote
Discount rate 3.0%NISTIR 85‐3273‐28
#1 Fuel oil inflation rate 3.3%WES E&E assumption
Wood pellet inflation rate 3.0%WES E&E assumption
O&M inflation rate 3.0%WES E&E assumption
Cord wood inflation rate 3.0%WES E&E assumption
6.0 CONCLUSIONS & RECOMMENDATIONS
This study concludes that the Tlingit‐Haida Regional Housing Authority can reduce annual
operating costs for space heating and domestic hot water heating by installing a high efficiency,
low emission wood fired heating system for the Craig and Klawock Senior Centers. The projects
will offset approximately 80% to 95% of the fuel oil use depending on the option selected.
The Klawock Senior Center has the potential for a cost effective project by using a high
efficiency gasification cord wood boiler system and hot water thermal storage. Depending on
the rates and structure of the financing, the project has the potential for a positive first year
cash flow. The Craig Senior Center has site space constraints that increase the capital costs of
the system. Additionally, there is less fuel oil to be offset, making the economics not as
attractive. Outside grant funding and low interest loans would improve economics and
potentially make a project possible. If 80% of the project costs were secured through grant
funding, simple paybacks would range from 5 years for wood pellets to 3 years for cord wood
for the Klawock Senior Center and 16.5 years for wood pellets to 6.5 years for cord wood for
the Craig Senior Center. Additional benefits that would be provided by a high efficiency, low
emission wood fired system include:
Purchase of cord wood will immediately impact the local economy since the fuel is
currently available in Thorne Bay;
Biomass Prefeasibility Report Date: September 2, 2014 Tlingit‐Haida Regional Housing Authority
FINAL Prince of Wales Island, Alaska
WES Energy & Environment
Page 20 of 24
Purchase of wood pellets will impact the regional economy, with pellet production
currently operational in Ketchikan, AK;
Decreased dependence on imported oil by replacing 2,400 to 2,850 gallons of #1 fuel oil
at the Craig Senior Center and 4,000 to 4,750 gallons of #1 fuel oil at the Klawock Senior
Center with renewable biomass fuel;
A hedge against volatility of the fossil fuel market;
As the Tlingit‐Haida Regional Housing Authority continues to pursue biomass energy options,
WES Energy & Environment recommends that the next level of evaluation includes detailed
consideration of the following items:
Selection of the wood fuel technology most appropriate for each site.
Siting of the fuel storage at the Klawock Senior Center.
Siting of the biomass plant and fuel storage at the Craig Senior Center.
Biomass system capital costs based on detailed site investigations, initial plant layout
and design, and direct quotes from manufacturers.
Alternative funding sources (low interest loans, grants, and incentives).
Biomass Prefeasibility Report Date: September 2, 2014 Tlingit‐Haida Regional Housing Authority
FINAL Prince of Wales Island, Alaska
WES Energy & Environment
Page 21 of 24
Source:
http://www.woodboilers.com/products/pellet‐
boilers/froling‐p4‐pellet.html
7.0 GENERAL BIOMASS TECHNOLOGY INFORMATION
This section describes technologies that can be used for efficiently using wood for space
heating and domestic hot water heating. Manufacturers of each technology are available both
domestically and abroad. A partial list of manufacturers is provided for technologies and does
not constitute an endorsement. Other manufacturers are available and individual
investigations should be completed prior to purchase. Local codes and regulations may require
modifications or additional components for compliance depending on the system considered.
High Efficiency Indoor Wood Pellet Boiler
High efficiency indoor wood pellet boilers utilize
premium wood pellets as a renewable biomass fuel
source for hot water space heating systems. Wood
pellets are automatically fed from an adjacent storage
hopper into the firebox based on heating demand.
Efficiencies can exceed 80% when coupled with a hot
water thermal storage system that allows the boiler to
operate at high fire to charge the hot water thermal
storage tank. Multiple boilers can be operated to
increase heating capacity. Equipment costs can vary
depending on the heating capacity required. Annual
savings can range from $3,000 to $6,000 per year based
on a facility using 5,000 gallons of #1 fuel oil per year at
current prices. Manual and automatic hopper loading is
available. Ash removal is manual. A partial list of
manufacturers include ACT Bioenergy, Froling, MESys,
Evo World, Windhager, Kedel, and Wood Master.
High Efficiency Indoor Cord Wood Boiler
High efficiency indoor cordwood boilers utilize split
cordwood as a renewable biomass fuel source for hot
water space heating systems. Efficiencies can exceed
70% when coupled with a hot water thermal storage
system that allows the cordwood boiler to operate at
high fire to charge the hot water thermal storage tank.
Equipment costs can range from $7,000 to $15,000 plus
installation. Annual savings can range from $1,800 to
$2,200 per year based on an average building using
1,500 gallons of #1 fuel oil per year at current prices.
