HomeMy WebLinkAboutKoyuk Kiniaq Building Integration Wood Fired Heating Systems Draft Report 07-16-2013-BIO
Pre-Feasibility Assessment for
Integration of Wood-Fired Heating Systems
Draft Report
July 16, 2013
Kiniaq Building
Koyuk , Alaska
Presented by
CTA Architects Engineers
Nathan Ratz & Jesse Vigil
R&M Engineering-Ketchikan, Inc.
Trevor Sande
For
Native Village of Koyuk
In partnership with
Fairbanks Economic Development Corporation
Alaska Wood Energy Development Task Group
Funded by
Alaska Energy Authority and U.S. Forest Service
306 W. Railroad, Suite 104
Missoula, MT 59802
406.728.9522
www.ctagroup.com
CTA Project: FEDC_KOYUK
Pre-Feasibility Assessment for Kiniaq Building
Integration of Wood-Fired Heating Systems Koyuk, Alaska
CTA Architects Engineers i
Draft Report July 16, 2013
TABLE OF CONTENTS
1.0 Executive Summary .................................................................................................... 1
2.0 Introduction ................................................................................................................. 3
3.0 Existing Building Systems ........................................................................................... 3
4.0 Energy Use ................................................................................................................. 3
5.0 Biomass Boiler Size .................................................................................................... 3
6.0 Wood Fuel Use ........................................................................................................... 4
7.0 Boiler Plant Location and Site Access ........................................................................ 5
8.0 Integration with Existing Heating Systems .................................................................. 5
9.0 Air Quality Permits ...................................................................................................... 6
10.0 Wood Heating Options ................................................................................................ 6
11.0 Estimated Costs .......................................................................................................... 6
12.0 Economic Analysis Assumptions ................................................................................ 6
13.0 Results of Evaluation .................................................................................................. 7
14.0 Project Funding ........................................................................................................... 8
15.0 Summary ..................................................................................................................... 8
16.0 Recommended Action ................................................................................................. 8
Appendixes
Appendix A: Preliminary Estimates of Probable Cost ................................................... 1 page
Appendix B: Cash Flow Analysis ................................................................................ 3 pages
Appendix C: Site Plan ................................................................................................... 1 page
Appendix D: Air Quality Report ................................................................................. 22 pages
Appendix E: Wood Fired Heating Technologies ......................................................... 4 pages
Pre-Feasibility Assessment for Kiniaq Building
Integration of Wood-Fired Heating Systems Koyuk, Alaska
CTA Architects Engineers Page 1 of 8
Draft Report July 16, 2013
1.0 Executive Summary
The following assessment was commissioned to determine the preliminary technical and
economic feasibility of integrating a wood fired heating system in the Kiniaq Building in
Koyuk, Alaska.
The following tables summarize the current fuel use and the potential wood fuel use:
Table 1.1 - Annual Fuel Use Summary
Fuel Avg. Use Current Annual
Facility Name Type (Gallons) Cost/Gal Cost
Kiniaq Building Fuel Oil 1,500 $6.50 $9,750
Table 1.2 - Annual Wood Fuel Use Summary
Fuel Cord Wood
Oil Wood Pellets
(Gallons) (Cords) (Tons)
Kiniaq
Building 1,500 15.4 14.1
The wood heating system options reviewed were:
Cord Wood Boiler Options:
C.1.A: A freestanding building with interior cordwood storage, 70% fuel oil offset.
C.1.B: A freestanding building with interior cordwood storage, 50% fuel oil offset.
Wood Stove Options:
D.1: Two freestanding wood stoves, 35% fuel oil offset.
Table 1.3 - Economic Evaluation Summary
Kiniaq Building Biomass Heating System
Year 1 NPV NPV
20
Yr
30
Yr
Project Operating 20 yr 30 yr B/C B/C ACF ACF YR
Cost Savings at 3% at 3% Ratio Ratio YR 20 YR 30 ACF=PC
C.1.A $226,000 -$9,709 -$114,067 -$129,668 -0.50 -0.57 -$150,022 -$181,797 31
C.1.B $226,000 -$7,538 -$85,189 -$97,747 -0.38 -0.43 -$111,997 -$137,711 31
D.1 $18,000 $125 $18,914 $43,452 1.05 2.41 $28,631 $81,553 17
The Kiniaq Building appears to be a fair candidate for the use of a wood biomass heating
system using wood stoves. With the current economic assumptions, the economic viability
of the cord wood boiler options is poor as none of the options meet the minimum
requirement of the 20 year B/C ratio exceeding 1.0. The amount of fuel oil use is not large
enough to economically leverage much capital costs, even if the most of the fuel oil use
Pre-Feasibility Assessment for Kiniaq Building
Integration of Wood-Fired Heating Systems Koyuk, Alaska
CTA Architects Engineers Page 2 of 8
Draft Report July 16, 2013
could be eliminated. The wood stove option does appear to be economically viable,
however, it is very sensitive to labor costs. For this analysis 2 hours a week of feeding the
stoves was assumed. If this was 3 hours a week, then the 20 year B/C ratio would drop
below 1.0. The wood stove option also assumed offsetting 35% of the current fuel oil use.
This was due to the typical occupancy of the building (no one to feed the fire on nights and
weekends) and because of the room layout of the building. The stoves would keep the
large open areas heated, but the perimeter offices would likely still require supplemental
heat from the boiler system.
The cord wood fuel source would benefit the community because the fuel is a renewable
resource, has a lower energy cost, and the money paid for the fuel would remain in the
local community and economy.
Pre-Feasibility Assessment for Kiniaq Building
Integration of Wood-Fired Heating Systems Koyuk, Alaska
CTA Architects Engineers Page 3 of 8
Draft Report July 16, 2013
2.0 Introduction
The following assessment was commissioned to determine the preliminary technical and
economic feasibility of integrating a wood fired heating system in the Kiniaq Building in
Koyuk, Alaska.
3.0 Existing Building Systems
The Kiniaq Building is a single story wood framed building constructed in 1996. Because
of poor soil conditions, the building is supported by piles and is elevated approximately
four feet above native grade. The facility is approximately 3,700 square feet and is
primarily heated by two 159,000 Btu/hr output hot water boilers. Domestic hot water is
provided by a 41 gallon indirect water heater using the boiler water as a heating source.
The existing boilers are original to the building and appear to be in fair condition. The
heating system infrastructure is original to the building and appears to be in fair condition.