Manual loading and ash removal are required. A partial
list of manufacturers include Wood Gun, Econoburn,
Froling, Windhager, and Wood Master.
Source:
http://www.woodboilers.com/product
s/woodboilers/froeling‐fhg.html
Biomass Prefeasibility Report Date: September 2, 2014 Tlingit‐Haida Regional Housing Authority
FINAL Prince of Wales Island, Alaska
WES Energy & Environment
Page 22 of 24
Source:
http://www.afsenergy.com/Biomass%20Energy.htm
Advanced Biomass Combustion Units and Boilers
Advanced biomass combustion units and boilers are
typically an engineered product capable of firing on
wood chips, saw mill residue, wood pellets, and saw
dust. Fuel is typically delivered in bulk semi‐trailer
loads and automatically conveyed to the
combustion unit. Efficiencies can exceed 70% when
coupled with a hot water thermal storage system.
Emission controls are typically required to clean up
exhaust gasses. Capital costs are high and vary
depending on many factors. Annual fuel cost savings
can range from $100,000 to $120,000 per year
based on a facility using 50,000 gallons of #1 fuel oil
per year at current prices. High fuel costs and high
fuel usage can potentially make a project feasible. A
partial list of manufacturers include Viessman, ACT
Bioenergy, Froling, MESys, Evo World, Wood
Master, Messersmith Manufacturing, AFS Energy
Systems, Solagen, Wellons FEI, and Hurst.
Hot Water Thermal Storage System
Thermal storage tanks, also known as accumulator
tanks or buffer tanks, can raise the efficiency of hot
water heating systems firing on wood. Solid fuels
burn more efficiently at higher firing rates than at
lower rates or idle modes where the fuel smolders,
smokes, and wastes energy. Hot water thermal
storage allows the solid fuel boiler to fire efficiently
at full output to store the heat at elevated
temperatures in storage tanks. For optimum
operation a mixing valve is installed to blend cold
water returning from the facility with hot water
stored in the thermal storage tank. Hot water is sent
back to the facility at a temperature that is lower
than the storage tanks, providing heat storage and a
buffer for short periods of high demand. This
method of operation reduces smoldering and
smoking from inefficient operation, fuel use,
creosote buildup, and the need for frequent stoking.
Source:
http://www.viessmann‐
us.com/en/District_Heating/Products/dhw/Stor
age_Tanks.html
Biomass Prefeasibility Report Date: September 2, 2014 Tlingit‐Haida Regional Housing Authority
FINAL Prince of Wales Island, Alaska
WES Energy & Environment
Page 23 of 24
Source:
WES Energy & Environment File Photo
District Piping Systems
It can often be cost effective to connect multiple
buildings to one central wood fired heating plant.
Long runs of buried piping can be installed cost
effectively using pre‐insulated PEX piping. It is
important to use factory injected close cell foam
insulation with a High Density Polyethylene (HDPE)
insulation jacket to prevent the insulation from being
compromised from ground water or leaks. Pipe sizes
can range from 3/4” to 5” with roll lengths up to 600
feet. Pipe material costs can be more expensive than
traditional iron pipe, however installation costs can
be reduced due to longer runs between splices and
connections.
Biomass Prefeasibility Report Date: September 2, 2014 Tlingit‐Haida Regional Housing Authority
FINAL Prince of Wales Island, Alaska
WES Energy & Environment
Appendix A
Conceptual Drawings
SCALE100'0'50'100'Klawock Senior CenterWESEE Klawock Senior Center
Klawock, AK
Site Plan
SCALE10'0'5'10'ThermalStorageTankBiomass BoilerExistingBoilersPavingCord WoodStorage 35'x20'ExistingStructureExisitng BuildingWESEE Klawock Senior Center
Klawock, AK
Option 1a Plan View
To ExistingHeating SystemWood PelletBoiler160,000 Btu/hr200 GallonThermalStorage TankFrom LoadTo LoadBoiler Protection ValveValve to be controlled to maintainDWOHDVWWRERLOHUVVFDTTTIVariable Frequency DriveTemperature TransmitterPumpThree Way Mixing ValveLegendFrom ExistingHeating SystemTTTIVFDTemperature IndicatorTTTI210,000 Btu/hrExisting FuelOil Boiler210,000 Btu/hrExisting FuelOil BoilerWESEE Klawock Senior Center
Klawock, AK
Option 1a SchematicNote: This drawing is a conceptual schematic for the purposesof showing a general biomass system arrangement. Equipment,final sizing, and pressures will vary depending on the engineer,manufacturer and contractor installing the biomass system.
SCALE10'0'5'10'ThermalStorageTankBiomass BoilerExistingBoilersPavingExistingStructureExisitng BuildingWood Pellet StorageFuel AugerFill Hole(Typ.)WESEE Klawock Senior Center
Klawock, AK
Option 1b Plan View
To ExistingHeating System200 GallonThermalStorage TankFrom LoadTo LoadBoiler Protection ValveValve to be controlled to maintainDWOHDVWWRERLOHUVVFDTTTIVariable Frequency DriveTemperature TransmitterPumpThree Way Mixing ValveLegendFrom ExistingHeating SystemTTTIVFDTemperature IndicatorTTTI210,000 Btu/hrExisting FuelOil Boiler210,000 Btu/hrExisting FuelOil BoilerCord WoodBoiler100,000 Btu/hrWESEE Klawock Senior Center
Klawock, AK
Option 1b SchematicNote: This drawing is a conceptual schematic for the purposesof showing a general biomass system arrangement. Equipment,final sizing, and pressures will vary depending on the engineer,manufacturer and contractor installing the biomass system.
Craig Senior CenterSCALE100'0'50'100'WESEE Craig Senior Center
Craig, AK
Site Plan
SCALE50'0'25'50'WESEE Craig Senior Center
Craig, AK
Option 2a Site Layout
BoilerMeteringBinStackExpansionTankRemove Stairs,Access via RampRamp UpCraig Senior CenterSCALE5'0'2.5'5'Ramp Up
ThermalStorage TankConcretePadFuel StorageFuel AugerWESEE Craig Senior Center
Craig, AK
Option 2a Site Plan
To ExistingHeating SystemWood PelletBoilerThermalStorageTankFrom LoadTo LoadBoiler Protection ValveValve to be controlled to maintainDWOHDVWWRERLOHUVVFDTTTIVariable Frequency DriveTemperature TransmitterPumpThree Way Mixing ValveLegendFrom ExistingHeating SystemTTTIVFDTemperature IndicatorTTTIExisting FuelOil BoilerTo Sr. CenterBoiler RoomFrom Sr. CenterBoiler RoomExisting FuelOil BoilerWESEE Craig Senior Center
Craig, AK
Option 2a SchematicNote: This drawing is a conceptual schematic for the purposesof showing a general biomass system arrangement. Equipment,final sizing, and pressures will vary depending on the engineer,manufacturer and contractor installing the biomass system.
SCALE50'0'25'50'WESEE Craig Senior Center
Craig, AK
Option 2b Site Layout
BoilerStackCord Wood Storage10'x20'ExpansionTankRamp UpCraig Senior CenterSCALE5'0'2.5'5'Ramp Up
ThermalStorage TankSidewalkWESEE Craig Senior Center
Craig, AK
Option 2b Site Plan
To ExistingHeating SystemCord WoodBoilerThermalStorageTankFrom LoadTo LoadBoiler Protection ValveValve to be controlled to maintainDWOHDVWWRERLOHUVVFDTTTIVariable Frequency DriveTemperature TransmitterPumpThree Way Mixing ValveLegendFrom ExistingHeating SystemTTTIVFDTemperature IndicatorTTTIExisting FuelOil BoilerTo Sr. CenterBoiler RoomFrom Sr. CenterBoiler RoomExisting FuelOil BoilerWESEE Craig Senior Center
Craig, AK
Option 2b SchematicNote: This drawing is a conceptual schematic for the purposesof showing a general biomass system arrangement. Equipment,final sizing, and pressures will vary depending on the engineer,manufacturer and contractor installing the biomass system.
Biomass Prefeasibility Report Date: September 2, 2014 Tlingit‐Haida Regional Housing Authority
FINAL Prince of Wales Island, Alaska
WES Energy & Environment
Appendix B
Preliminary Capital Cost Estimates
Appendix B Tlingit‐Haida Regional Housing Authority
Line Item Cost
One (1) ‐ 160,000 Btu/hr wood pellet hot water boiler, installed 30,000$
30 ton storage bin 15,000$
Storage bin site work 5,000$
Thermal storage 200 gal with insulation 7,000$
Interconnection with existing boiler room, pumps, installation 7,500$
Electrical 4,500$
Mechanical 4,500$
Sub‐Total 73,500$
Contractor Profit 10% 7,350$
Sub‐Total 80,850$
Contingency 10% 8,085$
Sub‐Total 88,935$
Profesional Services 15% 13,340$
Total 102,275$
Notes:
3 ‐ Estimate is based on competitive bidding.
Option 1a ‐ Conceptual Cost Estimate ‐ Klawock Senior Center
Wood Pellet Boiler System
1 ‐ The boiler system is to be installed in the existing boiler room. Pricing is based on a one‐boiler solution.
There are multiple manufacturers that can provide varying boiler sizes. Other boiler sizing combinations to
meet a similar output range may also be selected.
2 ‐ Professional Services includes permitting, legal, engineering, & project management. (Assumed that
minimal engineering is required.)