A heat recovery ventilator is used to provide ventilation air to the building and exhaust air
from the toilet rooms, kitchen, and health training area.
The US Postal Service rents a small portion of the building, and it is completely isolated
from the rest of the building, including the heating system. It is served by a 57 MBH output
fuel oil fired furnace, and is completely separated from the building heating system.
4.0 Current Heating Energy Use
A Fuel oil usage log for the facility was provided. The following table summarizes the
data:
Table 4.1 - Annual Fuel Use Summary
Fuel Avg. Use Current Annual
Facility Name Type (Gallons) Cost/Gal Cost
Kiniaq Building Fuel Oil 1,500 $6.50 $9,750
5.0 Biomass Boiler Size
The following table summarized the connected load of fuel fired boilers:
Table 5.1 - Connected Boiler Load Summary
Likely
Peak System
Output Load Peak
MBH Factor MBH
Kiniaq Bldg Boiler 1 Fuel Oil 159 0.60 95
Boiler 2
Fuel Oil 159 0.60 95
Total 318 191
Typically a wood heating system is sized to meet approximately 85% of the typical annual
heating energy use of the building. The existing heating boilers would be used for the
other 15% of the time during peak heating conditions, during times when the biomass
boiler is down for servicing, and during swing months when only a few hours of heating
each day are required. Recent energy models have found that a boiler sized at 50% to
60% of the building peak load will typically accommodate 85% of the boiler run hours.
Pre-Feasibility Assessment for Kiniaq Building
Integration of Wood-Fired Heating Systems Koyuk, Alaska
CTA Architects Engineers Page 4 of 8
Draft Report July 16, 2013
Table 5.2 - Proposed Biomass Boiler Size
Likely Biomass
System Biomass Boiler
Peak Boiler Size
MBH Factor MBH
Kiniaq Building 191 0.6 114
6.0 Wood Fuel Use and Cost
The only type of wood fuel currently available in the area is cord wood. The majority of
cordwood is harvested from the local forest land. Some wood is obtained from the Koyuk
River banks as driftwood that comes from upriver and is deposited along the river banks
during the spring break up. There are no commercial logging operations in the area. Most
wood is collected and cut up by private individuals for use in residential wood stoves.
Although cord wood is the only fuel type currently available in the area, the cost and
amount of pellets will be shown for comparison purposes only.
The estimated amount of wood fuel needed was calculated and is listed below:
Table 6.1 - Annual Wood Fuel Use Summary
Fuel Cord Wood
Oil Wood Pellets
(Gallons) (Cords) (Tons)
Kiniaq
Building 1,500 15.4 14.1
The amount of wood fuel shown in the table is for supplanting the entire amount of fuel oil
and is for comparison purposes only. It is extremely unlikely that wood fuel will be able to
completely replace the entire amount of fuel oil use. The moisture content of the wood
fuels and the overall wood burning system efficiencies were accounted for in these
calculations. The existing fuel oil boilers were assumed to be 80% efficient. Cord wood
was assumed to be 20% moisture content (MC) with a system efficiency of 65%. Wood
pellets were assumed to be 7% MC with a system efficiency of 70%.
The unit fuel costs for fuel oil and the different wood fuel types were calculated and
equalized to dollars per million Btu ($/MMBtu) to allow for direct comparison. The
Delivered $/MMBtu is the cost of the fuel based on what is actually delivered to the heating
system, which includes all the inefficiencies of the different systems. The Gross $/MMBtu
is the cost of the fuel based on raw fuel, or the higher heating value and does not account
for any system inefficiencies. The following table summarizes the equalized fuel costs at
different fuel unit costs:
Pre-Feasibility Assessment for Kiniaq Building
Integration of Wood-Fired Heating Systems Koyuk, Alaska
CTA Architects Engineers Page 5 of 8
Draft Report July 16, 2013
Table 6.2 - Unit Fuel Costs Equalized to $/MMBtu
Net
Gross System System
Delivered Gross
Fuel Type Units Btu/unit Efficiency Btu/unit $/unit $/MMBtu $/MMBtu
Fuel Oil gal 134500 0.8 107600 $6.00 $55.76 $44.61
$6.50 $60.41 $48.33
$7.00 $65.06 $52.04
Cord Wood cords 16173800 0.65 10512970 $300.00 $28.54 $18.55
$350.00 $33.29 $21.64
$400.00 $38.05 $24.73
Pellets tons 16400000 0.7 11480000 $500.00 $43.55 $30.49
$550.00 $47.91 $33.54
$600.00 $52.26 $36.59
7.0 Boiler Plant Location and Site Access
The boiler room is not large enough to accommodate a new wood fired boiler so a new
stand-alone plant would be required. The best location for a plant would be just north of
the building. See Appendix C for a site plan of this building.
Any type of biomass boiler plant will require access by delivery vehicles. For cord wood
systems this would likely be pick-up trucks, trucks with trailers, snow machines or ATV’s.
The existing road to the building is large enough to accommodate any type of delivery
vehicle that would be used for wood delivery.
8.0 Integration with Existing Heating System
Integration of a wood fired boiler system would be relatively straight forward in the
building. The field visit confirmed the location of the boiler room in order to identify an
approximate point of connection from a biomass boiler to the existing building. Piping from
the biomass boiler plant would likely be run below ground under the building in arctic pipe
and extend up to the boiler room. Once the hot water supply and return piping enters the
existing boiler room it would be connected to existing supply and return pipes in
appropriate locations in order to utilize the existing pumping systems within the building.
The wood heating system would inject heat into the existing heating hot water system.
The USPS would remain stand alone and would not be connected into this system.
The existing hot water heating system appears to be designed for a heating supply water
temperature of 180 deg. F. Perimeter finned tube heating elements are the primary
devices used to heat the spaces. Heat emanates from these elements via radiation and
natural convection. Because of this, the performance of the heating elements is greatly
influenced by heating water supply temperature. At 140 deg. F heating water supply
temperature, the heat output of these elements is approximately 50% of their output at 180
deg F. Wood chip and wood pellet boilers can consistently produce and maintain 180 deg.
F water because the fuel is automatically and mechanically fed into the boiler. However, it
can be difficult for manually fed cord wood systems to maintain this temperature unless
they are continuously tended to and wood is constantly fed into the boiler. For this
reason, cord wood boilers should be coupled with thermal storage tanks, so the boiler can
Pre-Feasibility Assessment for Kiniaq Building
Integration of Wood-Fired Heating Systems Koyuk, Alaska
CTA Architects Engineers Page 6 of 8
Draft Report July 16, 2013
be loaded, it can burn the wood hot and fast, and the water can be heated and “stored” in
the tank. In this scenario as long as the boiler is checked and tended to regularly (3 to 5
times a day depending on heating load) a consistent 140 deg. F supply temperature
generally can be maintained. A very basic and preliminary building heat load analysis was
performed and it appears that a 140 deg. F heating water supply temperature could
provide sufficient heat for the building down to approximately 22 deg. F outside air
temperature, which would cover approximately 70% of the heating hours over the course
of a year.
9.0 Air Quality Permits
Resource System Group (RSG) has done a preliminary review of potential air quality
issues in the area and has found no significant concerns. The proposed boiler size at this
location is small enough that the boiler is not likely to require any State or Federal permits.
See the air quality memo in Appendix D for more detailed information including design
criteria that has been suggested to minimize emissions and maximize dispersion.
10.0 Wood Heating Options
The technologies available to produce heating energy from wood based biomass are
varied in their approach, but largely can be separated into three types of heating plants:
cord wood, wood pellet and wood chip/ground wood fueled. See Appendix E for
summaries on these types of systems.
A cord wood boiler system and a wood stove are the only viable options at this time in
Koyuk. Two cord wood boiler options were developed, one offsetting 70% of the current
fuel oil usage and one offsetting 50% of the current fuel oil usage. Both cord wood options
have the same capital costs. A wood stove option was also developed. The concept
would be to install a wood stove in each of the two large open areas. For this option, it is
assumed that 35% of the fuel oil could be offset. An EPA certified wood stove is assumed
to be used. The EPA certification ensures a wood stove is well designed to have a good
combustion efficiency and good emissions.
The options reviewed were:
Cord Wood Boiler Options:
C.1.A: A freestanding building with interior cordwood storage, 70% fuel oil offset.
C.1.B: A freestanding building with interior cordwood storage, 50% fuel oil offset.
Wood Stove Options:
D.1: Two freestanding wood stoves, 35% fuel oil offset.
11.0 Estimated Costs
The total project costs are at a preliminary level and are based on RS Means and recent
biomass project construction cost data. The estimates are shown in Appendix A. These
costs are conservative and if a deeper level feasibility analysis is undertaken and/or further
design occurs, the costs may be able to be reduced.
12.0 Economic Analysis Assumptions
The cash flow analysis assumes fuel oil at $6.50/gal, electricity at $0.30/kwh, and cord
wood delivered at $300/cord. The fuel oil and electricity costs are based on the costs
Pre-Feasibility Assessment for Kiniaq Building
Integration of Wood-Fired Heating Systems Koyuk, Alaska
CTA Architects Engineers Page 7 of 8
Draft Report July 16, 2013
reported by the facility and by the State of Alaska. Cord wood pricing is based on what
was reported in the community.
It is assumed that the wood boiler would supplant 70% or 50% of the estimated heating
use as indicated in the option description, and the existing heating systems would heat the
remaining portion. Likewise, the wood stove option would supplant 35% of the estimated
fuel oil use. Each option assumes the total project can be funded with grants and non
obligated capital money. The following inflation rates were used:
O&M - 2% Fossil Fuel – 5%
Wood Fuel – 3% Discount Rate for NPV calculation – 3%
The fossil fuel inflation rate is based on the DOE EIA website. DOE is projecting a slight
plateau with a long term inflation of approximately 5%. As a point of comparison, oil prices
have increased at an annual rate of over 8% since 2001.
The analysis also accounts for additional electrical energy required for the wood fired
boiler system as well as the system pumps to distribute heating hot water to the building.
Wood fired boiler systems also will require more maintenance, and these additional
maintenance costs are also factored into the analysis.
13.0 Results of Evaluation
The following table summarizes the economic evaluation for each option:
Table 13.1 - Economic Evaluation Summary
Kiniaq Building Biomass Heating System
Year 1 NPV NPV
20
Yr
30
Yr
Project Operating 20 yr 30 yr B/C B/C ACF ACF YR
Cost Savings at 3% at 3% Ratio Ratio YR 20 YR 30 ACF=PC
C.1.A $226,000 -$9,709 -$114,067 -$129,668 -0.50 -0.57 -$150,022 -$181,797 31
C.1.B $226,000 -$7,538 -$85,189 -$97,747 -0.38 -0.43 -$111,997 -$137,711 31
D.1 $18,000 $125 $18,914 $43,452 1.05 2.41 $28,631 $81,553 17
The benefit to cost (B/C) ratio takes the net present value (NPV) of the net energy savings
and divides it by the estimated construction cost of the project. A B/C ratio greater than or
equal to 1.0 indicates an economically advantageous project.
Accumulated cash flow (ACF) is another evaluation measure that is calculated in this
report and is similar to simple payback with the exception that accumulated cash flow
takes the cost of financing and fuel escalation into account. For many building owners,
having the accumulated cash flow equal the project cost within 15 years is considered
necessary for implementation. If the accumulated cash flow equals project cost in 20
years or more, that indicates a challenged project. Positive accumulated cash flow should
also be considered an avoided cost as opposed to a pure savings.
See Appendix D for the full cash flow spread sheets for each option.
Pre-Feasibility Assessment for Kiniaq Building
Integration of Wood-Fired Heating Systems Koyuk, Alaska
CTA Architects Engineers Page 8 of 8
Draft Report July 16, 2013
14.0 Project Funding
The Native Village of Koyuk can pursue a biomass project grant from the Alaska Energy
Authority. See the following website for more information:
http://www.akenergyauthority.org/refund7.html
The Native Village of Koyuk could also enter into a performance contract for the project.
Companies such as Siemens, McKinstry, Johnson Controls and Chevron have expressed
an interest in participating in funding projects of all sizes throughout Alaska. This allows
the facility owner to pay for the project entirely from the guaranteed energy savings, and to
minimize the project funds required to initiate the project. The scope of the project may be
expanded to include additional energy conservation measures such as roof and wall
insulation and upgrading mechanical systems.