WES Energy & Environment
Appendix B Tlingit‐Haida Regional Housing Authority
Line Item Cost
One (1) ‐ 100,000 Btu/hr cord wood boiler, freight, and installed 13,000$
Stick frame storage building with poured concrete floor, 600 ft2 @ $50/ft2 30,000$
Thermal storage 500 gal with insulation 9,500$
Interconnection with existing boiler room, pumps, installation 7,500$
Electrical 5,000$
Mechanical 5,000$
Sub‐Total 70,000$
Contractor Profit 10% 7,000$
Sub‐Total 77,000$
Contingency 10% 7,700$
Sub‐Total 84,700$
Profesional Services 15% 12,705$
Total 97,405$
Notes:
3 ‐ Estimate is based on competitive bidding.
Option 1b ‐ Conceptual Cost Estimate ‐ Klawock Senior Center
Cord Wood Boiler System
1 ‐ The boiler system is to be installed in the existing boiler room. Pricing is based on a one‐boiler solution.
There are multiple manufacturers that can provide varying boiler sizes. Other boiler sizing combinations to
meet a similar output range may also be selected.
2 ‐ Professional Services includes permitting, legal, engineering, & project management. (Assumed that
minimal engineering is required.)
WES Energy Environment
Appendix B Tlingit‐Haida Regional Housing Authority
Line Item Cost
One (1) ‐ 100,000 Btu/hr wood pellet hot water boiler,
containerized 50,000$
30 ton storage bin 15,000$
Storage bin site work 5,000$
Thermal storage 200 gal with insulation 7,000$
Interconnection with existing boiler room, pumps, installation 7,500$
Electrical 5,000$
Mechanical 5,000$
Sub‐Total 94,500$
Contractor Profit 10% 9,450$
Sub‐Total 103,950$
Contingency 10% 10,395$
Sub‐Total 114,345$
Profesional Services 15% 17,152$
Total 131,497$
Notes:
3 ‐ Estimate is based on competitive bidding.
Option 2a ‐ Conceptual Cost Estimate ‐ Craig Senior Center
Wood Pellet Boiler System
1 ‐ The boiler system is to be installed in the existing boiler room. Pricing is based on a one‐boiler solution.
There are multiple manufacturers that can provide varying boiler sizes. Other boiler sizing combinations to
meet a similar output range may also be selected.
2 ‐ Professional Services includes permitting, legal, engineering, & project management. (Assumed that
minimal engineering is required.)
WES Energy & Environment
Appendix B Tlingit‐Haida Regional Housing Authority
Line Item Cost
One (1) ‐ 100,000 Btu/hr cord wood boiler, freight, containerized, and installed 40,000$
Stick frame storage building with poured concrete floor, 200 ft2 @ $50/ft2 10,000$
Thermal storage 500 gal with insulation 9,500$
Interconnection with existing boiler room, pumps, installation 5,000$
Electrical 5,000$
Mechanical 5,000$
Sub‐Total 74,500$
Contractor Profit 10% 7,450$
Sub‐Total 81,950$
Contingency 10% 8,195$
Sub‐Total 90,145$
Profesional Services 15% 13,522$
Total 103,667$
Notes:
3 ‐ Estimate is based on competitive bidding.
Option 2b ‐ Conceptual Cost Estimate ‐ Craig Senior Center
Cord Wood Boiler System
1 ‐ The boiler system is to be installed in the existing boiler room. Pricing is based on a one‐boiler solution.
There are multiple manufacturers that can provide varying boiler sizes. Other boiler sizing combinations to
meet a similar output range may also be selected.
2 ‐ Professional Services includes permitting, legal, engineering, & project management. (Assumed that
minimal engineering is required.)