15.0 Summary
The Kiniaq Building appears to be a fair candidate for the use of a wood biomass heating
system using wood stoves. With the current economic assumptions, the economic viability
of the cord wood boiler options is poor as none of the options meet the minimum
requirement of the 20 year B/C ratio exceeding 1.0. The amount of fuel oil use is not large
enough to economically leverage much capital costs, even if the most of the fuel oil use
could be eliminated. The wood stove option does appear to be economically viable,
however, it is very sensitive to labor costs. For this analysis 2 hours a week of feeding the
stoves was assumed. If this was 3 hours a week, then the 20 year B/C ratio would drop
below 1.0. The wood stove option also assumed offsetting 35% of the current fuel oil use.
This was due to the typical occupancy of the building (no one to feed the fire on nights and
weekends) and because of the room layout of the building. The stoves would keep the
large open areas heated, but the perimeter offices would likely still require supplemental
heat from the boiler system.
The cord wood fuel source would benefit the community because the fuel is a renewable
resource, has a lower energy cost, and the money paid for the fuel would remain in the
local community and economy.
16.0 Recommended Action
Pursue purchasing a wood stove. Determine best location to store wood.
APPENDIX A
Preliminary Estimates of Probable Cost
Preliminary Estimates of Probable Cost
Biomass Heating Options
Kiniaq Building
Koyuk, AK
Option C.1 Cord Wood Boiler
Biomass Boiler Building Including Wood Storage Area: $55,000
Cord Wood Boiler and Thermal Storage Tank: $19,000
Stack:$5,000
Mechanical/Electrical within Boiler Building: $25,000
Underground Piping:$9,500
Integration in Boiler Room:$8,500
Subtotal:$122,000
40% Remote Factor $48,800
Subtotal:$170,800
Design Fees, Building Permit, Miscellaneous Expenses 15%: $25,620
Subtotal:$196,420
15% Contingency:$29,463
Total Project Costs 225,883$
Option D.1 Wood Stove
(2) Wood Stoves:$7,600
(2) Stack Assemblies:$3,000
Subtotal:$10,600
40% Remote Factor $4,240
Subtotal:$14,840
Design Fees, Building Permit, Miscellaneous Expenses 5%: $742
Subtotal:$15,582
15% Contingency:$2,337
Total Project Costs 17,919$
APPENDIX B
Cash Flow Analysis
Kiniaq BuildingOption C.1.AKoyuk, AlaskaCord Wood Boiler 70% OffsetDate: July 15, 2013 Analyst: CTA Architects Engineers - Nathan Ratz EXISTING CONDITIONSStoreTotalExisting Fuel Type:Fuel Oil Fuel Oil Fuel Oil Fuel OilFuel Units:gal gal gal galCurrent Fuel Unit Cost:$6.50 Estimated Average Annual Fuel Usage:1,5001,500Annual Heating Costs:$9,750 $0 $0 $0 $9,750ENERGY CONVERSION (to 1,000,000 Btu; or 1 dkt)Fuel Heating Value (Btu/unit of fuel):134500 134500 134500 134500Current Annual Fuel Volume (Btu):201,750,000 0 0 0Assumed efficiency of existing heating system (%):80% 80% 80% 80% Net Annual Energy Produced (Btu):161,400,000 0 0 0 161,400,000WOOD FUEL COSTCord Wood$/cord: $300.00Assumed efficiency of wood heating system (%): 65% PROJECTED WOOD FUEL USAGEEstimated Btu content of wood fuel (Btu/cord) - Assumed 20% MC, 6,700 Btu/lb x 28.4 lb/cf x 85 cf16,173,800Cords of wood fuel to supplant net equivalent of 100% annual heating load.15Cords of wood fuel to supplant net equivalent of 85% annual heating load.1325 ton chip van loads to supplant net equivalent of 85% annual heating load.N/A Project Capital Cost-$226,000 Project Financing InformationPercent Financed0.0%Est. Pwr Use 1700 kWh Type Hr/Wk Wk/Yr Total Hr Wage/Hr TotalAmount Financed$0 Elec Rate $0.300 /kWh Biomass System 14.0 40 560 $20.00 $11,200Amount of Grants$226,000 Other 0.0 40 0 $20.00 $01st 2 Year Learning 2.0 40 80 $20.00 $1,600Interest Rate5.00%Term10Annual Finance Cost (years)$0 -23.3 years Net Benefit B/C Ratio-$129,668 -$355,668 -0.57-$114,067 -$340,067-0.50Year Accumulated Cash Flow > 031Year Accumulated Cash Flow > Project Capital Cost31Inflation FactorsO&M Inflation Rate2.0%Fossil Fuel Inflation Rate5.0%Wood Fuel Inflation Rate3.0%Electricity Inflation Rate3.0%Discount Rate for Net Present Value Calculation 3.0%Year Year Year Year Year Year Year Year Year Year Year Year Year Year Year Year Year YearCash flow Descriptions Unit Costs HeatingSource ProportionAnnual Heating Source VolumesHeating Units 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 20 25 30Existing Heating System Operating CostsDisplaced heating costs $6.50 1500 gal $9,750 $10,238 $10,749 $11,287 $11,851 $12,444 $13,066 $13,719 $14,405 $15,125 $15,882 $16,676 $17,510$18,385 $19,304 $24,638 $31,445 $40,132Displaced heating costs $0.000 gal $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0Displaced heating costs $0.000 gal $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0Displaced heating costs $0.000 gal $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0Biomass System Operating CostsWood Fuel ($/ton, delivered to boiler site)$300.00 70% 11 cords $3,224 $3,321 $3,420 $3,523 $3,629 $3,738 $3,850 $3,965 $4,084 $4,207 $4,333 $4,463 $4,597 $4,735 $4,877 $5,653 $6,554 $7,598Small load existing fuel$6.50 30% 450 gal $2,925 $3,071 $3,225 $3,386 $3,555 $3,733 $3,920 $4,116 $4,322 $4,538 $4,765 $5,003 $5,253 $5,516 $5,791 $7,391 $9,433 $12,040Small load existing fuel$0.00 15% 0 gal $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0Small load existing fuel$0.00 15% 0 gal $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0Small load existing fuel$0.00 15% 0 gal $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0Additional Operation and Maintenance Costs$11,200 $11,424 $11,652 $11,886 $12,123 $12,366 $12,613 $12,865 $13,123 $13,385 $13,653 $13,926 $14,204 $14,488 $14,778 $16,316 $18,014 $19,889Additional Operation and Maintenance Costs First 2 years$1,600 $1,632Additional Electrical Cost $0.300$510 $525 $541 $557 $574 $591 $609 $627 $646 $665 $685 $706 $727 $749 $771 $894 $1,037 $1,202Annual Operating Cost Savings-$9,709-$9,736-$8,089-$8,065-$8,030-$7,984-$7,925-$7,854-$7,769-$7,669-$7,554-$7,421-$7,271-$7,102-$6,913-$5,617-$3,594-$596Financed Project Costs - Principal and Interest0000000000 Displaced System Replacement Costs (year one only)0Net Annual Cash Flow(9,709) (9,736) (8,089) (8,065) (8,030) (7,984) (7,925) (7,854) (7,769) (7,669) (7,554) (7,421) (7,271) (7,102) (6,913) (5,617) (3,594) (596)Accumulated Cash Flow(9,709) (19,445) (27,534) (35,599) (43,629) (51,613) (59,539) (67,393) (75,162) (82,831) (90,385) (97,806) (105,078) (112,180) (119,093) (150,022) (172,373) (181,797)Additional Power UseAdditional MaintenanceSimple Payback: Total Project Cost/Year One Operating Cost Savings:Net Present Value (30 year analysis):Net Present Value (20 year analysis):
Kiniaq BuildingOption C.1.BKoyuk, AlaskaCord Wood Boiler 50% OffsetDate: July 15, 2013 Analyst: CTA Architects Engineers - Nathan Ratz EXISTING CONDITIONSStoreTotalExisting Fuel Type:Fuel Oil Fuel Oil Fuel Oil Fuel OilFuel Units:gal gal gal galCurrent Fuel Unit Cost:$6.50 Estimated Average Annual Fuel Usage:1,5001,500Annual Heating Costs:$9,750 $0 $0 $0 $9,750ENERGY CONVERSION (to 1,000,000 Btu; or 1 dkt)Fuel Heating Value (Btu/unit of fuel):134500 134500 134500 134500Current Annual Fuel Volume (Btu):201,750,000 0 0 0Assumed efficiency of existing heating system (%):80% 80% 80% 80% Net Annual Energy Produced (Btu):161,400,000 0 0 0 161,400,000WOOD FUEL COSTCord Wood$/cord: $300.00Assumed efficiency of wood heating system (%): 65% PROJECTED WOOD FUEL USAGEEstimated Btu content of wood fuel (Btu/cord) - Assumed 20% MC, 6,700 Btu/lb x 28.4 lb/cf x 85 cf16,173,800 Cords of wood fuel to supplant net equivalent of 100% annual heating load.15Cords of wood fuel to supplant net equivalent of 85% annual heating load.1325 ton chip van loads to supplant net equivalent of 85% annual heating load.N/A Project Capital Cost-$226,000 Project Financing InformationPercent Financed0.0%Est. Pwr Use 1700 kWh Type Hr/Wk Wk/Yr Total Hr Wage/Hr TotalAmount Financed$0 Elec Rate $0.300 /kWh Biomass System 10.0 40 400 $20.00 $8,000Amount of Grants$226,000 Other 0.0 40 0 $20.00 $01st 2 Year Learning 2.0 40 80 $20.00 $1,600Interest Rate5.00%Term10Annual Finance Cost (years)$0 -30.0 years Net Benefit B/C Ratio-$97,747 -$323,747 -0.43-$85,189 -$311,189-0.38Year Accumulated Cash Flow > 031Year Accumulated Cash Flow > Project Capital Cost31Inflation FactorsO&M Inflation Rate2.0%Fossil Fuel Inflation Rate5.0%Wood Fuel Inflation Rate3.0%Electricity Inflation Rate3.0%Discount Rate for Net Present Value Calculation 3.0%Year Year Year Year Year Year Year Year Year Year Year Year Year Year Year Year Year YearCash flow Descriptions Unit Costs HeatingSource ProportionAnnual Heating Source VolumesHeating Units 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 20 25 30Existing Heating System Operating CostsDisplaced heating costs $6.50 1500 gal $9,750 $10,238 $10,749 $11,287 $11,851 $12,444 $13,066 $13,719 $14,405 $15,125 $15,882 $16,676 $17,510$18,385 $19,304 $24,638 $31,445 $40,132Displaced heating costs $0.000 gal $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0Displaced heating costs $0.000 gal $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0Displaced heating costs $0.000 gal $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0Biomass System Operating CostsWood Fuel ($/ton, delivered to boiler site)$300.00 50% 8 cords $2,303 $2,372 $2,443 $2,516 $2,592 $2,670 $2,750 $2,832 $2,917 $3,005 $3,095 $3,188 $3,283 $3,382 $3,483 $4,038 $4,681 $5,427Small load existing fuel$6.50 50% 750 gal $4,875 $5,119 $5,375 $5,643 $5,926 $6,222 $6,533 $6,860 $7,203 $7,563 $7,941 $8,338 $8,755 $9,193 $9,652 $12,319 $15,722 $20,066Small load existing fuel$0.00 15% 0 gal $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0Small load existing fuel$0.00 15% 0 gal $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0Small load existing fuel$0.00 15% 0 gal $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0Additional Operation and Maintenance Costs$8,000 $8,160 $8,323 $8,490 $8,659 $8,833 $9,009 $9,189 $9,373 $9,561 $9,752 $9,947 $10,146 $10,349 $10,556 $11,654 $12,867 $14,207Additional Operation and Maintenance Costs First 2 years$1,600 $1,632Additional Electrical Cost $0.300$510 $525 $541 $557 $574 $591 $609 $627 $646 $665 $685 $706 $727 $749 $771 $894 $1,037 $1,202Annual Operating Cost Savings-$7,538-$7,571-$5,933-$5,920-$5,900-$5,872-$5,835-$5,789-$5,734-$5,668-$5,591-$5,503-$5,402-$5,287-$5,158-$4,268-$2,863-$769Financed Project Costs - Principal and Interest0000000000 Displaced System Replacement Costs (year one only)0Net Annual Cash Flow(7,538) (7,571) (5,933) (5,920) (5,900) (5,872) (5,835) (5,789) (5,734) (5,668) (5,591) (5,503) (5,402) (5,287) (5,158) (4,268) (2,863) (769)Accumulated Cash Flow(7,538) (15,108) (21,041) (26,961) (32,861) (38,732) (44,567) (50,357) (56,091) (61,759) (67,350) (72,853) (78,255) (83,542) (88,700) (111,997) (129,360) (137,711)Additional Power UseAdditional MaintenanceSimple Payback: Total Project Cost/Year One Operating Cost Savings:Net Present Value (30 year analysis):Net Present Value (20 year analysis):