WES Energy & Environment
Biomass Prefeasibility Report Date: September 2, 2014 Tlingit‐Haida Regional Housing Authority
FINAL Prince of Wales Island, Alaska
WES Energy & Environment
Appendix C
20 Year Financing at 4% APR Cash Flow Analysis
Appendix COption 1a ‐ Klawock Senior Center Wood Pellet Boiler System20 Year, 4% FinancingTlingit‐Haida Regional Housing AuthorityInput Variables Value Units Year #1 Fuel Oil Cost, Current System Wood Pellet Cost #1 Fuel Oil Cost, w/ Wood System Added O&M Cost Net Operating Savings Annual Financing Payment Net Cash Flow Present Value of Cash Flow Project Costs Financed 102,275 $ 1 20,650$ (13,860)$ (1,033)$ (1,590)$ 4,168$ (7,526)$ (3,358)$ (3,358)$ Financing Term 20 # years 2 21,331$ (14,276)$ (1,067)$ (1,638)$ 4,351$ (7,526)$ (3,174)$ (3,082)$ Financing Rate (apr) 4.0% Percent 3 22,035$ (14,704)$ (1,102)$ (1,687)$ 4,543$ (7,526)$ (2,983)$ (2,812)$ Current #1 Fuel Oil Usage5,000 gal 4 22,763$ (15,145)$ (1,138)$ (1,737)$ 4,742$ (7,526)$ (2,784)$ (2,548)$ Year 1 #1 Fuel Oil Average Price $4.13 $/gal 5 23,514$ (15,600)$ (1,176)$ (1,790)$ 4,949$ (7,526)$ (2,577)$ (2,289)$ Proposed Annual Wood Pellet Usage 42 tons/yr 6 24,290$ (16,068)$ (1,214)$ (1,843)$ 5,164$ (7,526)$ (2,361)$ (2,037)$ Year 1 Wood Pellet Purchase Price $330 $/ton 7 25,091$ (16,550)$ (1,255)$ (1,899)$ 5,389$ (7,526)$ (2,137)$ (1,790)$ Annual #1 Fuel Oil Usage w/ Wood System 250 gal/yr 8 25,919$ (17,046)$ (1,296)$ (1,955)$ 5,622$ (7,526)$ (1,904)$ (1,548)$ Fossil Fuel Inflation Rate (apr) 3.3% Percent 9 26,775$ (17,557)$ (1,339)$ (2,014)$ 5,864$ (7,526)$ (1,661)$ (1,311)$ Wood Pellet Inflation Rate (apr) 3.0% Percent 10 27,658$ (18,084)$ (1,383)$ (2,075)$ 6,116$ (7,526)$ (1,409)$ (1,080)$ O&M Inflation Rate 3.0% Percent 11 28,571$ (18,627)$ (1,429)$ (2,137)$ 6,379$ (7,526)$ (1,147)$ (853)$ Discount Rate (apr) 3.0% Percent 12 29,514$ (19,185)$ (1,476)$ (2,201)$ 6,652$ (7,526)$ (874)$ (631)$ Added Annual O&M Costs for Biomass Plant 1,590$ $/yr 13 30,488$ (19,761)$ (1,524)$ (2,267)$ 6,935$ (7,526)$ (590)$ (414)$ 14 31,494$ (20,354)$ (1,575)$ (2,335)$ 7,230$ (7,526)$ (295)$ (201)$ 15 32,533$ (20,964)$ (1,627)$ (2,405)$ 7,537$ (7,526)$ 11$ 7$ 16 33,607$ (21,593)$ (1,680)$ (2,477)$ 7,856$ (7,526)$ 330$ 212$ 17 34,716$ (22,241)$ (1,736)$ (2,551)$ 8,187$ (7,526)$ 662$ 412$ 18 35,861$ (22,908)$ (1,793)$ (2,628)$ 8,532$ (7,526)$ 1,006$ 609$ 19 37,045$ (23,596)$ (1,852)$ (2,707)$ 8,890$ (7,526)$ 1,364$ 801$ 20 38,267$ (24,304)$ (1,913)$ (2,788)$ 9,262$ (7,526)$ 1,737$ 990$ Present Value (20,922)$ WES Energy & Environment
Appendix COption 1b ‐ Klawock Senior Center ‐ Cord Wood Boiler System20 Year, 4% FinancingTlingit‐Haida Regional Housing AuthorityInput Variables Value Units Year #1 Fuel Oil Cost, Current System Cord Wood Cost #1 Fuel Oil Cost, w/ Wood System Added O&M Cost Net Operating Savings Annual Financing Payment Net Cash Flow Present Value of Cash Flow Project Costs Financed 97,405 $ 1 20,650$ (8,500)$ (4,130)$ (1,530)$ 6,490$ (7,167)$ (677)$ (658)$ Financing Term 20 # years 2 21,331$ (8,755)$ (4,266)$ (1,576)$ 6,734$ (7,167)$ (433)$ (408)$ Financing Rate (apr) 4.0% Percent 3 22,035$ (9,018)$ (4,407)$ (1,623)$ 6,987$ (7,167)$ (180)$ (164)$ Current #1 Fuel Oil Usage5,000 gal 4 22,763$ (9,288)$ (4,553)$ (1,672)$ 7,250$ (7,167)$ 83$ 74$ Year 1 #1 Fuel Oil Average Price $4.13 $/gal 5 23,514$ (9,567)$ (4,703)$ (1,722)$ 7,522$ (7,167)$ 355$ 306$ Proposed Annual Cord Wood Usage 34 Cords/yr 6 24,290$ (9,854)$ (4,858)$ (1,774)$ 7,804$ (7,167)$ 637$ 533$ Year 1 Cord Wood Purchase Price $250 $/Cord 7 25,091$ (10,149)$ (5,018)$ (1,827)$ 8,097$ (7,167)$ 929$ 756$ Annual #1 Fuel Oil Usage w/ Wood System 1,000 gal/yr 8 25,919$ (10,454)$ (5,184)$ (1,882)$ 8,400$ (7,167)$ 1,233$ 973$ Fossil Fuel Inflation Rate (apr) 3.3% Percent 9 26,775$ (10,768)$ (5,355)$ (1,938)$ 8,714$ (7,167)$ 1,547$ 1,185$ Cord Wood Inflation Rate (apr) 3.0% Percent 10 27,658$ (11,091)$ (5,532)$ (1,996)$ 9,040$ (7,167)$ 1,872$ 1,393$ O&M Inflation Rate 3.0% Percent 11 28,571$ (11,423)$ (5,714)$ (2,056)$ 9,377$ (7,167)$ 2,210$ 1,597$ Discount Rate (apr) 3.0% Percent 12 29,514$ (11,766)$ (5,903)$ (2,118)$ 9,727$ (7,167)$ 2,560$ 1,795$ Added Annual O&M Costs for Biomass Plant 1,530$ $/yr 13 30,488$ (12,119)$ (6,098)$ (2,181)$ 10,090$ (7,167)$ 2,923$ 1,990$ 14 31,494$ (12,483)$ (6,299)$ (2,247)$ 10,466$ (7,167)$ 3,298$ 2,181$ 15 32,533$ (12,857)$ (6,507)$ (2,314)$ 10,855$ (7,167)$ 3,688$ 2,367$ 16 33,607$ (13,243)$ (6,721)$ (2,384)$ 11,259$ (7,167)$ 4,092$ 2,550$ 17 34,716$ (13,640)$ (6,943)$ (2,455)$ 11,677$ (7,167)$ 4,510$ 2,729$ 18 35,861$ (14,049)$ (7,172)$ (2,529)$ 12,111$ (7,167)$ 4,944$ 2,904$ 19 37,045$ (14,471)$ (7,409)$ (2,605)$ 12,560$ (7,167)$ 5,393$ 3,076$ 20 38,267$ (14,905)$ (7,653)$ (2,683)$ 13,026$ (7,167)$ 5,859$ 3,244$ Present Value 28,422$ WES Energy & Environment
Appendix COption 2a ‐ Craig Senior Center Wood Pellet Boiler System20 Year, 4% FinancingTlingit‐Haida Regional Housing AuthorityInput Variables Value Units Year #1 Fuel Oil Cost, Current System Wood Pellet Cost #1 Fuel Oil Cost, w/ Wood System Added O&M Cost Net Operating Savings Annual Financing Payment Net Cash Flow Present Value of Cash Flow Project Costs Financed 131,497 $ 1 12,390$ (8,580)$ (620)$ (1,590)$ 1,601$ (9,676)$ (8,075)$ (7,840)$ Financing Term 20 # years 2 12,799$ (8,837)$ (640)$ (1,638)$ 1,684$ (9,676)$ (7,992)$ (7,533)$ Financing Rate (apr) 4.0% Percent 3 13,221$ (9,103)$ (661)$ (1,687)$ 1,771$ (9,676)$ (7,905)$ (7,234)$ Current #1 Fuel Oil Usage3,000 gal 4 13,658$ (9,376)$ (683)$ (1,737)$ 1,862$ (9,676)$ (7,814)$ (6,943)$ Year 1 #1 Fuel Oil Average Price $4.13 $/gal 5 14,108$ (9,657)$ (705)$ (1,790)$ 1,956$ (9,676)$ (7,719)$ (6,659)$ Proposed Annual Wood Pellet Usage 26 tons/yr 6 14,574$ (9,947)$ (729)$ (1,843)$ 2,055$ (9,676)$ (7,620)$ (6,382)$ Year 1 Wood Pellet Purchase Price $330 $/ton 7 15,055$ (10,245)$ (753)$ (1,899)$ 2,158$ (9,676)$ (7,517)$ (6,112)$ Annual #1 Fuel Oil Usage w/ Wood System 150 gal/yr 8 15,552$ (10,552)$ (778)$ (1,955)$ 2,266$ (9,676)$ (7,410)$ (5,849)$ Fossil Fuel Inflation Rate (apr) 3.3% Percent 9 16,065$ (10,869)$ (803)$ (2,014)$ 2,378$ (9,676)$ (7,297)$ (5,593)$ Wood Pellet Inflation Rate (apr) 3.0% Percent 10 16,595$ (11,195)$ (830)$ (2,075)$ 2,496$ (9,676)$ (7,180)$ (5,343)$ O&M Inflation Rate 3.0% Percent 11 17,143$ (11,531)$ (857)$ (2,137)$ 2,618$ (9,676)$ (7,058)$ (5,099)$ Discount