Kiniaq BuildingOption D.1Koyuk, AlaskaCord Wood Stove 35% OffsetDate: July 15, 2013 Analyst: CTA Architects Engineers - Nathan Ratz EXISTING CONDITIONSStoreTotalExisting Fuel Type:Fuel Oil Fuel Oil Fuel Oil Fuel OilFuel Units:gal gal gal galCurrent Fuel Unit Cost:$6.50 Estimated Average Annual Fuel Usage:1,5001,500Annual Heating Costs:$9,750 $0 $0 $0 $9,750ENERGY CONVERSION (to 1,000,000 Btu; or 1 dkt)Fuel Heating Value (Btu/unit of fuel):134500 134500 134500 134500Current Annual Fuel Volume (Btu):201,750,000 0 0 0Assumed efficiency of existing heating system (%):80% 80% 80% 80% Net Annual Energy Produced (Btu):161,400,000 0 0 0 161,400,000WOOD FUEL COSTCord Wood$/cord: $300.00Assumed efficiency of wood heating system (%): 65% PROJECTED WOOD FUEL USAGEEstimated Btu content of wood fuel (Btu/cord) - Assumed 20% MC, 6,700 Btu/lb x 28.4 lb/cf x 85 cf16,173,800 Cords of wood fuel to supplant net equivalent of 100% annual heating load.15Cords of wood fuel to supplant net equivalent of 85% annual heating load.1325 ton chip van loads to supplant net equivalent of 85% annual heating load.N/A Project Capital Cost-$18,000 Project Financing InformationPercent Financed0.0%Est. Pwr Use 250 kWh Type Hr/Wk Wk/Yr Total Hr Wage/Hr TotalAmount Financed$0 Elec Rate $0.300 /kWh Biomass System 2.0 40 80 $20.00 $1,600Amount of Grants$18,000 Other 0.0 40 0 $20.00 $01st 2 Year Learning 0.0 40 0 $20.00 $0Interest Rate5.00%Term10Annual Finance Cost (years)$0 143.4 years Net Benefit B/C Ratio$43,452 $25,452 2.41$18,914 $9141.05Year Accumulated Cash Flow > 0#N/AYear Accumulated Cash Flow > Project Capital Cost17Inflation FactorsO&M Inflation Rate2.0%Fossil Fuel Inflation Rate5.0%Wood Fuel Inflation Rate3.0%Electricity Inflation Rate3.0%Discount Rate for Net Present Value Calculation 3.0%Year Year Year Year Year Year Year Year Year Year Year Year Year Year Year Year Year YearCash flow Descriptions Unit Costs HeatingSource ProportionAnnual Heating Source VolumesHeating Units 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 20 25 30Existing Heating System Operating CostsDisplaced heating costs $6.50 1500 gal $9,750 $10,238 $10,749 $11,287 $11,851 $12,444 $13,066 $13,719 $14,405 $15,125 $15,882 $16,676 $17,510$18,385 $19,304 $24,638 $31,445 $40,132Displaced heating costs $0.000 gal $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0Displaced heating costs $0.000 gal $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0Displaced heating costs $0.000 gal $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0Biomass System Operating CostsWood Fuel ($/ton, delivered to boiler site)$300.00 35% 5 cords $1,612 $1,660 $1,710 $1,761 $1,814 $1,869 $1,925 $1,983 $2,042 $2,103 $2,166 $2,231 $2,298 $2,367 $2,438 $2,827 $3,277 $3,799Small load existing fuel$6.50 65% 975 gal $6,338 $6,654 $6,987 $7,336 $7,703 $8,088 $8,493 $8,917 $9,363 $9,832 $10,323 $10,839 $11,381 $11,950$12,548 $16,015 $20,439 $26,086Small load existing fuel$0.00 15% 0 gal $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0Small load existing fuel$0.00 15% 0 gal $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0Small load existing fuel$0.00 15% 0 gal $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0Additional Operation and Maintenance Costs$1,600 $1,632 $1,665 $1,698 $1,732 $1,767 $1,802 $1,838 $1,875 $1,912 $1,950 $1,989 $2,029 $2,070 $2,111 $2,331 $2,573$2,841Additional Operation and Maintenance Costs First 2 years$0 $0Additional Electrical Cost $0.300$75 $77 $80 $82 $84 $87 $90 $92 $95 $98 $101 $104 $107 $110 $113 $132 $152 $177Annual Operating Cost Savings$125$214$308$409$517$633$757$889$1,030$1,181$1,341$1,512$1,694$1,888$2,094$3,334$5,003$7,229Financed Project Costs - Principal and Interest0000000000 Displaced System Replacement Costs (year one only)0Net Annual Cash Flow125 214 308 409 517 633 757 889 1,030 1,181 1,341 1,512 1,694 1,888 2,094 3,334 5,003 7,229Accumulated Cash Flow125 339 647 1,056 1,573 2,206 2,963 3,852 4,882 6,063 7,404 8,916 10,610 12,497 14,591 28,631 50,113 81,553Additional Power UseAdditional MaintenanceSimple Payback: Total Project Cost/Year One Operating Cost Savings:Net Present Value (30 year analysis):Net Present Value (20 year analysis):
APPENDIX C
Site Plan
APPENDIX D
Air Quality Report
Resource Systems Group, Inc.
55 Railroad Row
White River Junction, VT 05001
TEL 802.295.4999 | FAX 802.295.1006
www.rsginc.com
Transportation &
Environment Practice
Air Quality Feasibility Report
For the:
FEDC Pre‐Feasibility Studies
on Wood‐Fired Heating
Projects
Prepared for:
CTA Architects Engineers
Missoula, MT
July, 2013
Prepared by:
RSG, Inc.