Rate (apr) 3.0% Percent 12 17,708$ (11,877)$ (885)$ (2,201)$ 2,745$ (9,676)$ (6,931)$ (4,861)$ Added Annual O&M Costs for Biomass Plant 1,590$ $/yr 13 18,293$ (12,233)$ (915)$ (2,267)$ 2,878$ (9,676)$ (6,798)$ (4,629)$ 14 18,896$ (12,600)$ (945)$ (2,335)$ 3,016$ (9,676)$ (6,659)$ (4,403)$ 15 19,520$ (12,978)$ (976)$ (2,405)$ 3,161$ (9,676)$ (6,515)$ (4,182)$ 16 20,164$ (13,367)$ (1,008)$ (2,477)$ 3,311$ (9,676)$ (6,365)$ (3,966)$ 17 20,829$ (13,768)$ (1,041)$ (2,551)$ 3,468$ (9,676)$ (6,208)$ (3,756)$ 18 21,517$ (14,181)$ (1,076)$ (2,628)$ 3,631$ (9,676)$ (6,044)$ (3,550)$ 19 22,227$ (14,607)$ (1,111)$ (2,707)$ 3,802$ (9,676)$ (5,874)$ (3,350)$ 20 22,960$ (15,045)$ (1,148)$ (2,788)$ 3,979$ (9,676)$ (5,697)$ (3,154)$ Present Value (106,437)$ WES Energy & Environment
Appendix COption 2b ‐ Craig Senior Center ‐ Cord Wood Boiler System20 Year, 4% FinancingTlingit‐Haida Regional Housing AuthorityInput Variables Value Units Year #1 Fuel Oil Cost, Current System Cord Wood Cost #1 Fuel Oil Cost, w/ Wood System Added O&M Cost Net Operating Savings Annual Financing Payment Net Cash Flow Present Value of Cash Flow Project Costs Financed 103,667 $ 1 12,390$ (5,250)$ (2,478)$ (1,480)$ 3,182$ (7,628)$ (4,446)$ (4,316)$ Financing Term 20 # years 2 12,799$ (5,408)$ (2,560)$ (1,524)$ 3,307$ (7,628)$ (4,321)$ (4,073)$ Financing Rate (apr) 4.0% Percent 3 13,221$ (5,570)$ (2,644)$ (1,570)$ 3,437$ (7,628)$ (4,191)$ (3,835)$ Current #1 Fuel Oil Usage3,000 gal 4 13,658$ (5,737)$ (2,732)$ (1,617)$ 3,572$ (7,628)$ (4,056)$ (3,604)$ Year 1 #1 Fuel Oil Average Price $4.13 $/gal 5 14,108$ (5,909)$ (2,822)$ (1,666)$ 3,712$ (7,628)$ (3,916)$ (3,378)$ Proposed Annual Cord Wood Usage 21 Cords/yr 6 14,574$ (6,086)$ (2,915)$ (1,716)$ 3,857$ (7,628)$ (3,771)$ (3,158)$ Year 1 Cord Wood Purchase Price $250 $/Cord 7 15,055$ (6,269)$ (3,011)$ (1,767)$ 4,008$ (7,628)$ (3,620)$ (2,944)$ Annual #1 Fuel Oil Usage w/ Wood System 600 gal/yr 8 15,552$ (6,457)$ (3,110)$ (1,820)$ 4,164$ (7,628)$ (3,464)$ (2,734)$ Fossil Fuel Inflation Rate (apr) 3.3% Percent 9 16,065$ (6,651)$ (3,213)$ (1,875)$ 4,326$ (7,628)$ (3,302)$ (2,530)$ Cord Wood Inflation Rate (apr) 3.0% Percent 10 16,595$ (6,850)$ (3,319)$ (1,931)$ 4,495$ (7,628)$ (3,133)$ (2,331)$ O&M Inflation Rate 3.0% Percent 11 17,143$ (7,056)$ (3,429)$ (1,989)$ 4,669$ (7,628)$ (2,959)$ (2,137)$ Discount Rate (apr) 3.0% Percent 12 17,708$ (7,267)$ (3,542)$ (2,049)$ 4,851$ (7,628)$ (2,777)$ (1,948)$ Added Annual O&M Costs for Biomass Plant 1,480$ $/yr 13 18,293$ (7,485)$ (3,659)$ (2,110)$ 5,039$ (7,628)$ (2,589)$ (1,763)$ 14 18,896$ (7,710)$ (3,779)$ (2,173)$ 5,234$ (7,628)$ (2,394)$ (1,583)$ 15 19,520$ (7,941)$ (3,904)$ (2,239)$ 5,436$ (7,628)$ (2,192)$ (1,407)$ 16 20,164$ (8,179)$ (4,033)$ (2,306)$ 5,646$ (7,628)$ (1,982)$ (1,235)$ 17 20,829$ (8,425)$ (4,166)$ (2,375)$ 5,864$ (7,628)$ (1,764)$ (1,067)$ 18 21,517$ (8,677)$ (4,303)$ (2,446)$ 6,090$ (7,628)$ (1,538)$ (904)$ 19 22,227$ (8,938)$ (4,445)$ (2,520)$ 6,324$ (7,628)$ (1,304)$ (744)$ 20 22,960$ (9,206)$ (4,592)$ (2,595)$ 6,567$ (7,628)$ (1,061)$ (587)$ Present Value (46,279)$ WES Energy & Environment
Biomass Prefeasibility Report Date: September 2, 2014 Tlingit‐Haida Regional Housing Authority