Alaska 2013 Air Quality Pre‐Feasibility Study
Page i
TABLE OF CONTENTS
1.0 INTRODUCTION ......................................................................................... 1
2.0 EQUIPMENT DESCRIPTION ............................................................................ 1
3.0 SITE DESCRIPTIONS .................................................................................... 2
3.1 Emmonak ................................................................................................................................................. 2
3.2 Koyuk ........................................................................................................................................................ 2
3.3 Lower Kalskag........................................................................................................................................... 2
3.4 Tuntutuliak ............................................................................................................................................... 2
4.0 METEOROLOGICAL CONDITIONS .................................................................... 3
5.0 REGULATORY CONSIDERATIONS ..................................................................... 4
6.0 DESIGN & OPERATION RECOMMENDATIONS .................................................... 4
LIST OF FIGURES
Figure 1: Wind Speed Data from Bethel, AK .......................................................................................................... 3
Figure 2: Wind Speed Data from Nome, AK ........................................................................................................... 3
Alaska 2013 Air Quality Pre‐Feasibility Study
Page 1
1.0 INTRODUCTION
At the request of CTA, RSG has completed an air quality pre‐feasibility study of implementing biomass
energy systems in Emmonak, Koyuk, Lower Kalskag, and Tuntutuliak, Alaska. These systems will displace
fossil fuel used in these locations and therefore displace fossil fuel‐related emissions.
This report is broken into the following sections:
Equipment description
Site descriptions
Meteorological conditions
Regulatory considerations
Design and operation recommendations
2.0 EQUIPMENT DESCRIPTION
The following details were provided for the boilers being considered. Equipment vendors have not been
selected.
Emmonak
o Fuel: cord wood likely, wood chips also possible.
o Heating capacity: 250,000 Btu/hr output.
Koyuk
o Fuel: cord wood.
o Heating capacity: 150,000 Btu/hr output.
Lower Kalskag
o Fuel: cord wood.
o Heating capacity.
Alternative A: one boiler at 625,000 Btu/hr output.
Alternative B: one boiler at 250,000 Btu/hr output coupled with several high
efficiency wood stoves.
Tuntutuliak
o Fuel: cord wood
o Heating capacity: 125,000 Btu/hr
3 July 2013
Page 2
3.0 SITE DESCRIPTIONS
Descriptions of each site are provided below. USGS maps, aerial photography, and site maps are provided
in the Appendix.
3.1 Emmonak
Emmonak is a small village located near the west coast of Alaska, on the north bank of the Kwiguk Pass of
the Yukon River. The area is relatively flat. No significant air pollution sources were identified in the
review for this site. One biomass plant is being considered for this site at the Emmonak Corporate Store
and Offices Building.
3.2 Koyuk
Koyuk is a small village located near the west coast of Alaska. It is situated on the north bank of the Koyuk
River at Koyuk Inlet. The village is bordered by hills to the north and flat terrain to the south. The land
slopes downhill from north to south, with ground elevation ranging from approximately 100 feet to 15
feet. No significant air pollution sources were identified in the review for this site. One Biomass plant is
being considered for this site at the Kiniaq Building.
3.3 Lower Kalskag
Lower Kalskag is a small inland village located on the western bank of the Kuskowim River. The site is
relatively flat. No significant air pollution sources were identified in the review for this site. Two biomass
plants are considered for this site. One at the school and one near the clinic.
3.4 Tuntutuliak
Tuntutuliak is a relatively small inland village located on the northern bank of the Kinak River. The site is
relatively flat. No significant air pollution sources were identified in the review for this site. One biomass
plant is being considered for this site at the Community Hall.
Alaska 2013 Air Quality Pre‐Feasibility Study
Page 3
4.0 METEOROLOGICAL CONDITIONS
Meteorological data from Bethel and Nome, AK, were reviewed to develop an understanding of weather
conditions which will affect the dispersion of emissions. Bethel is the closest weather station
approximating climactic conditions in the Emmonak, Lower Kalskag, and Tuntutuliak. Nome is the closest
weather data approximating Koyuk. The data indicates calm winds occur approximately only 10% of the
year. This suggests there will be minimal time periods when thermal inversions and therefore poor
emission dispersion conditions can occur.1
Figure 1: Wind Speed Data from Bethel, AK
Figure 2: Wind Speed Data from Nome, AK
1 See: http://climate.gi.alaska.edu/Climate/Wind/Speed/Annette/ANN.html
3 July 2013
Page 4
5.0 REGULATORY CONSIDERATIONS
The size of the proposed boilers will not trigger state or federal permitting requirements. Hot water
boilers burning wood which are less than 1.6 MMBtu/hr heat input are below the threshold for EPA
boiler requirements. More information about EPA boiler requirements can be obtained here:
http://www.epa.gov/boilercompliance/
6.0 DESIGN & OPERATION RECOMMENDATIONS
These design and operation recommendations are based on the assumption that state‐of‐the‐art
combustion equipment is installed. The following are suggested for designing this project:
Burn natural wood, whose characteristics (bark content, species, geometry) optimizes
combustion in the equipment selected for the project.
Burn seasoned cord wood. Burning wet wood generates excess emissions.
Do not install a rain cap above the stack. Rain caps obstruct vertical airflow and reduce
dispersion of emissions.
In situations where there are clusters of buildings, consider constructing the stack to at least 1.5
times the height of the tallest roofline of the adjacent building. Hence, a 20 foot roofline would
result in a minimum 30 foot stack. Special attention should be given to this in Koyuk due to the
moderate slopes present.
Operate and maintain the boiler according to manufacturer’s recommendations.
Perform a tune‐up at least every other year as per manufacturer’s recommendations.
Conduct regular observations of stack emissions. If emissions are not characteristic of good
boiler operation, make corrective actions.
More information can be found about controlling wood boiler emissions can be obtained in a report
written by RSG called “Emission Controls for Small Wood‐Fired Boilers”. The report can be downloaded
here: http://www.wflccenter.org/news_pdf/361_pdf.pdf.
APPENDIX A
EMMONAK SITE INFORMATION
APPENDIX B
KOYUK SITE INFORMATION
00.510.25
Miles I
Koyuk Aerial Photography MAP
APPENDIX C
LOWER KALSKAG SITE INFORMATION
00.510.25
Miles I
Lower Kalskag Aerial Photo MAP
APPENDIX D
TUNTUTULIAK SITE INFORMATION
APPENDIX E
Wood Fired Heating Technologies
WOOD FIRED HEATING TECHNOLOGIES
CTA has developed wood-fired heating system projects using cord wood, wood pellet
and wood chips as the primary feedstock. A summary of each system type with the
benefits and disadvantages is noted below.