FINAL Prince of Wales Island, Alaska
WES Energy & Environment
Appendix D
Sensitivity Analysis of Estimated Annual Operating Savings
to Oil and Biomass Fuel Prices
Appendix DOption 1a ‐ Klawock Senior Center Wood Pellet Boiler SystemSensitivity Analysis of 1st Year Operating Savings to Fuel CostsTlingit‐Haida Regional Housing Authority4,168$ $3.50 $3.75 $4.00 $4.13 $4.25 $4.50 $4.75 $5.00$225$5,585 $6,773 $7,960 $8,578 $9,148 $10,335 $11,523 $12,710$250$4,535 $5,723 $6,910 $7,528 $8,098 $9,285 $10,473 $11,660$275$3,485 $4,673 $5,860 $6,478 $7,048 $8,235 $9,423 $10,610$300$2,435 $3,623 $4,810 $5,428 $5,998 $7,185 $8,373 $9,560$330$1,175 $2,363 $3,550 $4,168 $4,738 $5,925 $7,113 $8,300$350$335 $1,523 $2,710 $3,328 $3,898 $5,085 $6,273 $7,460$375($715) $473 $1,660 $2,278 $2,848 $4,035 $5,223 $6,410*Note: Excludes financing costs.Price of Wood Pellets per TonPrice of Fuel Oil per GallonWES Energy & Environment
Appendix DOption 1b ‐ Klawock Senior Center ‐ Cord Wood Boiler SystemSensitivity Analysis of 1st Year Operating Savings to Fuel CostsTlingit‐Haida Regional Housing Authority6,490$ $3.50 $3.75 $4.00 $4.13 $4.25 $4.50 $4.75 $5.00$150$7,370 $8,370 $9,370 $9,890 $10,370 $11,370 $12,370 $13,370$175$6,520 $7,520 $8,520 $9,040 $9,520 $10,520 $11,520 $12,520$200$5,670 $6,670 $7,670 $8,190 $8,670 $9,670 $10,670 $11,670$225$4,820 $5,820 $6,820 $7,340 $7,820 $8,820 $9,820 $10,820$250$3,970 $4,970 $5,970 $6,490 $6,970 $7,970 $8,970 $9,970$275$3,120 $4,120 $5,120 $5,640 $6,120 $7,120 $8,120 $9,120$300$2,270 $3,270 $4,270 $4,790 $5,270 $6,270 $7,270 $8,270*Note: Excludes financing costs.Price of Cord Wood per CordPrice of Fuel Oil per GallonWES Energy & Environment
Appendix DOption 2a ‐ Craig Senior Center Wood Pellet Boiler SystemSensitivity Analysis of 1st Year Operating Savings to Fuel CostsTlingit‐Haida Regional Housing Authority1,601$ $3.50 $3.75 $4.00 $4.13 $4.25 $4.50 $4.75 $5.00$225$2,535 $3,248 $3,960 $4,331 $4,673 $5,385 $6,098 $6,810$250$1,885 $2,598 $3,310 $3,681 $4,023 $4,735 $5,448 $6,160$275$1,235 $1,948 $2,660 $3,031 $3,373 $4,085 $4,798 $5,510$300$585 $1,298 $2,010 $2,381 $2,723 $3,435 $4,148 $4,860$330($195) $518 $1,230 $1,601 $1,943 $2,655 $3,368 $4,080$350($715) ($3) $710 $1,081 $1,423 $2,135 $2,848 $3,560$375($1,365) ($653) $60 $431 $773 $1,485 $2,198 $2,910*Note: Excludes financing costs.Price of Wood Pellets per TonPrice of Fuel Oil per GallonWES Energy & Environment
Appendix DOption 2b ‐ Craig Senior Center ‐ Cord Wood Boiler SystemSensitivity Analysis of 1st Year Operating Savings to Fuel CostsTlingit‐Haida Regional Housing Authority3,182$ $3.50 $3.75 $4.00 $4.13 $4.25 $4.50 $4.75 $5.00$150$3,770 $4,370 $4,970 $5,282 $5,570 $6,170 $6,770 $7,370$175$3,245 $3,845 $4,445 $4,757 $5,045 $5,645 $6,245 $6,845$200$2,720 $3,320 $3,920 $4,232 $4,520 $5,120 $5,720 $6,320$225$2,195 $2,795 $3,395 $3,707 $3,995 $4,595 $5,195 $5,795$250$1,670 $2,270 $2,870 $3,182 $3,470 $4,070 $4,670 $5,270$275$1,145 $1,745 $2,345 $2,657 $2,945 $3,545 $4,145 $4,745$300$620 $1,220 $1,820 $2,132 $2,420 $3,020 $3,620 $4,220*Note: Excludes financing costs.Price of Cord Wood per CordPrice of Fuel Oil per GallonWES Energy & Environment