Cord Wood
Cord wood systems are hand-stoked wood boilers with a limited heat output of 150,000-
200,000 British Thermal Units per hour (Btu/hour). Cord wood systems are typically
linked to a thermal storage tank in order to optimize the efficiency of the system and
reduce the frequency of stoking. Cord wood boiler systems are also typically linked to
existing heat distribution systems via a heat exchanger. Product data from Garn, HS
Tarm and KOB identify outputs of 150,000-196,000 Btu/hr based upon burning eastern
hardwoods and stoking the boiler on an hourly basis. The cost and practicality of stoking
a wood boiler on an hourly basis has led most operators of cord wood systems to
integrate an adjacent thermal storage tank, acting similar to a battery, storing heat for
later use. The thermal storage tank allows the wood boiler to be stoked to a high fire
mode 3 times per day while storing heat for distribution between stoking. Cord wood
boilers require each piece of wood to be hand fed into the firebox, hand raking of the
grates and hand removal of ash. Ash is typically cooled in a barrel before being stock
piled and later broadcast as fertilizer.
Cordwood boilers are manufactured by a number of European manufacturers and an
American manufacturer with low emissions. These manufacturers currently do not
fabricate equipment with ASME (American Society of Mechanical Engineers)
certifications. When these non ASME boilers are installed in the United States,
atmospheric boilers rather than pressurized boilers are utilized. Atmospheric boilers
require more frequent maintenance of the boiler chemicals.
Emissions from cord wood systems are typically as follows:
PM2.5 >0.08 lb/MMbtu
NOx 0.23 lb/MMbtu
SO2 0.025 lb/MMbtu
CO2 195 lb/MMbtu
Benefits:
Small size
Lower cost
Local wood resource
Simple to operate
Disadvantages:
Hand fed - a large labor commitment
Typically atmospheric boilers (not ASME rated)
Thermal Storage is required
Page 1
Wood Pellet
Wood pellet systems can be hand fed from 40 pound bags, hand shoveled from 2,500
pound sacks of wood pellets, or automatically fed from an adjacent agricultural silo with
a capacity of 30-40 tons. Pellet boilers systems are typically linked to existing heat
distribution systems via a heat exchanger. Product data from KOB, Forest Energy and
Solagen identify outputs of 200,000-5,000,000 Btu/hr based upon burning pellets made
from waste products from the western timber industry. A number of pellet fuel
manufacturers produce all tree pellets utilizing bark and needles. All tree pellets have
significantly higher ash content, resulting in more frequent ash removal. Wood pellet
boilers typically require hand raking of the grates and hand removal of ash 2-3 times a
week. Automatic ash removal can be integrated into pellet boiler systems. Ash is
typically cooled in a barrel before being stock piled and later broadcast as fertilizer.
Pellet storage is very economical. Agricultural bin storage exterior to the building is
inexpensive and quick to install. Material conveyance is also borrowed from agricultural
technology. Flexible conveyors allow the storage to be located 20 feet or more from the
boiler with a single auger.
Emissions from wood pellet systems are typically as follows:
PM2.5 >0.09 lb/MMbtu
NOx 0.22 lb/MMbtu
SO2 0.025 lb/MMbtu
CO2 220 lb/MMbtu
Benefits:
Smaller size (relative to a chip system)
Consistent fuel and easy economical storage of fuel
Automated
Disadvantages:
Higher system cost
Higher cost wood fuel ($/MMBtu)
Page 2
Page 3
Wood Chip
Chip systems utilize wood fuel that is either chipped or ground into a consistent size of
2-4 inches long and 1-2 inches wide. Chipped and ground material includes fine
sawdust and other debris. The quality of the fuel varies based upon how the wood is
processed between the forest and the facility. Trees which are harvested in a manner
that minimizes contact with the ground and run through a chipper or grinder directly into
a clean chip van are less likely to be contaminated with rocks, dirt and other debris. The
quality of the wood fuel will also be impacted by the types of screens placed on the
chipper or grinder. Fuel can be screened to reduce the quantity of fines which typically
become airborne during combustion and represent lost heat and increased particulate
emissions.
Chipped fuel is fed from the chip van into a metering bin, or loaded into a bunker with a
capacity of 60 tons or more. Wood chip boilers systems are typically linked to existing
heat distribution systems via a heat exchanger. Product data from Hurst, Messersmith
and Biomass Combustion Systems identify outputs of 1,000,000 - 50,000,000 Btu/hr
based upon burning western wood fuels. Wood chip boilers typically require hand raking
of the grates and hand removal of ash daily. Automatic ash removal can be integrated
into wood chip boiler systems. Ash is typically cooled in a barrel before being stock piled
and later broadcast as fertilizer.
Emissions from wood chip systems are typically as follows:
PM2.5 0.21 lb/MMbtu
NOx 0.22 lb/MMbtu
SO2 0.025 lb/MMbtu
CO2 195 lb/MMbtu
Benefits:
Lowest fuel cost of three options ($/MMBtu)
Automated
Can use local wood resources
Disadvantages:
Highest initial cost of three types
Larger fuel storage required
Less consistent fuel can cause operational and performance issues
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Wood Stove
Wood stove systems are typically cast iron, hand-stoked wood heaters with a limited
output range of 10,000 – 50,000 BTU/hour. Wood stove systems are stand-alone
systems that heat a space or building and are required to be hand-fed. As these
systems are hand-fed, stoking is required. New wood stoves are feature improved
safety and efficiency over older models. Wood stoves are either catalytic or non-
catalytic combustion. Catalytic wood stoves are cleaner burning and more efficient than
non-catalytic wood stoves. However, catalytic wood stoves have a ceramic catalytic
piece which requires maintenance and eventual replacement. Wood stoves should be
EPA certified. For more information on wood stoves and a list of EPA certified wood
stoves, go to this website: http://www.epa.gov/burnwise/woodstoves.html
Wood stoves burn cord wood in smaller sizes than the cord wood boilers. Each piece of
wood must be hand fed into the stove, hand raking of the grate, and hand removal of
ash. Ash is typically cooled in a barrel before being stock piled and later broadcast as
fertilizer.
Emissions from wood stove systems are typically as follows:
PM2.5 >0.08 lb/MMbtu
NOx 0.23 lb/MMbtu
SO2 0.025 lb/MMbtu
CO2 195 lb/MMbtu
Benefits:
Small size
Local wood resource
Simple to operate
Optional cooking appliance
Disadvantages:
Equipment sits in the space being heated
Catalytic systems require maintenance
Non-catalytic systems are not as efficient as catalytic systems